dcgan.py

from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense
from tensorflow.keras.layers import Reshape
from tensorflow.keras.layers import Activation
from tensorflow.keras.layers import BatchNormalization
from tensorflow.keras.layers import UpSampling2D
from tensorflow.keras.layers import Conv2D, MaxPooling2D
from tensorflow.keras.layers import Flatten
from tensorflow.keras.optimizers import SGD
from tensorflow.keras.datasets import mnist
import numpy as np
from PIL import Image
import argparse
import math
import tensorflow as tf

def generator_model():
    model = Sequential()
    model.add(Dense(256*7*7,input_shape=(100,)))
    model.add(Activation('tanh'))
    model.add(Dense(128*7*7))
    model.add(BatchNormalization())
    model.add(Activation('tanh'))
    model.add(Reshape((7, 7, 128), input_shape=(128*7*7,)))
    model.add(UpSampling2D(size=(2, 2)))
    model.add(Conv2D(64, (5, 5), padding='same'))
    model.add(Activation('tanh'))
    model.add(UpSampling2D(size=(2, 2)))
    model.add(Conv2D(1, (5, 5), padding='same'))
    model.add(Activation('tanh'))
    return model


def discriminator_model():
    model = Sequential()
    model.add(
            Conv2D(64, (5, 5),
            padding='same',
            input_shape=(28, 28, 1))
            )
    model.add(Activation('tanh'))
    model.add(MaxPooling2D(pool_size=(2, 2)))
    model.add(Conv2D(128, (5, 5)))
    model.add(Activation('tanh'))
    model.add(MaxPooling2D(pool_size=(2, 2)))
    model.add(Flatten())
    model.add(Dense(1024))
    model.add(Activation('tanh'))
    model.add(Dense(1))
    model.add(Activation('sigmoid'))
    return model


def generator_containing_discriminator(g, d):
    model = Sequential()
    model.add(g)
    d.trainable = False
    model.add(d)
    return model


def combine_images(generated_images):
    num = generated_images.shape[0]
    width = int(math.sqrt(num))
    height = int(math.ceil(float(num)/width))
    shape = generated_images.shape[1:3]
    image = np.zeros((height*shape[0], width*shape[1]),
                     dtype=generated_images.dtype)
    for index, img in enumerate(generated_images):
        i = int(index/width)
        j = index % width
        image[i*shape[0]:(i+1)*shape[0], j*shape[1]:(j+1)*shape[1]] = \
            img[:, :, 0]
    return image


def train(BATCH_SIZE):
    (X_train, y_train), (X_test, y_test) = mnist.load_data()
    X_train = (X_train.astype(np.float32) - 127.5)/127.5
    X_train = X_train[:, :, :, None]
    X_test = X_test[:, :, :, None]
    # X_train = X_train.reshape((X_train.shape, 1) + X_train.shape[1:])
    d = discriminator_model()
    g = generator_model()
    d_on_g = generator_containing_discriminator(g, d)
    d_optim = SGD(lr=0.0005, momentum=0.9, nesterov=True)
    g_optim = SGD(lr=0.0005, momentum=0.9, nesterov=True)
    g.compile(loss='binary_crossentropy', optimizer="SGD")
    d_on_g.compile(loss='binary_crossentropy', optimizer=g_optim)
    d.trainable = True
    d.compile(loss='binary_crossentropy', optimizer=d_optim)
    for epoch in range(100):
        print("Epoch is", epoch)
        print("Number of batches", int(X_train.shape[0]/BATCH_SIZE))
        for index in range(int(X_train.shape[0]/BATCH_SIZE)):
            noise = np.random.uniform(-1, 1, size=(BATCH_SIZE, 100))
            image_batch = X_train[index*BATCH_SIZE:(index+1)*BATCH_SIZE]
            generated_images = g.predict(noise, verbose=0)
            if index % 20 == 0:
                image = combine_images(generated_images)
                image = image*127.5+127.5
                Image.fromarray(image.astype(np.uint8)).save(
                    str(epoch)+"_"+str(index)+".png")
            X = np.concatenate((image_batch, generated_images))
            y = [1] * BATCH_SIZE + [0] * BATCH_SIZE
            d_loss = d.train_on_batch(X, y)
            print("batch %d d_loss : %f" % (index, d_loss))
            noise = np.random.uniform(-1, 1, (BATCH_SIZE, 100))
            d.trainable = False
            g_loss = d_on_g.train_on_batch(noise, [1] * BATCH_SIZE)
            d.trainable = True
            print("batch %d g_loss : %f" % (index, g_loss))
            if index % 10 == 9:
                g.save_weights('generator', True)
                d.save_weights('discriminator', True)


def generate(BATCH_SIZE, nice=False):
    g = generator_model()
    g.compile(loss='binary_crossentropy', optimizer="SGD")
    g.load_weights('generator')
    if nice:
        d = discriminator_model()
        d.compile(loss='binary_crossentropy', optimizer="SGD")
        d.load_weights('discriminator')
        noise = np.random.uniform(-1, 1, (BATCH_SIZE*20, 100))
        generated_images = g.predict(noise, verbose=1)
        d_pret = d.predict(generated_images, verbose=1)
        index = np.arange(0, BATCH_SIZE*20)
        index.resize((BATCH_SIZE*20, 1))
        pre_with_index = list(np.append(d_pret, index, axis=1))
        pre_with_index.sort(key=lambda x: x[0], reverse=True)
        nice_images = np.zeros((BATCH_SIZE,) + generated_images.shape[1:3], dtype=np.float32)
        nice_images = nice_images[:, :, :, None]
        for i in range(BATCH_SIZE):
            idx = int(pre_with_index[i][1])
            nice_images[i, :, :, 0] = generated_images[idx, :, :, 0]
        image = combine_images(nice_images)
    else:
        noise = np.random.uniform(-1, 1, (BATCH_SIZE, 100))
        generated_images = g.predict(noise, verbose=1)
        image = combine_images(generated_images)
    image = image*127.5+127.5
    Image.fromarray(image.astype(np.uint8)).save(
        "generated_image.png")


def get_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("--mode", type=str)
    parser.add_argument("--batch_size", type=int, default=128)
    parser.add_argument("--nice", dest="nice", action="store_true")
    parser.set_defaults(nice=False)
    args = parser.parse_args()
    return args

if __name__ == "__main__":
    args = get_args()
    if args.mode == "train":
        train(BATCH_SIZE=args.batch_size)
    elif args.mode == "generate":
        generate(BATCH_SIZE=args.batch_size, nice=args.nice)