Mercurial > pylearn
changeset 650:83e8fe9b1c82
factoring out classification from LogReg_New
author | James Bergstra <bergstrj@iro.umontreal.ca> |
---|---|
date | Wed, 04 Feb 2009 18:04:05 -0500 |
parents | c433b9cf9d09 |
children | d03b5d8e4bf6 |
files | pylearn/algorithms/logistic_regression.py |
diffstat | 1 files changed, 35 insertions(+), 25 deletions(-) [+] |
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--- a/pylearn/algorithms/logistic_regression.py Wed Feb 04 15:56:20 2009 -0500 +++ b/pylearn/algorithms/logistic_regression.py Wed Feb 04 18:04:05 2009 -0500 @@ -192,6 +192,32 @@ updates = dict((p, p - self.lr * g) for p, g in zip(self.params, gparams))) +class classification: #this would go to a file called pylearn/algorithms/classification.py + + @staticmethod + def xent(p, q): + """The cross-entropy between the prediction from `input`, and the true `target`. + + This function returns a symbolic vector, with the cross-entropy for each row in + `input`. + + Hint: To sum these costs into a scalar value, use "xent(input, target).sum()" + """ + return p * tensor.log(q) + + @staticmethod + def errors(prediction, target): + """The zero-one error of the prediction from `input`, with respect to the true `target`. + + This function returns a symbolic vector, with the incorrectness of each prediction + (made row-wise from `input`). + + Hint: Count errors with "errors(prediction, target).sum()", and get the error-rate with + "errors(prediction, target).mean()" + + """ + return tensor.neq(tensor.argmax(prediction), target) + class LogReg_New(module.FancyModule): """A symbolic module for performing multi-class logistic regression.""" @@ -208,6 +234,11 @@ self.w = w if w is not None else module.Member(T.dmatrix()) self.b = b if b is not None else module.Member(T.dvector()) + def _instance_initialize(self, obj): + obj.w = N.zeros((self.n_in, self.n_out)) + obj.b = N.zeros(self.n_out) + obj.__pp_hide__ = ['params'] + def l1(self): return abs(self.w).sum() @@ -216,38 +247,17 @@ return (self.w**2).sum() def activation(self, input): - return T.dot(self.input, self.w) + self.b + return theano.dot(input, self.w) + self.b def softmax(self, input): return nnet.softmax(self.activation(input)) def argmax(self, input): - return T.max_and_argmax(self.linear_output(input))[1] + return tensor.argmax(self.activation(input)) def xent(self, input, target): - """The cross-entropy between the prediction from `input`, and the true `target`. - - This function returns a symbolic vector, with the cross-entropy for each row in - `input`. - - Hint: To sum these costs into a scalar value, use "xent(input, target).sum()" - """ - return target * T.log(self.softmax(input)) + return classification.xent(self.softmax(input), target) def errors(self, input, target): - """The zero-one error of the prediction from `input`, with respect to the true `target`. - - This function returns a symbolic vector, with the incorrectness of each prediction - (made row-wise from `input`). - - Hint: Count errors with "errors(input, target).sum()", and get the error-rate with - "errors(input, target).mean()" + return classification.errors(self.softmax(input), target) - """ - return T.neq(self.argmax(input), self.target) - - def _instance_initialize(self, obj): - obj.w = N.zeros((self.n_in, self.n_out)) - obj.b = N.zeros(self.n_out) - obj.__pp_hide__ = ['params'] -