class MLP(object):
def __init__(self, layers_size, hidden=None, out=None,
log_activation=T.nnet.softmax):
rng = numpy.random.RandomState(89677)
n_in = layers_size[0]
n_hid = layers_size[1]
n_out = layers_size[2]
self.x = T.matrix('x') # the chroma data
self.y = T.matrix('y') # target vectors
if (hidden):
self.hiddenLayer = HiddenRecurrentLayer(
rng=rng,
input=self.x,
n_in=n_in,
n_out=n_hid,
activation=theano.tensor.tanh,
W=hidden.W,
b=hidden.b,
U=hidden.U)
else:
self.hiddenLayer = HiddenRecurrentLayer(
rng=rng,
input=self.x,
n_in=n_in,
n_out=n_hid,
activation=theano.tensor.tanh)
if (out):
self.logRegressionLayer = LogisticRegression(
input=self.hiddenLayer.output,
n_in=n_hid,
n_out=n_out,
W = out.W,
b = out.b,
activation=log_activation)
else:
self.logRegressionLayer = LogisticRegression(
input=self.hiddenLayer.output,
n_in=n_hid,
n_out=n_out,
activation=log_activation)
# L1 norm ; one regularization option is to enforce L1 norm to
# be small
self.L1 = abs(self.hiddenLayer.W).sum() + abs(self.hiddenLayer.U).sum() \
+ abs(self.logRegressionLayer.W).sum()
# square of L2 norm ; one regularization option is to enforce
# square of L2 norm to be small
self.L2_sqr = (self.hiddenLayer.W ** 2).sum() + abs(self.hiddenLayer.U ** 2).sum()\
+ (self.logRegressionLayer.W ** 2).sum()
# negative log likelihood of the MLP is given by the negative
# log likelihood of the output of the model, computed in the
# logistic regression layer
# self.negative_log_likelihood = self.logRegressionLayer.negative_log_likelihood
# quadratic loss
[self.pre_act, self.quadratic_loss] = self.logRegressionLayer.quadratic_loss(self.y)
self.lin_hidden = self.hiddenLayer.lin_output
# same holds for the function computing the number of errors
#self.errors = self.logRegressionLayer.errors(self.y)
# the parameters of the model are the parameters of the two layer it is
# made out of
self.params = self.hiddenLayer.params + self.logRegressionLayer.params
def get_result(self, x):
return self.logRegressionLayer.p_y_given_x
class SdA(object):
"""Stacked denoising auto-encoder class (SdA)
A stacked denoising autoencoder model is obtained by stacking several
dAs. The hidden layer of the dA at layer `i` becomes the input of
the dA at layer `i+1`. The first layer dA gets as input the input of
the SdA, and the hidden layer of the last dA represents the output.
Note that after pretraining, the SdA is dealt with as a normal MLP,
the dAs are only used to initialize the weights.
"""
def __init__(self, n_ins, hidden_layers_sizes, n_outs,
layers=None, log_layer=None, recurrent_layer=-1,
is_vector_y=False, log_activation=T.nnet.softmax):
""" This class is made to support a variable number of layers.
:type theano_rng: theano.tensor.shared_randomstreams.RandomStreams
:param theano_rng: Theano random generator; if None is given one is
generated based on a seed drawn from `rng`
:type n_ins: int
:param n_ins: dimension of the input to the sdA
:type n_layers_sizes: list of ints
:param n_layers_sizes: intermediate layers size, must contain
at least one value
:type n_outs: int
:param n_outs: dimension of the output of the network
"""
if recurrent_layer >= 0 or (layers and isinstance(layers[1][-1], HiddenRecurrentLayer)):
print("Creating a recurrent stacked denoising autoencoder with:")
else:
print("Creating a stacked denoising autoencoder with:")
print("\tinput size: " + str(n_ins))
print("\thidden layers sizes: " + str(hidden_layers_sizes))
print("\toutput size: " + str(n_outs))
if recurrent_layer >= 0:
print recurrent_layer
elif (layers and isinstance(layers[1][-1], HiddenRecurrentLayer)):
print("\trecurrent layer #: " + str(len(layers[1]) - 1))
self.sigmoid_layers = []
self.dA_layers = []
self.n_layers = len(hidden_layers_sizes)
self.params = []
assert self.n_layers > 0
numpy_rng = numpy.random.RandomState(89677)
theano_rng = RandomStreams(numpy_rng.randint(2 ** 30))
# allocate symbolic variables for the data
self.x = T.matrix('x') # the spectrum data
if (is_vector_y):
self.y = T.ivector('y')
else:
self.y = T.matrix('y') # target tonnetz vectors
# The SdA is an MLP, for which all weights of intermediate layers
# are shared with a different denoising autoencoders
# We will first construct the SdA as a deep multilayer perceptron,
# and when constructing each sigmoidal layer we also construct a
# denoising autoencoder that shares weights with that layer
# During pretraining we will train these autoencoders (which will
# lead to chainging the weights of the MLP as well)
# During finetunining we will finish training the SdA by doing
# stochastich gradient descent on the MLP
for i in xrange(self.n_layers):
# construct the sigmoidal layer
# the size of the input is either the number of hidden units of
# the layer below or the input size if we are on the first layer
if i == 0:
input_size = n_ins
else:
input_size = hidden_layers_sizes[i - 1]
if (hidden_layers_sizes[i] - input_size > 0):
beta = 0.1
else:
beta = 0
# the input to this layer is either the activation of the hidden
# layer below or the input of the SdA if you are on the first
# layer
if i == 0:
layer_input = self.x
else:
layer_input = self.sigmoid_layers[-1].output
if (layers):
if isinstance(layers[1][i], HiddenRecurrentLayer):
sigmoid_layer = HiddenRecurrentLayer(rng=numpy_rng,
input=layer_input,
n_in=input_size,
n_out=hidden_layers_sizes[i],
activation=T.nnet.sigmoid,
W=layers[1][i].W,
b=layers[1][i].b,
U=layers[1][i].U)
else:
sigmoid_layer = HiddenLayer(rng=numpy_rng,
input=layer_input,
n_in=input_size,
n_out=hidden_layers_sizes[i],
activation=T.nnet.sigmoid,
W=layers[1][i].W,
b=layers[1][i].b)
else:
if i == recurrent_layer:
sigmoid_layer = HiddenRecurrentLayer(rng=numpy_rng,
input=layer_input,
n_in=input_size,
n_out=hidden_layers_sizes[i],
activation=T.nnet.sigmoid)
else:
sigmoid_layer = HiddenLayer(rng=numpy_rng,
input=layer_input,
n_in=input_size,
n_out=hidden_layers_sizes[i],
activation=T.nnet.sigmoid)
# add the layer to our list of layers
self.sigmoid_layers.append(sigmoid_layer)
# Construct a denoising autoencoder that shared weights with this
# layer
dA_layer = dA(numpy_rng=numpy_rng,
theano_rng=theano_rng,
input=layer_input,
n_visible=input_size,
beta = beta,
n_hidden=hidden_layers_sizes[i],
W=sigmoid_layer.W,
bhid=sigmoid_layer.b)
self.dA_layers.append(dA_layer)
# its arguably a philosophical question...
# but we are going to only declare that the parameters of the
# sigmoid_layers are parameters of the StackedDAA
# the visible biases in the dA are parameters of those
# dA, but not the SdA
self.params.extend(sigmoid_layer.params)
# We now need to add a logistic layer on top of the MLP
if (log_layer):
self.logLayer = LogisticRegression(
input=self.sigmoid_layers[-1].output,
n_in=hidden_layers_sizes[-1], n_out=n_outs,
W=log_layer.W, b=log_layer.b,
activation=log_activation)
else:
self.logLayer = LogisticRegression(
input=self.sigmoid_layers[-1].output,
n_in=hidden_layers_sizes[-1], n_out=n_outs,
activation=log_activation)
self.params.extend(self.logLayer.params)
# construct a function that implements one step of finetunining
if (is_vector_y):
# compute the cost for second phase of training,
# defined as the negative log likelihood
[self.pre_act, self.finetune_cost] = self.logLayer.negative_log_likelihood(self.y)
# compute the gradients with respect to the model parameters
# symbolic variable that points to the number of errors made on the
# minibatch given by self.x and self.y
self.errors = self.logLayer.errors(self.y)
else:
[self.pre_act, self.quadratic_loss] = self.logLayer.quadratic_loss(self.y)
def pretraining_functions(self, train_set_x, batch_size):
''' Generates a list of functions, each of them implementing one
step in trainnig the dA corresponding to the layer with same index.
The function will require as input the minibatch index, and to train
a dA you just need to iterate, calling the corresponding function on
all minibatch indexes.
:type train_set_x: theano.tensor.TensorType
:param train_set_x: Shared variable that contains all datapoints used
for training the dA
:type batch_size: int
:param batch_size: size of a [mini]batch
:type learning_rate: float
:param learning_rate: learning rate used during training for any of
the dA layers
'''
# index to a [mini]batch
index = T.lscalar('index') # index to a minibatch
corruption_level = T.scalar('corruption') # % of corruption to use
learning_rate = T.scalar('lr') # learning rate to use
# number of batches
n_batches = train_set_x.get_value(borrow=True).shape[0] / batch_size
# begining of a batch, given `index`
batch_begin = index * batch_size
# ending of a batch given `index`
batch_end = batch_begin + batch_size
def detect_nan(i, node, fn):
for output in fn.outputs:
if numpy.any(pandas.isnull(output[0])):
print '*** NaN detected ***'
print 'Inputs : %s' % [input[0] for input in fn.inputs]
# theano.printing.debugprint(node)
print 'Outputs: %s' % [output[0] for output in fn.outputs]
raise Exception('Nan detected')
break
pretrain_fns = []
for dA in self.dA_layers:
# get the cost and the updates list
cost, updates = dA.get_cost_updates(corruption_level,
learning_rate)
# compile the theano function
fn = theano.function(inputs=[index,
theano.Param(corruption_level, default=0.2),
theano.Param(learning_rate, default=0.1)],
outputs=cost,
updates=updates,
givens={self.x: train_set_x[batch_begin:
batch_end]})#, # comment here
#mode=theano.compile.MonitorMode(
#post_func=detect_nan))
# append `fn` to the list of functions
pretrain_fns.append(fn)
return pretrain_fns
def build_finetune_functions(self, datasets, batch_size, learning_rate, useQuadratic=True):
'''Generates a function `train` that implements one step of
finetuning, a function `validate` that computes the error on
a batch from the validation set, and a function `test` that
computes the error on a batch from the testing set
:type datasets: list of pairs of theano.tensor.TensorType
:param datasets: It is a list that contain all the datasets;
the has to contain three pairs, `train`,
`valid`, `test` in this order, where each pair
is formed of two Theano variables, one for the
datapoints, the other for the labels
:type batch_size: int
:param batch_size: size of a minibatch
:type learning_rate: float
:param learning_rate: learning rate used during finetune stage
'''
(train_set_x, train_set_y) = datasets[0]
(valid_set_x, valid_set_y) = datasets[1]
(test_set_x, test_set_y) = datasets[2]
# compute number of minibatches for training, validation and testing
n_valid_batches = valid_set_x.get_value(borrow=True).shape[0]
n_valid_batches /= batch_size
n_test_batches = test_set_x.get_value(borrow=True).shape[0]
n_test_batches /= batch_size
index = T.lscalar('index') # index to a [mini]batch
# compute the gradients with respect to the model parameters
if (useQuadratic):
gparams = T.grad(self.quadratic_loss, self.params)
else:
gparams = T.grad(self.finetune_cost, self.params)
# compute list of fine-tuning updates
updates = {}
for param, gparam in zip(self.params, gparams):
updates[param] = param - gparam * learning_rate
updates=collections.OrderedDict(updates.items())
if (useQuadratic):
train_fn = theano.function(inputs=[index],
outputs=[self.pre_act, self.quadratic_loss],
updates=updates,
givens={
self.x: train_set_x[index * batch_size:
(index + 1) * batch_size],
self.y: train_set_y[index * batch_size:
(index + 1) * batch_size]})
test_score_i = theano.function([index], [self.pre_act, self.quadratic_loss],
givens={
self.x: test_set_x[index * batch_size:
(index + 1) * batch_size],
self.y: test_set_y[index * batch_size:
(index + 1) * batch_size]})
valid_score_i = theano.function([index], [self.pre_act, self.quadratic_loss],
givens={
self.x: valid_set_x[index * batch_size:
(index + 1) * batch_size],
self.y: valid_set_y[index * batch_size:
(index + 1) * batch_size]})
else:
train_fn = theano.function(inputs=[index],
outputs=self.finetune_cost,
updates=updates,
givens={
self.x: train_set_x[index * batch_size:
(index + 1) * batch_size],
self.y: train_set_y[index * batch_size:
(index + 1) * batch_size]})
test_score_i = theano.function([index], self.errors,
givens={
self.x: test_set_x[index * batch_size:
(index + 1) * batch_size],
self.y: test_set_y[index * batch_size:
(index + 1) * batch_size]})
valid_score_i = theano.function([index], self.errors,
givens={
self.x: valid_set_x[index * batch_size:
(index + 1) * batch_size],
self.y: valid_set_y[index * batch_size:
(index + 1) * batch_size]})
# Create a function that scans the entire validation set
def valid_score():
return [valid_score_i(i) for i in xrange(n_valid_batches)]
# Create a function that scans the entire test set
def test_score():
return [test_score_i(i)[1] for i in xrange(n_test_batches)]
return train_fn, valid_score, test_score
def get_result(self, m):
z = self.logLayer.p_y_given_x
result = theano.function([], z, givens={self.x: m})
return result()
def get_pred(self, m):
z = self.logLayer.y_pred
result = theano.function([], z, givens={self.x: m})
return result()
def get_sda_features(self, m):
z = self.sigmoid_layers[-1].output
result = theano.function([], z, givens={self.x: m})
return result()