def test_forward(self):
x = np.array([[1, 2], [3, 4], [5, 6]])
b = np.array([[7, 8], [9, 10], [11, 12]])
dl_dxb = np.array([[13, 14], [15, 16], [17, 18]])
x_variable = Variable(x)
b_variable = Variable(b)
wx_variable = Add(x_variable, b_variable)
wx_variable.forward()
wx_variable.backward(dl_dxb)
dl_dx_actual = x_variable.get_gradient()
dl_db_actual = b_variable.get_gradient()
np.testing.assert_allclose(dl_dx_actual, dl_dxb)
np.testing.assert_allclose(dl_db_actual, dl_dxb)
def test_vector(self):
left = np.array([[1], [2], [3], [4]])
right = np.array([[5], [6], [7], [8]])
left_variable = Variable(left)
right_variable = Variable(right)
left_right_variable = Add(left_variable, right_variable)
dl_dleftright = np.array([[9], [10], [11], [12]])
left_right_variable.forward()
left_right_variable.backward(grad=dl_dleftright)
dl_dleft_actual = left_variable.get_gradient()
dl_dright_actual = right_variable.get_gradient()
np.testing.assert_allclose(dl_dleft_actual, dl_dleftright)
np.testing.assert_allclose(dl_dright_actual, dl_dleftright)
class mydnn:
def __init__(self, architecture: list, loss, weight_decay=0.0):
weight_decay = np.float64(weight_decay)
self._x_variable = Variable(None) # TODO: call it placeholder
self._y_variable = Variable(None)
self._architecture, self._prediction_variable, regularization_cost = \
mydnn._build_architecture_get_prediction_and_regularization_cost(
architecture,
weight_decay,
self._x_variable
)
loss_class = loss_name_to_class[loss]
self._is_classification = loss_class == CrossEntropy
self._loss_variable = Add(
loss_class(self._y_variable, self._prediction_variable),
regularization_cost)
def fit(self,
x_train,
y_train,
epochs,
batch_size,
learning_rate,
x_val=None,
y_val=None):
number_of_samples = x_train.shape[0]
assert x_train.shape[0] == number_of_samples
assert y_train.shape[0] == number_of_samples
history = list()
for epoch_index in range(epochs):
permutation = np.random.permutation(number_of_samples)
# Other dimensions are left
# TODO: should we avoid copying the data?
x_train = x_train[permutation]
y_train = y_train[permutation]
seconds = time()
train_loss_and_accuracy = self._do_epoch(x_train, y_train,
batch_size, learning_rate)
seconds = time() - seconds
history_entry = {
'epoch': 1 + epoch_index,
'seconds': seconds,
}
# TODO: calculate average, we do need to include regularization here
train_validation_loss_accuracy = [
string.format(number)
# Exploit the fact that length of zip is minimum
for string, number in zip(['loss: {:.2f}', 'acc: {:.2f}'],
train_loss_and_accuracy)
]
history_entry.update(
dict(
zip(['train loss', 'train accuracy'],
train_loss_and_accuracy)))
if x_val is not None and y_val is not None:
validation_loss_and_accuracy = self.evaluate(x_val, y_val)
train_validation_loss_accuracy.extend([
string.format(number) for string, number in
zip(['val_loss: {:.2f}', 'val_acc: {:.2f}'],
validation_loss_and_accuracy)
])
history_entry.update(
dict(
zip(['validation loss', 'validation accuracy'],
validation_loss_and_accuracy)))
print(' - '.join([
'Epoch {}/{}'.format(1 + epoch_index,
epochs), # TODO: is it one based?
'{:.2f} seconds'.format(seconds),
] # TODO: how many digits after second
+ train_validation_loss_accuracy))
history.append(history_entry)
return history
def predict(self, X, batch_size=None):
"""
:param X:
:param batch_size:
:return: Returns number_of_samplesxnumber_of_classes numpy array output of last network layer
"""
number_of_samples = X.shape[0]
if batch_size is None:
batch_size = number_of_samples
batch_index_to_y = list()
for batch_offset in range(0, number_of_samples, batch_size):
self._x_variable.set_value(X[batch_offset:batch_offset +
batch_size])
y_batch = self._prediction_variable.forward()
batch_index_to_y.append(y_batch)
y = np.concatenate(batch_index_to_y)
assert y.shape[0] == number_of_samples
return y
def evaluate(self, X, y, batch_size=None):
number_of_samples = X.shape[0]
if batch_size is None:
batch_size = number_of_samples
total_loss = 0.0
total_correctly_predicted = 0
for batch_offset in range(0, number_of_samples, batch_size):
actual_batch_size = min(batch_offset + batch_size,
number_of_samples)
self._x_variable.set_value(X[batch_offset:actual_batch_size])
self._y_variable.set_value(y[batch_offset:actual_batch_size])
loss = self._loss_variable.forward(
) # TODO: should I include regularization
total_loss += loss * actual_batch_size
if self._is_classification:
total_correctly_predicted += \
accuracy(y[batch_offset:actual_batch_size],
self._prediction_variable.get_value()) * actual_batch_size
return_list = [
total_loss / number_of_samples,
]
if self._is_classification:
computed_accuracy = 1.0 * total_correctly_predicted / number_of_samples
return_list.append(computed_accuracy)
return return_list
@staticmethod
def _build_architecture_get_prediction_and_regularization_cost(
architecture, weight_decay, current_input):
architecture_built = list()
regularization_cost = Variable(0.0)
weight_decay_variable = Variable(weight_decay) # TODO: constant
previous_layer_output = architecture[0]['input']
for layer_dictionary in architecture:
assert previous_layer_output == layer_dictionary["input"], \
'Inconsistent architecture: can not feed {} outputs to {} inputs'.format(
previous_layer_output,
layer_dictionary['input']
)
activation_function = activation_function_name_to_class[
layer_dictionary["nonlinear"]]
regularization_method = regularization_method_name_to_class[
layer_dictionary["regularization"]]
layer = FullyConnectedLayer(layer_dictionary["input"],
layer_dictionary["output"],
activation_function, current_input)
regularization_cost = Add(
regularization_cost,
Multiply(weight_decay_variable,
regularization_method(layer.get_weight())))
architecture_built.append(layer)
current_input = layer
previous_layer_output = layer_dictionary['output']
return architecture_built, current_input, regularization_cost
def _do_epoch(self, x_train, y_train, batch_size, learning_rate):
number_of_samples = x_train.shape[0]
if self._is_classification:
total_loss_accuracy = np.zeros((2, ))
else:
total_loss_accuracy = np.zeros((1, ))
for batch_offset in range(0, number_of_samples, batch_size):
# Other dimensions are left
actual_batch_size = min(number_of_samples - batch_offset,
batch_size)
x_batch = x_train[batch_offset:batch_offset + actual_batch_size]
y_batch = y_train[batch_offset:batch_offset + actual_batch_size]
total_loss_accuracy += np.array(
self._do_iteration(x_batch, y_batch,
learning_rate)) * actual_batch_size
return total_loss_accuracy / number_of_samples
def _do_iteration(self, x_batch, y_batch, learning_rate):
self._x_variable.set_value(x_batch)
self._y_variable.set_value(y_batch)
mini_batch_loss_accuracy = list()
mini_batch_loss = self._loss_variable.forward()
mini_batch_loss_accuracy.append(mini_batch_loss)
if self._is_classification:
mini_batch_accuracy = accuracy(
y_batch, self._prediction_variable.get_value())
mini_batch_loss_accuracy.append(mini_batch_accuracy)
self._loss_variable.backward()
for current_layer in self._architecture:
current_layer.update_grad(learning_rate)
self._loss_variable.reset()
return mini_batch_loss_accuracy