Question

I have Matrix A:

A= [ 1 1 0 2 2 2 2 0 0 3 3 0 0;
     0 1 1 0 0 2 2 2 2 3 3 0 0 ];

and I want to make another matrix B, so that this matrix contains the number of value occurences of the original matrix A: ie each iith row of B contains how many times ii occurs in the corresponding columns of A. The number 0 may be ignored.

For example: in the 2nd column of A, only the number 1 occurs, to be specific two times –> hence B(1,2) = 2 and B(other,2) = 0.

For my example matrix A, the output should be

Res = [ 1 2 1 0 0 0 0 0 0 0 0 0 0;
        0 0 0 1 1 2 2 1 1 0 0 0 0;
        0 0 0 0 0 0 0 0 0 2 2 0 0 ];

Answer 1

You can use

A= [ 1 1 0 2 2 2 2 0 0 3 3 0 0;
     0 1 1 0 0 2 2 2 2 3 3 0 0 ];


cell2mat(arrayfun(@(b) sum(A == b),nonzeros(unique(A)), 'UniformOutput', false))

This results in

ans =

     1     2     1     0     0     0     0     0     0     0     0     0     0
     0     0     0     1     1     2     2     1     1     0     0     0     0
     0     0     0     0     0     0     0     0     0     2     2     0     0

If, as asked in the comments, the matrix a has three dimensions, you need to sum the result along the third dimension:

sum(cell2mat(arrayfun(@(b) sum(A == b,1),nonzeros(unique(A)), 'UniformOutput', false)),3)