Hi,
I've installed openmpi-3.1.0 on my "SUSE Linux Enterprise Server
12.3 (x86_64)" with gcc-6.4.0. Why do I get "extent: 0" instead of
"extent: 1" for my small program. In my opinion the extent of the
old data type and the resized extent of the new data type should
be the same. Am I wrong, is something wrong with my program, or
results the unexpected value from an error of the MPI Java method
getExtent() for a derived data type? I get the value 1, if I use
MPI.DOUBLE.getSize() or MPI.DOUBLE.getExtent().
loki java 130 which \mpijavac
/usr/local/openmpi-3.1.0_64_gcc/bin/mpijavac
loki java 131 \mpijavac SizeExtentMain.java
loki java 132 mpiexec -np 1 java SizeExtentMain
strided vector:
size of old data type: 1
count: 2
blocklength: 2
stride: 4
size: 4
lower bound: 0
extent: 0
true lower bound: 0
true extent: 6
loki java 133
I would be grateful, if somebody can fix the problem, if it is a
problem of the MPI Java method or if somebody knows, what I'm doing
wrong in my program. Thank you very much for any help in advance.
Kind regards
Siegmar
/* A small MPI Java program that creates a vector and prints
* its size and extent.
*
* "mpijavac" and Java-bindings are available in "Open MPI
* version 1.7.4" or newer.
*
*
* Class file generation:
* mpijavac SizeExtentMain.java
*
* Usage:
* mpiexec [parameters] java [parameters] SizeExtentMain
*
* Examples:
* mpiexec java SizeExtentMain
* mpiexec java -cp $HOME/mpi_classfiles SizeExtentMain
*
*
* File: SizeExtentMain.java Author: S. Gross
* Date: 19.07.2018
*
*/
import mpi.*;
public class SizeExtentMain
{
static final int COUNT = 2;
static final int BLOCKLENGTH = 2;
static final int STRIDE = 4;
public static void main (String args[]) throws MPIException
{
int mytid, /* my task id */
size, /* size of vector */
sizeMpiDouble; /* size of MPI.DOUBLE */
long extent, trueExtent, /* extent of (resized) vector */
lb, trueLb; /* lower bound of (resized) vect*/
Datatype vector_t, /* strided vector */
tmp_vector_t;
MPI.Init (args);
mytid = MPI.COMM_WORLD.getRank ();
sizeMpiDouble = MPI.DOUBLE.getSize ();
/* Build the new type for a strided vector and resize the extent
* of the new datatype in such a way that the extent of the whole
* vector looks like just one element.
*/
tmp_vector_t = Datatype.createVector (COUNT, BLOCKLENGTH, STRIDE,
MPI.DOUBLE);
vector_t = Datatype.createResized (tmp_vector_t, 0, sizeMpiDouble);
vector_t.commit ();
tmp_vector_t.free ();
if (mytid == 0)
{
size = vector_t.getSize ();
extent = vector_t.getExtent ();
trueExtent = vector_t.getTrueExtent ();
lb = vector_t.getLb ();
trueLb = vector_t.getTrueLb ();
System.out.println ("strided vector:\n" +
" size of old data type: " + sizeMpiDouble + "\n" +
" count: " + COUNT + "\n" +
" blocklength: " + BLOCKLENGTH + "\n" +
" stride: " + STRIDE + "\n" +
" size: " + size + "\n" +
" lower bound: " + lb + "\n" +
" extent: " + extent + "\n" +
" true lower bound: " + trueLb + "\n" +
" true extent: " + trueExtent + "\n");
}
vector_t.free ();
MPI.Finalize ();
}
}
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