adding two matrices with different descriptors

[Monika Wierse]

Hello all,
I'm new to Scalapack and do have a simple question.
Let's assume I have two matrices A and A1 with same size (M x N), but different distributed over the processor grid (both having different descriptors).

How would I implement: A = A - A1?

Is this the way to go?

do I = 1,N
* do it for each column
CALL PDAXPY(M,-1.d0,A1,1, I,DESCA1,1,A, 1,I, DESCA, 1)
enddo

Many thanks,
Monika