#pragma once

#include <petscdmcomposite.h>     /*I "petscdmcomposite.h" I*/
#include <petsc/private/dmimpl.h> /*I      "petscdm.h"     I*/

/*
   rstart is where an array/subvector starts in the global parallel vector, so arrays
   rstarts are meaningless (and set to the previous one) except on the processor where the array lives
*/

struct DMCompositeLink {
  struct DMCompositeLink *next;
  PetscInt                n;       /* number of owned */
  PetscInt                rstart;  /* rstart is relative to this process */
  PetscInt                grstart; /* grstart is relative to all processes */
  PetscInt                nlocal;

  /* only used for DMCOMPOSITE_DM */
  PetscInt *grstarts; /* global row for first unknown of this DM on each process */
  DM        dm;
};

typedef struct {
  PetscInt                n, N, rstart; /* rstart is relative to all processors, n unknowns owned by this process, N is total unknowns */
  PetscInt                nghost;       /* number of all local entries (includes DMDA ghost points) */
  PetscInt                nDM, nmine;   /* how many DM's and separate redundant arrays used to build DM(nmine is ones on this process) */
  PetscBool               setup;        /* after this is set, cannot add new links to the DM*/
  struct DMCompositeLink *next;

  PetscErrorCode (*FormCoupleLocations)(DM, Mat, PetscInt *, PetscInt *, PetscInt, PetscInt, PetscInt, PetscInt);
} DM_Composite;

PETSC_INTERN PetscErrorCode DMCreateMatrix_Composite(DM, Mat *);