From 884b83d6069d3a90482203dd665dc49965fdc5a4 Mon Sep 17 00:00:00 2001
From: Albert Cheng <acheng@hdfgroup.org>
Date: Mon, 9 Oct 2000 21:32:45 -0500
Subject: [svn-r2646] Purpose:     Bug fix (done by Kim Yates) Description:    
 The optimized mpio code was broken and when read was done, it hanged.
 Solution: H5FDmpio.c:     In H5FD_mpio_write, moved the 16-line block of code
 in which     all procs other than p0 skip the actual write     to be just
 before the call to MPI_File_write_at.     Previously, the values of the local
 vars that controlled     "allsame" were not always set correctly when the
 moved block     was reached. H5S.c:     Changed default value of
 H5_mpi_opt_types_g to TRUE, so that     the MPI-IO hyperslab code is executed
 by default in parallel HDF5,     rather than executing the serial hyperslab
 code. H5Smpio.c:     In function H5S_mpio_hyper_type, added a call to free   
  an intermediate type. Cures a small memory leak.     Added code for cases of
 empty hyperslab     Changed displacements to be MPI_Aint Platforms tested:   
  modi4 -64: worked fine with mpich 1.2.0 but failed with the messages    
 saying it ran out of entries for MPI_Types during the collective_read    
 test.  After tracing the code all the way to the collective read, all     MPI
 Types have been freed properly.  It aborted with the above message     when
 it executed the line if (MPI_SUCCESS!= MPI_File_read_at_all(file->f, mpi_off,
 buf, size_i, buf_type, &mpi_stat ))     Could not see any problem with this
 line.  It could be a bug in the     SGI version of MPI.

---
 src/H5S.c     |  2 +-
 src/H5Smpio.c | 32 +++++++++++++++++++++++++++-----
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/H5S.c b/src/H5S.c
index 94949e5..485d92f 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -42,7 +42,7 @@ static size_t			H5S_nconv_g = 0;	/*entries used*/
 
 #ifdef H5_HAVE_PARALLEL
 /* Global var whose value comes from environment variable */
-hbool_t         H5_mpi_opt_types_g = FALSE;
+hbool_t         H5_mpi_opt_types_g = TRUE;
 #endif
 
 /* Declare a free list to manage the H5S_simple_t struct */
diff --git a/src/H5Smpio.c b/src/H5Smpio.c
index 87ecd30..0c4c6e1 100644
--- a/src/H5Smpio.c
+++ b/src/H5Smpio.c
@@ -126,6 +126,9 @@ H5S_mpio_all_type( const H5S_t *space, const size_t elmt_size,
  * Programmer:	rky 980813
  *
  * Modifications:  ppw 990401
+ *		rky, ppw 2000-09-26 Freed old type after creating struct type.
+ *		rky 2000-10-05 Changed displacements to be MPI_Aint.
+ *		rky 2000-10-06 Added code for cases of empty hyperslab.
  *
  *-------------------------------------------------------------------------
  */
@@ -145,20 +148,23 @@ H5S_mpio_hyper_type( const H5S_t *space, const size_t elmt_size,
     } d[32];
 
     int			i, err, new_rank, num_to_collapse;
-    int			offset[32], max_xtent[32], block_length[2], displacement[2];
+    int			offset[32], max_xtent[32], block_length[2];
     H5S_hyper_dim_t	*diminfo;		/* [rank] */
     intn		rank;
     MPI_Datatype	inner_type, outer_type, old_type[32];
-    MPI_Aint            extent_len;
+    MPI_Aint            extent_len, displacement[2];
 
     FUNC_ENTER (H5S_mpio_hyper_type, FAIL);
 
     /* Check and abbreviate args */
     assert (space);
+    assert(sizeof(MPI_Aint) >= sizeof(elmt_size));
     diminfo = space->select.sel_info.hslab.diminfo;
     assert (diminfo);
     rank = space->extent.u.simple.rank;
     assert (rank >= 0);
+    if (0==rank) goto empty;
+    if (0==elmt_size) goto empty;
 
     /* make a local copy of the dimension info so we can transform them */
     assert(rank<=32);	/* within array bounds */
@@ -175,6 +181,9 @@ H5S_mpio_hyper_type( const H5S_t *space, const size_t elmt_size,
 	if (i==0) fprintf(stdout, "  rank=%d\n", rank );
 	else	  fprintf(stdout, "\n" );
 #endif
+	if (0==d[i].block) goto empty;
+	if (0==d[i].count) goto empty;
+	if (0==d[i].xtent) goto empty;
     }
     
 /**********************************************************************
@@ -232,11 +241,11 @@ H5S_mpio_hyper_type( const H5S_t *space, const size_t elmt_size,
     } /* end for */
     num_to_collapse = i;
     if (num_to_collapse == rank) num_to_collapse--;
-    printf ("num_to_collapse=%d\n", num_to_collapse);
 
     assert(0<=num_to_collapse && num_to_collapse<rank);
     new_rank = rank - num_to_collapse;
 #ifdef H5Smpi_DEBUG
+    fprintf(stdout, "num_to_collapse=%d\n", num_to_collapse);
     fprintf(stdout, "hyper_type: new_rank=%d\n", new_rank );
 #endif
 
@@ -389,6 +398,10 @@ H5S_mpio_hyper_type( const H5S_t *space, const size_t elmt_size,
       if (err) {
          HRETURN_ERROR(H5E_DATASPACE, H5E_MPI, FAIL,"couldn't create MPI struct type");
       }
+      MPI_Type_free (&old_type[0]);
+      if (err) {
+            HRETURN_ERROR(H5E_DATASPACE, H5E_MPI, FAIL,"couldn't resize MPI vector type");
+      }
     }
     else {
       *new_type = inner_type;
@@ -402,9 +415,18 @@ H5S_mpio_hyper_type( const H5S_t *space, const size_t elmt_size,
     /* fill in the remaining return values */
     *count = 1;			/* only have to move one of these suckers! */
     *is_derived_type = 1;
+    goto done;
+
+empty:
+    /* special case: empty hyperslab */
+    *new_type = MPI_BYTE;
+    *count = 0;
+    *is_derived_type = 0;
 
+done:
 #ifdef H5Smpi_DEBUG
-    fprintf(stdout, "Leave %s\n", FUNC );
+    HDfprintf(stdout, "Leave %s, count=%Hu  is_derived_type=%d\n",
+		FUNC, *count, *is_derived_type );
 #endif
     FUNC_LEAVE (SUCCEED);
 }
@@ -574,7 +596,7 @@ H5S_mpio_spaces_xfer(H5F_t *f, const struct H5O_layout_t *layout,
     /* calculate the absolute base addr (i.e., the file view disp) */
     disp = f->shared->base_addr + layout->addr;
 #ifdef H5Smpi_DEBUG
-    fprintf(stdout, "spaces_xfer: disp=%Hu\n", disp.offset );
+    HDfprintf(stdout, "spaces_xfer: disp=%Hu\n", disp );
 #endif
 
     /* Effective address determined by base addr and the MPI file type */
-- 
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