#include "mpi.h" int MPI_Allgather ( sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype, comm ) void *sendbuf; int sendcount; MPI_Datatype sendtype; void *recvbuf; int recvcount; MPI_Datatype recvtype; MPI_Comm comm;
|sendbuf||starting address of send buffer (choice)
|sendcount||number of elements in send buffer (integer)
|sendtype||data type of send buffer elements (handle)
|recvcount||number of elements received from any process (integer)
|recvtype||data type of receive buffer elements (handle)
The jth block of data sent fromeach proess is received by every process and placed in the jth block of thebuffer recvbuf.
This is misleading; a better description is
The block of data sent from the jth process is received by everyprocess and placed in the jth block of the buffer recvbuf.
This text was suggested by Rajeev Thakur.
All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGERin Fortran.
All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value; C routines as the value of the function and Fortran routines in the lastargument. Before the value is returned, the current MPI error handler iscalled. By default, this error handler aborts the MPI job. The error handlermay be changed with MPI_Errhandler_set; the predefined error handlerMPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue pastan error.