tf.keras.backend.mean( x, axis=None, keepdims=False )
Mean of a tensor, alongside the specified axis.
x: A tensor or variable.
axis: A list of integer. Axes to compute the mean.
keepdims: A boolean, whether to keep the dimensions or not. If
False, the rank of the tensor is reduced by 1 for each entry in
True, the reduced dimensions are retained with length 1.
A tensor with the mean of elements of