handleClearBenchmarks

function handleClearBenchmarks
%Examine Matlab's "clear" behavior with different reference configurations
%
%   Create N handle objects, store 1-3 references to each.
%
%   Order of object creation, number of references, and configuration of
%   references all have drastic impact on "clear" time as function of
%   number of objects.  Times range from flat, to linear, to quadratic.
%
%   Note the log scale y-axis.
%
%   Using a simple handle class:
%
% % classdef simpleHandle < handle
% %     properties
% %         ref1;
% %         ref2;
% %     end
% %     methods
% %         function self = simpleHandel
% %         end
% %     end
% % end

% [e-mail]
%   Feb. 2009, Seattle, WA

funs = { ...
    @arrayAndDoubleLL, ...
    @doubleLL, ...
    @arrayAndBackwardLL, ...
    @backwardLL, ...
    @array, ...
    @forwardLL};

N = 100;

cla
for ii = 1:length(funs)
    clearTimes = zeros(1,N);
    for jj = 1:N
        clearTimes(jj) = feval(funs{ii}, jj);
    end
    line(1:N, clearTimes, 'Color', dec2bin(ii,3)=='1');
    strs{ii} = func2str(funs{ii});
end
xlabel('number of objects');
ylabel('time to "clear"');
set(gca, 'YScale', 'log');
legend(strs{:}, 'Location', 'NorthWest');

% object refers to previously created object
function clearTime = backwardLL(n)
r1 = simpleHandle;
for ii = 2:n
    r2 = simpleHandle;
    r2.ref1 = r1;
    r1 = r2;
end
tic
clear
clearTime = toc;

% array of objects
function clearTime = array(n)
for ii = n:-1:1
    refs(ii) = simpleHandle;
end
tic
clear
clearTime = toc;

% object refers to subsequently created object
function clearTime = forwardLL(n)
r1 = simpleHandle;
for ii = 2:n
    r2 = simpleHandle;
    r1.ref1 = r2;
    r1 = r2;
end
tic
clear
clearTime = toc;

% object refers to previously and subsequently created objects
function clearTime = doubleLL(n)
r1 = simpleHandle;
for ii = 2:n
    r2 = simpleHandle;
    r1.ref1 = r2;
    r2.ref2 = r1;
    r1 = r2;
end
tic
clear
clearTime = toc;

% array of objects, 
% each refers to previously created object
function clearTime = arrayAndBackwardLL(n)
refs(n) = simpleHandle;
for ii = n-1:-1:1
    refs(ii) = simpleHandle;
    refs(ii+1).ref1 = refs(ii);
end
tic
clear
clearTime = toc;

% array of objects, 
% each refers to previously and subsequently created objects
function clearTime = arrayAndDoubleLL(n)
refs(n) = simpleHandle;
for ii = n-1:-1:1
    refs(ii) = simpleHandle;
    refs(ii).ref1 = refs(ii+1);
    refs(ii+1).ref2 = refs(ii);
end
tic
clear
clearTime = toc;