def test_params(learning_rate,
n_epochs,
window_size,
datasets,
output_folder,
base_folder):
"""
Demonstrate stochastic gradient descent optimization of a log-linear
model
This is demonstrated on ICHI.
:type learning_rate: float
:param learning_rate: learning rate used (factor for the stochastic
gradient)
:type n_epochs: int
:param n_epochs: maximal number of epochs to run the optimizer
"""
# split the datasets
(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 examples given in datasets
n_train_samples = train_set_x.get_value(borrow=True).shape[0] - window_size + 1
n_valid_samples = valid_set_x.get_value(borrow=True).shape[0] - window_size + 1
n_test_samples = test_set_x.get_value(borrow=True).shape[0] - window_size + 1
######################
# BUILD ACTUAL MODEL #
######################
print '... building the model'
# allocate symbolic variables for the data
index = T.lscalar() # index to a [mini]batch
# generate symbolic variables for input (x and y represent a
# minibatch)
x = T.matrix('x') # data, presented as window with x, y, x for each sample
y = T.iscalar('y') # labels, presented as int label
# construct the logistic regression class
# Each ICHI input has size window_size*3
classifier = LogisticRegression(input=x, n_in=window_size*3, n_out=7)
classifier.print_log_reg_types()
# the cost we minimize during training is the negative log likelihood of
# the model in symbolic format
cost = classifier.negative_log_likelihood(y)
predict = classifier.predict()
# compiling a Theano function that computes the mistakes that are made by
# the model on a row
test_model = theano.function(
inputs=[index],
outputs=[classifier.errors(y), predict, y],
givens={
x: test_set_x[index: index + window_size],
y: test_set_y[index + window_size - 1]
}
)
validate_model = theano.function(
inputs=[index],
outputs=[classifier.errors(y), predict, y],
givens={
x: valid_set_x[index: index + window_size],
y: valid_set_y[index + window_size - 1]
}
)
# compute the gradient of cost with respect to theta = (W,b)
g_W = T.grad(cost=cost, wrt=classifier.W)
g_b = T.grad(cost=cost, wrt=classifier.b)
# start-snippet-3
# specify how to update the parameters of the model as a list of
# (variable, update expression) pairs.
updates = [(classifier.W, classifier.W - learning_rate * g_W),
(classifier.b, classifier.b - learning_rate * g_b)]
# compiling a Theano function `train_model` that returns the cost, but in
# the same time updates the parameter of the model based on the rules
# defined in `updates`
train_model = theano.function(
inputs=[index],
outputs=[cost, classifier.errors(y), predict, y],
updates=updates,
givens={
x: train_set_x[index: index + window_size],
y: train_set_y[index + window_size - 1]
}
)
# end-snippet-3
###############
# TRAIN MODEL #
###############
print '... training the model'
# early-stopping parameters
patience = n_train_samples*2 # look as this many examples regardless
patience_increase = 25 # wait this much longer when a new best is
# found
improvement_threshold = 0.995 # a relative improvement of this much is
# considered significant
validation_frequency = patience / 4
best_validation_loss = numpy.inf
start_time = time.clock()
done_looping = False
epoch = 0
iter = 0
train_cost_array = []
train_error_array = []
valid_error_array = []
test_error_array = []
cur_train_cost =[]
cur_train_error = []
train_confusion_matrix = numpy.zeros((7, 7))
valid_confusion_matrix = numpy.zeros((7, 7))
print(n_train_samples, 'train_samples')
while (epoch < n_epochs) and (not done_looping):
train_confusion_matrix = zero_in_array(train_confusion_matrix)
for index in xrange(n_train_samples):
sample_cost, sample_error, cur_pred, cur_actual = train_model(index)
# iteration number
iter = epoch * n_train_samples + index
cur_train_cost.append(sample_cost)
cur_train_error.append(sample_error)
train_confusion_matrix[cur_actual][cur_pred] += 1
if (iter + 1) % validation_frequency == 0:
valid_confusion_matrix = zero_in_array(valid_confusion_matrix)
# compute zero-one loss on validation set
validation_losses = []
for i in xrange(n_valid_samples):
validation_loss, cur_pred, cur_actual = validate_model(i)
validation_losses.append(validation_loss)
valid_confusion_matrix[cur_actual][cur_pred] += 1
this_validation_loss = float(numpy.mean(validation_losses))*100
valid_error_array.append([])
valid_error_array[-1].append(float(iter)/n_train_samples)
valid_error_array[-1].append(this_validation_loss)
print(
'epoch %i, iter %i/%i, validation error %f %%' %
(
epoch,
index + 1,
n_train_samples,
this_validation_loss
)
)
# if we got the best validation score until now
if this_validation_loss < best_validation_loss:
#improve patience if loss improvement is good enough
if this_validation_loss < best_validation_loss * \
improvement_threshold:
patience = max(patience, iter * patience_increase)
best_validation_loss = this_validation_loss
# test it on the test set
test_result = [test_model(i)
for i in xrange(n_test_samples)]
test_result = numpy.asarray(test_result)
test_losses = test_result[:,0]
test_score = float(numpy.mean(test_losses))*100
test_error_array.append([])
test_error_array[-1].append(float(iter)/n_train_samples)
test_error_array[-1].append(test_score)
print(
(
' epoch %i, iter %i/%i, test error of'
' best model %f %%'
) %
(
epoch,
index + 1,
n_train_samples,
test_score
)
)
if patience*4 <= iter:
done_looping = True
print('Done looping')
break
train_cost_array.append([])
train_cost_array[-1].append(float(iter)/n_train_samples)
train_cost_array[-1].append(float(numpy.mean(cur_train_cost)))
cur_train_cost =[]
train_error_array.append([])
train_error_array[-1].append(float(iter)/n_train_samples)
train_error_array[-1].append(float(numpy.mean(cur_train_error)*100))
cur_train_error =[]
epoch = epoch + 1
gc.collect()
test_confusion_matrix = zero_in_array(numpy.zeros((7, 7)))
test_losses = []
for i in xrange(n_test_samples):
test_loss, cur_pred, cur_actual = test_model(i)
test_losses.append(test_loss)
test_confusion_matrix[cur_actual][cur_pred] += 1
test_score = numpy.mean(test_losses)*100
test_error_array.append([])
test_error_array[-1].append(float(iter)/n_train_samples)
test_error_array[-1].append(test_score)
visualize_logistic(train_cost=train_cost_array,
train_error=train_error_array,
valid_error=valid_error_array,
test_error=test_error_array,
window_size=window_size,
learning_rate=learning_rate,
output_folder=output_folder,
base_folder=base_folder)
end_time = time.clock()
print(
(
'Optimization complete with best validation score of %f %%,'
'with test performance %f %%'
)
% (best_validation_loss, test_score)
)
print 'The code run for %d epochs, with %f epochs/sec' % (
epoch, 1. * epoch / (end_time - start_time))
print >> sys.stderr, ('The code for file ' +
os.path.split(__file__)[1] +
' ran for %.1fs' % ((end_time - start_time)))
print(train_confusion_matrix, 'train_confusion_matrix')
print(valid_confusion_matrix, 'valid_confusion_matrix')
print(test_confusion_matrix, 'test_confusion_matrix')
def test_params(datasets, output_folder, base_folder,
window_size, n_epochs=50):
"""Demonstrate conjugate gradient optimization of a log-linear model
This is demonstrated on ICHI.
:type n_epochs: int
:param n_epochs: number of epochs to run the optimizer
"""
#############
# LOAD DATA #
#############
# split the datasets
(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 examples given in datasets
n_train_samples = train_set_x.get_value(borrow=True).shape[0] - window_size + 1
n_valid_samples = valid_set_x.get_value(borrow=True).shape[0] - window_size + 1
n_test_samples = test_set_x.get_value(borrow=True).shape[0] - window_size + 1
n_in = window_size*3 # number of input units
n_out = 7 # number of output units
######################
# BUILD ACTUAL MODEL #
######################
print '... building the model'
# allocate symbolic variables for the data
index = T.lscalar()
# generate symbolic variables for input
x = T.matrix('x') # data, presented as window with x, y, x for each sample
y = T.iscalar('y') # labels, presented as int label
# construct the logistic regression class
classifier = LogisticRegression(input=x, n_in=n_in, n_out=n_out)
# the cost we minimize during training is the negative log likelihood of
# the model in symbolic format
cost = classifier.negative_log_likelihood(y)
# compile a theano function that computes the mistakes that are made by
# the model on a minibatch
test_model = theano.function(
[index],
classifier.errors(y),
givens={
x: test_set_x[index:index + window_size],
y: test_set_y[index + window_size - 1]
},
name="test"
)
validate_model = theano.function(
[index],
classifier.errors(y),
givens={
x: valid_set_x[index: index + window_size],
y: valid_set_y[index + window_size - 1]
},
name="validate"
)
# compile a theano function that returns the cost
conj_cost = theano.function(
inputs=[index],
outputs=[cost, classifier.errors(y), classifier.predict(), y],
givens={
x: train_set_x[index: index + window_size],
y: train_set_y[index + window_size - 1]
},
name="conj_cost"
)
# compile a theano function that returns the gradient with respect to theta
conj_grad = theano.function(
[index],
T.grad(cost, classifier.theta),
givens={
x: train_set_x[index: index + window_size],
y: train_set_y[index + window_size - 1]
},
name="conj_grad"
)
classifier.train_cost_array = []
classifier.train_error_array = []
train_confusion_matrix = numpy.zeros((7, 7))
classifier.epoch = 0
# creates a function that computes the average cost on the training set
def train_fn(theta_value):
classifier.theta.set_value(theta_value, borrow=True)
cur_train_cost = []
cur_train_error =[]
for i in xrange(n_train_samples):
sample_cost, sample_error, cur_pred, cur_actual = conj_cost(i)
cur_train_cost.append(sample_cost)
cur_train_error.append(sample_error)
train_confusion_matrix[cur_actual][cur_pred] += 1
this_train_loss = float(numpy.mean(cur_train_cost))
classifier.train_cost_array.append([])
classifier.train_cost_array[-1].append(classifier.epoch)
classifier.train_cost_array[-1].append(this_train_loss)
classifier.train_error_array.append([])
classifier.train_error_array[-1].append(classifier.epoch)
classifier.train_error_array[-1].append(float(numpy.mean(cur_train_error)*100))
classifier.epoch += 1
return this_train_loss
# creates a function that computes the average gradient of cost with
# respect to theta
def train_fn_grad(theta_value):
classifier.theta.set_value(theta_value, borrow=True)
grad = conj_grad(0)
for i in xrange(1, n_train_samples):
grad += conj_grad(i)
return grad / n_train_samples
classifier.validation_scores = [numpy.inf, 0]
classifier.valid_error_array = []
classifier.test_error_array = []
# creates the validation function
def callback(theta_value):
classifier.theta.set_value(theta_value, borrow=True)
#compute the validation loss
validation_losses = [validate_model(i)
for i in xrange(n_valid_samples)]
this_validation_loss = float(numpy.mean(validation_losses) * 100.,)
print('validation error %f %%' % (this_validation_loss))
classifier.valid_error_array.append([])
classifier.valid_error_array[-1].append(classifier.epoch)
classifier.valid_error_array[-1].append(this_validation_loss)
# check if it is better then best validation score got until now
if this_validation_loss < classifier.validation_scores[0]:
# if so, replace the old one, and compute the score on the
# testing dataset
classifier.validation_scores[0] = this_validation_loss
test_losses = [test_model(i)
for i in xrange(n_test_samples)]
classifier.validation_scores[1] = float(numpy.mean(test_losses))
classifier.test_error_array.append([])
classifier.test_error_array[-1].append(classifier.epoch)
classifier.test_error_array[-1].append(classifier.validation_scores[1])
###############
# TRAIN MODEL #
###############
# using scipy conjugate gradient optimizer
import scipy.optimize
print ("Optimizing using scipy.optimize.fmin_cg...")
start_time = timeit.default_timer()
best_theta = scipy.optimize.fmin_cg(
f=train_fn,
x0=numpy.zeros((n_in + 1) * n_out, dtype=x.dtype),
fprime=train_fn_grad,
callback=callback,
disp=0,
maxiter=n_epochs
)
visualize_logistic(train_cost=classifier.train_cost_array,
train_error=classifier.train_error_array,
valid_error=classifier.valid_error_array,
test_error=classifier.test_error_array,
window_size=window_size,
learning_rate=0,
output_folder=output_folder,
base_folder=base_folder)
end_time = timeit.default_timer()
print(
(
'Optimization complete with best validation score of %f %%, with '
'test performance %f %%'
)
% (classifier.validation_scores[0] * 100., classifier.validation_scores[1] * 100.)
)
print >> sys.stderr, ('The code for file ' +
os.path.split(__file__)[1] +
' ran for %.1fs' % ((end_time - start_time)))
