写一段GAN代码,用于解决样本不均衡问题
时间: 2023-04-02 21:01:38 浏览: 228
以下是一段GAN代码,用于解决样本不均衡问题:
```
import tensorflow as tf
from tensorflow.keras import layers
# 定义生成器模型
def make_generator_model():
model = tf.keras.Sequential()
model.add(layers.Dense(256, input_shape=(100,), use_bias=False))
model.add(layers.BatchNormalization())
model.add(layers.LeakyReLU())
model.add(layers.Dense(512, use_bias=False))
model.add(layers.BatchNormalization())
model.add(layers.LeakyReLU())
model.add(layers.Dense(1024, use_bias=False))
model.add(layers.BatchNormalization())
model.add(layers.LeakyReLU())
model.add(layers.Dense(784, activation='tanh'))
return model
# 定义判别器模型
def make_discriminator_model():
model = tf.keras.Sequential()
model.add(layers.Dense(1024, input_shape=(784,), use_bias=False))
model.add(layers.BatchNormalization())
model.add(layers.LeakyReLU())
model.add(layers.Dropout(.3))
model.add(layers.Dense(512, use_bias=False))
model.add(layers.BatchNormalization())
model.add(layers.LeakyReLU())
model.add(layers.Dropout(.3))
model.add(layers.Dense(256, use_bias=False))
model.add(layers.BatchNormalization())
model.add(layers.LeakyReLU())
model.add(layers.Dropout(.3))
model.add(layers.Dense(1))
return model
# 定义损失函数
cross_entropy = tf.keras.losses.BinaryCrossentropy(from_logits=True)
# 定义生成器损失函数
def generator_loss(fake_output):
return cross_entropy(tf.ones_like(fake_output), fake_output)
# 定义判别器损失函数
def discriminator_loss(real_output, fake_output):
real_loss = cross_entropy(tf.ones_like(real_output), real_output)
fake_loss = cross_entropy(tf.zeros_like(fake_output), fake_output)
total_loss = real_loss + fake_loss
return total_loss
# 定义优化器
generator_optimizer = tf.keras.optimizers.Adam(1e-4)
discriminator_optimizer = tf.keras.optimizers.Adam(1e-4)
# 定义训练函数
@tf.function
def train_step(images):
noise = tf.random.normal([BATCH_SIZE, 100])
with tf.GradientTape() as gen_tape, tf.GradientTape() as disc_tape:
generated_images = generator(noise, training=True)
real_output = discriminator(images, training=True)
fake_output = discriminator(generated_images, training=True)
gen_loss = generator_loss(fake_output)
disc_loss = discriminator_loss(real_output, fake_output)
gradients_of_generator = gen_tape.gradient(gen_loss, generator.trainable_variables)
gradients_of_discriminator = disc_tape.gradient(disc_loss, discriminator.trainable_variables)
generator_optimizer.apply_gradients(zip(gradients_of_generator, generator.trainable_variables))
discriminator_optimizer.apply_gradients(zip(gradients_of_discriminator, discriminator.trainable_variables))
# 定义训练过程
def train(dataset, epochs):
for epoch in range(epochs):
for image_batch in dataset:
train_step(image_batch)
# 加载数据集
(train_images, train_labels), (_, _) = tf.keras.datasets.mnist.load_data()
train_images = train_images.reshape(train_images.shape[], 784).astype('float32')
train_images = (train_images - 127.5) / 127.5 # 将像素值归一化到[-1, 1]之间
BUFFER_SIZE = 60000
BATCH_SIZE = 256
train_dataset = tf.data.Dataset.from_tensor_slices(train_images).shuffle(BUFFER_SIZE).batch(BATCH_SIZE)
# 创建生成器和判别器
generator = make_generator_model()
discriminator = make_discriminator_model()
# 训练模型
EPOCHS = 50
train(train_dataset, EPOCHS)
```
这段代码使用了生成对抗网络(GAN)来解决样本不均衡问题。GAN由一个生成器和一个判别器组成,生成器用于生成假样本,判别器用于判断样本是真实的还是假的。在训练过程中,生成器和判别器相互竞争,最终生成器可以生成与真实样本相似的假样本。这种方法可以用于解决样本不均衡问题,因为生成器可以生成更多的少数类样本,从而平衡数据集。
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