psychtoolbox-3-common 3.0.14.20170103+git6-g605ff5c.dfsg1-1build1 / usr / share / psychtoolbox-3 / PsychProbability / NRandPerm.m

function p = NRandPerm(n,nret)
%NRandPerm Random permutation.
%   NRandPerm(n,nret) is a random permutation of the integers from 1 to n,
%   of which nret elements are returned.
%   NRandPerm thus returns a random selection of integers from 1 to n with
%   no repeats.
%
%   For example, NRandPerm(6,4) might be [2 4 5 6].
%   
%   Note that NRandPerm calls RAND and therefore changes RAND's state.
%
%   See also PERMUTE, RANDPERM.

% DN 2008-07-30 Wrote it

psychassert(nret<=n,'More return elements requested (nret: %d) than elements in random permutation (n: %d)',nret,n);

[ignore,p]  = sort(rand(1,n));
p           = p(1:nret);