Create model.py
Browse files
model.py
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import numpy as np
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import tensorflow as tf
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import matplotlib.pyplot as plt
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# Parameters
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IMG_SIZE = 64
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LATENT_DIM = 128 # Dimension of the input noise
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BATCH_SIZE = 1
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# Generator (turns noise into an image)
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def build_generator():
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model = tf.keras.Sequential([
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tf.keras.layers.Dense(8 * 8 * 64, activation='relu', input_dim=LATENT_DIM),
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tf.keras.layers.Reshape((8, 8, 64)),
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tf.keras.layers.Conv2DTranspose(64, (4,4), strides=2, padding='same', activation='relu'),
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tf.keras.layers.Conv2DTranspose(32, (4,4), strides=2, padding='same', activation='relu'),
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tf.keras.layers.Conv2DTranspose(3, (4,4), strides=2, padding='same', activation='sigmoid') # RGB [0,1]
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])
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return model
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# Discriminator (evaluates how "interesting" an image is)
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def build_discriminator():
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model = tf.keras.Sequential([
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tf.keras.layers.Conv2D(32, (3,3), strides=2, padding='same', input_shape=(IMG_SIZE, IMG_SIZE, 3)),
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tf.keras.layers.LeakyReLU(0.2),
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tf.keras.layers.Conv2D(64, (3,3), strides=2, padding='same'),
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tf.keras.layers.LeakyReLU(0.2),
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tf.keras.layers.Flatten(),
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tf.keras.layers.Dense(1, activation='sigmoid') # "How cool is this?"
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])
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return model
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# Create models
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generator = build_generator()
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discriminator = build_discriminator()
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# Loss function and optimizers
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cross_entropy = tf.keras.losses.BinaryCrossentropy()
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g_optimizer = tf.keras.optimizers.Adam(0.0002, beta_1=0.5)
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d_optimizer = tf.keras.optimizers.Adam(0.0002, beta_1=0.5)
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# Training function
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@tf.function
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def train_step():
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# 1. Generate random noise
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noise = tf.random.normal([BATCH_SIZE, LATENT_DIM])
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# 2. Train discriminator on "good" data (but we don't have any → just learn to distinguish noise)
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with tf.GradientTape() as d_tape:
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generated_images = generator(noise, training=True)
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real_output = discriminator(tf.random.uniform((BATCH_SIZE, IMG_SIZE, IMG_SIZE, 3)), training=True) # fake "real" data
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fake_output = discriminator(generated_images, training=True)
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d_loss = cross_entropy(tf.ones_like(fake_output), fake_output) # force it to think generated images are "real"
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d_gradients = d_tape.gradient(d_loss, discriminator.trainable_variables)
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d_optimizer.apply_gradients(zip(d_gradients, discriminator.trainable_variables))
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# 3. Train generator
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with tf.GradientTape() as g_tape:
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generated_images = generator(noise, training=True)
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fake_output = discriminator(generated_images, training=True)
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g_loss = cross_entropy(tf.ones_like(fake_output), fake_output) # goal is to fool the discriminator
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g_gradients = g_tape.gradient(g_loss, generator.trainable_variables)
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g_optimizer.apply_gradients(zip(g_gradients, generator.trainable_variables))
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return d_loss, g_loss
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# Mini-training (50 steps)
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for epoch in range(50):
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d_loss, g_loss = train_step()
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if epoch % 10 == 0:
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print(f"Epoch {epoch}, D Loss: {d_loss:.3f}, G Loss: {g_loss:.3f}")
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# Generate sample image
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test_noise = tf.random.normal([1, LATENT_DIM])
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generated_img = generator(test_noise, training=False)[0]
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plt.imshow(generated_img)
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plt.axis('off')
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plt.show()
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