Perform this operation on a scalar/vector or matrix

I have a code like this

The function takes z as argument. z can be a scalar or vector or matrix

IF it is a vector, I want the operation stated to be performed on every element of a vector, if its a matrix I want the operation to be performed on every element of a matrix and if its a scalar on the scalar

It is not working. See below

1) If I give z as scalar 0. I get 0.5 which is correct

2) If I give z as 0.5, I get 0.6225 which is correct

3) I give as z as [0;0;0.5], I expect the answer to be 0.5 0.5 0.6225 but it doesn't work

function g = sigmoid(z)
%SIGMOID Compute sigmoid function
%   g = SIGMOID(z) computes the sigmoid of z.

% You need to return the following variables correctly 
g = zeros(size(z));

g = (1/(1+exp(-z)));

Answer 1

[Stephan]

g = (1./(1+exp(-z)));
%     ^
%     |______ perform elementwise

[madhan ravi]

Also

g = zeros(...) % line is unnecessary

[atan]

Thanks !

This works:

g = (1./(1+exp(-z)));

I know that "." does the magic to perfoirm the element wise operation. I'm still unsure on where exactly one should insert that "."

Thanks !