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## Import Necessary Modules | |
from __future__ import print_function | |
import keras | |
from keras.layers import Dense, Conv2D, BatchNormalization, Activation | |
from keras.layers import AveragePooling2D, Input, Flatten | |
from keras.optimizers import Adam | |
from keras.callbacks import ModelCheckpoint, LearningRateScheduler | |
from keras.callbacks import ReduceLROnPlateau | |
from keras.preprocessing.image import ImageDataGenerator | |
from keras.regularizers import l2 | |
from keras import backend as K | |
from keras.models import Model | |
from keras.datasets import cifar10 | |
import numpy as np | |
import os | |
##Import Mish | |
from mish import Mish | |
# Training parameters | |
batch_size = 32 # orig paper trained all networks with batch_size=128 | |
epochs = 1 | |
data_augmentation = True | |
num_classes = 10 | |
# Subtracting pixel mean improves accuracy | |
subtract_pixel_mean = True | |
# Model parameter | |
# ---------------------------------------------------------------------------- | |
# | | 200-epoch | Orig Paper| 200-epoch | Orig Paper| sec/epoch | |
# Model | n | ResNet v1 | ResNet v1 | ResNet v2 | ResNet v2 | GTX1080Ti | |
# |v1(v2)| %Accuracy | %Accuracy | %Accuracy | %Accuracy | v1 (v2) | |
# ---------------------------------------------------------------------------- | |
# ResNet20 | 3 (2)| 92.16 | 91.25 | ----- | ----- | 35 (---) | |
# ResNet32 | 5(NA)| 92.46 | 92.49 | NA | NA | 50 ( NA) | |
# ResNet44 | 7(NA)| 92.50 | 92.83 | NA | NA | 70 ( NA) | |
# ResNet56 | 9 (6)| 92.71 | 93.03 | 93.01 | NA | 90 (100) | |
# ResNet110 |18(12)| 92.65 | 93.39+-.16| 93.15 | 93.63 | 165(180) | |
# ResNet164 |27(18)| ----- | 94.07 | ----- | 94.54 | ---(---) | |
# ResNet1001| (111)| ----- | 92.39 | ----- | 95.08+-.14| ---(---) | |
# --------------------------------------------------------------------------- | |
n = 3 | |
# Model version | |
# Orig paper: version = 1 (ResNet v1), Improved ResNet: version = 2 (ResNet v2) | |
version = 1 | |
# Computed depth from supplied model parameter n | |
if version == 1: | |
depth = n * 6 + 2 | |
# Model name, depth and version | |
model_type = 'ResNet%dv%d' % (depth, version) | |
# Load the CIFAR10 data. | |
(x_train, y_train), (x_test, y_test) = cifar10.load_data() | |
# Input image dimensions. | |
input_shape = x_train.shape[1:] | |
# Normalize data. | |
x_train = x_train.astype('float32') / 255 | |
x_test = x_test.astype('float32') / 255 | |
# If subtract pixel mean is enabled | |
if subtract_pixel_mean: | |
x_train_mean = np.mean(x_train, axis=0) | |
x_train -= x_train_mean | |
x_test -= x_train_mean | |
print('x_train shape:', x_train.shape) | |
print(x_train.shape[0], 'train samples') | |
print(x_test.shape[0], 'test samples') | |
print('y_train shape:', y_train.shape) | |
# Convert class vectors to binary class matrices. | |
y_train = keras.utils.to_categorical(y_train, num_classes) | |
y_test = keras.utils.to_categorical(y_test, num_classes) | |
def lr_schedule(epoch): | |
"""Learning Rate Schedule | |
Learning rate is scheduled to be reduced after 80, 120, 160, 180 epochs. | |
Called automatically every epoch as part of callbacks during training. | |
# Arguments | |
epoch (int): The number of epochs | |
# Returns | |
lr (float32): learning rate | |
""" | |
lr = 1e-3 | |
if epoch > 180: | |
lr *= 0.5e-3 | |
elif epoch > 160: | |
lr *= 1e-3 | |
elif epoch > 120: | |
lr *= 1e-2 | |
elif epoch > 80: | |
lr *= 1e-1 | |
print('Learning rate: ', lr) | |
return lr | |
def resnet_layer(inputs, | |
num_filters=16, | |
kernel_size=3, | |
strides=1, | |
activation = Mish, | |
batch_normalization=True, | |
conv_first=True): | |
"""2D Convolution-Batch Normalization-Activation stack builder | |
# Arguments | |
inputs (tensor): input tensor from input image or previous layer | |
num_filters (int): Conv2D number of filters | |
kernel_size (int): Conv2D square kernel dimensions | |
strides (int): Conv2D square stride dimensions | |
activation (string): activation name | |
batch_normalization (bool): whether to include batch normalization | |
conv_first (bool): conv-bn-activation (True) or | |
bn-activation-conv (False) | |
# Returns | |
x (tensor): tensor as input to the next layer | |
""" | |
conv = Conv2D(num_filters, | |
kernel_size=kernel_size, | |
strides=strides, | |
padding='same', | |
kernel_initializer='he_normal', | |
kernel_regularizer=l2(1e-4)) | |
x = inputs | |
if conv_first: | |
x = conv(x) | |
if batch_normalization: | |
x = BatchNormalization()(x) | |
if activation is not None: | |
x = Mish()(x) | |
else: | |
if batch_normalization: | |
x = BatchNormalization()(x) | |
if activation is not None: | |
x = Mish()(x) | |
x = conv(x) | |
return x | |
def resnet_v1(input_shape, depth, num_classes=10): | |
"""ResNet Version 1 Model builder [a] | |
Stacks of 2 x (3 x 3) Conv2D-BN-ReLU | |
Last ReLU is after the shortcut connection. | |
At the beginning of each stage, the feature map size is halved (downsampled) | |
by a convolutional layer with strides=2, while the number of filters is | |
doubled. Within each stage, the layers have the same number filters and the | |
same number of filters. | |
Features maps sizes: | |
stage 0: 32x32, 16 | |
stage 1: 16x16, 32 | |
stage 2: 8x8, 64 | |
The Number of parameters is approx the same as Table 6 of [a]: | |
ResNet20 0.27M | |
ResNet32 0.46M | |
ResNet44 0.66M | |
ResNet56 0.85M | |
ResNet110 1.7M | |
# Arguments | |
input_shape (tensor): shape of input image tensor | |
depth (int): number of core convolutional layers | |
num_classes (int): number of classes (CIFAR10 has 10) | |
# Returns | |
model (Model): Keras model instance | |
""" | |
if (depth - 2) % 6 != 0: | |
raise ValueError('depth should be 6n+2 (eg 20, 32, 44 in [a])') | |
# Start model definition. | |
num_filters = 16 | |
num_res_blocks = int((depth - 2) / 6) | |
inputs = Input(shape=input_shape) | |
x = resnet_layer(inputs=inputs) | |
# Instantiate the stack of residual units | |
for stack in range(3): | |
for res_block in range(num_res_blocks): | |
strides = 1 | |
if stack > 0 and res_block == 0: # first layer but not first stack | |
strides = 2 # downsample | |
y = resnet_layer(inputs=x, | |
num_filters=num_filters, | |
strides=strides) | |
y = resnet_layer(inputs=y, | |
num_filters=num_filters, | |
activation=None) | |
if stack > 0 and res_block == 0: # first layer but not first stack | |
# linear projection residual shortcut connection to match | |
# changed dims | |
x = resnet_layer(inputs=x, | |
num_filters=num_filters, | |
kernel_size=1, | |
strides=strides, | |
activation=None, | |
batch_normalization=False) | |
x = keras.layers.add([x, y]) | |
x = Mish()(x) | |
num_filters *= 2 | |
# Add classifier on top. | |
# v1 does not use BN after last shortcut connection-ReLU | |
x = AveragePooling2D(pool_size=8)(x) | |
y = Flatten()(x) | |
outputs = Dense(num_classes, | |
activation='softmax', | |
kernel_initializer='he_normal')(y) | |
# Instantiate model. | |
model = Model(inputs=inputs, outputs=outputs) | |
return model | |
model = resnet_v1(input_shape=input_shape, depth=depth) | |
model.compile(loss='categorical_crossentropy', | |
optimizer=Adam(lr=lr_schedule(0)), | |
metrics=['accuracy']) | |
model.summary() | |
print(model_type) | |
# Prepare model model saving directory. | |
save_dir = os.path.join(os.getcwd(), 'saved_models') | |
model_name = 'cifar10_%s_model.{epoch:03d}.h5' % model_type | |
if not os.path.isdir(save_dir): | |
os.makedirs(save_dir) | |
filepath = os.path.join(save_dir, model_name) | |
# Prepare callbacks for model saving and for learning rate adjustment. | |
checkpoint = ModelCheckpoint(filepath=filepath, | |
monitor='val_acc', | |
verbose=1, | |
save_best_only=True) | |
lr_scheduler = LearningRateScheduler(lr_schedule) | |
lr_reducer = ReduceLROnPlateau(factor=np.sqrt(0.1), | |
cooldown=0, | |
patience=5, | |
min_lr=0.5e-6) | |
callbacks = [checkpoint, lr_reducer, lr_scheduler] | |
# Run training, with or without data augmentation. | |
if not data_augmentation: | |
print('Not using data augmentation.') | |
model.fit(x_train, y_train, | |
batch_size=batch_size, | |
epochs=epochs, | |
validation_data=(x_test, y_test), | |
shuffle=True, | |
callbacks=callbacks) | |
else: | |
print('Using real-time data augmentation.') | |
# This will do preprocessing and realtime data augmentation: | |
datagen = ImageDataGenerator( | |
# set input mean to 0 over the dataset | |
featurewise_center=False, | |
# set each sample mean to 0 | |
samplewise_center=False, | |
# divide inputs by std of dataset | |
featurewise_std_normalization=False, | |
# divide each input by its std | |
samplewise_std_normalization=False, | |
# apply ZCA whitening | |
zca_whitening=False, | |
# epsilon for ZCA whitening | |
zca_epsilon=1e-06, | |
# randomly rotate images in the range (deg 0 to 180) | |
rotation_range=0, | |
# randomly shift images horizontally | |
width_shift_range=0.1, | |
# randomly shift images vertically | |
height_shift_range=0.1, | |
# set range for random shear | |
shear_range=0., | |
# set range for random zoom | |
zoom_range=0., | |
# set range for random channel shifts | |
channel_shift_range=0., | |
# set mode for filling points outside the input boundaries | |
fill_mode='nearest', | |
# value used for fill_mode = "constant" | |
cval=0., | |
# randomly flip images | |
horizontal_flip=True, | |
# randomly flip images | |
vertical_flip=False, | |
# set rescaling factor (applied before any other transformation) | |
rescale=None, | |
# set function that will be applied on each input | |
preprocessing_function=None, | |
# image data format, either "channels_first" or "channels_last" | |
data_format=None, | |
# fraction of images reserved for validation (strictly between 0 and 1) | |
validation_split=0.0) | |
# Compute quantities required for featurewise normalization | |
# (std, mean, and principal components if ZCA whitening is applied). | |
datagen.fit(x_train) | |
# Fit the model on the batches generated by datagen.flow(). | |
model.fit_generator(datagen.flow(x_train, y_train, batch_size=batch_size), | |
validation_data=(x_test, y_test), | |
epochs=epochs, verbose=1, workers=4,steps_per_epoch = 1563, | |
callbacks=callbacks) | |
# Score trained model. | |
scores = model.evaluate(x_test, y_test, verbose=1) | |
print('Test loss:', scores[0]) | |
print('Test accuracy:', scores[1]) |
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