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/* Staged write example code.
Assumptions:
- one output step fits into the memory of the staged writer.
Actually, this means, even more memory is needed than the size of output.
We need to read each variable while also buffering all of them for output.
- output steps contain the same variable set (no changes in variables)
- attributes are the same for all steps (will write only once here)
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include "adios_read.h"
#include "adios_error.h"
// Input arguments
enum ADIOS_READ_METHOD read_method = ADIOS_READ_METHOD_BP;
static const int max_read_buffer_size = 1024*1024*1024;
static const int max_write_buffer_size = 1024*1024*1024;
static int timeout_sec = 30; // will stop if no data found for this time (-1: never stop)
// Global variables
int rank, numproc;
MPI_Comm comm;
ADIOS_FILE *f; // stream for reading
int64_t fh; // ADIOS output file handle
int64_t gh; // ADIOS group for output definitions
uint64_t write_total; // data size written by one processor
uint64_t largest_block; // the largest variable block one process reads
char ** group_namelist; // name of ADIOS group
char *readbuf; // read buffer
int decomp_values[10];
int process_metadata();
int read_records();
int main (int argc, char ** argv)
{
int err;
int steps = 0, curr_step;
int retval = 0;
MPI_Init (&argc, &argv);
comm = MPI_COMM_WORLD;
MPI_Comm_rank (comm, &rank);
MPI_Comm_size (comm, &numproc);
char infilename[] = "steps.bp";
err = adios_read_init_method(ADIOS_READ_METHOD_BP, comm,
"max_chunk_size=100; "
"app_id =32767; \n"
"verbose= 3;"
"poll_interval = 100;"
);
if (!err) {
printf ("%s\n", adios_errmsg());
}
printf ("Waiting to open stream %s...\n", infilename);
f = adios_read_open_file (infilename, read_method, comm);
if (adios_errno == err_file_not_found)
{
printf ("rank %d: Stream not found after waiting %d seconds: %s\n",
rank, timeout_sec, adios_errmsg());
retval = adios_errno;
}
else if (adios_errno == err_end_of_stream)
{
printf ("rank %d: Stream terminated before open. %s\n", rank, adios_errmsg());
retval = adios_errno;
}
else if (f == NULL) {
printf ("rank %d: Error at opening stream: %s\n", rank, adios_errmsg());
retval = adios_errno;
}
else
{
// read data here...
/*
printf ("File info:\n");
printf (" current step: %d\n", f->current_step);
printf (" last step: %d\n", f->last_step);
printf (" # of variables: %d:\n", f->nvars);
*/
retval = process_metadata();
retval = read_records();
adios_read_close (f);
}
adios_read_finalize_method (read_method);
MPI_Finalize ();
return retval;
}
ADIOS_VARINFO * varinfo;
int NX, Width;
int process_metadata()
{
int retval = 0;
int i, j;
char gdims[256], ldims[256], offs[256];
uint64_t sum_count;
ADIOS_VARINFO *v; // shortcut pointer
/* First step processing */
printf ("Get info on variable Width\n");
v = adios_inq_var (f, "Width");
if (v == NULL) {
printf ("rank %d: ERROR: Variable %s inquiry failed: %s\n",
rank, "Width", adios_errmsg());
return 1;
}
Width = *(int *)v->value;
adios_free_varinfo (v);
printf ("rank %d: Width = %d\n", rank, Width);
printf ("Get info on variable NX\n");
v = adios_inq_var (f, "NX");
if (v == NULL) {
printf ("rank %d: ERROR: Variable %s inquiry failed: %s\n",
rank, "NX", adios_errmsg());
return 1;
}
NX = *(int *)v->value;
adios_free_varinfo (v);
printf ("rank %d: NX = %d\n", rank, NX);
printf ("Get info on variable record: %s\n", "record");
varinfo = adios_inq_var (f, "record"); // need this struct to the end of reading
if (varinfo == NULL) {
printf ("rank %d: ERROR: Variable %s inquiry failed: %s\n",
rank, "record", adios_errmsg());
return 1;
}
printf ("rank %d: record dims = %" PRIu64 " * %" PRIu64 " \n", rank, varinfo->dims[0], varinfo->dims[1]);
printf ("rank %d: total nblocks = %d in %d steps\n",
rank, varinfo->sum_nblocks, varinfo->nsteps);
return retval;
}
int read_records()
{
int retval = 0;
int i,j;
int N = varinfo->sum_nblocks/numproc;
int startidx=N*rank;
char *text;
text = malloc (Width*NX+1);
text[Width*NX] = 0;
for (i=0; i<N; i++)
{
memset (text, '+', Width*NX);
// read one block of record
//printf ("rank %d: Read block %d\n", rank, startidx+i);
ADIOS_SELECTION *sel = adios_selection_writeblock (startidx+i);
adios_schedule_read (f, sel, "record", 0, 1, text);
adios_perform_reads (f, 1);
adios_selection_delete (sel);
printf ("block %2d = ", startidx+i);
for (j=0; j<NX; j++)
printf ("[%s]", text+j*Width);
printf ("\n");
}
adios_free_varinfo (varinfo); // now we don't need this struct
return retval;
}
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