#ifndef PETSCPC_TELESCOPE_H
#define PETSCPC_TELESCOPE_H

/* Telescope */
typedef enum { TELESCOPE_DEFAULT = 0, TELESCOPE_DMDA, TELESCOPE_DMPLEX, TELESCOPE_COARSEDM } PCTelescopeType;

typedef struct _PC_Telescope *PC_Telescope;
struct _PC_Telescope {
  PetscSubcomm      psubcomm;
  PetscSubcommType  subcommtype;
  MPI_Comm          subcomm;
  PetscInt          redfactor; /* factor to reduce comm size by */
  KSP               ksp;
  IS                isin;
  VecScatter        scatter;
  Vec               xred,yred,xtmp;
  Mat               Bred;
  PetscBool         ignore_dm,ignore_kspcomputeoperators,use_coarse_dm;
  PCTelescopeType   sr_type;
  void              *dm_ctx;
  PetscErrorCode    (*pctelescope_setup_type)(PC,PC_Telescope);
  PetscErrorCode    (*pctelescope_matcreate_type)(PC,PC_Telescope,MatReuse,Mat*);
  PetscErrorCode    (*pctelescope_matnullspacecreate_type)(PC,PC_Telescope,Mat);
  PetscErrorCode    (*pctelescope_reset_type)(PC);
};

/* DMDA */
typedef struct {
  DM              dmrepart;
  Mat             permutation;
  Vec             xp;
  PetscInt        Mp_re,Np_re,Pp_re;
  PetscInt        *range_i_re,*range_j_re,*range_k_re;
  PetscInt        *start_i_re,*start_j_re,*start_k_re;
} PC_Telescope_DMDACtx;

PETSC_STATIC_INLINE PetscBool PetscSubcomm_isActiveRank(PetscSubcomm scomm)
{
  if (scomm->color == 0) return(PETSC_TRUE);
  else return(PETSC_FALSE);
}

PETSC_STATIC_INLINE PetscBool PCTelescope_isActiveRank(PC_Telescope sred)
{
  if (sred->psubcomm) return(PetscSubcomm_isActiveRank(sred->psubcomm));
  else {
    if (sred->subcomm != MPI_COMM_NULL) return(PETSC_TRUE);
    else return (PETSC_FALSE);
  }
}

PetscErrorCode PCTelescopeSetUp_dmda(PC,PC_Telescope);
PetscErrorCode PCTelescopeMatCreate_dmda(PC,PC_Telescope,MatReuse,Mat*);
PetscErrorCode PCTelescopeMatNullSpaceCreate_dmda(PC,PC_Telescope,Mat);
PetscErrorCode PCApply_Telescope_dmda(PC,Vec,Vec);
PetscErrorCode PCApplyRichardson_Telescope_dmda(PC,Vec,Vec,Vec,PetscReal,PetscReal,PetscReal,PetscInt,PetscBool,PetscInt*,PCRichardsonConvergedReason*);
PetscErrorCode PCReset_Telescope_dmda(PC);
PetscErrorCode PCTelescopeSetUp_CoarseDM(PC,PC_Telescope);
PetscErrorCode PCApply_Telescope_CoarseDM(PC,Vec,Vec);
PetscErrorCode PCTelescopeMatNullSpaceCreate_CoarseDM(PC,PC_Telescope,Mat);
PetscErrorCode PCReset_Telescope_CoarseDM(PC);
PetscErrorCode PCApplyRichardson_Telescope_CoarseDM(PC,Vec,Vec,Vec,PetscReal,PetscReal,PetscReal,PetscInt,PetscBool,PetscInt*,PCRichardsonConvergedReason*);
PetscErrorCode DMView_DA_Short(DM,PetscViewer);

#endif