Setting all negative values of a tensor to zero (in tensorflow)

Question

Here's my problem. I have a tensor X and I want to set all negative values to zero. In numpy, I would do the following np.maximum(0, X). Is there any way to achieve the same effect in tensorflow? I tried tf.maximum(tf.fill(X.get_shape(), 0.0), X), but this throws ValueError: Cannot convert a partially known TensorShape to a Tensor: (?,).

PS. X is a 1-D tensor of shape (?,).

Answer 1

As it happens, your problem is exactly the same as computing the rectifier activation function, and TensorFlow has a built-in operator, tf.nn.relu(), that does exactly what you need:

X_with_negatives_set_to_zero = tf.nn.relu(X)

Answer 2

You can use tf.clip_by_value function as follows:

t = tf.clip_by_value(t, min_val, max_val)

It will clip tensor t in the range [min_val, max_val]. Here you can set min_val to 0 to clip all negative values and set those to 0. More documentation about clip_by_value.