Mercurial > pylearn
diff doc/v2_planning/arch_src/plugin_JB_comments_RP.txt @ 1214:681b5e7e3b81
a few comments on James version
author | Razvan Pascanu <r.pascanu@gmail.com> |
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date | Wed, 22 Sep 2010 10:39:39 -0400 |
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children | 5a8930e089ed |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/doc/v2_planning/arch_src/plugin_JB_comments_RP.txt Wed Sep 22 10:39:39 2010 -0400 @@ -0,0 +1,60 @@ +I agree with Ian, maybe using caps is not the best idea. It reminds be of BASIC which I used to do long time ago :). It also makes the code look a bit scary. + +I like the approach and I think it goes close to my earliest proposition and to what I am proposing for the layer committeee ( though we did not have a meeting yet). +I would though write it in a more Theano like ( Ian has a example of how that would look). I would also drop the CALL and FLIT constructs, and actually have a +decorator ( or something ) that wraps around a function to transform it into a call or flit. I hope that this is only syntactic sugar ( does this change anything +in the actual implementation ?? ) that makes things more natural. What I want to reach is something that looks very much as Theano, just that now you are creating +the graph of execution steps. Refractoring what you wrote this will look like + +x = buffer_repeat( 1000, dataset.next()) +train_pca = pca.analyze(x) + +train_pca.run() + +If you allow a FLIT to also get multiple inputs ( so not just the one) which comes natural in this way of writing you can get to describe a DAG that not only +describes the order of execution but also deals with what takes data from what. I'm sorry for not being there yesturday, from what I remember I have the +feeling that for you that is done under the hood and not taken care by this flow control structures. + +To be a bit more explicit, in the way of writing the code above you can see that : + a) dataset_next() has to run before pca_analyze + b) pca_analyze needs the result (data) object of buffer_repeat( dataset.next()) + +I've actually elaborated on this idea here and there, and figured out what the result from such a control flow thing is, and how to make everything explicit +in the graph. Parts of this is in my plugin_RP.py ( Step 1) though it is a bit of a moving target. I also have a sligtly different way of writing REPEAT +and BUFFER_REPEAT .. though I think is mostly the same. I actually did not know how to deal with distributed things until I saw how you deal with that in your code. +Copy-pasted a version of a SDAA with my way of writing : + + ## Layer 1: + + data_x,data_y = GPU_transform(load_mnist()) + noisy_data_x = gaussian_noise(data_x, amount = 0.1) + hidden1 = tanh(dotW_b(data_x, n_units = 200)) + reconstruct1 = reconstruct(hidden1.replace(data_x, noisy_data_x), + noisy_data_x) + err1 = cross_entropy(reconstruct1, data_x) + learner1 = SGD(err1) + + # Layer 2 : + noisy_hidden1 = gaussian_noise(hidden1, amount = 0.1) + hidden2 = tanh(dotW_b(hidden1, n_units = 200)) + reconstruct2 = reconstruct(hidden2.replace(hidden1,noisy_hidden1), + noisy_hidden1) + err2 = cross_entropy(reconstruct2, hidden) + learner2 = SGD(err2) + + # Top layer: + + output = sigmoid(dotW_b(hidden2, n_units = 10)) + err = cross_entropy(output, data_y) + learner = SGD(err) + + +GPU_transform,gaussian_noise and so on are functions that have been decorated ( or classes if you want) +that you would write using FLIT. Reconstruct for me is a different CONTROL FLOW element. +In this case I don't use REPEAT or BUFFER_REPEAT or the other very cool control flow elements, but you +can easily imagine writing something like + +pretrained_in_parallel = weave( learner1, learner2) +results = spawn(repeat(5000,learner1),repeat(500,learner2)) + +