def main():
print('=========================================')
print(' Numpy DNN ')
print(' 26/Nov/2017 ')
print(' By Thang Vu ([email protected]) ')
print('=========================================')
# load datasets
path = 'data/mnist.pkl.gz'
train_set, val_set, test_set = load_mnist_datasets(path)
batch_size = 128
X_train, y_train = train_set
X_val, y_val = val_set
X_test, y_test = test_set
# bookeeping for best model based on validation set
best_val_acc = -1
best_model = None
# create model and optimization method
dnn = DNN()
sgd = SGD(lr=0.1, lr_decay=0.1, weight_decay=1e-3, momentum=0.9)
# Train
batch_size = 128
for epoch in range(20):
dnn.train_mode() # set model to train mode (because of dropout)
num_train = X_train.shape[0]
num_batch = num_train//batch_size
for batch in range(num_batch):
# get batch data
batch_mask = np.random.choice(num_train, batch_size)
X_batch = X_train[batch_mask]
y_batch = y_train[batch_mask]
# forward
output = dnn.forward(X_batch)
loss, dout = softmax_cross_entropy_loss(output, y_batch)
if batch%100 == 0:
print("Epoch %2d Iter %3d Loss %.5f" %(epoch, batch, loss))
# backward and update
grads = dnn.backward(dout)
sgd.step(dnn.params, grads)
sgd.decay_learning_rate() # decay learning rate after one epoch
dnn.eval_mode() # set model to eval mode
train_acc = check_acc(dnn, X_train, y_train)
val_acc = check_acc(dnn, X_val, y_val)
if(best_val_acc < val_acc):
best_val_acc = val_acc
best_model = dnn
# store best model based n acc_val
print('Epoch finish. ')
print('Train acc %.3f' %train_acc)
print('Val acc %.3f' %val_acc)
print('-'*30)
print('')
print('Train finished. Best acc %.3f' %best_val_acc)
test_acc = check_acc(best_model, X_test, y_test)
print('Test acc %.3f' %test_acc)
class MLSLNN(Serializable):
"""
This class initializes a neural network
based on the size of features per entry along
with a provided MLSL which generates certain number of outputs
"""
def __init__(self):
pass
def initialize(self,
mlsl,
nnl,
seed=None,
weight_range=1.0,
outputs_from_mlsl=None,
use_softmax=True):
"""
Initialize an object of this class that binds a new NN on top
of an existing MLSL object
:param mlsl:
:type mlsl: MLSL
:param nnl:
:type nnl: list
:param seed:
:type seed:
:param weight_range:
:type weight_range:
:return:
:rtype:
"""
self.mlsl_output_size = mlsl.output_sizes[
-1] if outputs_from_mlsl else outputs_from_mlsl
# Change input size of Neural net to assigned feature size plus MLSL outputs
nnl[0] += self.mlsl_output_size
self.outputs_from_mlsl = outputs_from_mlsl
self.mlsl = mlsl
self.nnet = DNN()
self.nnet.initialize(nnl=nnl, seed=seed, weight_range=weight_range)
self.use_softmax = use_softmax
def forward(self, input_to_mlsl, additional_input_to_nn, target):
"""
This runs a forward through the entire model comprising of an MLSL
followed by a NN
:param input_to_mlsl:
:type input_to_mlsl:
:param additional_input_to_nn:
:type additional_input_to_nn:
:return:
:rtype:
"""
mlsl_output = self.mlsl._forward_instance(input_to_mlsl, 0)
input_to_nn = np.concatenate(
(mlsl_output[:self.mlsl_output_size], additional_input_to_nn))
nnet_output = self.nnet.forward(input_to_nn)
if self.use_softmax:
nnet_output = softmax(nnet_output)
return nnet_output
def get_objective_derivative(self, output, target):
if self.use_softmax:
return output - target
else:
raise ValueError
def backward(self, loss_deriv, instance_node):
# Run derivative through LSTM first
nn_deriv = self.nnet.backward_adadelta(loss_deriv)
deriv = nn_deriv[:self.mlsl_output_size]
self.mlsl._compute_backward_gradients(instance_node, deriv, 0)
self.mlsl._compute_LSTM_updates(instance_node, 0)
# updating the weights of the LSTM modules and
# updating momentum_dW of LSTM modules with sums of dWs
# and the other variables for adadelta
# these momentum/adadelta specific updates happen regardless of whether we use steady rate, momentum, or adadelta
# if we use steady rate those variables play no role in the computation of dW
for d in range(self.mlsl.max_depth + 1):
self.mlsl.lstm_stack[d].WLSTM += self.mlsl.sum_of_dWs[
d] / self.mlsl.number_of_nodes_per_level[d]
self.mlsl.lstm_stack[d].momentum_dW = self.mlsl.sum_of_dWs[
d] / self.mlsl.number_of_nodes_per_level[d]
self.mlsl.lstm_stack[
d].tot_gradient_weight = self.mlsl.sum_tot_delta_weight[
d] / self.mlsl.number_of_nodes_per_level[d]
self.mlsl.lstm_stack[
d].tot_sq_gradient = self.mlsl.sum_tot_sq_gradient[
d] / self.mlsl.number_of_nodes_per_level[d]
self.mlsl.lstm_stack[
d].tot_delta_weight = self.mlsl.sum_tot_delta_weight[
d] / self.mlsl.number_of_nodes_per_level[d]
self.mlsl.lstm_stack[d].tot_sq_delta = self.mlsl.sum_tot_sq_delta[
d] / self.mlsl.number_of_nodes_per_level[d]
def run_through_the_model(self, instance_node, target,
additional_input_to_nn):
self.mlsl._reset_learning_parameters()
return self.backward(
self.get(self.forward(instance_node, additional_input_to_nn),
target), instance_node)
