function y=tri(x)
% TRI  Triangle Function.
%
%      Y=TRI(t) is a triangular pulse with height=1, width=2, centered at t=0
%
%      TRI (with no input arguments) invokes the following example:
%
%        % Plot 3*tri[(t-1)/2] (height=3,width=4, centered at t=1) 
%        >>t=-4:.05:4;
%        >>yt=3*tri((t-1)/2);
%        >>plot(t,yt)
%        >>grid
%
%      See Also: UDELTA, URAMP, URECT, USTEP


% ADSP Toolbox: Version 2.0 
% For use with "Analog and Digital Signal Processing", 2nd Ed.
% Published by PWS Publishing Co.
%
% Ashok Ambardar, EE Dept. MTU, Houghton, MI 49931, USA
% http://www.ee.mtu/faculty/akambard.html
% e-mail: akambard@mtu.edu
% Copyright (c) 1998


if nargin==0,
 help tri
 disp('Strike a key to see results of the example')
 pause
 t=-4:.05:4;
 yt=3*tri((t-1)/2);
  v=matverch;
 if v < 4, eval('clg');else,eval('clf');end

 plot(t,yt)
 grid
 return
end

if nargin == 1,
 z=abs(x);
 y=(1-z).*(z<=1);
elseif nargin > 1,
 error('Too many input arguments');
end