def loss(self, X, y=None):
"""
Evaluate loss and gradient for the three-layer convolutional network.
"""
W1 = self.params['W1']
W2, b2 = self.params['W2'], self.params['b2']
W3, b3 = self.params['W3'], self.params['b3']
# pass pool_param to the forward pass for the max-pooling layer
pool_param = {'pool_height': 2, 'pool_width': 2, 'stride': 2}
scores = None
conv, cache1 = layers.conv_forward(X,W1)
relu1, cache2 = layers.relu_forward(conv)
maxp, cache3 = layers.max_pool_forward(relu1,pool_param)
fc1, cache4 = layers.fc_forward(maxp,W2,b2)
relu2, cache5 = layers.relu_forward(fc1)
scores, cache6 = layers.fc_forward(relu2,W3,b3)
if y is None:
return scores
loss, grads = 0, {}
loss, dscores = layers.softmax_loss(scores,y)
dx3, dW3, db3 = layers.fc_backward(dscores,cache6)
dRelu2 = layers.relu_backward(dx3,cache5)
dx2, dW2, db2 = layers.fc_backward(dRelu2,cache4)
dmaxp = layers.max_pool_backward(dx2.reshape(maxp.shape),cache3)
dRelu1 = layers.relu_backward(dmaxp,cache2)
dx,dW1 = layers.conv_backward(dRelu1,cache1)
grads = {'W1':dW1,'W2':dW2,'b2':db2,'W3':dW3,'b3':db3}
return loss, grads
def loss(self, X, y=None, reg=1e-5):
print 'start computing loss and grad.............'
W1, b1 = self.params['W1'], self.params['b1']
W2, b2 = self.params['W2'], self.params['b2']
W3, b3 = self.params['W3'], self.params['b3']
# pass conv_param to the forward pass for the convolutional layer
filter_size = W1.shape[2]
conv_param = {'stride': 1, 'pad': (filter_size - 1) / 2}
# pass pool_param to the forward pass for the max-pooling layer
pool_param = {'pool_height': 2, 'pool_width': 2, 'stride': 2}
# compute the forward pass
print 'compute the forward pass......'
print 'compute the w1 conv_relu_pool_forward forward pass......'
a1, cache1 = layers.conv_relu_pool_forward(X, W1, b1, conv_param,
pool_param)
print 'compute the w2 affine_relu_forward forward pass......'
a2, cache2 = layers.affine_relu_forward(a1, W2, b2)
print 'compute the w3 affine_forward forward pass......'
scores, cache3 = layers.affine_forward(a2, W3, b3)
if y is None:
return scores
# compute the backward pass
print 'compute the backward pass......'
print 'compute the softmax_loss backward pass......'
data_loss, dscores = layers.softmax_loss(scores, y)
print 'compute the dw3 affine_backward backward pass......'
da2, dW3, db3 = layers.affine_backward(dscores, cache3)
print 'compute the dw2 affine_relu_backward backward pass......'
da1, dW2, db2 = layers.affine_relu_backward(da2, cache2)
print 'compute the dw1 conv_relu_pool_backward backward pass......'
dX, dW1, db1 = layers.conv_relu_pool_backward(da1, cache1)
# Add regularization
dW1 += self.reg * W1
dW2 += self.reg * W2
dW3 += self.reg * W3
reg_loss = 0.5 * self.reg * sum(np.sum(W * W) for W in [W1, W2, W3])
loss = data_loss + reg_loss
grads = {
'W1': dW1,
'b1': db1,
'W2': dW2,
'b2': db2,
'W3': dW3,
'b3': db3
}
print ' computing loss and grad end !!!!!!!!!!!!!!!!!'
print 'loss is :', loss
return loss, grads
def test_softmax_loss(self):
# Softmax loss
np.random.seed(498)
num_classes, num_inputs = 10, 50
x = 0.001 * np.random.randn(num_inputs, num_classes)
y = np.random.randint(num_classes, size=num_inputs)
dx_num = eval_numerical_gradient(
lambda x: layers.softmax_loss(x, y)[0], x, verbose=False)
loss, dx = layers.softmax_loss(x, y)
# Test softmax_loss function. Loss should be 2.3 and dx error might be 1e-8
# As long as your error is small enough, your implementation should pass this test.
print('\nTesting softmax_loss:')
print('loss: ', loss)
print('dx error: ', rel_error(dx_num, dx))
np.testing.assert_allclose(loss, 2.3, atol=0.05)
np.testing.assert_allclose(dx, dx_num, atol=1e-7)
def loss(self, X, y=None):
"""
Compute loss and gradient for a minibatch of data.
Inputs:
- X: Array of input data of shape (N, d_1, ..., d_k)
- y: Array of labels, of shape (N,). y[i] gives the label for X[i].
Returns:
If y is None, then run a test-time forward pass of the model and return:
- scores: Array of shape (N, C) giving classification scores, where
scores[i, c] is the classification score for X[i] and class c.
If y is not None, then run a training-time forward and backward pass and
return a tuple of:
- loss: Scalar value giving the loss
- grads: Dictionary with the same keys as self.params, mapping parameter
names to gradients of the loss with respect to those parameters.
"""
out1, cache1 = layer_utilities.affine_relu_forward(
X, self.params['W1'], self.params['b1'])
out2, cache2 = layers.affine_forward(
out1, self.params['W2'],
self.params['b2']) # last layer no need to use relu
scores = out2
if y is None:
return scores
# backward
loss, grads = 0, {}
loss, d_scores = layers.softmax_loss(scores, y)
loss = loss + 0.5 * self.reg * (
np.sum(self.params['W1'] * self.params['W1']) +
np.sum(self.params['W2'] * self.params['W2']))
dout1, dW2, db2 = layers.affine_backward(d_scores, cache2)
dx, dW1, db1 = layer_utilities.affine_relu_backward(dout1, cache1)
grads['W2'] = dW2 + self.reg * self.params['W2']
grads['b2'] = db2
grads['W1'] = dW1 + self.reg * self.params['W1']
grads['b1'] = db1
return loss, grads
def training_step(model, X_batch, y_batch, reg):
"""
Compute the loss and gradients for a single training iteration of a model
given a minibatch of data. The loss should be a sum of a cross-entropy loss
between the model predictions and the ground-truth image labels, and
an L2 regularization term on all weight matrices in the fully-connected
layers of the model. You should not regularize the bias vectors.
Inputs:
- model: A Classifier instance
- X_batch: A numpy array of shape (N, D) giving a minibatch of images
- y_batch: A numpy array of shape (N,) where 0 <= y_batch[i] < C is the
ground-truth label for the image X_batch[i]
- reg: A float giving the strength of L2 regularization to use.
Returns a tuple of:
- loss: A float giving the loss (data loss + regularization loss) for the
model on this minibatch of data
- grads: A dictionary giving gradients of the loss with respect to the
parameters of the model. In particular grads[k] should be the gradient
of the loss with respect to model.parameters()[k].
"""
loss, grads = None, None
###########################################################################
# TODO: Compute the loss and gradient for one training iteration. #
###########################################################################
scores, cache = model.forward(X_batch)
data_loss, grad_scores = softmax_loss(scores, y_batch)
grads = model.backward(grad_scores, cache)
#regularization
W1_loss, grad_W1 = l2_regularization(model.W1, reg)
W2_loss, grad_W2 = l2_regularization(model.W2, reg)
loss = data_loss + W1_loss + W2_loss
grads['W1'] += grad_W1
grads['W2'] += grad_W2
#breakpoint()
###########################################################################
# END OF YOUR CODE #
###########################################################################
return loss, grads
def loss(self,X,y=None):
"""
Compute loss and gradient for a minibatch of data.
Inputs:
- X: Array of input data of shape (N, d_1, ..., d_k)
- y: Array of labels, of shape (N,). y[i] gives the label for X[i].
Returns:
If y is None, then run a test-time forward pass of the model and return:
- scores: Array of shape (N, C) giving classification scores, where
scores[i, c] is the classification score for X[i] and class c.
If y is not None, then run a training-time forward and backward pass and
return a tuple of:
- loss: Scalar value giving the loss
- grads: Dictionary with the same keys as self.params, mapping parameter
names to gradients of the loss with respect to those parameters.
"""
scores = None
W1,b1 = self.params['W1'],self.params['b1']
W2,b2 = self.params['W2'],self.params['b2']
ar1_out,ar1_cache = affine_relu_forward(X,W1,b1)
ar2_out,ar2_cache = affine_forward(ar1_out,W2,b2)
scores = ar2_out
if y is None:
return scores
loss,grads = 0,{}
loss,dout = softmax_loss(scores,y)
loss = loss+0.5*self.reg*np.sum(W1*W1)+0.5*self.reg*np.sum(W2*W2)
dx2,dw2,db2 = affine_backward(dout,ar2_cache)
grads['W2'] = dw2 +self.reg*W2
grads['b2'] = db2
dx1,dw1,db1 = affine_relu_backward(dx2,ar1_cache)
grads['W1'] = dw1+self.reg*W1
grads['b1'] = db1
return loss,grads
def loss(self, X, y=None):
"""
Compute loss and gradient for a minibatch of data.
Inputs:
- X: Array of input data of shape (N, d_in)
- y: Array of labels, of shape (N,). y[i] gives the label for X[i].
Returns:
If y is None, then run a test-time forward pass of the model and return:
- scores: Array of shape (N, C) giving classification scores, where
scores[i, c] is the classification score for X[i] and class c.
If y is not None, then run a training-time forward and backward pass and
return a tuple of:
- loss: Scalar value giving the loss
- grads: Dictionary with the same keys as self.params, mapping parameter
names to gradients of the loss with respect to those parameters.
"""
W1, b1 = self.params['W1'], self.params['b1']
W3, b3 = self.params['W3'], self.params['b3']
N, d_in = X.shape
scores = None
f, cache1 = layers.fc_forward(X, W1, b1) #fc
h, cache2 = layers.relu_forward(f) #relu
scores, cache3 = layers.fc_forward(h, W3, b3) #fc
# If y is None then we are in test mode so just return scores
if y is None:
return scores
loss, grads = 0, {}
loss, dscores = layers.softmax_loss(scores, y)
dx2, dW3, db3 = layers.fc_backward(dscores, cache3)
dx1 = layers.relu_backward(dx2, cache2)
dx, dW1, db1 = layers.fc_backward(dx1, cache1)
grads = {'W1': dW1, 'b1': db1, 'W3': dW3, 'b3': db3}
return loss, grads
def loss(self,X,L,Y=None):
out_gcnrelu1,cache_gcnrelu1 = gcn_relu_fw(L,X,self.params['Theta1'])
out_sum2, cache_sum2 = sum_out_fw(self.params['W2'],out_gcnrelu1)
scores = out_sum2
if Y is None:
return scores
loss,dout = softmax_loss(scores,Y)
loss += self.reg * .5 * ( LA.norm(self.params['Theta1'])**2 +
LA.norm(self.params['W2'])**2)
dx2,dw2 = sum_out_bw(dout,cache_sum2)
dw2 += self.reg * self.params['W2']
dx1,dtheta1 = gcn_relu_bw(dx2,cache_gcnrelu1)
dtheta1 += self.reg * self.params['Theta1']
grads = {'Theta1':dtheta1,'W2':dw2}
return loss,grads
def test_onelayer_gcn():
#Test loss func
N, n, l, K = 10, 5, 3, 2
X = np.random.rand(N, n)
y = np.random.randint(l, size=N)
L = [sp.rand(n, n, density=1, format='csr') for i in range(N)]
model = OneLayer(N, K, l, weight_scale=1e-3)
loss, grads = model.loss(X, L, y)
Theta1 = model.params['Theta1']
W2 = model.params['W2']
out1 = np.array([expmulit(L[i], X[i], Theta1) for i in range(N)])
out1 = np.maximum(out1, 0)
out2 = np.dot(out1, np.ones(n)).reshape(-1, 1).dot(W2.reshape(1, -1))
correct_loss, _ = softmax_loss(out2, y)
print('check loss diff')
assert_diff(loss, correct_loss)
#Test gradient
_, grads = model.loss(X, L, y)
for name in ['Theta1', 'W2']:
grad = grads[name]
f = lambda _: model.loss(X, L, y)[0]
grad_num = eval_numerical_gradient(f,
model.params[name],
verbose=False)
print('Check grad', name)
assert_diff(grad, grad_num, 1e-8)
def loss(self, X, y=None):
"""
Compute loss and gradient for the fully-connected net.
Input / output: Same as TwoLayerNet above.
"""
X = X.astype(self.dtype)
mode = 'test' if y is None else 'train'
# Set train/test mode for batchnorm params and dropout param since they
# behave differently during training and testing.
if self.dropout_param is not None:
self.dropout_param['mode'] = mode
if self.use_batchnorm:
for bn_param in self.bn_params:
bn_param['mode'] = mode
scores = None
############################################################################
# TODO: Implement the forward pass for the fully-connected net, computing #
# the class scores for X and storing them in the scores variable. #
# #
# When using dropout, you'll need to pass self.dropout_param to each #
# dropout forward pass. #
# #
# When using batch normalization, you'll need to pass self.bn_params[0] to #
# the forward pass for the first batch normalization layer, pass #
# self.bn_params[1] to the forward pass for the second batch normalization #
# layer, etc. #
############################################################################
layer_input = X
ar_cache = {}
dp_cache = {}
for lay in xrange(self.num_layers - 1):
if self.use_batchnorm:
layer_input, ar_cache[lay] = affine_bn_relu_forward(layer_input,
self.params['W%d' % (lay + 1)],
self.params['b%d' % (lay + 1)],
self.params['gamma%d' % (lay + 1)],
self.params['beta%d' % (lay + 1)],
self.bn_params[lay])
else:
layer_input, ar_cache[lay] = affine_relu_forward(layer_input, self.params['W%d' % (lay + 1)],
self.params['b%d' % (lay + 1)])
if self.use_dropout:
layer_input, dp_cache[lay] = dropout_forward(layer_input, self.dropout_param)
ar_out, ar_cache[self.num_layers] = affine_forward(layer_input, self.params['W%d' % (self.num_layers)],
self.params['b%d' % (self.num_layers)])
scores = ar_out
# pass
############################################################################
# END OF YOUR CODE #
############################################################################
# If test mode return early
if mode == 'test':
return scores
loss, grads = 0.0, {}
############################################################################
# TODO: Implement the backward pass for the fully-connected net. Store the #
# loss in the loss variable and gradients in the grads dictionary. Compute #
# data loss using softmax, and make sure that grads[k] holds the gradients #
# for self.params[k]. Don't forget to add L2 regularization! #
# #
# When using batch normalization, you don't need to regularize the scale #
# and shift parameters. #
# #
# NOTE: To ensure that your implementation matches ours and you pass the #
# automated tests, make sure that your L2 regularization includes a factor #
# of 0.5 to simplify the expression for the gradient. #
############################################################################
loss, dscores = softmax_loss(scores, y)
dhout = dscores
loss = loss + 0.5 * self.reg * np.sum(
self.params['W%d' % (self.num_layers)] * self.params['W%d' % (self.num_layers)])
dx, dw, db = affine_backward(dhout, ar_cache[self.num_layers])
grads['W%d' % (self.num_layers)] = dw + self.reg * self.params['W%d' % (self.num_layers)]
grads['b%d' % (self.num_layers)] = db
dhout = dx
for idx in xrange(self.num_layers - 1):
lay = self.num_layers - 1 - idx - 1
loss = loss + 0.5 * self.reg * np.sum(self.params['W%d' % (lay + 1)] * self.params['W%d' % (lay + 1)])
if self.use_dropout:
dhout = dropout_backward(dhout, dp_cache[lay])
if self.use_batchnorm:
dx, dw, db, dgamma, dbeta = affine_bn_relu_backward(dhout, ar_cache[lay])
else:
dx, dw, db = affine_relu_backward(dhout, ar_cache[lay])
grads['W%d' % (lay + 1)] = dw + self.reg * self.params['W%d' % (lay + 1)]
grads['b%d' % (lay + 1)] = db
if self.use_batchnorm:
grads['gamma%d' % (lay + 1)] = dgamma
grads['beta%d' % (lay + 1)] = dbeta
dhout = dx
# pass
############################################################################
# END OF YOUR CODE #
############################################################################
return loss, grads
def loss(self,X,y=None):
X = X.astype(self.dtype)
mode = 'test' if y is None else 'train'
if self.use_dropout :
self.dropout_param['mode'] = mode
if self.use_batchnorm:
for bn_param in self.bn_params:
bn_param['mode'] = mode
scores = None
inputi = X
batch_size = X.shape[0]
X = np.reshape(X,[batch_size,-1])
fc_cache_list = []
relu_cache_list = []
bn_cache_list = []
dropout_cache_list = []
for i in range(self.num_layers-1):
fc_act,fc_cache= affine_forward(X,self.params['W'+str(i+1)],self.params['b'+str(i+1)])
fc_cache_list.append(fc_cache)
if self.use_batchnorm:
bn_act,bn_cache = batchnorm_forward(fc_act,self.params['gamma'+str(i+1)],self.params['beta'+str(i+1)],self.bn_params[i])
bn_cache_list.append(bn_cache)
relu_act,relu_cache = relu_forward(bn_act)
relu_cache_list.append(relu_cache)
else:
relu_act,relu_cache = relu_forward(fc_act)
relu_cache_list.append(relu_cache)
if self.use_dropout:
relu_act,dropout_cache = dropout_forward(relu_act,self.dropout_param)
dropout_cache_list.append(dropout_cache)
X = relu_act.copy()
########最后一层
scores,final_cache = affine_forward(X,self.params['W'+str(self.num_layers)],self.params['b'+str(self.num_layers)])
#
# for layer in range(self.num_layers):
# Wi,bi = self.params['W%d'%(layer+1)],self.params['b%d'%(layer+1)]
# outi,fc_cachei = affine_forward(inputi,Wi,bi)
# fc_cache_list.append(fc_cachei)
#
# if self.use_batchnorm and layer!=self.num_layers-1:
# gammai,betai = self.params['gamma%d'%(layer+1)],self.params['beta%d'%(layer+1)]
#
# outi,bn_cachei = batchnorm_forward(outi,gammai,betai,self.bn_params[layer])
# bn_cache_list.append(bn_cachei)
# outi,relu_cachei = relu_forward(outi)
# relu_cache_list.append(relu_cachei)
#
# if self.use_dropout:
# outi,dropout_cachei = dropout_forward(outi,self.dropout_param)
# dropout_cache_list.append(dropout_cachei)
#
# inputi = outi
#
# scores = outi
if mode == 'test':
return scores
loss,grads = 0.0,{}
loss,dsoft = softmax_loss(scores,y)
loss += 0.5*self.reg*(np.sum(np.square(self.params['W'+str(self.num_layers)])))
#########最后一层的反向传播
dx_last,dw_last,db_last = affine_backward(dsoft,final_cache)
grads['W'+str(self.num_layers)] = dw_last+self.reg*self.params['W'+str(self.num_layers)]
grads['b'+str(self.num_layers)] = db_last
for i in range(self.num_layers-1,0,-1):
if self.use_dropout:
dx_last = dropout_backward(dx_last,dropout_cache_list[i-1])
drelu = relu_backward(dx_last,relu_cache_list[i-1])
if self.use_batchnorm:
dbatchnorm,dgamma,dbeta = batchnorm_backward(drelu,bn_cache_list[i-1])
dx_last,dw_last,db_last = affine_backward(dbatchnorm,fc_cache_list[i-1])
grads['beta'+str(i)] = dbeta
grads['gamma'+str(i)] = dgamma
else:
dx_last,dw_last,db_last = affine_backward(drelu,fc_cache_list[i-1])
grads['W'+str(i)] = dw_last+self.reg*self.params['W'+str(i)]
grads['b'+str(i)] = db_last
loss += 0.5*self.reg*(np.sum(np.square(self.params['W'+str(i)])))
return loss,grads
lambda w: affine_relu_forward(x, w, b)[0], w, dout)
db_num = eval_numerical_gradient_array(
lambda b: affine_relu_forward(x, w, b)[0], b, dout)
print('Testing affine_relu_forward:')
print('dx error: ', rel_error(dx_num, dx))
print('dw error: ', rel_error(dw_num, dw))
print('db error: ', rel_error(db_num, db))
#######################################################################################
#######################################################################################
# Test the softmax _loss function
######################################################################################
from layers import softmax_loss
np.random.seed(231)
num_classes, num_inputs = 10, 50
x = 0.001 * np.random.randn(num_inputs, num_classes)
y = np.random.randint(num_classes, size=num_inputs)
dx_num = eval_numerical_gradient(lambda x: softmax_loss(x, y)[0],
x,
verbose=False)
loss, dx = softmax_loss(x, y)
# Test softmax_loss function. Loss should be 2.3 and dx error should be 1e-8
print('\nTesting softmax_loss:')
print('loss: ', loss)
print('dx error: ', rel_error(dx_num, dx))
#######################################################################################
# Multilayer Perceptron classifier
###########################
# Initialise parameters
cnn1 = cnn2d(input_shape=(Xh, Xw, Xd),
filter_shape=(f1_field, f1_field),
num_filters=h1_units)
def flatten(x, n_examples):
return np.reshape(x, (n_examples, -1))
relu1 = relu()
fc2 = fc2d(cnn1.yw * cnn1.yh * Xd * h1_units, K)
data_loss_fn = softmax_loss(y_train)
for i in range(n_epochs):
# Forward pass
conv1 = cnn1.forward(X_train)
print("conv1:", conv1.shape)
flatten1 = flatten(conv1, num_examples)
h1 = relu1.forward(flatten1)
scores = fc2.forward(h1)
data_loss = data_loss_fn.forward(scores)
reg_loss = 0.5 * reg * (np.sum(cnn1.W * cnn1.W) + np.sum(fc2.W * fc2.W))
loss = data_loss + reg_loss
if i % 1 == 0:
print("Epoch: %d, Loss: %f" % (i, loss))
# Backprop
# Number of dimensions of input
D = 2
# Number of classes
K = 3
X, y = generate_spiral_data(N, D, K, plot=False)
###########################
# Multilayer Perceptron classifier
###########################
# Initialise parameters
fc1 = fc2d(D, h1_units)
relu1 = relu()
fc2 = fc2d(h1_units, K)
data_loss_fn = softmax_loss(y)
for i in range(n_epochs):
# Forward pass
h1_prod = fc1.forward(X)
h1 = relu1.forward(h1_prod)
scores = fc2.forward(h1)
data_loss = data_loss_fn.forward(scores)
reg_loss = 0.5*reg*(np.sum(fc1.W * fc1.W) + np.sum(fc2.W*fc2.W))
loss = data_loss + reg_loss
if i % 1000 == 0:
print("Epoch: %d, Loss: %f" % (i, loss))
# Backprop
# dLi/dfk = pk - 1(yi=k)
dscores = data_loss_fn.backward()
