Hi thanks for the quick response. Yes, that is what I meant. I thought there was no other way around what I am doing but It is always good to ask a expert rather than assume!
Cheers, C.S.N On Thu, Oct 29, 2009 at 11:25 AM, Eugene Loh <eugene....@sun.com> wrote: > Natarajan CS wrote: > > Hello all, >> Firstly, My apologies for a duplicate post in LAM/MPI list I have >> the following simple MPI code. I was wondering if there was a workaround for >> sending a dynamically allocated 2-D matrix? Currently I can send the matrix >> row-by-row, however, since rows are not contiguous I cannot send the entire >> matrix at once. I realize one option is to change the malloc to act as one >> contiguous block but can I keep the matrix definition as below and still >> send the entire matrix in one go? >> > > You mean with one standard MPI call? I don't think so. > > In MPI, there is a notion of derived datatypes, but I'm not convinced this > is what you want. A derived datatype is basically a static template of data > and holes in memory. E.g., 3 bytes, then skip 7 bytes, then another 2 > bytes, then skip 500 bytes, then 1 last byte. Something like that. Your 2d > matrices differ in two respects. One is that the pattern in memory is > different for each matrix you allocate. The other is that your matrix > definition includes pointer information that won't be the same in every > process's address space. I guess you could overcome the first problem by > changing alloc_matrix() to some fixed pattern in memory for some r and c, > but you'd still have pointer information in there that you couldn't blindly > copy from one process address space to another. > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
