Section: PVM Version 3.4 (3PVM)
Updated: 21 April, 1994
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pvm_scatter - Sends to each member of a group a section of an array
from a specified member of the group.
C int info = pvm_scatter( void *result, void *data,
int count, int datatype, int msgtag,
char *group, int rootginst)
Fortran call pvmfscatter(result, data, count, datatype,
msgtag, group, rootginst, info)
Pointer to the starting address of an array of length
which will be
overwritten by the message from the specified root member of the group.
On the root this is a
pointer to the starting address of an array
of local values
which are to be distributed to the members of the group.
If n is the number of members in the group, then this array of
should be of length at least n*count.
This argument is meaningful only on the root.
Integer specifying the number of elements of
to be sent to each member of the group from the root.
Integer specifying the type of the entries in the result and data arrays.
(See below for defined types.)
Integer message tag supplied by the user.
msgtag should be >= 0. It allows the user's program to
distinguish between different kinds of messages.
Character string group name of an existing group.
Integer instance number of group member who performs
the scatter of its array to the members of the group.
Integer status code returned by the routine.
Values less than zero indicate an error.
performs a scatter of data from the specified root member of the group
to each of the members of the group, including itself.
All group members must call pvm_scatter(),
each receives a portion of the
array from the root in
It is as if the root node sends to the ith member of the group
elements from its array
starting at offset i*count from the beginning of the
And, it is as if, each member of the group performs a corresponding
The root task is identified by its instance number in the group.
C and Fortran defined
C datatypes FORTRAN datatypes
In using the scatter and gather routines, keep in mind that
C stores multidimensional arrays in row order,
typically starting with an initial index of 0; whereas,
Fortran stores arrays in column order,
typically starting with an offset of 1.
The current algorithm is very simple and robust. A future implementation
may make more efficient use of the architecture to allow greater
info = pvm_scatter(&getmyrow, &matrix, 10, PVM_INT,
msgtag, "workers", rootginst);
CALL PVMFSCATTER(GETMYCOLUMN, MATRIX, COUNT, INTEGER4,
& MTAG, 'workers', ROOT, INFO)
These error conditions can be returned by
Calling task is not in the group
The datatype specified is not appropriate
Pvm system error
- SEE ALSO
linux.jgfs.net manual pages