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

#include <petscis.h> /*I "petscis.h" I*/
#include <petscsf.h>

/*@
  PetscLayoutCreate - Allocates PetscLayout space and sets the map contents to the default.

  Collective on MPI_Comm

  Input Parameters:
+ comm - the MPI communicator
- map - pointer to the map

  Level: advanced

  Notes:
  Typical calling sequence
.vb
       PetscLayoutCreate(MPI_Comm,PetscLayout *);
       PetscLayoutSetBlockSize(PetscLayout,1);
       PetscLayoutSetSize(PetscLayout,N) // or PetscLayoutSetLocalSize(PetscLayout,n);
       PetscLayoutSetUp(PetscLayout);
.ve
  Optionally use any of the following:

+ PetscLayoutGetSize(PetscLayout,PetscInt *);
. PetscLayoutGetLocalSize(PetscLayout,PetscInt *);
. PetscLayoutGetRange(PetscLayout,PetscInt *rstart,PetscInt *rend);
. PetscLayoutGetRanges(PetscLayout,const PetscInt *range[]);
- PetscLayoutDestroy(PetscLayout*);

  The PetscLayout object and methods are intended to be used in the PETSc Vec and Mat implementions; it is often not needed in
  user codes unless you really gain something in their use.

.seealso: PetscLayoutSetLocalSize(), PetscLayoutSetSize(), PetscLayoutGetSize(), PetscLayoutGetLocalSize(), PetscLayout, PetscLayoutDestroy(),
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetBlockSize(), PetscLayoutSetUp()

@*/
PetscErrorCode PetscLayoutCreate(MPI_Comm comm,PetscLayout *map)
{
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = PetscNew(map);CHKERRQ(ierr);

  (*map)->comm   = comm;
  (*map)->bs     = -1;
  (*map)->n      = -1;
  (*map)->N      = -1;
  (*map)->range  = NULL;
  (*map)->rstart = 0;
  (*map)->rend   = 0;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutDestroy - Frees a map object and frees its range if that exists.

  Collective on MPI_Comm

  Input Parameters:
. map - the PetscLayout

  Level: developer

  Note:
  The PetscLayout object and methods are intended to be used in the PETSc Vec and Mat implementions; it is
  recommended they not be used in user codes unless you really gain something in their use.

.seealso: PetscLayoutSetLocalSize(), PetscLayoutSetSize(), PetscLayoutGetSize(), PetscLayoutGetLocalSize(), PetscLayout, PetscLayoutCreate(),
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetBlockSize(), PetscLayoutSetUp()

@*/
PetscErrorCode PetscLayoutDestroy(PetscLayout *map)
{
  PetscErrorCode ierr;

  PetscFunctionBegin;
  if (!*map) PetscFunctionReturn(0);
  if (!(*map)->refcnt--) {
    ierr = PetscFree((*map)->range);CHKERRQ(ierr);
    ierr = ISLocalToGlobalMappingDestroy(&(*map)->mapping);CHKERRQ(ierr);
    ierr = PetscFree((*map));CHKERRQ(ierr);
  }
  *map = NULL;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutSetUp - given a map where you have set either the global or local
                     size sets up the map so that it may be used.

  Collective on MPI_Comm

  Input Parameters:
. map - pointer to the map

  Level: developer

  Notes: Typical calling sequence
$ PetscLayoutCreate(MPI_Comm,PetscLayout *);
$ PetscLayoutSetBlockSize(PetscLayout,1);
$ PetscLayoutSetSize(PetscLayout,n) or PetscLayoutSetLocalSize(PetscLayout,N); or both
$ PetscLayoutSetUp(PetscLayout);
$ PetscLayoutGetSize(PetscLayout,PetscInt *);


  If the local size, global size are already set and range exists then this does nothing.

.seealso: PetscLayoutSetLocalSize(), PetscLayoutSetSize(), PetscLayoutGetSize(), PetscLayoutGetLocalSize(), PetscLayout, PetscLayoutDestroy(),
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetBlockSize(), PetscLayoutCreate()
@*/
PetscErrorCode PetscLayoutSetUp(PetscLayout map)
{
  PetscMPIInt    rank,size;
  PetscInt       p;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  if ((map->n >= 0) && (map->N >= 0) && (map->range)) PetscFunctionReturn(0);

  if (map->n > 0 && map->bs > 1) {
    if (map->n % map->bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Local matrix size %D must be divisible by blocksize %D",map->n,map->bs);
  }
  if (map->N > 0 && map->bs > 1) {
    if (map->N % map->bs) SETERRQ2(map->comm,PETSC_ERR_PLIB,"Global matrix size %D must be divisible by blocksize %D",map->N,map->bs);
  }

  ierr = MPI_Comm_size(map->comm, &size);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(map->comm, &rank);CHKERRQ(ierr);
  if (map->n > 0) map->n = map->n/PetscAbs(map->bs);
  if (map->N > 0) map->N = map->N/PetscAbs(map->bs);
  ierr = PetscSplitOwnership(map->comm,&map->n,&map->N);CHKERRQ(ierr);
  map->n = map->n*PetscAbs(map->bs);
  map->N = map->N*PetscAbs(map->bs);
  if (!map->range) {
    ierr = PetscMalloc1(size+1, &map->range);CHKERRQ(ierr);
  }
  ierr = MPI_Allgather(&map->n, 1, MPIU_INT, map->range+1, 1, MPIU_INT, map->comm);CHKERRQ(ierr);

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

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

/*@
  PetscLayoutDuplicate - creates a new PetscLayout with the same information as a given one. If the PetscLayout already exists it is destroyed first.

  Collective on PetscLayout

  Input Parameter:
. in - input PetscLayout to be duplicated

  Output Parameter:
. out - the copy

  Level: developer

  Notes: PetscLayoutSetUp() does not need to be called on the resulting PetscLayout

.seealso: PetscLayoutCreate(), PetscLayoutDestroy(), PetscLayoutSetUp(), PetscLayoutReference()
@*/
PetscErrorCode PetscLayoutDuplicate(PetscLayout in,PetscLayout *out)
{
  PetscMPIInt    size;
  PetscErrorCode ierr;
  MPI_Comm       comm = in->comm;

  PetscFunctionBegin;
  ierr = PetscLayoutDestroy(out);CHKERRQ(ierr);
  ierr = PetscLayoutCreate(comm,out);CHKERRQ(ierr);
  ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
  ierr = PetscMemcpy(*out,in,sizeof(struct _n_PetscLayout));CHKERRQ(ierr);
  ierr = PetscMalloc1(size+1,&(*out)->range);CHKERRQ(ierr);
  ierr = PetscMemcpy((*out)->range,in->range,(size+1)*sizeof(PetscInt));CHKERRQ(ierr);

  (*out)->refcnt = 0;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutReference - Causes a PETSc Vec or Mat to share a PetscLayout with one that already exists. Used by Vec/MatDuplicate_XXX()

  Collective on PetscLayout

  Input Parameter:
. in - input PetscLayout to be copied

  Output Parameter:
. out - the reference location

  Level: developer

  Notes: PetscLayoutSetUp() does not need to be called on the resulting PetscLayout

  If the out location already contains a PetscLayout it is destroyed

.seealso: PetscLayoutCreate(), PetscLayoutDestroy(), PetscLayoutSetUp(), PetscLayoutDuplicate()
@*/
PetscErrorCode PetscLayoutReference(PetscLayout in,PetscLayout *out)
{
  PetscErrorCode ierr;

  PetscFunctionBegin;
  in->refcnt++;
  ierr = PetscLayoutDestroy(out);CHKERRQ(ierr);
  *out = in;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutSetISLocalToGlobalMapping - sets a ISLocalGlobalMapping into a PetscLayout

  Collective on PetscLayout

  Input Parameter:
+ in - input PetscLayout
- ltog - the local to global mapping


  Level: developer

  Notes: PetscLayoutSetUp() does not need to be called on the resulting PetscLayout

  If the ltog location already contains a PetscLayout it is destroyed

.seealso: PetscLayoutCreate(), PetscLayoutDestroy(), PetscLayoutSetUp(), PetscLayoutDuplicate()
@*/
PetscErrorCode PetscLayoutSetISLocalToGlobalMapping(PetscLayout in,ISLocalToGlobalMapping ltog)
{
  PetscErrorCode ierr;
  PetscInt       bs;

  PetscFunctionBegin;
  ierr = ISLocalToGlobalMappingGetBlockSize(ltog,&bs);CHKERRQ(ierr);
  if (in->bs > 0 && in->bs != bs) SETERRQ2(in->comm,PETSC_ERR_PLIB,"Blocksize of layout %D must match that of mapping %D",in->bs,bs);
  ierr = PetscObjectReference((PetscObject)ltog);CHKERRQ(ierr);
  ierr = ISLocalToGlobalMappingDestroy(&in->mapping);CHKERRQ(ierr);
  in->mapping = ltog;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutSetLocalSize - Sets the local size for a PetscLayout object.

  Collective on PetscLayout

  Input Parameters:
+ map - pointer to the map
- n - the local size

  Level: developer

  Notes:
  Call this after the call to PetscLayoutCreate()

.seealso: PetscLayoutCreate(), PetscLayoutSetSize(), PetscLayoutGetSize(), PetscLayoutGetLocalSize(), PetscLayoutSetUp()
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetBlockSize()
@*/
PetscErrorCode PetscLayoutSetLocalSize(PetscLayout map,PetscInt n)
{
  PetscFunctionBegin;
  if (map->bs > 1 && n % map->bs) SETERRQ2(map->comm,PETSC_ERR_ARG_INCOMP,"Local size %D not compatible with block size %D",n,map->bs);
  map->n = n;
  PetscFunctionReturn(0);
}

/*@C
     PetscLayoutGetLocalSize - Gets the local size for a PetscLayout object.

    Not Collective

   Input Parameters:
.    map - pointer to the map

   Output Parameters:
.    n - the local size

   Level: developer

    Notes:
       Call this after the call to PetscLayoutSetUp()

    Fortran Notes:
      Not available from Fortran

.seealso: PetscLayoutCreate(), PetscLayoutSetSize(), PetscLayoutGetSize(), PetscLayoutGetLocalSize(), PetscLayoutSetUp()
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetBlockSize()

@*/
PetscErrorCode  PetscLayoutGetLocalSize(PetscLayout map,PetscInt *n)
{
  PetscFunctionBegin;
  *n = map->n;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutSetSize - Sets the global size for a PetscLayout object.

  Logically Collective on PetscLayout

  Input Parameters:
+ map - pointer to the map
- n - the global size

  Level: developer

  Notes:
  Call this after the call to PetscLayoutCreate()

.seealso: PetscLayoutCreate(), PetscLayoutSetLocalSize(), PetscLayoutGetLocalSize(), PetscLayoutGetSize(), PetscLayoutSetUp()
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetBlockSize()
@*/
PetscErrorCode PetscLayoutSetSize(PetscLayout map,PetscInt n)
{
  PetscFunctionBegin;
  map->N = n;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutGetSize - Gets the global size for a PetscLayout object.

  Not Collective

  Input Parameters:
. map - pointer to the map

  Output Parameters:
. n - the global size

  Level: developer

  Notes:
  Call this after the call to PetscLayoutSetUp()

.seealso: PetscLayoutCreate(), PetscLayoutSetLocalSize(), PetscLayoutGetLocalSize(), PetscLayoutSetSize(), PetscLayoutSetUp()
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetBlockSize()
@*/
PetscErrorCode PetscLayoutGetSize(PetscLayout map,PetscInt *n)
{
  PetscFunctionBegin;
  *n = map->N;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutSetBlockSize - Sets the block size for a PetscLayout object.

  Logically Collective on PetscLayout

  Input Parameters:
+ map - pointer to the map
- bs - the size

  Level: developer

  Notes:
  Call this after the call to PetscLayoutCreate()

.seealso: PetscLayoutCreate(), PetscLayoutSetLocalSize(), PetscLayoutGetLocalSize(), PetscLayoutGetBlockSize(),
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetSize(), PetscLayoutGetSize(), PetscLayoutSetUp()
@*/
PetscErrorCode PetscLayoutSetBlockSize(PetscLayout map,PetscInt bs)
{
  PetscFunctionBegin;
  if (bs < 0) PetscFunctionReturn(0);
  if (map->n > 0 && map->n % bs) SETERRQ2(map->comm,PETSC_ERR_ARG_INCOMP,"Local size %D not compatible with block size %D",map->n,bs);
  if (map->mapping) {
    PetscInt       obs;
    PetscErrorCode ierr;

    ierr = ISLocalToGlobalMappingGetBlockSize(map->mapping,&obs);CHKERRQ(ierr);
    if (obs > 1) {
      ierr = ISLocalToGlobalMappingSetBlockSize(map->mapping,bs);CHKERRQ(ierr);
    }
  }
  map->bs = bs;
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutGetBlockSize - Gets the block size for a PetscLayout object.

  Not Collective

  Input Parameters:
. map - pointer to the map

  Output Parameters:
. bs - the size

  Level: developer

  Notes:
  Call this after the call to PetscLayoutSetUp()

.seealso: PetscLayoutCreate(), PetscLayoutSetLocalSize(), PetscLayoutGetLocalSize(), PetscLayoutSetSize(), PetscLayoutSetUp()
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetSize()
@*/
PetscErrorCode PetscLayoutGetBlockSize(PetscLayout map,PetscInt *bs)
{
  PetscFunctionBegin;
  *bs = PetscAbs(map->bs);
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutGetRange - gets the range of values owned by this process

  Not Collective

  Input Parameters:
. map - pointer to the map

  Output Parameters:
+ rstart - first index owned by this process
- rend   - one more than the last index owned by this process

  Level: developer

  Notes:
  Call this after the call to PetscLayoutSetUp()

.seealso: PetscLayoutCreate(), PetscLayoutSetLocalSize(), PetscLayoutGetLocalSize(), PetscLayoutSetSize(),
          PetscLayoutGetSize(), PetscLayoutGetRanges(), PetscLayoutSetBlockSize(), PetscLayoutGetSize(), PetscLayoutSetUp()
@*/
PetscErrorCode PetscLayoutGetRange(PetscLayout map,PetscInt *rstart,PetscInt *rend)
{
  PetscFunctionBegin;
  if (rstart) *rstart = map->rstart;
  if (rend)   *rend   = map->rend;
  PetscFunctionReturn(0);
}

/*@C
     PetscLayoutGetRanges - gets the range of values owned by all processes

    Not Collective

   Input Parameters:
.    map - pointer to the map

   Output Parameters:
.    range - start of each processors range of indices (the final entry is one more then the
             last index on the last process)

   Level: developer

    Notes:
       Call this after the call to PetscLayoutSetUp()

    Fortran Notes:
      Not available from Fortran

.seealso: PetscLayoutCreate(), PetscLayoutSetLocalSize(), PetscLayoutGetLocalSize(), PetscLayoutSetSize(),
          PetscLayoutGetSize(), PetscLayoutGetRange(), PetscLayoutSetBlockSize(), PetscLayoutGetSize(), PetscLayoutSetUp()

@*/
PetscErrorCode  PetscLayoutGetRanges(PetscLayout map,const PetscInt *range[])
{
  PetscFunctionBegin;
  *range = map->range;
  PetscFunctionReturn(0);
}

/*@C
   PetscSFSetGraphLayout - Set a parallel star forest via global indices and a PetscLayout

   Collective

   Input Arguments:
+  sf - star forest
.  layout - PetscLayout defining the global space
.  nleaves - number of leaf vertices on the current process, each of these references a root on any process
.  ilocal - locations of leaves in leafdata buffers, pass NULL for contiguous storage
-  iremote - remote locations of root vertices for each leaf on the current process

   Level: intermediate

.seealso: PetscSFCreate(), PetscSFView(), PetscSFSetGraph(), PetscSFGetGraph()
@*/
PetscErrorCode PetscSFSetGraphLayout(PetscSF sf,PetscLayout layout,PetscInt nleaves,const PetscInt *ilocal,PetscCopyMode localmode,const PetscInt *iremote)
{
  PetscErrorCode ierr;
  PetscInt       i,nroots;
  PetscSFNode    *remote;

  PetscFunctionBegin;
  ierr = PetscLayoutGetLocalSize(layout,&nroots);CHKERRQ(ierr);
  ierr = PetscMalloc1(nleaves,&remote);CHKERRQ(ierr);
  for (i=0; i<nleaves; i++) {
    PetscInt owner = -1;
    ierr = PetscLayoutFindOwner(layout,iremote[i],&owner);CHKERRQ(ierr);
    remote[i].rank  = owner;
    remote[i].index = iremote[i] - layout->range[owner];
  }
  ierr = PetscSFSetGraph(sf,nroots,nleaves,ilocal,localmode,remote,PETSC_OWN_POINTER);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

/*@
  PetscLayoutCompare - Compares two layouts

  Not Collective

  Input Parameters:
+ mapa - pointer to the first map
- mapb - pointer to the second map

  Output Parameters:
. congruent - PETSC_TRUE if the two layouts are congruent, PETSC_FALSE otherwise

  Level: beginner

  Notes:

.seealso: PetscLayoutCreate(), PetscLayoutSetLocalSize(), PetscLayoutGetLocalSize(), PetscLayoutGetBlockSize(),
          PetscLayoutGetRange(), PetscLayoutGetRanges(), PetscLayoutSetSize(), PetscLayoutGetSize(), PetscLayoutSetUp()
@*/
PetscErrorCode PetscLayoutCompare(PetscLayout mapa,PetscLayout mapb,PetscBool *congruent)
{
  PetscErrorCode ierr;
  PetscMPIInt    sizea,sizeb;

  PetscFunctionBegin;
  *congruent = PETSC_FALSE;
  ierr = MPI_Comm_size(mapa->comm,&sizea);CHKERRQ(ierr);
  ierr = MPI_Comm_size(mapb->comm,&sizeb);CHKERRQ(ierr);
  if (mapa->N == mapb->N && mapa->range && mapb->range && sizea == sizeb) {
    ierr = PetscMemcmp(mapa->range,mapb->range,(sizea+1)*sizeof(PetscInt),congruent);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}