Hello all Sorry, may be this is a stupid question, bat a have a big problem with maloc() and matrix arrays. I want to make a program that do very simple thing like matriA * matrixB = matrixC. Because I need more matrix size than 100x100 (5000x5000), I have to use maloc() for memory allocation. First I tried this way:
The typical form for dynamically allocating an NxM array of type T is: T **a = malloc(sizeof *a * N); if (a) { for (i = 0; i < N; i++) { a[i] = malloc(sizeof *a[i] * M); } } // the arrays are created before split to nodes No problem with create, fill array,but the problem started when I have send and receive it. Of course before send I calculated "cont" for MPI_Send. To be shore, that the count for MPI_Send i MPI_Recv is the same I also send "count". count = rows*matrix_size*sizeof (double); //part of matrix MPI_Send(&count, 1, MPI_INT, dest, mtype,MPI_COMM_WORLD); MPI_Send(&matrixA[offset][0], count, MPI_DOUBLE, dest, mtype, MPI_COMM_WORLD); from worker side the code looks like: MPI_Recv(&countA, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status); MPI_Recv(&matrixA[0][0], countA, MPI_DOUBLE, source, mtype, MPI_COMM_WORLD, &status); An error looks like: [pawcioj-VirtualBox:01700] *** Process received signal *** [pawcioj-VirtualBox:01700] Signal: Segmentation fault (11) [pawcioj-VirtualBox:01700] Signal code: Address not mapped (1) [pawcioj-VirtualBox:01700] Failing at address: 0x88fa000 [pawcioj-VirtualBox:01700] [ 0] [0xc2740c] [pawcioj-VirtualBox:01700] [ 1] /usr/lib/openmpi/lib/openmpi/mca_pml_ob1.so(+0x906c) [0x17606c] [pawcioj-VirtualBox:01700] [ 2] /usr/lib/openmpi/lib/openmpi/mca_pml_ob1.so(+0x6a1b) [0x173a1b] [pawcioj-VirtualBox:01700] [ 3] /usr/lib/openmpi/lib/openmpi/mca_btl_sm.so(+0x3ae6) [0x7b7ae6] [pawcioj-VirtualBox:01700] [ 4] /usr/lib/libopen-pal.so.0(opal_progress+0x81) [0x406fa1] [pawcioj-VirtualBox:01700] [ 5] /usr/lib/openmpi/lib/openmpi/mca_pml_ob1.so(+0x48e5) [0x1718e5] [pawcioj-VirtualBox:01700] [ 6] /usr/lib/libmpi.so.0(MPI_Recv+0x165) [0x1ef9d5] [pawcioj-VirtualBox:01700] [ 7] macierz_V.02(main+0x927) [0x8049870] [pawcioj-VirtualBox:01700] [ 8] /lib/libc.so.6(__libc_start_main+0xe7) [0xddfce7] [pawcioj-VirtualBox:01700] [ 9] macierz_V.02() [0x8048b71] [pawcioj-VirtualBox:01700] *** End of error message *** -------------------------------------------------------------------------- mpirun noticed that process rank 1 with PID 1700 on node pawcioj-VirtualBox exited on signal 11 (Segmentation fault). Because I have no result, I tied do that by 1D array but the problem seems similar. Probably I do something wrong, so I would like to ask you about advice how do that proper or maybe link to useful tutorial. I spend two weeks to find out how do that but unfortunately without result :(. -- ------------------ pozdrawiam Paweł Jaromin