function g = sigmoid(z,s)
%SIGMOID Compute sigmoid functoon
%   J = SIGMOID(z) computes the sigmoid of z.

% SIGMOID
%g = 1.0 ./ (1.0 + exp(-2*s*z));

% tanh AKA Sigmoid Symmetric
%g = 2.0 ./ (1.0 + exp(-2*s*z)) -1;
g = tanh(s*z);

% elliot symmetric
% g = (z.*s) ./ (1 + abs(z.*s));
end
