pylearn: doc/v2_planning/learner.txt annotate

annotate doc/v2_planning/learner.txt @ 1093:a65598681620

v2planning - initial commit of use_cases, requirements

author	James Bergstra <bergstrj@iro.umontreal.ca>
date	Sun, 12 Sep 2010 21:45:22 -0400
parents	f082a6c0b008
children	7a8dcf87d780

rev	line source
1041 38cc6e075d9b PV added to learner committee Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1038 diff changeset	1
38cc6e075d9b PV added to learner committee Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1038 diff changeset	2 Comittee: AB, PL, GM, IG, RP, NB, PV
38cc6e075d9b PV added to learner committee Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1038 diff changeset	3 Leader: ?
1002 f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	4
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	5 Discussion of Function Specification for Learner Types
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	6 ======================================================
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	7
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	8 In its most abstract form, a learner is an object with the
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	9 following semantics:
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	10
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	11 * A learner has named hyper-parameters that control how it learns (these can be viewed
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	12 as options of the constructor, or might be set directly by a user)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	13
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	14 * A learner also has an internal state that depends on what it has learned.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	15
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	16 * A learner reads and produces data, so the definition of learner is
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	17 intimately linked to the definition of dataset (and task).
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	18
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	19 * A learner has one or more 'train' or 'adapt' functions by which
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	20 it is given a sample of data (typically either the whole training set, or
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	21 a mini-batch, which contains as a special case a single 'example'). Learners
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	22 interface with datasets in order to obtain data. These functions cause the
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	23 learner to change its internal state and take advantage to some extent
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	24 of the data provided. The 'train' function should take charge of
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	25 completely exploiting the dataset, as specified per the hyper-parameters,
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	26 so that it would typically be called only once. An 'adapt' function
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	27 is meant for learners that can operate in an 'online' setting where
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	28 data continually arrive and the control loop (when to stop) is to
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	29 be managed outside of it. For most intents and purposes, the
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	30 'train' function could also handle the 'online' case by providing
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	31 the controlled iterations over the dataset (which would then be
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	32 seen as a stream of examples).
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	33 * learner.train(dataset)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	34 * learner.adapt(data)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	35
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	36 * Different types of learners can then exploit their internal state
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	37 in order to perform various computations after training is completed,
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	38 or in the middle of training, e.g.,
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	39
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	40 * y=learner.predict(x)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	41 for learners that see (x,y) pairs during training and predict y given x,
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	42 or for learners that see only x's and learn a transformation of it (i.e. feature extraction).
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	43 Here and below, x and y are tensor-like objects whose first index iterates
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	44 over particular examples in a batch or minibatch of examples.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	45
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	46 * p=learner.probability(examples)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	47 p=learner.log_probability(examples)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	48 for learners that can estimate probability density or probability functions,
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	49 note that example could be a pair (x,y) for learners that expect each example
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	50 to represent such a pair. The second form is provided in case the example
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	51 is high-dimensional and computations in the log-domain are numerically preferable.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	52 The first dimension of examples or of x and y is an index over a minibatch or a dataset.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	53
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	54 * p=learner.free_energy(x)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	55 for learners that can estimate a log unnormalized probability; the output has the same length as the input.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	56
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	57 * c=learner.costs(examples)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	58 returns a matrix of costs (one row per example, i.e., again the output has the same length
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	59 as the input), the first column of which represents the cost whose expectation
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	60 we wish to minimize over new samples from the unknown underlying data distribution.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	61
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	62
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	63 Some learners may be able to handle x's and y's that contain missing values.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	64
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	65 * For convenience, some of these operations could be bundled, e.g.
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	66
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	67 * [prediction,costs] = learner.predict_and_adapt((x,y))
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	68
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	69 * Some learners could include in their internal state not only what they
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	70 have learned but some information about recently seen examples that conditions
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	71 the expected distribution of upcoming examples. In that case, they might
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	72 be used, e.g. in an online setting as follows:
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	73 for (x,y) in data_stream:
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	74 [prediction,costs]=learner.predict((x,y))
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	75 accumulate_statistics(prediction,costs)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	76
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	77 * In some cases, each example is itself a (possibly variable-size) sequence
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	78 or other variable-size object (e.g. an image, or a video)
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	79
f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	80
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	81
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	82
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	83
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	84
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	85
1002 f82093bf4405 adding learner.txt and dataset.txt in v2_planning/ Yoshua Bengio <bengioy@iro.umontreal.ca> parents: diff changeset	86
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	87
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	88
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	89 James's idea for Learner Interface
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	90 ===================================
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	91
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	92 Theory:
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	93 -------
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	94
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	95 Think about the unfolding of a learning algorithm as exploring a path in a vast
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	96 directed graph.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	97
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	98 There are some source nodes, which are potential initial conditions for the
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	99 learning algorithm.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	100
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	101 At any node, there are a number of outgoing labeled edges that represent
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	102 distinct directions of exploration: like "allocate a model with N hidden units",
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	103 or "set the l1 weight decay on such-and-such units to 0.1" or "adapt for T
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	104 iterations" or "refresh the GPU dataset memory with the next batch of data".
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	105
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	106 Not all nodes have the same outgoing edge labels. The dataset, model, and
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	107 optimization algorithm implementations may each have their various
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	108 hyper-parameters with various restrictions on what values they can take, and
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	109 when they can be changed.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	110
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	111 Every move in this graph incurs some storage and computational expense, and
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	112 explores the graph.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	113
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	114 Learners typically engage in goal-directed exploration of this graph - for
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	115 example to find the node with the best validation-set performance given a
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	116 certain computational budget. We might often be interested in the best node
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	117 found.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	118
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	119 The predict(), log_probability(), free_energy() etc correspond to costs that we
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	120 can measure at any particular node (at some computational expense) to see how we
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	121 are doing in our exploration.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	122
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	123 Many semantically distinct components come into the definition of this graph:
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	124 the model (e.g. DAA) the dataset (e.g. an online one), the inference and
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	125 learning strategy. I'm not sure what to call this graph than an 'experiment
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	126 graph'... so I'll go with that for now.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	127
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	128
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	129
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	130
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	131
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	132 Use Cases
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	133 ----------
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	134
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	135 Early stopping
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	136 ~~~~~~~~~~~~~~
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	137
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	138 Early stopping can be implemented as a learner that progresses along a
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	139 particular kind of edge (e.g. "train more") until a stopping criterion (in terms
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	140 of a cost computed from nodes along the path) is met.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	141
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	142
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	143 Grid Search
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	144 ~~~~~~~~~~~
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	145
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	146 Grid search is a learner policy that can be implemented in an experiment graph
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	147 where all paths have the form:
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	148
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	149 ( "set param 0 to X",
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	150 "set param 1 to Y",
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	151 ... ,
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	152 "set param N to Z",
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	153 adapt,
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	154 [early stop...],
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	155 test)
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	156
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	157 It would explore all paths of this form and then return the best node.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	158
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	159
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	160 Stagewise learning of DBNs combined with early stopping and grid search
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	161 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	162
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	163 This would be a learner that is effective for experiment graphs that reflect the
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	164 greedy-stagewise optimization of DBNs.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	165
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	166
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	167 Boosting
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	168 ~~~~~~~~
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	169
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	170 Given an ExperimentGraph that permits re-weighting of examples, it is
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	171 straightforward to write a meta-ExperimentGraph around it that implements AdaBoost.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	172 A meta-meta-ExperimentGraph around that that does early-stopping would complete
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	173 the picture and make a useful boosting implementation.
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	174
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	175
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	176 Using External Hyper-Parameter Optimization Software
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	177 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	178 TODO: use-case - show how we could use the optimizer from
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	179 http://www.cs.ubc.ca/labs/beta/Projects/ParamILS/
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	180
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	181
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	182 Implementation Details / API
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	183 ----------------------------
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	184
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	185 Learner
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	186 ~~~~~~~
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	187 An object that allows us to explore the graph discussed above. Specifically, it represents
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	188 an explored node in that graph.
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	189
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	190 def active_instructions()
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	191 """ Return a list/set of Instruction instances (see below) that the Learner is prepared
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	192 to handle.
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	193 """
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	194
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	195 def copy(), deepcopy()
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	196 """ Learners should be serializable """
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	197
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	198
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	199 To make the implementation easier, I found it was helpful to introduce a string-valued
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	200 `fsa_state` member attribute and associate methods to these states. That made it
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	201 syntactically easy to build relatively complex finite-state transition graphs to describe
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	202 which instructions were active at which times in the life-cycle of a learner.
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	203
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	204
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	205 Instruction
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	206 ~~~~~~~~~~~
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	207 An object that represents a potential edge in the graph discussed above. It is an
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	208 operation that a learner can perform.
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	209
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	210 arg_types
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	211 """a list of Type object (see below) indicating what args are required by execute"""
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	212
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	213 def execute(learner, args, kwargs):
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	214 """ Perform some operation on the learner (follow an edge in the graph discussed above)
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	215 and modify the learner in-place. Calling execute 'moves' the learner from one node in
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	216 the graph along an edge. To have the old learner as well, it must be copied prior to
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	217 calling execute().
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	218 """
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	219
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	220 def expense(learner, args, kwargs, resource_type='CPUtime'):
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	221 """ Return an estimated cost of performing this instruction (calling execute), in time,
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	222 space, number of computers, disk requierement, etc.
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	223 """
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	224
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	225 Type
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	226 ~~~~
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	227 An object that describes a parameter domain for a call to Instruction.execute.
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	228 It is not necessary that a Type specifies exactly which arguments are legal, but it should
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	229 `include` all legal arguments, and exclude as many illegal ones as possible.
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	230
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	231 def includes(value):
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	232 """return True if value is a legal argument"""
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	233
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	234
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	235 To make things a bit more practical, there are some Type subclasses like Int, Float, Str,
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	236 ImageDataset, SgdOptimizer, that include additional attributes (e.g. min, max, default) so
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	237 that automatic graph exploration algorithms can generate legal arguments with reasonable
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	238 efficiency.
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	239
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	240
38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	241
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	242 The proxy pattern is a powerful way to combine learners. Especially when proxy Learner
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	243 instances also introduce Proxy Instruction classes.
1026 38f799f8b6cd v2_planning - thoughts on learner James Bergstra <bergstrj@iro.umontreal.ca> parents: 1002 diff changeset	244
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	245 For example, it is straightforward to implement a hyper-learner by implementing a Learner with
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	246 another learner (sub-learner) as a member attribute. The hyper-learner makes some
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	247 modifications to the instruction_set() return value of the sub-learner, typically to introduce
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	248 more powerful instructions and hide simpler ones.
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	249
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	250 It is less straightforward, but consistent with the design to implement a Learner that
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	251 encompasses job management. Such a learner would retain the semantics of the
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	252 instruction_set of the sub-learner, but would replace the Instruction objects themselves with
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	253 Instructions that arranged for remote procedure calls (e.g. jobman, multiprocessing, bqtools,
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	254 etc.) Such a learner would replace synchronous instructions (return on completion) with
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	255 asynchronous ones (return after scheduling) and the active instruction set would also change
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	256 asynchronously, but neither of these things is inconsistent with the Learner API.
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	257
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	258
1058 e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	259 TODO - Experiment API?
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	260 ~~~~~~~~~~~~~~~~~~~~~~
1043 3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	261
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	262 I feel like something is missing from the API - and that is an interface to the graph structure
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	263 discussed above. The nodes in this graph are natural places to store meta-information for
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	264 visualization, statistics-gathering etc. But none of the APIs above corresponds to the graph
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	265 itself. In other words, there is no API through which to attach information to nodes. It is
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	266 not good to say that the Learner instance is the node because (a) learner instances change
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	267 during graph exploration and (b) learner instances are big, and we don't want to have to keep a
3f528656855b v2planning learner.txt - updated API recommendation James Bergstra <bergstrj@iro.umontreal.ca> parents: 1041 diff changeset	268 whole saved model just to attach meta-info e.g. validation score. Choosing this API spills
1058 e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	269 over into other committees, so we should get their feedback about how to resolve
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	270 it. Maybe we need an 'Experiment' API to stand for this graph?
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	271
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	272
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	273 TODO: Validation & Monitoring Costs
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	274 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1044 3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	275
1058 e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	276 Even if we do have the Experiment API as a structure to hang validation and
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	277 monitoring results, what should be the mechanism for extracting those results.
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	278 The Learner API is not right because extracting a monitoring cost doesn't change
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	279 the model, doesn't change the legal instructions/edges etc. Maybe we should use
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	280 a similar mechanism to Instruction, called something like Measurement? Any node
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	281 / learner can report the list of instructions (for moving) and the list of
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	282 measurements (and the cost of computing them too)
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	283
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	284
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	285 TODO - Parameter Distributions
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	286 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1055 bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	287
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	288 YB asks: it seems to me that what we really need from "Type" is not just
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	289 testing that a value is legal, but more practically a function that specifies the
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	290 prior distribution for the hyper-parameter, i.e., how to sample from it,
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	291 and possibly some representation of it that could be used to infer
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	292 a posterior (such as an unnormalized log-density or log-probability).
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	293 Having the min and max and default limits us to the uniform distribution,
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	294 which may not always be appropriate. For example sometimes we'd like
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	295 Gaussian (-infty to infty) or Exponential (0 to infty) or Poisson (non-negative integers).
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	296 For that reason, I think that "Type" is not a very good name.
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	297 How about "Prior" or "Density" or something like that?
bc3f7834db83 added a comment/question about Type Yoshua Bengio <bengioy@iro.umontreal.ca> parents: 1053 diff changeset	298
1058 e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	299 JB replies: I agree that being able to choose (and update) distributions over
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	300 these values is important. I don't think the Type structure is the right place
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	301 to handle it though. The challenge is to allow those distributions to change
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	302 for a variety of reasons - e.g. the sampling distribution on the capacity
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	303 variables is affected by the size of the dataset, it is also affected by
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	304 previous experience in general as well as experiments on that particular
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	305 dataset. I'm not sure that the 'Type' structure is right to deal with this.
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	306 Also, even with a strategy for handling these distributions, I believe a simple
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	307 mechanism for rejecting insane values might be useful.
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	308
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	309 So how should we handle it? Hmmm...
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	310
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	311
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	312 Comments
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	313 ~~~~~~~~
e342de3ae485 v2planning learner - added comments and TODO points James Bergstra <bergstrj@iro.umontreal.ca> parents: 1055 diff changeset	314
1052 84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	315 OD asks: (I hope it's ok to leave comments even though I'm not in committee... I'm
1045 d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	316 interested to see how the learner interface is shaping up so I'll be keeping
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	317 an eye on this file)
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	318 I'm wondering what's the benefit of such an API compared to simply defining a
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	319 new method for each instruction. It seems to me that typically, the 'execute'
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	320 method would end up being something like
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	321 if instruction == 'do_x':
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	322 self.do_x(..)
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	323 elif instruction == 'do_y':
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	324 self.do_y(..)
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	325 ...
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	326 so why not directly call do_x / do_y instead?
d57bdd9a9980 learner: Left a comment about James' design Olivier Delalleau <delallea@iro> parents: 1044 diff changeset	327
1046 f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	328
1052 84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	329 JB replies: I agree with you, and in the implementation of a Learner I suggest
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	330 using Python decorators to get the best of both worlds:
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	331
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	332 class NNet(Learner):
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	333
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	334 ...
1046 f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	335
1052 84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	336 @Instruction.new(arg_types=(Float(min=-8, max=-1, default=-4),))
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	337 def set_log_lr(self, log_lr):
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	338 self.lr.value = numpy.exp(log_lr)
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	339
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	340 ...
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	341
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	342 The Learner base class can implement a instruction_set() that walks through the
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	343 methods of 'self' and pick out the ones that have corresponding instructions.
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	344 But anyone can call the method normally. The NNet class can also have methods
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	345 that are not instructions.
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	346
1053 390166ace9e5 learner: Reply to James Olivier Delalleau <delallea@iro> parents: 1052 diff changeset	347 OD replies: Ok thanks. I'm still unsure what is the end goal, but I'll keep
390166ace9e5 learner: Reply to James Olivier Delalleau <delallea@iro> parents: 1052 diff changeset	348 watching while you guys work on it, and hopefully it'll become clearer for me ;)
1052 84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	349
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	350 RP asks: James correct me if I'm wrong, but I think each instruction has a execute
1046 f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	351 command. The job of the learner is to traverse the graph and for each edge
f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	352 that it decides to cross to call the execute of that edge. Maybe James has
f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	353 something else in mind, but this was my understanding.
f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	354
1052 84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	355 JB replies: close, but let me make a bit of a clarification. The job of a
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	356 Learner is simply to implement the API of a Learner - to list what edges are
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	357 available and to be able to cross them if asked. The code using the Learner
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	358 (client) decides which edges to cross. The client may also be a Learner, but
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	359 maybe not.
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	360
1046 f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	361
f1732269bce8 comment on Olivier's comment Razvan Pascanu <r.pascanu@gmail.com> parents: 1045 diff changeset	362
1044 3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	363 Just another view/spin on the same idea (Razvan)
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	364 ================================================
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	365
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	366
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	367 My idea is probably just a spin off from what James wrote. It is an extension
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	368 of what I send on the mailing list some time ago.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	369
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	370 Big Picture
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	371 -----------
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	372
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	373 What do we care about ?
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	374 ~~~~~~~~~~~~~~~~~~~~~~~
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	375
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	376 This is the list of the main points that I have in mind :
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	377
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	378 * Re-usability
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	379 * Extensibility
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	380 * Simplicity or easily readable code ( connected to re-usability )
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	381 * Modularity ( connected to extensibility )
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	382 * Fast to write code ( - sort of comes out of simplicity)
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	383 * Efficient code
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	384
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	385
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	386 Composition
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	387 ~~~~~~~~~~~
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	388
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	389 To me this reads as code generated by composing pieces. Imagine this :
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	390 you start of with something primitive that I will call a "variable", which
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	391 probably is a very unsuitable name. And then you compose those intial
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	392 "variables" or transform them through several "functions". Each such
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	393 "function" hides some logic, that you as the user don't care about.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	394 You can have low-level or micro "functions" and high-level or macro
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	395 "functions", where a high-level function is just a certain compositional
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	396 pattern of low-level "functions". There are several classes of "functions"
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	397 and "variables" that can be inter-changable. This is how modularity is
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	398 obtained, by chainging between functions from a certain class.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	399
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	400 Now when you want to research something, what you do is first select
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	401 the step you want to look into. If you are lucky you can re-write this
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	402 step as certain decomposition of low-level transformations ( there can be
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	403 multiple such decompositions). If not you have to implement such a
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	404 decompositions acording to your needs. Pick the low-level transformations you want
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	405 to change and write new versions that implement your logic.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	406
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	407 I think the code will be easy to read, because it is just applying a fixed
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	408 set of transformations, one after the other. The one who writes the code can
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	409 decide how explicit he wants to write things by switching between high-level
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	410 and low-level functions.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	411
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	412 I think the code this way is re-usable, because you can just take this chain
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	413 of transformation and replace the one you care about, without looking into
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	414 the rest.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	415
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	416 You get this fractal property of the code. Zooming in, you always get just
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	417 a set of functions applied to a set of variables. In the begining those might
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	418 not be there, and you would have to create new "low level" decompositions,
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	419 maybe even new "variables" that get data between those decompositions.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	420
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	421 The thing with variables here, is that I don't want this "functions" to have
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	422 a state. All the information is passed along through these variables. This
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	423 way understanding the graph is easy, debugging it is also easier ( then having
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	424 all these hidden states ..)
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	425
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	426 Note that while doing so we might ( and I strongly think we should) create
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	427 a (symbolic) DAG of operations. ( this is where it becomes what James was saying).
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	428 In such a DAG the "variables" will the nodes and the functions will be edges.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	429 I think having a DAG is useful in many ways (all this are things that one
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	430 might think about implementing in a far future, I'm not proposing to implement
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	431 them unless we want to use them - like the reconstruction ):
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	432 * there exist the posibility of writing optimizations ( theano style )
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	433 * there exist the posibility to add global view utility functions ( like
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	434 a reconstruction function for SdA - extremely low level here), or global
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	435 view diagnostic tools
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	436 * the posibility of creating a GUI ( where you just create the Graph by
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	437 picking transforms and variables from a list ) or working interactively
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	438 and then generating code that will reproduce the graph
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	439 * you can view the graph and different granularity levels to understand
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	440 things ( global diagnostics)
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	441
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	442 We should have a taxonomy of possible classes of functions and possible
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	443 classes of variables, but those should not be exclusive. We can work at a high
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	444 level for now, and decompose those high level functions to lower level when
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	445 we need to. We can introduce new classes of functions or intermediate
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	446 variables between those low level functions.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	447
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	448
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	449 Similarities with James' idea
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	450 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	451
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	452 As I said before, this is I think just another view on what James proposed.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	453 The learner in his case is the module that traverses the graph of this
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	454 operations, which makes sense here as well.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	455
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	456 The 'execute' command in his api is just applying a function to some variables in
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	457 my case.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	458
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	459 The learner keeps track of the graph that is formed I think in both cases.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	460
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	461 His view is a bit more general. I see the graph as fully created by the user,
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	462 and the learner just has to go from the start to the end. In his case the
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	463 traversal is conditioned on some policies. I think these ideas can be mixed /
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	464 united. What I would see in my case to have this functionality is something
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	465 similar to the lazy linker for Theano.
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	466
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	467
3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	468
1052 84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	469 JB asks: There is definitely a strong theme of graphs in both suggestions,
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	470 furthermore graphs that have heavy-duty nodes and light-weight edges. But I
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	471 don't necessarily think that we're proposing the same thing. One difference is
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	472 that the graph I talked about would be infinite in most cases of interest, so
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	473 it's not going to be representable by Theano's data structures (even with lazy
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	474 if). Another difference is that the graph I had in mind doesn't feel fractal -
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	475 it would be very common for a graph edge to be atomic. A proxy pattern, such as
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	476 in a hyper-learner would create a notion of being able to zoom in, but other
84f62533e7a8 v2planning learner - reply to comments James Bergstra <bergstrj@iro.umontreal.ca> parents: 1046 diff changeset	477 than that, i'm not sure what you mean.
1044 3b1fd599bafd my first draft of my own views which are close to be just a reformulation of what James proposes Razvan Pascanu <r.pascanu@gmail.com> parents: 1043 diff changeset	478
1056 19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	479 RP replies: I've been thinking about my idea a bit and yes, it might be
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	480 quite different from what James has in mind, though there are plently of common
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	481 elements. I might have exagerated a bit with the zooming in, so in some cases
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	482 you will end up with atomic edges, though my hope is that is not most of the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	483 edges.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	484
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	485 I think I should go into mode details when answering this question because
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	486 I feel I have not explained things sufficiently clear. Note, in many places
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	487 I replaced the word "function" by "transform".
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	488
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	489 Think of the learner as an object that traverses a DAG of steps created by the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	490 user. On this DAG the learner can potentially do a lot of cool stuff, but we
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	491 won't care about that for now. The DAG can be infinite in principle, and what
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	492 the learner does is just to go on the path described by the user ( and here
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	493 described is not through heuristics like in James case, but by giving the list
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	494 of edges it needs to follow). A potential cool thing the learner can do is to
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	495 regard the path given by the user as a suggestion ( or some form of heuristic)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	496 and try to improve it. This would be much closer to what James has in mind,
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	497 and I definetely think is a cool way to go about it.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	498
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	499 Now this path in the graph is given by the user by composing subgraphs or
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	500 adding nodes to the graph. Or (expressing this in a more simple way) by applying
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	501 functions to variables. Any such function will introduce an edge ( or a subgraph) that
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	502 will connect the vertices corresponding to the input variables to the vertices
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	503 corresponding to the output variables. The variables store the state of the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	504 learner. These functions are state-less, I think if you would give them states
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	505 you will make this approach really ugly (I might be wrong).
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	506 The variables would contain informations required by the function, like
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	507 number of layers, on how many cores to run, cluster configurations, and so on.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	508
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	509 Now about the zooming part, that James asked. I might have exagerated a bit,
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	510 is not that you can zoom in on any part infinitely. You will end up with
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	511 things that are atomic. The idea is that any such "transformation" or edge
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	512 has the potential to be split up in several "transformations". This offers
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	513 (in my view) a way of solving the time constraints of our project. We can
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	514 start by difining a coarse division in segments. For now we can have
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	515 a structure transform that makes a list of parameters into a deep
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	516 network of some type, then a learner transform that adds SGD + pre-training
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	517 on top of network, and then early stopper on top of that, and then a
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	518 run_on_cluster on that.We would probably want something more finely grained
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	519 even from the start .. this is just to prove my point. When any of us
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	520 starts experimenting with a certain sub-step of this process ( like the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	521 structure) we will split that transform into several ( like ones that create
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	522 a layer and so on) that make sense for that case, and then start working on
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	523 the low level transform that we cares ( like the layer) introducing new
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	524 versions of it. I think we can not find a universal split that will cover
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	525 all of our cases, so I think we should allow different such splits. The one
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	526 who researches should look at what low-level transforms are available and use
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	527 those if they make sense, if not he would have to create a different split.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	528 Creating a different split might involve a lot of work and taking care of
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	529 several issues so it should be done with care.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	530
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	531 I'll give an example from where I started thinking this way. Let say we want
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	532 to do the SdA with auxiliary inputs that encourages separation of the features
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	533 in the hidden layer that Yoshua was saying ( I had an attempt
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	534 at it some time ago for speech but I never eneded up finishing that project).
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	535
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	536 You start up with something like :
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	537
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	538 learner = Learner()
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	539 # This will create the learner that will traverse our graph. We might
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	540 # want it to be a function ``execute``, I just randomly picked this option.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	541 #I have no preference of this detail for now .. this is mostly work in progress
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	542
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	543 data = someSpeechData(path = 'some path')
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	544 # This is such a transform that will generate from the string representing the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	545 # path a dataset variable ( that will contain all informations you need to
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	546 # access data). This will probably be the object the datasets comittee will
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	547 # provide. Note, you might need to provide more information then the path, but
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	548 # you can easily see how to do that. All these stuff start from simple
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	549 # variables like path, batch size and so on and return a complex heavy duty
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	550 # variable (node).
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	551
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	552
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	553 model = earlyStopping(pretrain(SdA(layers = [524, 500, 500,27], noise = [0.1,0.1]),data, epochs = 10), data)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	554 # This is a composition of two transforms. The SdA transform starts from the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	555 # info about layers and corruption /noise for each layer and construct a SdA.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	556 # This is a high level transform, so it will take care of defining all
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	557 # details, like pre-training, defining the cost and so on. Note that maybe it will
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	558 # require some more parameters .. you can assume that for anything else there
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	559 # is a default value that the SdA will use. earlyStopping is yet another
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	560 # transform that takes a model ( that we know how to train ) and some data,
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	561 # and does early stoppign on it. For bravity I did not provide all the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	562 # information required like patience and so on. The SdA only knows how to do a
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	563 # step of training. Same holds for pretrain. It will loop over the layers of
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	564 # SdA and will train each one.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	565
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	566 steps = cluster(model, getPropertiesAndRanges(model), n_jobs = 20, cluster_info = getClusterInfo())
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	567 # This will lunch the wanted jobs. getPropertiesAndRanges will get from a
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	568 # model all knobs that need to be turn, and their ranges and will uniformly
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	569 # sample from them in each jobs. getCluterInfo will return a variable
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	570 # containing informations about the cluster ( I added this for simplicity, it
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	571 # should probably be replaced with something like username, password,
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	572 # clusterpath or whatever).
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	573
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	574 learner.execute(steps)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	575 # As an option, each of this output variables could contain the entire graph
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	576 # until that point. We could also have this in a different way .. this is
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	577 # adhoc at the moment
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	578
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	579
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	580 Now this is a coarse vanila SdA which is not what we wanted. We do not have a
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	581 way of incorporating our auxiliary information in this. So what we have to do
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	582 is split/change the SdA transform. We would re-write it as :
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	583
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	584
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	585 arch = SdA(layers = [524, 500, 500, 27], noise = [0.1,0.1])
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	586 model = earlyStopping(pretrain(arch,data,epochs = 10)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	587 ...
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	588
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	589 And then re-write things like :
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	590
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	591 arch = SGD( cross_entropy( logreg( DAAlayer( [DAAlayer([524,500],0.1),500],0.1))))
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	592
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	593
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	594 We would re-write the DAAlayer as :
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	595
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	596 layer0 = DAAlayer([524,500],0.1)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	597 layer1 = cross_entropy(reconstruct( tanh(dotW_b( layer0,500)),noise = 0.1))
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	598
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	599 At this point of detail, we can start inserting our new stuff in as follows :
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	600
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	601
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	602 input = empty_layer(600)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	603 # empty layer is a wrapper ; if I would to write dotW_b(200,500) which means
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	604 # go from a layer of 200 units to a one of 500 by multiplying with a matrix
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	605 # and adding a bias, what I would mean is dotW_b( empty_layer(200), 500).
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	606 # an implementation of empty_layer could be just theano.tensor.vector()
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	607 # where we add the size tag ( we will need it later)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	608
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	609
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	610 hidden0_mfcc = dotW_b(input[0:524],100)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	611 hidden0_noise = dotW_b(input[0:560],50)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	612 hidden0_speakerID = dotW_b(join(input[0:524], input[560:600]),50)
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	613 hidden0 = tanh(join( layer0_mfcc, layer0_noise, layer0_speakerID))
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	614 layer0 = cross_entropy( reconstruct( hidden0, noise = 0.1))
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	615
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	616 and so on. Hopefully you got what I mean by spliting a transform, or zooming
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	617 in. When doing all this we did not change anything about the early stopping or
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	618 lunching jobs on the cluster. In the same manner, if one would like to look
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	619 into how jobs are send to the cluster, it could just expand that part. Note
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	620 that if we wanted to do something else we might have split the DAA
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	621 differently.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	622
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	623 The key of this approach is to identify such low level units that can be
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	624 shared by 90% of our architectures, and the splits that make most sense
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	625 from a functional point of view that will cover the main points where people
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	626 will like to change things. This will ensure that almost all the time we have
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	627 the wanted low-level bits that we want to write our code into, and most of the
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	628 time we will only work on one of that bit. There will definetely be cases when
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	629 whatever we have will not be sufficient or convinient. In that case some
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	630 effort has to be invested by the user to create a different decomposition of
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	631 the problem in the elements he need.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	632
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	633 I've been thinking about this a bit, and it definetely works in for deep
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	634 networks and theano ( the approach was inspired by theano). From what James
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	635 said, I think that other stuff might be possible to incorporate, at least as
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	636 atomic transforms if not in any other way.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	637
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	638 TODO: one has to give some thought of this low-level transform, to find a
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	639 suitable set of them ( and variables) so that would end up most of the time
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	640 re-using things and not creating new things.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	641
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	642 NOTES: there are some other implementation details missing of what this state
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	643 variables should contain. I did not want to clutter this with what tricks
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	644 could be used to get this transparent interface. I have a few of them in mind
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	645 though..
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	646 there is a lot of hardcoded values in this example. Usually each transform
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	647 that takes an input should "know" which of these inputs are tunable and mark
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	648 them as such. The order of the input in this example is important as well.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	649 This can be easily solved at the expense of a few more lines of code that
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	650 I did not want to write.
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	651
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	652
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	653
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	654
19033ef1636d some more details on my approach Razvan Pascanu <r.pascanu@gmail.com> parents: 1055 diff changeset	655

Mercurial > pylearn

annotate doc/v2_planning/learner.txt @ 1093:a65598681620