% SECH SECH Hyperbolic Secant Function
% 
% Usage
% 
% Computes the hyperbolic secant of the argument.
% The syntax for its use is
% 
%    y = sech(x)
% 
function y = sech(x)
  if (nargin == 0 || ~isnumeric(x))
    error('sech expects a numeric input');
  end
  y = 1.0f./cosh(x);