/* 
        Provides an interface to the IBM RS6000 Essl sparse solver

*/
#include "src/mat/impls/aij/seq/aij.h"
/* #include <essl.h> This doesn't work!  */

typedef struct {
  int         n,nz;
  PetscScalar *a;
  int         *ia;
  int         *ja;
  int         lna;
  int         iparm[5];
  PetscReal   rparm[5];
  PetscReal   oparm[5];
  PetscScalar *aux;
  int         naux;

  int (*MatDuplicate)(Mat,MatDuplicateOption,Mat*);
  int (*MatAssemblyEnd)(Mat,MatAssemblyType);
  int (*MatLUFactorSymbolic)(Mat,IS,IS,MatFactorInfo*,Mat*);
  int (*MatDestroy)(Mat);
  PetscTruth CleanUpESSL;
} Mat_Essl;

EXTERN int MatDuplicate_Essl(Mat,MatDuplicateOption,Mat*);

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "MatConvert_Essl_SeqAIJ"
int MatConvert_Essl_SeqAIJ(Mat A,const MatType type,Mat *newmat) {
  int      ierr;
  Mat      B=*newmat;
  Mat_Essl *essl=(Mat_Essl*)A->spptr;
  
  PetscFunctionBegin;
  if (B != A) {
    ierr = MatDuplicate(A,MAT_COPY_VALUES,&B);
  }
  B->ops->duplicate        = essl->MatDuplicate;
  B->ops->assemblyend      = essl->MatAssemblyEnd;
  B->ops->lufactorsymbolic = essl->MatLUFactorSymbolic;
  B->ops->destroy          = essl->MatDestroy;

  /* free the Essl datastructures */
  ierr = PetscFree(essl);CHKERRQ(ierr);
  ierr = PetscObjectChangeTypeName((PetscObject)B,MATSEQAIJ);CHKERRQ(ierr);
  *newmat = B;
  PetscFunctionReturn(0);
}
EXTERN_C_END  

#undef __FUNCT__  
#define __FUNCT__ "MatDestroy_Essl"
int MatDestroy_Essl(Mat A) {
  int       ierr;
  Mat_Essl *essl=(Mat_Essl*)A->spptr;

  PetscFunctionBegin;
  if (essl->CleanUpESSL) {
    ierr = PetscFree(essl->a);CHKERRQ(ierr);
  }
  ierr = MatConvert_Essl_SeqAIJ(A,MATSEQAIJ,&A);
  ierr = (*A->ops->destroy)(A);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__  
#define __FUNCT__ "MatSolve_Essl"
int MatSolve_Essl(Mat A,Vec b,Vec x) {
  Mat_Essl    *essl = (Mat_Essl*)A->spptr;
  PetscScalar *xx;
  int         ierr,m,zero = 0;

  PetscFunctionBegin;
  ierr = VecGetLocalSize(b,&m);CHKERRQ(ierr);
  ierr = VecCopy(b,x);CHKERRQ(ierr);
  ierr = VecGetArray(x,&xx);CHKERRQ(ierr);
  dgss(&zero,&A->n,essl->a,essl->ia,essl->ja,&essl->lna,xx,essl->aux,&essl->naux);
  ierr = VecRestoreArray(x,&xx);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__  
#define __FUNCT__ "MatLUFactorNumeric_Essl"
int MatLUFactorNumeric_Essl(Mat A,Mat *F) {
  Mat_SeqAIJ *aa=(Mat_SeqAIJ*)(A)->data;
  Mat_Essl   *essl=(Mat_Essl*)(*F)->spptr;
  int        i,ierr,one = 1;

  PetscFunctionBegin;
  /* copy matrix data into silly ESSL data structure (1-based Frotran style) */
  for (i=0; i<A->m+1; i++) essl->ia[i] = aa->i[i] + 1;
  for (i=0; i<aa->nz; i++) essl->ja[i]  = aa->j[i] + 1;
 
  ierr = PetscMemcpy(essl->a,aa->a,(aa->nz)*sizeof(PetscScalar));CHKERRQ(ierr);
  
  /* set Essl options */
  essl->iparm[0] = 1; 
  essl->iparm[1] = 5;
  essl->iparm[2] = 1;
  essl->iparm[3] = 0;
  essl->rparm[0] = 1.e-12;
  essl->rparm[1] = A->lupivotthreshold;

  dgsf(&one,&A->m,&essl->nz,essl->a,essl->ia,essl->ja,&essl->lna,essl->iparm,
               essl->rparm,essl->oparm,essl->aux,&essl->naux);

  PetscFunctionReturn(0);
}

#undef __FUNCT__  
#define __FUNCT__ "MatLUFactorSymbolic_Essl"
int MatLUFactorSymbolic_Essl(Mat A,IS r,IS c,MatFactorInfo *info,Mat *F) {
  Mat        B;
  Mat_SeqAIJ *a = (Mat_SeqAIJ*)A->data;
  int        ierr,len;
  Mat_Essl   *essl;
  PetscReal  f = 1.0;

  PetscFunctionBegin;
  if (A->N != A->M) SETERRQ(PETSC_ERR_ARG_SIZ,"matrix must be square"); 
  ierr = MatCreate(A->comm,PETSC_DECIDE,PETSC_DECIDE,A->m,A->n,&B);CHKERRQ(ierr);
  ierr = MatSetType(B,A->type_name);CHKERRQ(ierr);
  ierr = MatSeqAIJSetPreallocation(B,0,PETSC_NULL);CHKERRQ(ierr);

  B->ops->solve           = MatSolve_Essl;
  B->ops->lufactornumeric = MatLUFactorNumeric_Essl;
  B->factor               = FACTOR_LU;
  
  essl = (Mat_Essl *)(B->spptr);

  /* allocate the work arrays required by ESSL */
  f = info->fill;
  essl->nz   = a->nz;
  essl->lna  = (int)a->nz*f;
  essl->naux = 100 + 10*A->m;

  /* since malloc is slow on IBM we try a single malloc */
  len               = essl->lna*(2*sizeof(int)+sizeof(PetscScalar)) + essl->naux*sizeof(PetscScalar);
  ierr              = PetscMalloc(len,&essl->a);CHKERRQ(ierr);
  essl->aux         = essl->a + essl->lna;
  essl->ia          = (int*)(essl->aux + essl->naux);
  essl->ja          = essl->ia + essl->lna;
  essl->CleanUpESSL = PETSC_TRUE;

  PetscLogObjectMemory(B,len+sizeof(Mat_Essl));
  *F = B;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "MatAssemblyEnd_Essl"
int MatAssemblyEnd_Essl(Mat A,MatAssemblyType mode) {
  int      ierr;
  Mat_Essl *essl=(Mat_Essl*)(A->spptr);

  PetscFunctionBegin;
  ierr = (*essl->MatAssemblyEnd)(A,mode);CHKERRQ(ierr);

  essl->MatLUFactorSymbolic = A->ops->lufactorsymbolic;
  A->ops->lufactorsymbolic  = MatLUFactorSymbolic_Essl;
  PetscLogInfo(0,"Using ESSL for LU factorization and solves");
  PetscFunctionReturn(0);
}

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "MatConvert_SeqAIJ_Essl"
int MatConvert_SeqAIJ_Essl(Mat A,const MatType type,Mat *newmat) {
  Mat      B=*newmat;
  int      ierr;
  Mat_Essl *essl;

  PetscFunctionBegin;

  if (B != A) {
    ierr = MatDuplicate(A,MAT_COPY_VALUES,&B);CHKERRQ(ierr);
  }

  ierr                      = PetscNew(Mat_Essl,&essl);CHKERRQ(ierr);
  essl->MatDuplicate        = A->ops->duplicate;
  essl->MatAssemblyEnd      = A->ops->assemblyend;
  essl->MatLUFactorSymbolic = A->ops->lufactorsymbolic;
  essl->MatDestroy          = A->ops->destroy;
  essl->CleanUpESSL         = PETSC_FALSE;

  B->spptr                  = (void*)essl;
  B->ops->duplicate         = MatDuplicate_Essl;
  B->ops->assemblyend       = MatAssemblyEnd_Essl;
  B->ops->lufactorsymbolic  = MatLUFactorSymbolic_Essl;
  B->ops->destroy           = MatDestroy_Essl;

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatConvert_seqaij_essl_C",
                                           "MatConvert_SeqAIJ_Essl",MatConvert_SeqAIJ_Essl);CHKERRQ(ierr);
  ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatConvert_essl_seqaij_C",
                                           "MatConvert_Essl_SeqAIJ",MatConvert_Essl_SeqAIJ);CHKERRQ(ierr);
  ierr = PetscObjectChangeTypeName((PetscObject)B,type);CHKERRQ(ierr);
  *newmat = B;
  PetscFunctionReturn(0);
}
EXTERN_C_END

#undef __FUNCT__
#define __FUNCT__ "MatDuplicate_Essl"
int MatDuplicate_Essl(Mat A, MatDuplicateOption op, Mat *M) {
  int      ierr;
  Mat_Essl *lu = (Mat_Essl *)A->spptr;

  PetscFunctionBegin;
  ierr = (*lu->MatDuplicate)(A,op,M);CHKERRQ(ierr);
  ierr = PetscMemcpy((*M)->spptr,lu,sizeof(Mat_Essl));CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

/*MC
  MATESSL - MATESSL = "essl" - A matrix type providing direct solvers (LU) for sequential matrices 
  via the external package ESSL.

  If ESSL is installed (see the manual for
  instructions on how to declare the existence of external packages),
  a matrix type can be constructed which invokes ESSL solvers.
  After calling MatCreate(...,A), simply call MatSetType(A,MATESSL).
  This matrix type is only supported for double precision real.

  This matrix inherits from MATSEQAIJ.  As a result, MatSeqAIJSetPreallocation is 
  supported for this matrix type.  One can also call MatConvert for an inplace conversion to or from 
  the MATSEQAIJ type without data copy.

  Options Database Keys:
. -mat_type essl - sets the matrix type to "essl" during a call to MatSetFromOptions()

   Level: beginner

.seealso: PCLU
M*/

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "MatCreate_Essl"
int MatCreate_Essl(Mat A) {
  int ierr;

  PetscFunctionBegin;
  /* Change type name before calling MatSetType to force proper construction of SeqAIJ and Essl types */
  ierr = PetscObjectChangeTypeName((PetscObject)A,MATESSL);CHKERRQ(ierr);
  ierr = MatSetType(A,MATSEQAIJ);
  ierr = MatConvert_SeqAIJ_Essl(A,MATESSL,&A);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}
EXTERN_C_END