This function attempts to partially evaluate the given tensor, and
returns its value as a numpy ndarray if this succeeds.
Compatibility(V1): If constant_value(tensor) returns a non-None result, it
will no longer be possible to feed a different value for tensor. This allows
the result of this function to influence the graph that is constructed, and
permits static shape optimizations.
Args
tensor
The Tensor to be evaluated.
partial
If True, the returned numpy array is allowed to have partially
evaluated values. Values that can't be evaluated will be None.
Returns
A numpy ndarray containing the constant value of the given tensor,
or None if it cannot be calculated.