Here’s a concise cheat sheet for getting started with TensorFlow

1. Import TensorFlow

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import tensorflow as tf

2. Tensors

• Create constant tensor:

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tensor = tf.constant([[1, 2], [3, 4]])

• Create variable tensor:

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var = tf.Variable([[1, 2], [3, 4]], dtype=tf.float32)

• Convert NumPy array to tensor:

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import numpy as np
array = np.array([1, 2, 3])
tensor = tf.convert_to_tensor(array)

3. Tensor Operations

• Element-wise addition:

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result = tf.add(tensor1, tensor2)

• Element-wise multiplication:

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result = tf.multiply(tensor1, tensor2)

• Matrix multiplication:

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result = tf.matmul(tensor1, tensor2)

• Reshape tensor:

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result = tf.reshape(tensor, new_shape)

4. Eager Execution

• Check if eager execution is enabled:

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print(tf.executing_eagerly())

5. Gradient Tape

• Compute gradients:

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with tf.GradientTape() as tape:
    loss = compute_loss()
gradients = tape.gradient(loss, variables)

6. Keras

• Create a simple sequential model:

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from tensorflow.keras import layers

model = tf.keras.Sequential([
    layers.Dense(64, activation='relu', input_shape=(input_shape,)),
    layers.Dense(64, activation='relu'),
    layers.Dense(num_classes, activation='softmax')
])

• Compile the model:

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model.compile(optimizer=tf.keras.optimizers.Adam(),
              loss=tf.keras.losses.CategoricalCrossentropy(),
              metrics=['accuracy'])

• Train the model:

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history = model.fit(x_train, y_train, epochs=num_epochs, batch_size=batch_size, validation_split=0.2)

• Evaluate the model:

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loss, accuracy = model.evaluate(x_test, y_test)

• Save and load the model:

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model.save('my_model.h5')
loaded_model = tf.keras.models.load_model('my_model.h5')

7. Custom Layers and Models

• Create a custom layer:

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class CustomDense(layers.Layer):
    def __init__(self, units):
        super(CustomDense, self).__init__()
        self.units = units

    def build(self, input_shape):
        self.w = self.add_weight(shape=(input_shape[-1], self.units),
                                 initializer='random_normal',
                                 trainable=True)
        self.b = self.add_weight(shape=(self.units,),
                                 initializer='zeros',
                                 trainable=True)

    def call(self, inputs):
        return tf.matmul(inputs, self.w) + self.b

• Create a custom model:

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class CustomModel(tf.keras.Model):
    def __init__(self, num_classes):
        super(CustomModel, self).__init__()
        self.dense1 = CustomDense(64)
        self.dense2 = CustomDense(64)
        self.dense3 = CustomDense(num_classes)

    def call(self, inputs):
        x = tf.nn.relu(self.dense1(inputs))
        x = tf.nn.relu(self.dense2(x))
        return self.dense3(x)

This cheat sheet covers the basic elements of TensorFlow. For more advanced topics and detailed explanations, refer to the official TensorFlow documentation.