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Applies the rectified linear unit activation function.

    x, alpha=0.0, max_value=None, threshold=0

With default values, this returns the standard ReLU activation: max(x, 0), the element-wise maximum of 0 and the input tensor.

Modifying default parameters allows you to use non-zero thresholds, change the max value of the activation, and to use a non-zero multiple of the input for values below the threshold.

For example:

foo = tf.constant([-10, -5, 0.0, 5, 10], dtype = tf.float32) tf.keras.activations.relu(foo).numpy() array([ 0., 0., 0., 5., 10.], dtype=float32) tf.keras.activations.relu(foo, alpha=0.5).numpy() array([-5. , -2.5, 0. , 5. , 10. ], dtype=float32) tf.keras.activations.relu(foo, max_value=5).numpy() array([0., 0., 0., 5., 5.], dtype=float32) tf.keras.activations.relu(foo, threshold=5).numpy() array([-0., -0., 0., 0., 10.], dtype=float32)


  • x: Input tensor or variable.
  • alpha: A float that governs the slope for values lower than the threshold.
  • max_value: A float that sets the saturation threshold (the largest value the function will return).
  • threshold: A float giving the threshold value of the activation function below which values will be damped or set to zero.


A Tensor representing the input tensor, transformed by the relu activation function. Tensor will be of the same shape and dtype of input x.