Hello,
My solution for A9 is to split the domain over the rows of rho: (i.e if I have two processes, process 1 runs the for loop from 1 to 1023, and process 2 runs the for loop from 1024 to 2047)
I am also using MPI_REDUCE at the end to sum up all the partial sums.
However, when debugging, I notice that splitting the for loop like this doesn't work. In the for loop above, a+b != t. Why? Sorry if I'm missing something super obvious