It sounds like you have some kind of memory error in your application; you should run your code through a memory-checking debugger, such as valgrind.
On Jul 24, 2013, at 2:44 AM, Zhubq <zhubenqi...@gmail.com> wrote: > >> >> Hi all, >> >> I got a problem when call MPI subroutines in a loop. For example, I have >> Fortran codes to randomly >> select 10 points in a 2D space domain and change the values at those points >> near these 10 points to -10: >> >> real A( (100*rank+1):(100*rank+100),100 ) >> real inmax(2),outmax(2) >> integer maxlocation(2),maxrank >> >> >> call random_number(A) >> maxlocation=maxloc(A); !!! find the coordinates of the local maximum; >> inmax(1)=maxval(A); !!! get the local maximum value >> inmax(2)=myrank; !!!! put the process rank >> do i=1, 10 >> >> call MPI_allreduce(inmax,outmax,1,mpi_2real, >> mpi_maxloc,MPI_comm_world,error) !!!get the global maximum and the >> corresponding rank >> maxrank=outmax(2） >> call >> MPI_Bcast(maxlocation,2,mpi_integer,maxrank,mpi_comm_world,error); >> ... >> let points around maxlocation within distance of 10 equal to -10; >> .... >> enddo >> >> >> The problem is there is runtime error like " segmentation fault". >> But If I put the codes within the loop into a subroutine, then write the >> code as >> do i=1,10 >> call subroutine >> >> enddo >> >> there will be no error. >> >> Another problem is MPI_allreduce seems not as efficient as the combined >> use of " MPI_reduce & MPI_Bcast" to realize the same purpose. >> >> >> Ben > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
