Mercurial > pylearn
diff algorithms/logistic_regression.py @ 470:bd937e845bbb
new stuff: algorithms/logistic_regression, datasets/MNIST
author | James Bergstra <bergstrj@iro.umontreal.ca> |
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date | Wed, 22 Oct 2008 15:56:53 -0400 |
parents | |
children | 69c800af1370 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/algorithms/logistic_regression.py Wed Oct 22 15:56:53 2008 -0400 @@ -0,0 +1,95 @@ +import theano +from theano import tensor as T +from theano.tensor import nnet_ops +from theano.compile import module +from theano import printing, pprint +from theano import compile + +import numpy as N + + +class Module_Nclass(module.FancyModule): + class __instance_type__(module.FancyModuleInstance): + def initialize(self, n_in, n_out, rng=N.random): + #self.component is the LogisticRegressionTemplate instance that built this guy. + + self.w = rng.randn(n_in, n_out) + self.b = rng.randn(n_out) + self.lr = 0.01 + self.__hide__ = ['params'] + + def __init__(self, x=None, targ=None, w=None, b=None, lr=None): + super(Module_Nclass, self).__init__() #boilerplate + + self.x = x if x is not None else T.matrix() + self.targ = targ if targ is not None else T.lvector() + + 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()) + self.lr = lr if lr is not None else module.Member(T.dscalar()) + + self.params = [p for p in [self.w, self.b] if p.owner is None] + + xent, y = nnet_ops.crossentropy_softmax_1hot( + T.dot(self.x, self.w) + self.b, self.targ) + sum_xent = T.sum(xent) + + self.y = y + self.sum_xent = sum_xent + + #define the apply method + self.pred = T.argmax(T.dot(self.x, self.w) + self.b, axis=1) + self.apply = module.Method([self.x], self.pred) + + if self.params: + gparams = T.grad(sum_xent, self.params) + + self.update = module.Method([self.x, self.targ], sum_xent, + updates = dict((p, p - self.lr * g) for p, g in zip(self.params, gparams))) + +class Module(module.FancyModule): + class __instance_type__(module.FancyModuleInstance): + def initialize(self, n_in): + #self.component is the LogisticRegressionTemplate instance that built this guy. + + self.w = N.random.randn(n_in,1) + self.b = N.random.randn(1) + self.lr = 0.01 + self.__hide__ = ['params'] + + def __init__(self, x=None, targ=None, w=None, b=None, lr=None): + super(Module, self).__init__() #boilerplate + + self.x = x if x is not None else T.matrix() + self.targ = targ if targ is not None else T.lcol() + + 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()) + self.lr = lr if lr is not None else module.Member(T.dscalar()) + + self.params = [p for p in [self.w, self.b] if p.owner is None] + + y = nnet_ops.sigmoid(T.dot(self.x, self.w)) + xent = -self.targ * T.log(y) - (1.0 - self.targ) * T.log(1.0 - y) + sum_xent = T.sum(xent) + + self.y = y + self.xent = xent + self.sum_xent = sum_xent + + #define the apply method + self.pred = (T.dot(self.x, self.w) + self.b) > 0.0 + self.apply = module.Method([self.x], self.pred) + + #if this module has any internal parameters, define an update function for them + if self.params: + gparams = T.grad(sum_xent, self.params) + self.update = module.Method([self.x, self.targ], sum_xent, + updates = dict((p, p - self.lr * g) for p, g in zip(self.params, gparams))) + + + +class Learner(object): + """TODO: Encapsulate the algorithm for finding an optimal regularization coefficient""" + pass +