Question
Need an detailed analysis of what this code/model is doing. Thanks #Step 1: Import the required Python libraries: import numpy as np import matplotlib.pyplot as
Need an detailed analysis of what this code/model is doing. Thanks
#Step 1: Import the required Python libraries:
import numpy as np import matplotlib.pyplot as plt import keras from keras.layers import Input, Dense, Reshape, Flatten, Dropout from keras.layers import BatchNormalization, Activation, ZeroPadding2D from keras.layers import LeakyReLU from keras.layers.convolutional import UpSampling2D, Conv2D from keras.models import Sequential, Model from keras.optimizers import Adam,SGD from keras.datasets import cifar10
#Step 2: Load the data. #Loading the CIFAR10 data
(X, y), (_, _) = keras.datasets.cifar10.load_data()
#Selecting a single class of images #The number was randomly chosen and any number #between 1 and 10 can be chosen
X = X[y.flatten() == 8]
#Step 3: Define parameters to be used in later processes. #Defining the Input shape
image_shape = (32, 32, 3)
latent_dimensions = 100
#Step 4: Define a utility function to build the generator.
def build_generator():
model = Sequential()
#Building the input layer
model.add(Dense(128 * 8 * 8, activation="relu",
input_dim=latent_dimensions))
model.add(Reshape((8, 8, 128)))
model.add(UpSampling2D())
model.add(Conv2D(128, kernel_size=3, padding="same"))
model.add(BatchNormalization(momentum=0.78))
model.add(Activation("relu"))
model.add(UpSampling2D())
model.add(Conv2D(64, kernel_size=3, padding="same"))
model.add(BatchNormalization(momentum=0.78))
model.add(Activation("relu"))
model.add(Conv2D(3, kernel_size=3, padding="same"))
model.add(Activation("tanh"))
#Generating the output image
noise = Input(shape=(latent_dimensions,))
image = model(noise)
return Model(noise, image)
#Step 5: Define a utility function to build the discriminator.
def build_discriminator():
#Building the convolutional layers #to classify whether an image is real or fake
model = Sequential()
model.add(Conv2D(32, kernel_size=3, strides=2,
input_shape=image_shape, padding="same"))
model.add(LeakyReLU(alpha=0.2))
model.add(Dropout(0.25))
model.add(Conv2D(64, kernel_size=3, strides=2, padding="same"))
model.add(ZeroPadding2D(padding=((0,1),(0,1))))
model.add(BatchNormalization(momentum=0.82))
model.add(LeakyReLU(alpha=0.25))
model.add(Dropout(0.25))
model.add(Conv2D(128, kernel_size=3, strides=2, padding="same"))
model.add(BatchNormalization(momentum=0.82))
model.add(LeakyReLU(alpha=0.2))
model.add(Dropout(0.25))
model.add(Conv2D(256, kernel_size=3, strides=1, padding="same"))
model.add(BatchNormalization(momentum=0.8))
model.add(LeakyReLU(alpha=0.25))
model.add(Dropout(0.25))
#Building the output layer
model.add(Flatten())
model.add(Dense(1, activation='sigmoid'))
image = Input(shape=image_shape)
validity = model(image)
return Model(image, validity)
#Step 6: Define a utility function to display the generated images.
def display_images():
# Generate a batch of random noise noise = np.random.normal(0, 1, (16, latent_dimensions))
# Generate images from the noise generated_images = generator.predict(noise)
# Rescale the images to 0-1 range generated_images = 0.5 * generated_images + 0.5
# Plot the generated images plt.figure(figsize=(6, 6)) for i in range(generated_images.shape[0]): plt.subplot(4, 4, i+1) plt.imshow(generated_images[i]) plt.axis('off') plt.tight_layout() plt.show() plt.close()
#Step 7: Build the GAN. # Building and compiling the discriminator
discriminator = build_discriminator()
discriminator.compile(loss='binary_crossentropy',
optimizer=Adam(0.0002,0.5),
metrics=['accuracy'])
#Making the discriminator untrainable #so that the generator can learn from fixed gradient
discriminator.trainable = False
# Building the generator
generator = build_generator()
#Defining the input for the generator #and generating the images
z = Input(shape=(latent_dimensions,))
image = generator(z)
#Checking the validity of the generated image
valid = discriminator(image)
#Defining the combined model of the generator and the discriminator
combined_network = Model(z, valid)
combined_network.compile(loss='binary_crossentropy',
optimizer=Adam(0.0002,0.5))
#Step 8: Train the network.
num_epochs=15000
batch_size=32
display_interval=1000
losses=[]
#Normalizing the input
X = (X / 127.5) - 1.
#Defining the Adversarial ground truths
valid = np.ones((batch_size, 1))
#Adding some noise
valid += 0.05 * np.random.random(valid.shape)
fake = np.zeros((batch_size, 1))
fake += 0.05 * np.random.random(fake.shape)
for epoch in range(num_epochs):
#Training the Discriminator #Sampling a random half of images
index = np.random.randint(0, X.shape[0], batch_size)
images = X[index]
#Sampling noise and generating a batch of new images
noise = np.random.normal(0, 1, (batch_size, latent_dimensions))
generated_images = generator.predict(noise)
#Training the discriminator to detect more accurately #whether a generated image is real or fake
discm_loss_real = discriminator.train_on_batch(images, valid)
discm_loss_fake = discriminator.train_on_batch(generated_images, fake)
discm_loss = 0.5 * np.add(discm_loss_real, discm_loss_fake)
#Training the Generator #Sampling noise and generating a batch of new images noise = np.random.normal(0, 1, (batch_size, latent_dimensions))
misleading_targets = np.ones((batch_size, 1)) #Training the generator to generate images #that pass the authenticity test
genr_loss = combined_network.train_on_batch(noise, misleading_targets)
# Display generated images at the end of every 1000th epoch #Tracking the progress
if epoch % display_interval == 0:
display_images() noise = np.random.normal(0, 1, (16, latent_dimensions)) generated_images = generator.predict(noise) generated_images = 0.5 * generated_images + 0.5 plt.figure(figsize=(6, 6)) for i in range(generated_images.shape[0]): plt.subplot(4, 4, i+1) plt.imshow(generated_images[i]) plt.axis('off') plt.tight_layout() plt.savefig(f"epoch_{epoch+1}.png") plt.close()
#Printing the progress and losses of the current epoch print(f"Epoch {epoch} Discriminator Loss: {discm_loss[0]} Generator Loss: {genr_loss}") |
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