How to implement a MPI filter on C code? -


i trying implement mpi of filter code below, i'm facing difficulties doing it. how should done?:

filter code:

int a[100000][100000]; int b[100000][100000];  (int i=1; i<(100000 - 1); i++)  (int i=1; j<(100000 - 1); j++)   b[i][j] = a[i-1][j] + a[i+1][j] + a[i][j-1] + a[i][j+1] - 4*a[i][j];

this have tried while following 6 functions of mpi:

 int myrank; /* rank of process */     int numprocs; /* number of processes */     int source; /* rank of sender */     int dest; /* rank of receiver */      char message[100]; /* storage message */     mpi_status status; /* return status receive */     mpi_init( & argc, & argv);     mpi_comm_size(mpi_comm_world, & numprocs);     mpi_comm_rank(mpi_comm_world, & myrank);      if (myrank != 0)     {         dest = 0;         mpi_send(message, strlen(message) + 1,           mpi_char, dest, 15, mpi_comm_world);       } else {         (source = 1; source < numprocs; source++) {           mpi_recv(message, 100, mpi_char, source,             15, mpi_comm_world, & status);         }       }       mpi_finalize();

i'd go this. first of all, i'd have code

int a[100000][100000]; int b[100000][100000];

replaced dynamic allocations. don't need memory each , every process.

then, i'd send array different processes. rows.

what "height" of data frame (number of rows):

delta = (100000 - 2) / (numprocs-1);     // don't count first , last row reminder = (100000 - 2) % (numprocs-1);  // might need give                                           // little bit more calculate                                          // 1 of processes  // starting row idx=1 (second row) , want finish when // hit last row if(myrank == 0) {   for( int i=1; < numprocs; i++ ) {     // +100000 - need 2 more rows calculate data     int how_many_bytes = delta * 100000 + 200000;      if(reminder != 0 && == (numprocs-1)) {       how_many_bytes += reminder * 100000;     }     mpi_send(&(a[(i-1)*delta][0]), how_many_bytes, mpi_int, i, 0,                  mpi_comm_world);   } } else {   // allocate memory bytes   int *local_array = null;   int how_many_bytes = delta * 100000 + 200000;    if(reminder != 0 && == (numprocs-1)) {     how_many_bytes += reminder * 100000;   }   local_array = malloc(how_many_bytes * sizeof(int));   mpi_status status;    mpi_recv(     local_array,     how_many_bytes,     mpi_int,     0,     0,     mpi_comm_world,     &status); }   // perform calculations each , every slice // remembering have on row on // top , 1 @ bottom // send data master (as above, vice versa).

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