#include "petscsys.h"
PetscErrorCode PetscCommBuildTwoSidedFReq(MPI_Comm comm,PetscMPIInt count,MPI_Datatype dtype,PetscMPIInt nto,const PetscMPIInt *toranks,const void *todata,
PetscMPIInt *nfrom,PetscMPIInt **fromranks,void *fromdata,PetscMPIInt ntags,MPI_Request **toreqs,MPI_Request **fromreqs,
PetscErrorCode (*send)(MPI_Comm,const PetscMPIInt[],PetscMPIInt,PetscMPIInt,void*,MPI_Request[],void*),
PetscErrorCode (*recv)(MPI_Comm,const PetscMPIInt[],PetscMPIInt,void*,MPI_Request[],void*),void *ctx)
Collective on MPI_Comm
| comm | - communicator | |
| count | - number of entries to send/receive in initial rendezvous (must match on all ranks) | |
| dtype | - datatype to send/receive from each rank (must match on all ranks) | |
| nto | - number of ranks to send data to | |
| toranks | - ranks to send to (array of length nto) | |
| todata | - data to send to each rank (packed) | |
| ntags | - number of tags needed by send/recv callbacks | |
| send | - callback invoked on sending process when ready to send primary payload | |
| recv | - callback invoked on receiving process after delivery of rendezvous message | |
| ctx | - context for callbacks |
| nfrom | - number of ranks receiving messages from | |
| fromranks | - ranks receiving messages from (length nfrom; caller should PetscFree()) | |
| fromdata | - packed data from each rank, each with count entries of type dtype (length nfrom, caller responsible for PetscFree()) | |
| toreqs | - array of nto*ntags sender requests (caller must wait on these, then PetscFree()) | |
| fromreqs | - array of nfrom*ntags receiver requests (caller must wait on these, then PetscFree()) |
Basic data types as well as contiguous types are supported, but non-contiguous (e.g., strided) types are not.