MatLab: Variable assigned during function can be used in another function

Question

I have a function with an output q. This function will generate a matrix, A, in order to find q. Matrix A is 100x100x100, so it takes a really long time to run this code and I want to do (lots) of other calculations with the information from A without having to run that code over and over again.

Is there a way to make both q and A (q has dimensions 100x1) accessible in another function without running the original function each time?

I though about using "global" but I'm not sure how that works.

Answer 1

You can use

assignin('base', 'var1', var1)

To assign variable var in the base work-space. This will allow you to parse it to other functions and it will persist.

Alternatively you can simply return it:

function [other_vars var1] = theFunk(input)

Then to use it in other functions you can make it global:

global VAR_GLOBAL = var;

and in your function use:

function [stuff] = someOtherFunction(input)
    global VAR_GLOBAL
    % Do some stuff with VAR_GLOBAL

or simply pass it into your other functions:

function [stuff] = someOtherFunction(input, var1)

Answer 2

It appears to me that your function is doing two separate things, and needs some refactoring...

Consider extracting the part that computes the matrix A into a separate function. The other function will take the produced matrix A as input and compute the output q . Otherwise known as the "Extract Till You Drop" principle :)