91 строка
2.6 KiB
C
91 строка
2.6 KiB
C
/* -*- Mode: C; c-basic-offset:4 ; -*- */
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#include "mpi.h"
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#include "mpio.h" /* not necessary with MPICH 1.1.1 or HPMPI 1.4 */
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#define SIZE (65536)
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/* Uses asynchronous I/O. Each process writes to separate files and
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reads them back. The file name is taken as a command-line argument,
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and the process rank is appended to it.*/
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int main(int argc, char **argv)
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{
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int *buf, i, rank, nints, len;
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char *filename, *tmp;
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MPI_File fh;
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MPI_Status status;
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MPIO_Request request;
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MPI_Init(&argc,&argv);
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MPI_Comm_rank(MPI_COMM_WORLD, &rank);
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/* process 0 takes the file name as a command-line argument and
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broadcasts it to other processes */
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if (!rank) {
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i = 1;
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while ((i < argc) && strcmp("-fname", *argv)) {
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i++;
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argv++;
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}
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if (i >= argc) {
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fprintf(stderr, "\n*# Usage: async -fname filename\n\n");
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MPI_Abort(MPI_COMM_WORLD, 1);
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}
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argv++;
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len = strlen(*argv);
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filename = (char *) malloc(len+10);
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strcpy(filename, *argv);
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MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
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MPI_Bcast(filename, len+10, MPI_CHAR, 0, MPI_COMM_WORLD);
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}
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else {
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MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
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filename = (char *) malloc(len+10);
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MPI_Bcast(filename, len+10, MPI_CHAR, 0, MPI_COMM_WORLD);
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}
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buf = (int *) malloc(SIZE);
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nints = SIZE/sizeof(int);
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for (i=0; i<nints; i++) buf[i] = rank*100000 + i;
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/* each process opens a separate file called filename.'myrank' */
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tmp = (char *) malloc(len+10);
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strcpy(tmp, filename);
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sprintf(filename, "%s.%d", tmp, rank);
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MPI_File_open(MPI_COMM_SELF, filename, MPI_MODE_CREATE | MPI_MODE_RDWR,
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MPI_INFO_NULL, &fh);
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MPI_File_set_view(fh, 0, MPI_INT, MPI_INT, "native", MPI_INFO_NULL);
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MPI_File_iwrite(fh, buf, nints, MPI_INT, &request);
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MPIO_Wait(&request, &status);
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MPI_File_close(&fh);
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/* reopen the file and read the data back */
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for (i=0; i<nints; i++) buf[i] = 0;
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MPI_File_open(MPI_COMM_SELF, filename, MPI_MODE_CREATE | MPI_MODE_RDWR,
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MPI_INFO_NULL, &fh);
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MPI_File_set_view(fh, 0, MPI_INT, MPI_INT, "native", MPI_INFO_NULL);
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MPI_File_iread(fh, buf, nints, MPI_INT, &request);
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MPIO_Wait(&request, &status);
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MPI_File_close(&fh);
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/* check if the data read is correct */
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for (i=0; i<nints; i++)
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if (buf[i] != (rank*100000 + i))
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fprintf(stderr, "Process %d: error, read %d, should be %d\n", rank, buf[i], rank*100000+i);
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if (!rank) fprintf(stderr, "Done\n");
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free(buf);
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free(filename);
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free(tmp);
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MPI_Finalize();
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return 0;
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}
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