def linear_activation_backward(dA, cache, activation):
'''
Implementa backpropagation para la LINEAR->ACTIVATION de la capa actual
Arguments:
dA: Gradiente del costo respecto a la función de activación, de dimensiones igual a A
cache: tupla que contiene el cache de la parte lineal y el cache de la activación
activation: string que contiene el nombre de la activación usada, "Sigmoid" o "Relu"
Returns:
dA_prev -- Gradiente del costo respecto a la activación de la capa anterior, de dimensiones iguales a A_prev
dW -- Gradiente del costo respecto a los pesos de la capa actual, de dimensiones iguales a W
db -- Gradiente del costo respecto a los sesgos de la capa actual, de dimensiones iguales a b
'''
linear_c, activation_c = cache
if activation == "Relu":
dZ = relu_backward(dA, activation_c)
dA_prev, dW, db = linear_backward(dZ, linear_c)
elif activation == "Sigmoid":
dZ = sigmoid_backward(dA, activation_c)
dA_prev, dW, db = linear_backward(dZ, linear_c)
return dA_prev, dW, db
def linear_activation_backward(dA, cache, activation):
linear_cache, activation_cache = cache
if activation == "relu":
dZ = relu_backward(dA, activation_cache)
elif activation == "sigmoid":
dZ = sigmoid_backward(dA, activation_cache)
dA_prev, dW, db = linear_backward(dZ, linear_cache)
return dA_prev, dW, db
def linear_activation_backward(self, dA, cache, activation):
linear_cache, activation_cache = cache
if activation == 'relu':
dZ = relu_backward(dA, activation_cache)
elif activation == 'sigmoid':
dZ = sigmoid_backward(dA, activation_cache)
dA_prev, dW, db = self.linear_backward(dZ, linear_cache)
return dA_prev, dW, db
def linear_activation_backward(dA, cache, activation):
linear_cache, activation_cache = cache
if activation == 'relu':
dZ = np.dot(dA, activations.relu_backward(dA, activation_cache))
dA_prev, dW, db = linear_backward(dZ, linear_cache)
elif activation == 'sigmoid':
dZ = np.dot(dA, activations.sigmoid_backward(dA, activation_cache))
dA_prev, dW, db = linear_backward(dZ, linear_cache)
return dA_prev, dW, db
def linear_activation_backward(dA, cache, activation):
# Retriving cache
linear_cache, activation_cache = cache
# Backward activation step
if activation == 'relu':
dZ = relu_backward(dA, activation_cache)
elif activation == 'sigmoid':
dZ = sigmoid_backward(dA, activation_cache)
# Linear backward step
dA_prev, dW, db = linear_backward(dZ, linear_cache)
return dA_prev, dW, db
def linear_act_backward(dA, cache, act):
"""
Implements the linear and activation function derivatives of single node
"""
lin_cache, act_cache = cache
if act == "relu":
dZ = relu_backward(dA, act_cache)
dA, dW, db = linear_backward(dZ, lin_cache)
elif act == "sigmoid":
dZ = sigmoid_backward(dA, act_cache)
dA, dW, db = linear_backward(dZ, lin_cache)
return dA, dW, db
def linear_activation_backward_with_regularization(dA, cache, activation,
_lambda):
# Retriving cache
linear_cache, activation_cache = cache
# Activation backward step
if activation == 'relu':
dZ = relu_backward(dA, activation_cache)
elif activation == 'sigmoid':
dZ = sigmoid_backward(dA, activation_cache)
# Linear backward step
dA_prev, dW, db = linear_backward_with_regularization(
dZ, linear_cache, _lambda)
return dA_prev, dW, db
def linear_activation_backward_with_dropout(dA, cache, activation, keep_prob):
# Retriving cache
linear_cache, activation_cache, D = cache
# Linear backward and activation steps
if activation == 'relu':
# Implementing dropout
dA = dA * D # Apply mask D to shut down the same neurons as during the forward propagation
dA = np.divide(
dA, keep_prob
) # Scale the value of neurons that haven't been shut down
dZ = relu_backward(dA, activation_cache)
dA_prev, dW, db = linear_backward_with_dropout(dZ, linear_cache, D,
keep_prob)
elif activation == 'sigmoid':
dZ = sigmoid_backward(dA, activation_cache)
dA_prev, dW, db = linear_backward(dZ, linear_cache)
return dA_prev, dW, db
def linear_activation_backward(dA,
cache,
lambd,
activation,
sparse_ae_parameters=()):
"""
Implement the backward propagation for the LINEAR->ACTIVATION layer.
Arguments:
dA -- post-activation gradient for current layer l
cache -- tuple of values (linear_cache, activation_cache) we store for computing backward propagation efficiently
activation -- the activation to be used in this layer, stored as a text string: "sigmoid" or "relu"
Returns:
dA_prev -- Gradient of the cost with respect to the activation (of the previous layer l-1), same shape as A_prev
dW -- Gradient of the cost with respect to W (current layer l), same shape as W
db -- Gradient of the cost with respect to b (current layer l), same shape as b
"""
linear_cache, activation_cache = cache
if activation == "relu":
if sparse_ae_parameters:
sparse_beta, rho, rho_hat = sparse_ae_parameters
#print("dA1's shape:", dA.shape)
#print("rho_hat's shape:", rho_hat.shape)
dA = dA + sparse_beta * (-rho / rho_hat + (1 - rho) /
(1 - rho_hat))
dZ = relu_backward(dA, activation_cache)
dA_prev, dW, db = linear_backward(dZ, linear_cache, lambd)
elif activation == "sigmoid":
if sparse_ae_parameters:
sparse_beta, rho, rho_hat = sparse_ae_parameters
#print("dA1's shape:", dA.shape)
#print("rho_hat's shape:", rho_hat.shape)
dA = dA + sparse_beta * (-rho / rho_hat + (1 - rho) /
(1 - rho_hat))
dZ = sigmoid_backward(dA, activation_cache)
dA_prev, dW, db = linear_backward(dZ, linear_cache, lambd)
return dA_prev, dW, db
def network(params,
layers,
data,
labels,
reconstruction=False,
addnoise=False):
l = len(layers)
batch_size = layers[1]['batch_size']
param_grad = {}
cp = {}
output = {}
data_orig = copy.deepcopy(data)
if addnoise:
noise = np.random.binomial(1, 0.75, size=data.shape)
data = data * noise
output[1] = {
'data': data,
'height': layers[1]['height'],
'channel': layers[1]['channel'],
'batch_size': layers[1]['batch_size'],
'diff': 0
}
for i in range(2, l + 1):
if layers[i]['type'] == 'IP':
output[i] = fully_connected.inner_product_forward(
output[i - 1], layers[i], params[i - 1])
elif layers[i]['type'] == 'RELU':
output[i] = activations.relu_forward(output[i - 1], layers[i])
elif layers[i]['type'] == 'Sigmoid':
output[i] = activations.sigmoid_forward(output[i - 1], layers[i])
elif layers[i]['type'] == 'Tanh':
output[i] = activations.tanh_forward(output[i - 1], layers[i])
elif layers[i]['type'] == 'LOSS':
[obj, grad_w, grad_b, input_back_deriv,
success_rate] = loss_func(params[i - 1]['w'], params[i - 1]['b'],
output[i - 1]['data'], labels,
layers[i]['num'], 1)
param_grad[i - 1] = {
'w': grad_w / batch_size,
'b': grad_b / batch_size
}
elif layers[i]['type'] == 'autoEnc':
[obj, input_back_deriv,
success_rate] = autoEnc_loss(output[i - 1]['data'], data_orig)
param_grad[i - 1] = {'w': 0.0, 'b': 0.0}
if reconstruction:
return output[i - 1]['data']
for i in range(l - 1, 1, -1):
param_grad[i - 1] = {}
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
if layers[i]['type'] == 'IP':
output[i]['diff'] = input_back_deriv
param_grad[
i -
1], input_back_deriv = fully_connected.inner_product_backward(
output[i], output[i - 1], layers[i], params[i - 1])
elif layers[i]['type'] == 'RELU':
output[i]['diff'] = input_back_deriv
input_back_deriv = activations.relu_backward(
output[i], output[i - 1], layers[i])
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
elif layers[i]['type'] == 'Sigmoid':
output[i]['diff'] = input_back_deriv
input_back_deriv = activations.sigmoid_backward(
output[i], output[i - 1], layers[i])
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
elif layers[i]['type'] == 'Tanh':
output[i]['diff'] = input_back_deriv
input_back_deriv = activations.tanh_backward(
output[i], output[i - 1], layers[i])
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
return (obj / batch_size), success_rate, param_grad
def network(params, layers, data, labels):
l = len(layers)
batch_size = layers[1]['batch_size']
param_grad = {}
cp = {}
output = {}
output[1] = {
'data': data,
'height': layers[1]['height'],
'channel': layers[1]['channel'],
'batch_size': layers[1]['batch_size'],
'diff': 0
}
for i in range(2, l):
if layers[i]['type'] == 'IP':
output[i] = fully_connected.inner_product_forward(
output[i - 1], layers[i], params[i - 1])
elif layers[i]['type'] == 'RELU':
output[i] = activations.relu_forward(output[i - 1], layers[i])
elif layers[i]['type'] == 'Sigmoid':
output[i] = activations.sigmoid_forward(output[i - 1], layers[i])
elif layers[i]['type'] == 'Tanh':
output[i] = activations.tanh_forward(output[i - 1], layers[i])
elif layers[i]['type'] == 'batch_norm':
output[i] = activations.batch_normalization_forward(
output[i - 1], layers[i], params[i - 1])
i = l
[obj, grad_w, grad_b, input_back_deriv,
success_rate] = loss_func(params[i - 1]['w'], params[i - 1]['b'],
output[i - 1]['data'], labels, layers[i]['num'],
1)
param_grad[i - 1] = {'w': grad_w / batch_size, 'b': grad_b / batch_size}
for i in range(l - 1, 1, -1):
param_grad[i - 1] = {}
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
if layers[i]['type'] == 'IP':
output[i]['diff'] = input_back_deriv
param_grad[
i -
1], input_back_deriv = fully_connected.inner_product_backward(
output[i], output[i - 1], layers[i], params[i - 1])
elif layers[i]['type'] == 'RELU':
output[i]['diff'] = input_back_deriv
input_back_deriv = activations.relu_backward(
output[i], output[i - 1], layers[i])
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
elif layers[i]['type'] == 'Sigmoid':
output[i]['diff'] = input_back_deriv
input_back_deriv = activations.sigmoid_backward(
output[i], output[i - 1], layers[i])
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
elif layers[i]['type'] == 'Tanh':
output[i]['diff'] = input_back_deriv
input_back_deriv = activations.tanh_backward(
output[i], output[i - 1], layers[i])
param_grad[i - 1]['w'] = np.array([])
param_grad[i - 1]['b'] = np.array([])
elif layers[i]['type'] == 'batch_norm':
output[i]['diff'] = input_back_deriv
param_grad[
i -
1], input_back_deriv = activations.batch_normalization_backward(
output[i], output[i - 1], layers[i], params[i - 1])
param_grad[i - 1]['w'] = param_grad[i - 1]['w'] / batch_size
param_grad[i - 1]['b'] = param_grad[i - 1]['b'] / batch_size
return (obj / batch_size), success_rate, param_grad