Creating new variable in a subfunction .m file

Here's the case, I have one main matlab file (main.m) and another sub matlab file (sub.m)

And I need to loop over main.m multiple times to execute sub.m, is it possible to create a new array containing the output of the sub.m? Or I must have a global variable declared and include it in the function

Let this be the case:

 First loop:
      A=[1 2 3 4 5];

 Second loop:
      A=[2 8 5 9 6];

 Nth loop:
      A=[x x x x x];

I need to create an array in the subfunction so that it is able to recognize and store all the maximum of As in the loop

Max_A=
        5
        9
        .
        .
        N

Answer 1

[Shameer Parmar]

file 1

function main()
% your code
for loop for calling the sub () for N number of time
% your code which calculating the following 1x5 array.
% A = [1 2 3 4 5]     % this is just example
% now pass this array as input to sub () like
max{i} = sub(A).....% here you passing A array to sub() and it giving you max value which store into another array max.
end of for loop.

file 2

% following code for sub()
function output = sub(inputArray)
output = max(inputArray);
% end of function sub()

So in this way you are calling sub function for N number of time and all time it giving you max value which store into new aray Max, so at the end you will get all max values in variable Max.

Answer 2

[per isakson]

No globals needed. Try

%%in main
R = nan( N, 5 ); % pre-allocate memory
for jj = 1 : N
    R(jj,:) = sub();
end

I don't get the last part. Why not simply add after the loop

max_A = max( R, 2 );

[Wei Nick Chan]

because I need to run that particular function multiple times in the main .m file. I need to export part of the variable created in the subfunction out to the main function so that all the data can be combined instead of overwriting each other

[per isakson]

"instead of overwriting each other" &nbsp the code I proposed doesn't overwrite.

If the problem is that R outgrows the physical memory (RAM), then you need to store to a file.

See matfile, Access and change variables directly in MAT-files, without loading into memory

[per isakson]

• "particular function" &nbsp I assume that's sub
• Is max values from previous calls used in sub? If so, sub has state. You could use a persistent variable to keep previous max values. However, there must be a better way.