MATLAB: Problem with rng shuffle

rngshuffle

Hello everyone, I am running my simulation for like 50000 iterations but when i use

rng('shuffle')

during each iteration, the processing speed of my computer gets very slow. I want to understand that why this one line of code has so much effect on my computer ?

Best Answer

As Sean said, don't reset the random number generator in a loop. There's no good reason to do it. You are NOT making your random number "more random", and in fact, you are likely making them less random in very complicated ways. DON'T DO THIS. I can't say that strongly enough.

'shuffle' pauses for .01s each time you call it to ensure that it uses a new seed that's different than the last time you called it. That's why it's slowing down your code.

Related Solutions

MATLAB: Randomization measure in rand

2^53 different possibilities.

You should also be caring about how long the period is (that is, the time until the sequence repeats.) It is on the order of 2^11000 for the default randomization routine.

MATLAB: How to set a global random seed in a GUI

You're on the right track. Choose a random seed when the GUI initializes and store it in your GUI using guidata() so all components have access to it and can reseed it whenever necessary.

Here's a demo. Based on your examples, I'm assuming you're not using app designer.

% At the end of the GUI opening function
function myOpeningFcn(hObject, . . .)
. . .
handles.rngSeed = randi(2^32 - 1); 
guidata(hObject, handles); 
end
% Some callback function
function myCallbackFcn(. . ., handles)
. . .
rng(handles.rngSeed)
end

Another good idea would be to add the following line to your closereq function so that your rng seed is randomized again.

rng shuffle

Best Answer

Related Solutions

MATLAB: Randomization measure in rand

MATLAB: How to set a global random seed in a GUI

Related Question