How to set a global random seed in a GUI?

Can you just do something like handles.rng('default') and then handles.rng(1) to initialize a seed and reinitialize the same seed later in the code?

Not sure how to go about this. I need a global random seed that I can reinitialize (with the same seed) in different callback functions (and functions called within callback functions).

Answer 1

[Adam Danz]

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

[Ajay Peddada]

Thanks! Why do you do randi(2^32-1)? I’m confused how this creates a new seed instead of just generating a random number between 0 and (2^32-1)

Edit: rather - why don’t you do rng(randi(2^32-1))?

[Adam Danz]

randi(2^32-1) merely chooses a random seed. Seeds are positive integers that must be less than or equal to that number in randi().

Once you have chosen a random integer, that value will be available anywhere in your code to be re-seeded using rng(). If you wanted to re-seed when you open the gui, you could run that line if your comment above. I was under the impression that you'd like to re-seed with the same value at different places in your GUI.

[Ajay Peddada]

I see. To clarify - I will always be able to sample from the same “random” distribution in any matlab session as long as I seed the generator with the positive integer each time?