hdf5/testpar/t_span_tree.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
   This program will test irregular hyperslab selections with collective write and read.
   The way to test whether collective write and read works is to use independent IO
   output to verify the collective output.

   1) We will write two datasets with the same hyperslab selection settings;
   one in independent mode,
   one in collective mode,
   2) We will read two datasets with the same hyperslab selection settings,
      1.  independent read to read independent output,
          independent read to read collecive   output,
	  Compare the result,
	  If the result is the same, then collective write succeeds.
      2.  collective read to read independent output,
          independent read to read independent output,
	  Compare the result,
	  If the result is the same, then collective read succeeds.

 */

#include "hdf5.h"
#include "H5private.h"
#include "testphdf5.h"


static void coll_write_test(int chunk_factor);
static void coll_read_test(int chunk_factor);


/*-------------------------------------------------------------------------
 * Function:	coll_irregular_cont_write
 *
 * Purpose:	Wrapper to test the collectively irregular hyperslab write in
                contiguous storage
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void
coll_irregular_cont_write(void)
{

  coll_write_test(0);

}



/*-------------------------------------------------------------------------
 * Function:	coll_irregular_cont_read
 *
 * Purpose:	Wrapper to test the collectively irregular hyperslab read in
                contiguous storage
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void
coll_irregular_cont_read(void)
{

  coll_read_test(0);

}


/*-------------------------------------------------------------------------
 * Function:	coll_irregular_simple_chunk_write
 *
 * Purpose:	Wrapper to test the collectively irregular hyperslab write in
                chunk storage(1 chunk)
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void
coll_irregular_simple_chunk_write(void)
{

  coll_write_test(1);

}



/*-------------------------------------------------------------------------
 * Function:	coll_irregular_simple_chunk_read
 *
 * Purpose:	Wrapper to test the collectively irregular hyperslab read in chunk
                storage(1 chunk)
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void
coll_irregular_simple_chunk_read(void)
{

  coll_read_test(1);

}

/*-------------------------------------------------------------------------
 * Function:	coll_irregular_complex_chunk_write
 *
 * Purpose:	Wrapper to test the collectively irregular hyperslab write in chunk
                storage(4 chunks)
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void
coll_irregular_complex_chunk_write(void)
{

  coll_write_test(4);

}



/*-------------------------------------------------------------------------
 * Function:	coll_irregular_complex_chunk_read
 *
 * Purpose:	Wrapper to test the collectively irregular hyperslab read in chunk
                storage(1 chunk)
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void
coll_irregular_complex_chunk_read(void)
{

  coll_read_test(4);

}


/*-------------------------------------------------------------------------
 * Function:	coll_write_test
 *
 * Purpose:	To test the collectively irregular hyperslab write in chunk
                storage
 *  Input:      number of chunks on each dimension
                if number is equal to 0, contiguous storage
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications: Oct 18th, 2005
 *
 *-------------------------------------------------------------------------
 */
void coll_write_test(int chunk_factor)
{

  const    char *filename;
  hid_t    facc_plist,dxfer_plist,dcrt_plist;
  hid_t    file, datasetc,dataseti;      /* File and dataset identifiers */
  hid_t    mspaceid1, mspaceid, fspaceid,fspaceid1; /* Dataspace identifiers */

  hsize_t mdim1[1],fsdim[2],mdim[2];

#if 0
  hsize_t  mdim1[] = {MSPACE1_DIM};  /* Dimension size of the first dataset
				      (in memory) */
  hsize_t  fsdim[] = {FSPACE_DIM1, FSPACE_DIM2}; /* Dimension sizes of the dataset
                                                    (on disk) */

  hsize_t  mdim[] = {MSPACE_DIM1, MSPACE_DIM2}; /* Dimension sizes of the
						  dataset in memory when we
						  read selection from the
						  dataset on the disk */
#endif

  hsize_t  start[2];  /* Start of hyperslab */
  hsize_t  stride[2]; /* Stride of hyperslab */
  hsize_t  count[2];  /* Block count */
  hsize_t  block[2];  /* Block sizes */
  hsize_t  chunk_dims[2];

  herr_t   ret;
  unsigned i,j;
  int      fillvalue = 0;   /* Fill value for the dataset */

#if 0
  int      matrix_out[MSPACE_DIM1][MSPACE_DIM2];
  int      matrix_out1[MSPACE_DIM1][MSPACE_DIM2];   /* Buffer to read from the
						       dataset */
  int      vector[MSPACE1_DIM];
#endif


  int      *matrix_out, *matrix_out1, *vector;

  hbool_t  use_gpfs = FALSE;
  int      mpi_size,mpi_rank;

  MPI_Comm comm = MPI_COMM_WORLD;
  MPI_Info info = MPI_INFO_NULL;

  /*set up MPI parameters */
  MPI_Comm_size(comm,&mpi_size);
  MPI_Comm_rank(comm,&mpi_rank);

  /* Obtain file name */
  filename = GetTestParameters();

  /*
   * Buffers' initialization.
   */

  mdim1[0] = MSPACE1_DIM *mpi_size;
  mdim[0]  = MSPACE_DIM1;
  mdim[1]  = MSPACE_DIM2*mpi_size;
  fsdim[0] = FSPACE_DIM1;
  fsdim[1] = FSPACE_DIM2*mpi_size;

  vector = (int*)HDmalloc(sizeof(int)*mdim1[0]*mpi_size);
  matrix_out  = (int*)HDmalloc(sizeof(int)*mdim[0]*mdim[1]*mpi_size);
  matrix_out1 = (int*)HDmalloc(sizeof(int)*mdim[0]*mdim[1]*mpi_size);

  HDmemset(vector,0,sizeof(int)*mdim1[0]*mpi_size);
  vector[0] = vector[MSPACE1_DIM*mpi_size - 1] = -1;
  for (i = 1; i < MSPACE1_DIM*mpi_size - 1; i++) vector[i] = i;

  /* Grab file access property list */
  facc_plist = create_faccess_plist(comm, info, facc_type, use_gpfs);
  VRFY((facc_plist >= 0),"");

  /*
   * Create a file.
   */
  file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, facc_plist);
  VRFY((file >= 0),"H5Fcreate succeeded");

  /*
   * Create property list for a dataset and set up fill values.
   */
  dcrt_plist = H5Pcreate(H5P_DATASET_CREATE);
  VRFY((dcrt_plist >= 0),"");

  ret   = H5Pset_fill_value(dcrt_plist, H5T_NATIVE_INT, &fillvalue);
  VRFY((ret >= 0),"Fill value creation property list succeeded");

  if(chunk_factor != 0) {
    chunk_dims[0] = fsdim[0] / chunk_factor;
    chunk_dims[1] = fsdim[1] / chunk_factor;
    ret = H5Pset_chunk(dcrt_plist, 2, chunk_dims);
    VRFY((ret >= 0),"chunk creation property list succeeded");
  }

  /*
   *
   * Create dataspace for the first dataset in the disk.
   * dim1 = 9
   * dim2 = 3600
   *
   *
   */
  fspaceid = H5Screate_simple(FSPACE_RANK, fsdim, NULL);
  VRFY((fspaceid >= 0),"file dataspace created succeeded");

  /*
   * Create dataset in the file. Notice that creation
   * property list dcrt_plist is used.
   */
  datasetc = H5Dcreate2(file, "collect_write", H5T_NATIVE_INT, fspaceid, H5P_DEFAULT, dcrt_plist, H5P_DEFAULT);
  VRFY((datasetc >= 0),"dataset created succeeded");

  dataseti = H5Dcreate2(file, "independ_write", H5T_NATIVE_INT, fspaceid, H5P_DEFAULT, dcrt_plist, H5P_DEFAULT);
  VRFY((dataseti >= 0),"dataset created succeeded");

  /* The First selection for FILE
   *
   *  block (3,2)
   *  stride(4,3)
   *  count (1,768/mpi_size)
   *  start (0,1+768*3*mpi_rank/mpi_size)
   *
   */

  start[0]  = FHSTART0;
  start[1]  = FHSTART1 + mpi_rank * FHSTRIDE1 * FHCOUNT1;
  stride[0] = FHSTRIDE0;
  stride[1] = FHSTRIDE1;
  count[0]  = FHCOUNT0;
  count[1]  = FHCOUNT1;
  block[0]  = FHBLOCK0;
  block[1]  = FHBLOCK1;

  ret = H5Sselect_hyperslab(fspaceid, H5S_SELECT_SET, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /* The Second selection for FILE
   *
   *  block  (3,768)
   *  stride (1,1)
   *  count  (1,1)
   *  start  (4,768*mpi_rank/mpi_size)
   *
   */

  start[0]  = SHSTART0;
  start[1]  = SHSTART1+SHCOUNT1*SHBLOCK1*mpi_rank;
  stride[0] = SHSTRIDE0;
  stride[1] = SHSTRIDE1;
  count[0]  = SHCOUNT0;
  count[1]  = SHCOUNT1;
  block[0]  = SHBLOCK0;
  block[1]  = SHBLOCK1;

  ret = H5Sselect_hyperslab(fspaceid, H5S_SELECT_OR, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /*
   * Create dataspace for the first dataset in the memory
   * dim1 = 27000
   *
   */
  mspaceid1 = H5Screate_simple(MSPACE1_RANK, mdim1, NULL);
  VRFY((mspaceid1 >= 0),"memory dataspace created succeeded");

  /*
   * Memory space is 1-D, this is a good test to check
   * whether a span-tree derived datatype needs to be built.
   * block  1
   * stride 1
   * count  6912/mpi_size
   * start  1
   *
   */
  start[0]  = MHSTART0;
  stride[0] = MHSTRIDE0;
  count[0]  = MHCOUNT0;
  block[0]  = MHBLOCK0;

  ret = H5Sselect_hyperslab(mspaceid1, H5S_SELECT_SET, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /* independent write */
  ret = H5Dwrite(dataseti, H5T_NATIVE_INT, mspaceid1, fspaceid, H5P_DEFAULT, vector);
  VRFY((ret >= 0),"dataset independent write succeed");

  dxfer_plist = H5Pcreate(H5P_DATASET_XFER);
  VRFY((dxfer_plist >= 0),"");

  ret = H5Pset_dxpl_mpio(dxfer_plist, H5FD_MPIO_COLLECTIVE);
  VRFY((ret >= 0),"MPIO data transfer property list succeed");
  if(dxfer_coll_type == DXFER_INDEPENDENT_IO) {
     ret = H5Pset_dxpl_mpio_collective_opt(dxfer_plist,H5FD_MPIO_INDIVIDUAL_IO);
     VRFY((ret>= 0),"set independent IO collectively succeeded");
  }


  /* collective write */
  ret = H5Dwrite(datasetc, H5T_NATIVE_INT, mspaceid1, fspaceid, dxfer_plist, vector);
  VRFY((ret >= 0),"dataset collective write succeed");

  ret = H5Sclose(mspaceid1);
  VRFY((ret >= 0),"");

  ret = H5Sclose(fspaceid);
  VRFY((ret >= 0),"");

  /*
   * Close dataset.
   */
  ret = H5Dclose(datasetc);
  VRFY((ret >= 0),"");

  ret = H5Dclose(dataseti);
  VRFY((ret >= 0),"");

  /*
   * Close the file.
   */
  ret = H5Fclose(file);
  VRFY((ret >= 0),"");
  /*
   * Close property list
   */

  ret = H5Pclose(facc_plist);
  VRFY((ret >= 0),"");
  ret = H5Pclose(dxfer_plist);
  VRFY((ret >= 0),"");
  ret = H5Pclose(dcrt_plist);
  VRFY((ret >= 0),"");

  /*
   * Open the file.
   */

  /***

       For testing collective hyperslab selection write
       In this test, we are using independent read to check
       the correctedness of collective write compared with
       independent write,

       In order to throughly test this feature, we choose
       a different selection set for reading the data out.


  ***/

  /* Obtain file access property list with MPI-IO driver */
  facc_plist = create_faccess_plist(comm, info, facc_type, use_gpfs);
  VRFY((facc_plist >= 0),"");

  file = H5Fopen(filename, H5F_ACC_RDONLY, facc_plist);
  VRFY((file >= 0),"H5Fopen succeeded");

  /*
   * Open the dataset.
   */
  datasetc = H5Dopen2(file,"collect_write", H5P_DEFAULT);
  VRFY((datasetc >= 0),"H5Dopen2 succeeded");

  dataseti = H5Dopen2(file,"independ_write", H5P_DEFAULT);
  VRFY((dataseti >= 0),"H5Dopen2 succeeded");

  /*
   * Get dataspace of the open dataset.
   */
  fspaceid  = H5Dget_space(datasetc);
  VRFY((fspaceid >= 0),"file dataspace obtained succeeded");

  fspaceid1 = H5Dget_space(dataseti);
  VRFY((fspaceid1 >= 0),"file dataspace obtained succeeded");


  /* The First selection for FILE to read
   *
   *  block (1,1)
   *  stride(1.1)
   *  count (3,768/mpi_size)
   *  start (1,2+768*mpi_rank/mpi_size)
   *
   */
  start[0]  = RFFHSTART0;
  start[1]  = RFFHSTART1+mpi_rank*RFFHCOUNT1;
  block[0]  = RFFHBLOCK0;
  block[1]  = RFFHBLOCK1;
  stride[0] = RFFHSTRIDE0;
  stride[1] = RFFHSTRIDE1;
  count[0]  = RFFHCOUNT0;
  count[1]  = RFFHCOUNT1;


  /* The first selection of the dataset generated by collective write */
  ret = H5Sselect_hyperslab(fspaceid, H5S_SELECT_SET, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /* The first selection of the dataset generated by independent write */
  ret = H5Sselect_hyperslab(fspaceid1, H5S_SELECT_SET, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /* The Second selection for FILE to read
   *
   *  block (1,1)
   *  stride(1.1)
   *  count (3,1536/mpi_size)
   *  start (2,4+1536*mpi_rank/mpi_size)
   *
   */

  start[0] = RFSHSTART0;
  start[1] = RFSHSTART1+RFSHCOUNT1*mpi_rank;
  block[0] = RFSHBLOCK0;
  block[1] = RFSHBLOCK1;
  stride[0] = RFSHSTRIDE0;
  stride[1] = RFSHSTRIDE0;
  count[0]  = RFSHCOUNT0;
  count[1]  = RFSHCOUNT1;

  /* The second selection of the dataset generated by collective write */
  ret = H5Sselect_hyperslab(fspaceid, H5S_SELECT_OR, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /* The second selection of the dataset generated by independent write */
  ret = H5Sselect_hyperslab(fspaceid1, H5S_SELECT_OR, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /*
   * Create memory dataspace.
   * rank  = 2
   * mdim1 = 9
   * mdim2 = 3600
   *
   */
  mspaceid = H5Screate_simple(MSPACE_RANK, mdim, NULL);

  /*
   * Select two hyperslabs in memory. Hyperslabs has the same
   * size and shape as the selected hyperslabs for the file dataspace
   * Only the starting point is different.
   * The first selection
   *  block (1,1)
   *  stride(1.1)
   *  count (3,768/mpi_size)
   *  start (0,768*mpi_rank/mpi_size)
   *
   */


  start[0]  = RMFHSTART0;
  start[1]  = RMFHSTART1+mpi_rank*RMFHCOUNT1;
  block[0]  = RMFHBLOCK0;
  block[1]  = RMFHBLOCK1;
  stride[0] = RMFHSTRIDE0;
  stride[1] = RMFHSTRIDE1;
  count[0]  = RMFHCOUNT0;
  count[1]  = RMFHCOUNT1;

  ret = H5Sselect_hyperslab(mspaceid, H5S_SELECT_SET, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /*
   * Select two hyperslabs in memory. Hyperslabs has the same
   * size and shape as the selected hyperslabs for the file dataspace
   * Only the starting point is different.
   * The second selection
   *  block (1,1)
   *  stride(1,1)
   *  count (3,1536/mpi_size)
   *  start (1,2+1536*mpi_rank/mpi_size)
   *
   */
  start[0]  = RMSHSTART0;
  start[1]  = RMSHSTART1+mpi_rank*RMSHCOUNT1;
  block[0]  = RMSHBLOCK0;
  block[1]  = RMSHBLOCK1;
  stride[0] = RMSHSTRIDE0;
  stride[1] = RMSHSTRIDE1;
  count[0]  = RMSHCOUNT0;
  count[1]  = RMSHCOUNT1;

  ret = H5Sselect_hyperslab(mspaceid, H5S_SELECT_OR, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /*
   * Initialize data buffer.
   */

  HDmemset(matrix_out,0,sizeof(int)*MSPACE_DIM1*MSPACE_DIM2*mpi_size);
  HDmemset(matrix_out1,0,sizeof(int)*MSPACE_DIM1*MSPACE_DIM2*mpi_size);
  /*
   * Read data back to the buffer matrix_out.
   */

  ret = H5Dread(datasetc, H5T_NATIVE_INT, mspaceid, fspaceid,
		H5P_DEFAULT, matrix_out);
  VRFY((ret >= 0),"H5D independent read succeed");


  ret = H5Dread(dataseti, H5T_NATIVE_INT, mspaceid, fspaceid,
		H5P_DEFAULT, matrix_out1);
  VRFY((ret >= 0),"H5D independent read succeed");

  ret = 0;

  for (i = 0; i < MSPACE_DIM1*MSPACE_DIM2*mpi_size; i++){
         if(matrix_out[i]!=matrix_out1[i]) ret = -1;
      if(ret < 0) break;
    }

  VRFY((ret >= 0),"H5D irregular collective write succeed");

  /*
   * Close memory file and memory dataspaces.
   */
  ret = H5Sclose(mspaceid);
  VRFY((ret >= 0),"");
  ret = H5Sclose(fspaceid);
  VRFY((ret >= 0),"");

  /*
   * Close dataset.
   */
  ret = H5Dclose(dataseti);
  VRFY((ret >= 0),"");

  ret = H5Dclose(datasetc);
  VRFY((ret >= 0),"");

  /*
   * Close property list
   */

  ret = H5Pclose(facc_plist);
  VRFY((ret >= 0),"");


  /*
   * Close the file.
   */
  ret = H5Fclose(file);
  VRFY((ret >= 0),"");

  return ;
}

/*-------------------------------------------------------------------------
 * Function:	coll_read_test
 *
 * Purpose:	To test the collectively irregular hyperslab read in chunk
                storage
 * Input:       number of chunks on each dimension
                if number is equal to 0, contiguous storage
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Unknown
 *		Dec 2nd, 2004
 *
 * Modifications: Oct 18th, 2005
 * Note:        This test must be used with the correpsonding
                coll_write_test.
 *-------------------------------------------------------------------------
 */
void coll_read_test(int chunk_factor)
{

  const   char *filename;
  hid_t   facc_plist,dxfer_plist;
  hid_t   file, dataseti;           /* File and dataset identifiers */
  hid_t   mspaceid, fspaceid1;      /* Dataspace identifiers */


  /* Dimension sizes of the dataset (on disk) */
#if 0
  hsize_t mdim[] = {MSPACE_DIM1, MSPACE_DIM2}; /* Dimension sizes of the
						  dataset in memory when we
						  read selection from the
						  dataset on the disk */

#endif
  hsize_t mdim[2];
  hsize_t  start[2];  /* Start of hyperslab */
  hsize_t  stride[2]; /* Stride of hyperslab */
  hsize_t  count[2];  /* Block count */
  hsize_t  block[2];  /* Block sizes */
  herr_t   ret;

  unsigned i,j;

  int     *matrix_out;
  int     *matrix_out1;
#if 0
  int      matrix_out[MSPACE_DIM1][MSPACE_DIM2];
  int      matrix_out1[MSPACE_DIM1][MSPACE_DIM2];   /* Buffer to read from the
						       dataset */

#endif
  hbool_t  use_gpfs = FALSE;
  int      mpi_size,mpi_rank;

  MPI_Comm comm = MPI_COMM_WORLD;
  MPI_Info info = MPI_INFO_NULL;

  /*set up MPI parameters */
  MPI_Comm_size(comm,&mpi_size);
  MPI_Comm_rank(comm,&mpi_rank);


  /* Obtain file name */
  filename = GetTestParameters();


  /* Initialize the buffer */

  mdim[0] = MSPACE_DIM1;
  mdim[1] = MSPACE_DIM2*mpi_size;
  matrix_out =(int*)HDmalloc(sizeof(int)*MSPACE_DIM1*MSPACE_DIM2*mpi_size);
  matrix_out1=(int*)HDmalloc(sizeof(int)*MSPACE_DIM1*MSPACE_DIM2*mpi_size);

  /*** For testing collective hyperslab selection read ***/

  /* Obtain file access property list */
  facc_plist = create_faccess_plist(comm, info, facc_type, use_gpfs);
  VRFY((facc_plist >= 0),"");

   /*
   * Open the file.
   */
  file = H5Fopen(filename, H5F_ACC_RDONLY, facc_plist);
  VRFY((file >= 0),"H5Fopen succeeded");

  /*
   * Open the dataset.
   */
  dataseti = H5Dopen2(file,"independ_write", H5P_DEFAULT);
  VRFY((dataseti >= 0),"H5Dopen2 succeeded");

  /*
   * Get dataspace of the open dataset.
   */
  fspaceid1 = H5Dget_space(dataseti);
  VRFY((fspaceid1 >= 0),"file dataspace obtained succeeded");

  /* The First selection for FILE to read
   *
   *  block (1,1)
   *  stride(1.1)
   *  count (3,768/mpi_size)
   *  start (1,2+768*mpi_rank/mpi_size)
   *
   */
  start[0]  = RFFHSTART0;
  start[1]  = RFFHSTART1+mpi_rank*RFFHCOUNT1;
  block[0]  = RFFHBLOCK0;
  block[1]  = RFFHBLOCK1;
  stride[0] = RFFHSTRIDE0;
  stride[1] = RFFHSTRIDE1;
  count[0]  = RFFHCOUNT0;
  count[1]  = RFFHCOUNT1;

  ret = H5Sselect_hyperslab(fspaceid1, H5S_SELECT_SET, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /* The Second selection for FILE to read
   *
   *  block (1,1)
   *  stride(1.1)
   *  count (3,1536/mpi_size)
   *  start (2,4+1536*mpi_rank/mpi_size)
   *
   */
  start[0]  = RFSHSTART0;
  start[1]  = RFSHSTART1+RFSHCOUNT1*mpi_rank;
  block[0]  = RFSHBLOCK0;
  block[1]  = RFSHBLOCK1;
  stride[0] = RFSHSTRIDE0;
  stride[1] = RFSHSTRIDE0;
  count[0]  = RFSHCOUNT0;
  count[1]  = RFSHCOUNT1;

  ret = H5Sselect_hyperslab(fspaceid1, H5S_SELECT_OR, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");


  /*
   * Create memory dataspace.
   */
  mspaceid = H5Screate_simple(MSPACE_RANK, mdim, NULL);

  /*
   * Select two hyperslabs in memory. Hyperslabs has the same
   * size and shape as the selected hyperslabs for the file dataspace.
   * Only the starting point is different.
   * The first selection
   *  block (1,1)
   *  stride(1.1)
   *  count (3,768/mpi_size)
   *  start (0,768*mpi_rank/mpi_size)
   *
   */

  start[0]  = RMFHSTART0;
  start[1]  = RMFHSTART1+mpi_rank*RMFHCOUNT1;
  block[0]  = RMFHBLOCK0;
  block[1]  = RMFHBLOCK1;
  stride[0] = RMFHSTRIDE0;
  stride[1] = RMFHSTRIDE1;
  count[0]  = RMFHCOUNT0;
  count[1]  = RMFHCOUNT1;
  ret = H5Sselect_hyperslab(mspaceid, H5S_SELECT_SET, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");

  /*
   * Select two hyperslabs in memory. Hyperslabs has the same
   * size and shape as the selected hyperslabs for the file dataspace
   * Only the starting point is different.
   * The second selection
   *  block (1,1)
   *  stride(1,1)
   *  count (3,1536/mpi_size)
   *  start (1,2+1536*mpi_rank/mpi_size)
   *
   */
  start[0]  = RMSHSTART0;
  start[1]  = RMSHSTART1+mpi_rank*RMSHCOUNT1;
  block[0]  = RMSHBLOCK0;
  block[1]  = RMSHBLOCK1;
  stride[0] = RMSHSTRIDE0;
  stride[1] = RMSHSTRIDE1;
  count[0]  = RMSHCOUNT0;
  count[1]  = RMSHCOUNT1;
  ret = H5Sselect_hyperslab(mspaceid, H5S_SELECT_OR, start, stride, count, block);
  VRFY((ret >= 0),"hyperslab selection succeeded");


  /*
   * Initialize data buffer.
   */

  HDmemset(matrix_out,0,sizeof(int)*MSPACE_DIM1*MSPACE_DIM2*mpi_size);
  HDmemset(matrix_out1,0,sizeof(int)*MSPACE_DIM1*MSPACE_DIM2*mpi_size);

  /*
   * Read data back to the buffer matrix_out.
   */

  dxfer_plist = H5Pcreate(H5P_DATASET_XFER);
  VRFY((dxfer_plist >= 0),"");

  ret = H5Pset_dxpl_mpio(dxfer_plist, H5FD_MPIO_COLLECTIVE);
  VRFY((ret >= 0),"MPIO data transfer property list succeed");
  if(dxfer_coll_type == DXFER_INDEPENDENT_IO) {
     ret = H5Pset_dxpl_mpio_collective_opt(dxfer_plist,H5FD_MPIO_INDIVIDUAL_IO);
     VRFY((ret>= 0),"set independent IO collectively succeeded");
  }


  /* Collective read */
  ret = H5Dread(dataseti, H5T_NATIVE_INT, mspaceid, fspaceid1,
		dxfer_plist, matrix_out);
  VRFY((ret >= 0),"H5D collecive read succeed");

  ret = H5Pclose(dxfer_plist);
  VRFY((ret >= 0),"");

  /* Independent read */
  ret = H5Dread(dataseti, H5T_NATIVE_INT, mspaceid, fspaceid1,
		H5P_DEFAULT, matrix_out1);
  VRFY((ret >= 0),"H5D independent read succeed");

  ret = 0;
  for (i = 0; i < MSPACE_DIM1*MSPACE_DIM2*mpi_size; i++){
      if(matrix_out[i]!=matrix_out1[i])ret = -1;
      if(ret < 0) break;
  }
  VRFY((ret >= 0),"H5D contiguous irregular collective read succeed");

  /*
   * Close memory file and memory dataspaces.
   */
  ret = H5Sclose(mspaceid);
  VRFY((ret >= 0),"");
  ret = H5Sclose(fspaceid1);
  VRFY((ret >= 0),"");

  /*
   * Close dataset.
   */
  ret = H5Dclose(dataseti);
  VRFY((ret >= 0),"");

  /*
   * Close property list
   */
  ret = H5Pclose(facc_plist);
  VRFY((ret >= 0),"");


  /*
   * Close the file.
   */
  ret = H5Fclose(file);
  VRFY((ret >= 0),"");

  return ;
}