How to sum frequency of the duplicate value in an array

I have a n-dimensional array that I want to sum in a specifc dimension according to an index array, where I want to sum repeated indexes.

[new_index,~]=unique(Index,'stable');
new_A=arrayfun(@(x) sum(A(:,. . .,Index==x,. . .,:),n),new_index,'UniformOutput',false);

where n is the applied dimension.

It is doind the job very well, the problem is I need to use this property to false.

'UniformOutput',false

and when using with codegen I get this error:

??? For code generation, UniformOutput must be true.

[Darshan Ramakant Bhat]

Unfortuenately this is a documented limitation in "arrayfun"

https://www.mathworks.com/help/matlab/ref/arrayfun.html#d122e47610

[JONATHAN SOARES]

What would be a code which does the job?

I made a palliative solution.

    [new_index,~]=unique(Index,'stable');
    for x = 1:3
        new_A(:,x,:,:) = sum(A(:,. . .,Index==new_index(x),. . .,:),n);
    end

where n is the applied dimension.

But I would like to not implement with loops

[Walter Roberson]

arrayfun() is a loop, just a disguised one.

If you are trying to avoid using arrayfun() thinking that using arrayfun() would surely be faster than using an explicit loop, then you would probably be disappointed when you did timing tests: except for some obscure legacy operations, arrayfun() is typically slower than an explicit loop.