% TRIRND   Generate numbers from a triangular distribution
%
% Density is f(x) = 2x for x in [0,1].
%
function X=trirnd(m,n)
if nargin<1, m=1; end
if nargin<2, n=m; m=1; end

% This may look like magic, but it is not.
% We want random numbers X whose density is f(x)=2x,
% so their cdf must be F(x)=x^2, by integration.
% We first take uniformly distributed numbers U,
% and apply the INVERSE FUNCTION of F, that is, square root.
% The results will have cdf F as require.
% This is the "inverse transform method" for generating
% random numbers according to some desired distribution.
% https://en.wikipedia.org/wiki/Inverse_transform_sampling

U = unifrnd(0,1,m,n);
X = sqrt(U);