function fh = loadBig
% Contrived example to show how one might load a variable once and use it
% without using a PERSISTENT variable.

X = [];
caption = [];
map = [];
load clown
lmap = length(map);
h = image(X); colormap(map);
fh = @changePix;
    function changePix(i,j)
       X(i,j) = round(rand(length(i),length(j))*lmap);  % replace pix with random integers
       set(h,'CData',X);
    end
end

An advantage of this method over persistent is that I can have 2 function handles to this, with different data (don’t hardwire in the filename, for example) and work on them simultaneously. With the persistent solution, I can have only one instance.

function obj = whatever(obj, varargin)

persistent param1 param2

if length(varargin) > 1
param1 = obj.param1;
param2 = obj.param2;
return
end

The function is called with an extra argument in the initialization.