/*$Id: pmap.c,v 1.21 2001/07/20 21:18:16 bsmith Exp $*/

/*
   This file contains routines for basic map object implementation.
*/

#include "src/vec/vecimpl.h"   /*I  "petscvec.h"   I*/

#undef __FUNCT__  
#define __FUNCT__ "PetscMapDestroy_MPI"
int PetscMapDestroy_MPI(PetscMap m)
{
  PetscFunctionBegin;
  PetscFunctionReturn(0);
}

static struct _PetscMapOps DvOps = {
  PETSC_NULL,
  PetscMapDestroy_MPI,
};

EXTERN_C_BEGIN
#undef __FUNCT__  
#define __FUNCT__ "PetscMapCreate_MPI"
int PetscMapCreate_MPI(PetscMap m)
{
  int rank,size;
  int p;
  int ierr;

  PetscFunctionBegin;
  ierr = PetscMemcpy(m->ops, &DvOps, sizeof(DvOps));                                                      CHKERRQ(ierr);

  ierr = MPI_Comm_size(m->comm, &size);                                                                   CHKERRQ(ierr);
  ierr = MPI_Comm_rank(m->comm, &rank);                                                                   CHKERRQ(ierr); 
  ierr = PetscSplitOwnership(m->comm,&m->n,&m->N);                                                        CHKERRQ(ierr);
  ierr = PetscMalloc((size+1)*sizeof(int), &m->range);                                                    CHKERRQ(ierr);
  ierr = MPI_Allgather(&m->n, 1, MPI_INT, m->range+1, 1, MPI_INT, m->comm);                               CHKERRQ(ierr);

  m->range[0] = 0;
  for(p = 2; p <= size; p++) {
    m->range[p] += m->range[p-1];
  }

  m->rstart = m->range[rank];
  m->rend   = m->range[rank+1];
  PetscFunctionReturn(0);
}
EXTERN_C_END

EXTERN_C_BEGIN
#undef __FUNCT__  
#define __FUNCT__ "PetscMapSerialize_MPI"
int PetscMapSerialize_MPI(MPI_Comm comm, PetscMap *map, PetscViewer viewer, PetscTruth store)
{
  PetscMap m;
  int      fd;
  int      n, N, checkN;
  int      numProcs;
  int      ierr;

  PetscFunctionBegin;
  ierr = PetscViewerBinaryGetDescriptor(viewer, &fd);                                                     CHKERRQ(ierr);
  if (store) {
    m    = *map;
    ierr = MPI_Comm_size(m->comm, &numProcs);                                                             CHKERRQ(ierr);
    ierr = PetscBinaryWrite(fd, &m->n,      1,          PETSC_INT, 0);                                    CHKERRQ(ierr);
    ierr = PetscBinaryWrite(fd, &m->N,      1,          PETSC_INT, 0);                                    CHKERRQ(ierr);
    ierr = PetscBinaryWrite(fd, &m->rstart, 1,          PETSC_INT, 0);                                    CHKERRQ(ierr);
    ierr = PetscBinaryWrite(fd, &m->rend,   1,          PETSC_INT, 0);                                    CHKERRQ(ierr);
    ierr = PetscBinaryWrite(fd,  m->range,  numProcs+1, PETSC_INT, 0);                                    CHKERRQ(ierr);
  } else {
    ierr = PetscBinaryRead(fd, &n,         1,          PETSC_INT);                                        CHKERRQ(ierr);
    ierr = PetscBinaryRead(fd, &N,         1,          PETSC_INT);                                        CHKERRQ(ierr);
    ierr = MPI_Allreduce(&n, &checkN, 1, MPI_INT, MPI_SUM, comm);                                         CHKERRQ(ierr);
    if (checkN != N) SETERRQ(PETSC_ERR_ARG_CORRUPT, "Invalid partition");
    ierr = PetscMapCreate(comm, &m);                                                                      CHKERRQ(ierr);
    ierr = PetscMapSetLocalSize(m, n);                                                                    CHKERRQ(ierr);
    ierr = PetscMapSetSize(m, N);                                                                         CHKERRQ(ierr);
    ierr = MPI_Comm_size(comm, &numProcs);                                                                CHKERRQ(ierr);
    ierr = PetscMalloc((numProcs+1) * sizeof(int), &m->range);                                            CHKERRQ(ierr);
    ierr = PetscBinaryRead(fd, &m->rstart, 1,          PETSC_INT);                                        CHKERRQ(ierr);
    ierr = PetscBinaryRead(fd, &m->rend,   1,          PETSC_INT);                                        CHKERRQ(ierr);
    ierr = PetscBinaryRead(fd,  m->range,  numProcs+1, PETSC_INT);                                        CHKERRQ(ierr);

    *map = m;
  }

  PetscFunctionReturn(0);
}
EXTERN_C_END

#undef __FUNCT__  
#define __FUNCT__ "PetscMapCreateMPI"
/*@C
   PetscMapCreateMPI - Creates a map object.

   Collective on MPI_Comm
 
   Input Parameters:
+  comm - the MPI communicator to use 
.  n - local vector length (or PETSC_DECIDE to have calculated if N is given)
-  N - global vector length (or PETSC_DECIDE to have calculated if n is given)

   Output Parameter:
.  mm - the map object

   Suggested by:
   Robert Clay and Alan Williams, developers of ISIS++, Sandia National Laboratories.

   Level: developer

   Concepts: maps^creating

.seealso: PetscMapDestroy(), PetscMapGetLocalSize(), PetscMapGetSize(), PetscMapGetGlobalRange(),
          PetscMapGetLocalRange()

@*/ 
int PetscMapCreateMPI(MPI_Comm comm,int n,int N,PetscMap *m)
{
  int ierr;

  PetscFunctionBegin;
  ierr = PetscMapCreate(comm, m);                                                                         CHKERRQ(ierr);
  ierr = PetscMapSetLocalSize(*m, n);                                                                     CHKERRQ(ierr);
  ierr = PetscMapSetSize(*m, N);                                                                          CHKERRQ(ierr);
  ierr = PetscMapSetType(*m, MAP_MPI);                                                                    CHKERRQ(ierr);
  PetscFunctionReturn(0);
}