--- /dev/null
+/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
+/*
+ * (C) 2014 by Argonne National Laboratory.
+ * See COPYRIGHT in top-level directory.
+ */
+
+#include "mpi.h"
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+/* A 32^3 array. For other array sizes, change array_of_gsizes below. */
+
+/* Uses nonblocking collective I/O. Writes a 3D block-distributed array to
+ a file corresponding to the global array in row-major (C) order, reads it
+ back, and checks that the data read is correct. */
+
+/* Note that the file access pattern is noncontiguous. */
+
+void handle_error(int errcode, const char *str);
+
+void handle_error(int errcode, const char *str)
+{
+ char msg[MPI_MAX_ERROR_STRING];
+ int resultlen;
+ MPI_Error_string(errcode, msg, &resultlen);
+ fprintf(stderr, "%s: %s\n", str, msg);
+ MPI_Abort(MPI_COMM_WORLD, 1);
+}
+
+int main(int argc, char **argv)
+{
+ MPI_Datatype newtype;
+ int i, ndims, array_of_gsizes[3], array_of_distribs[3];
+ int order, nprocs, j, len;
+ int array_of_dargs[3], array_of_psizes[3];
+ int *readbuf, *writebuf, mynod, *tmpbuf, array_size;
+ MPI_Count bufcount;
+ char *filename;
+ int errs = 0, toterrs;
+ MPI_File fh;
+ MPI_Status status;
+ MPI_Request request;
+ MPI_Info info = MPI_INFO_NULL;
+ int errcode;
+
+ MPI_Init(&argc, &argv);
+ MPI_Comm_rank(MPI_COMM_WORLD, &mynod);
+ MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
+
+ /* process 0 broadcasts the file name to other processes */
+ if (!mynod) {
+ filename = (char*)"testfile";
+ len = strlen(filename);
+ MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
+ MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);
+ }
+ else {
+ MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
+ filename = (char *) malloc(len + 1);
+ MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);
+ }
+
+
+ /* create the distributed array filetype */
+ ndims = 3;
+ order = MPI_ORDER_C;
+
+ array_of_gsizes[0] = 32;
+ array_of_gsizes[1] = 32;
+ array_of_gsizes[2] = 32;
+
+ array_of_distribs[0] = MPI_DISTRIBUTE_BLOCK;
+ array_of_distribs[1] = MPI_DISTRIBUTE_BLOCK;
+ array_of_distribs[2] = MPI_DISTRIBUTE_BLOCK;
+
+ array_of_dargs[0] = MPI_DISTRIBUTE_DFLT_DARG;
+ array_of_dargs[1] = MPI_DISTRIBUTE_DFLT_DARG;
+ array_of_dargs[2] = MPI_DISTRIBUTE_DFLT_DARG;
+
+ for (i = 0; i < ndims; i++)
+ array_of_psizes[i] = 0;
+ MPI_Dims_create(nprocs, ndims, array_of_psizes);
+
+ MPI_Type_create_darray(nprocs, mynod, ndims, array_of_gsizes,
+ array_of_distribs, array_of_dargs,
+ array_of_psizes, order, MPI_INT, &newtype);
+ MPI_Type_commit(&newtype);
+
+ /* initialize writebuf */
+
+ MPI_Type_size_x(newtype, &bufcount);
+ bufcount = bufcount / sizeof(int);
+ writebuf = (int *) malloc(bufcount * sizeof(int));
+ for (i = 0; i < bufcount; i++)
+ writebuf[i] = 1;
+
+ array_size = array_of_gsizes[0] * array_of_gsizes[1] * array_of_gsizes[2];
+ tmpbuf = (int *) calloc(array_size, sizeof(int));
+ MPI_Irecv(tmpbuf, 1, newtype, mynod, 10, MPI_COMM_WORLD, &request);
+ MPI_Send(writebuf, bufcount, MPI_INT, mynod, 10, MPI_COMM_WORLD);
+ MPI_Wait(&request, &status);
+
+ j = 0;
+ for (i = 0; i < array_size; i++)
+ if (tmpbuf[i]) {
+ writebuf[j] = i;
+ j++;
+ }
+ free(tmpbuf);
+
+ if (j != bufcount) {
+ fprintf(stderr, "Error in initializing writebuf on process %d\n", mynod);
+ MPI_Abort(MPI_COMM_WORLD, 1);
+ }
+ /* end of initialization */
+
+ /* write the array to the file */
+ errcode = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE | MPI_MODE_RDWR, info, &fh);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_open");
+
+ errcode = MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", info);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_set_view");
+
+ errcode = MPI_File_iwrite_all(fh, writebuf, bufcount, MPI_INT, &request);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_iwrite_all");
+ MPI_Wait(&request, &status);
+
+ errcode = MPI_File_close(&fh);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_close");
+
+ if (!mynod) {
+ /* wkl suggests potential for false " No Errors" if both read
+ * and write use the same file view */
+ /* solution: rank 0 reads entire file and checks write values */
+ errcode = MPI_File_open(MPI_COMM_SELF, filename, MPI_MODE_RDONLY, info, &fh);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_open");
+
+ readbuf = (int *) malloc(array_size * sizeof(int));
+ errcode = MPI_File_read(fh, readbuf, array_size, MPI_INT, &status);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_read");
+
+ errcode = MPI_File_close(&fh);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_close");
+
+ for (i = 0; i < array_size; i++)
+ if (readbuf[i] != i) {
+ errs++;
+ fprintf(stderr, "Error: write integer %d but read %d\n", i, readbuf[i]);
+ break;
+ }
+ free(readbuf);
+ }
+ MPI_Barrier(MPI_COMM_WORLD);
+
+ /* now read it back */
+ readbuf = (int *) malloc(bufcount * sizeof(int));
+ errcode = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE | MPI_MODE_RDWR, info, &fh);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_open");
+
+ errcode = MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", info);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_set_view");
+ errcode = MPI_File_iread_all(fh, readbuf, bufcount, MPI_INT, &request);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_iread_all");
+ MPI_Wait(&request, &status);
+ errcode = MPI_File_close(&fh);
+ if (errcode != MPI_SUCCESS)
+ handle_error(errcode, "MPI_File_close");
+
+ /* check the data read */
+ for (i = 0; i < bufcount; i++) {
+ if (readbuf[i] != writebuf[i]) {
+ errs++;
+ fprintf(stderr, "Process %d, readbuf %d, writebuf %d, i %d\n",
+ mynod, readbuf[i], writebuf[i], i);
+ }
+ }
+
+ MPI_Allreduce(&errs, &toterrs, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
+ if (mynod == 0) {
+ if (toterrs > 0) {
+ fprintf(stderr, "Found %d errors\n", toterrs);
+ }
+ else {
+ fprintf(stdout, " No Errors\n");
+ }
+ }
+
+ MPI_Type_free(&newtype);
+ free(readbuf);
+ free(writebuf);
+ if (mynod)
+ free(filename);
+
+ MPI_Finalize();
+ return 0;
+}
