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

function x=PsychRandSample(list,dims)
% x=PsychRandSample(list,[dims])
%
% Returns a random sample from a list. The optional second argument may be
% used to request an array (of size dims) of independent samples. E.g.
% PsychRandSample(-1:1,[10,10]) returns a 10x10 array of samples from the list
% -1:1.  PsychRandSample is a quick way to generate samples (e.g. visual noise)
% from a bounded Gaussian distribution. Also see RAND, RANDN, Randi,
% Sample, and Shuffle.
% 
% "list" can be a double, char, cell, or struct array, but it must be a 
% vector (1xn or nx1). In the future, we may accept matrices (mxn) and treat
% columns separately, as other Matlab functions do.

% Denis Pelli 7/22/97 3/24/98
% 8/14/99 dgp Renamed from "Rands" (which conflicts with Neural Net Toolbox) to
%             "RandSample".
% 6/22/02 dgp Fixed bug. The shape specified by dims was being lost in the table-lookup
%             through "list". I was asking for 256x1 and getting 1x256. Now fixed.
% 7/24/04 awi Cosmetic.
% 12/13/04 dgp & kat Enhanced to support cell arrays.
% 1/22/2012 dgp renamed from RandSample to PsychRandSample to avoid conflict with new MATLAB function.

if nargin<1 || nargin>2 || min(size(list))~=1
	error('Usage: x=PsychRandSample(list,[dims])')
end
if nargin==1
	dims=[1 1];
end
i=ceil(length(list)*rand(dims)); % equivalent to calling Randi.
if iscell(list)
	x=reshape({list{i(:)}},dims);
else
	x=reshape(list(i(:)),dims);
end