PetscGatherNumberOfMessages#
Computes the number of messages an MPI rank expects to receive during a neighbor communication
Synopsis#
#include "petscsys.h"
PetscErrorCode PetscGatherNumberOfMessages(MPI_Comm comm, const PetscMPIInt iflags[], const PetscMPIInt ilengths[], PetscMPIInt *nrecvs)
Collective
Input Parameters#
comm - Communicator
iflags - an array of integers of length sizeof(comm). A ‘1’ in ilengths[i] represent a message from current node to ith node. Optionally NULL
ilengths - Non zero ilengths[i] represent a message to i of length ilengths[i]. Optionally NULL.
Output Parameters#
nrecvs - number of messages received
Notes#
With this info, the correct message lengths can be determined using
PetscGatherMessageLengths()
Either iflags or ilengths should be provided. If iflags is not provided (NULL) it can be computed from ilengths. If iflags is provided, ilengths is not required.
See Also#
PetscGatherMessageLengths()
, PetscGatherMessageLengths2()
, PetscCommBuildTwoSided()
Level#
developer
Location#
Index of all Sys routines
Table of Contents for all manual pages
Index of all manual pages