petsc-3.3-p7 2013-05-11

PetscGatherNumberOfMessages

 Computes the number of messages a node expects to receive

Synopsis

#include "petscsys.h"  
PetscErrorCode  PetscGatherNumberOfMessages(MPI_Comm comm,const PetscMPIInt iflags[],const PetscMPIInt ilengths[],PetscMPIInt *nrecvs)
Collective on MPI_Comm

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 PETSC_NULL
ilengths - Non zero ilengths[i] represent a message to i of length ilengths[i]. Optionally PETSC_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 (PETSC_NULL) it can be computed from ilengths. If iflags is provided, ilengths is not required.

See Also

PetscGatherMessageLengths()

Level:developer
Location:src/sys/utils/mpimesg.c
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