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/*********************************************************************
*
* Copyright (C) 2012, Northwestern University and Argonne National Laboratory
* See COPYRIGHT notice in top-level directory.
*
*********************************************************************/
/* $Id$ */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include <pnetcdf.h>
#define ERRCODE 2
#define ERR(e) {printf("Error at line %d: err=%d %s\n", __LINE__, e, ncmpi_strerror(e)); exit(ERRCODE);}
/*----< main() >------------------------------------------------------------*/
int main(int argc, char **argv) {
int i, j, ncid, dimid[2], varid, err, rank, nprocs, cmode;
int req[2], status[2];
float var[4][6];
char filename[256];
MPI_Offset start[2], count[2], stride[2], imap[2];
MPI_Offset bufsize;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
if (argc > 2) {
if (rank == 0) printf("Usage: %s filename\n", argv[0]);
MPI_Finalize();
exit(-1);
}
if (argc > 1) snprintf(filename, 256, "%s", argv[1]);
else strcpy(filename, "testfile.nc");
cmode = NC_CLOBBER | NC_64BIT_DATA;
if (NC_NOERR != (err = ncmpi_create(MPI_COMM_WORLD, filename,
cmode, MPI_INFO_NULL, &ncid)))
ERR(err);
/* define a variable of a 6 x (4*nprocs) int64 array in the nc file */
if (NC_NOERR != (err = ncmpi_def_dim(ncid, "Y", 6, &dimid[0])))
ERR(err);
if (NC_NOERR != (err = ncmpi_def_dim(ncid, "X", 4*nprocs, &dimid[1])))
ERR(err);
if (NC_NOERR != (err = ncmpi_def_var(ncid, "var", NC_INT64, 2, dimid,
&varid)))
ERR(err);
if (NC_NOERR != (err = ncmpi_enddef(ncid)))
ERR(err);
/* set the contents of the local write buffer var, a 4 x 6 float array
for example, for rank == 2, var[4][6] =
48, 49, 50, 51, 52, 53,
54, 55, 56, 57, 58, 59,
60, 61, 62, 63, 64, 65,
66, 67, 68, 69, 70, 71
*/
for (j=0; j<4; j++)
for (i=0; i<6; i++)
var[j][i] = j*6+i + rank*24;
/* bufsize must be the max of data type converted before and after */
bufsize = 4*6*sizeof(long long); /* as var is of NC_INT64 */
if (NC_NOERR != (err = ncmpi_buffer_attach(ncid, bufsize)))
ERR(err);
/* write var to the NC variable in the matrix transposed way */
count[0] = 6; count[1] = 2;
stride[0] = 1; stride[1] = 1;
imap[0] = 1; imap[1] = 6;
/* write to the 1st two columns of the variable in matrix transposed way */
start[0] = 0;
start[1] = rank*4;
if (NC_NOERR != (err = ncmpi_bput_varm_float(ncid, varid, start, count,
stride, imap, &var[0][0], &req[0])))
ERR(err);
/* write to the 2nd two columns of the variable in transposed way */
start[0] = 0;
start[1] = rank*4+2;
if (NC_NOERR != (err = ncmpi_bput_varm_float(ncid, varid, start, count,
stride, imap, &var[2][0], &req[1])))
ERR(err);
/* You are now free to change contents of the buffer, var.
It will not change the data supposed to be written in the file.
*/
for (j=0; j<4; j++)
for (i=0; i<6; i++)
var[j][i] = -1.1; /* or any numbers */
if (NC_NOERR != (err = ncmpi_wait_all(ncid, 2, req, status)))
ERR(err);
/* check each bput status */
for (i=0; i<2; i++)
if (status[i] != NC_NOERR) ERR(status[i]);
if (NC_NOERR != (err = ncmpi_buffer_detach(ncid)))
ERR(err);
if (NC_NOERR != (err = ncmpi_close(ncid))) ERR(err);
/* The output from command "ncmpidump test.nc" is shown below if run
this example on 4 processes.
netcdf test {
// file format: CDF-5 (big variables)
dimensions:
Y = 6 ;
X = 16 ;
variables:
int64 var(Y, X) ;
data:
var =
0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90,
1, 7, 13, 19, 25, 31, 37, 43, 49, 55, 61, 67, 73, 79, 85, 91,
2, 8, 14, 20, 26, 32, 38, 44, 50, 56, 62, 68, 74, 80, 86, 92,
3, 9, 15, 21, 27, 33, 39, 45, 51, 57, 63, 69, 75, 81, 87, 93,
4, 10, 16, 22, 28, 34, 40, 46, 52, 58, 64, 70, 76, 82, 88, 94,
5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89, 95 ;
<---- P0 ---->|<---- P1 ----->|<---- P2 ----->|<---- P3 ---->
*/
MPI_Finalize();
return 0;
}
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