Extract submatrix from matrix with particular indexing

I have 3D-array A of size (m,n,p) and matrix B of size (m,n) I want C of size (m,n) such as C(i,j)=A(i,j,b_{i,j})

Is there a simple way to do this without using a loop?

Thank you for helping.

Answer 1

[Roger Stafford]

   AT = reshape(A,m*n,[]);
   C  = reshape(AT((1:m*n).'+m*n*(B(:)-1)),m,n);

[Coriolis]

Thanks :)

[Roger Stafford]

It just occurred to me that only one line is needed:

   C  = reshape(A((1:m*n).'+m*n*(B(:)-1)),m,n);

[Star Strider]

I’m not surprised that you understand it!

+1

(I’m also deleting my Answer.)