Jos (10584)

Indeed poorly coded using an unnecessary double-for loop (with pre-allocation though!), limited to 2D sqaure matrices only.

A vectorized, (too!) simple and flexible approach:

function R = rand01(varargin)
% H1 line goes here
% help goes here
R = 2*(rand(varargin{:})>0.5)-1 ;

Hmm, you should definitely improve the help! This is what "help rank" returns:
UNTITLED2 Summary of this function goes here
   Detailed explanation goes here

Also choose a better name, as RANK is already taken by matlab itself.

What an elegant piece of code! Thanks for this.

% I had to comment-out uistack(h,'bottom') for an imagesc plot
% (Otherwise, the grid lines are not visible.)
% These examples worked for me & simplified some aspects of using this function:
gridxy(get(gca,'XTick'),get(gca,'YTick'), 'Color',[1,1,1]*0.4,'Linestyle',':');

gridxy(get(gca,'XTick'),get(gca,'YTick'), 'Color','y','Linestyle',':');

Very nice!