text: 
  /*
   * -- SuperLU routine (version 3.0) --
   * Univ. of California Berkeley, Xerox Palo Alto Research Center,
   * and Lawrence Berkeley National Lab.
   * October 15, 2003
   *
   */
  /*
    Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
   
    THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
    EXPRESSED OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   
    Permission is hereby granted to use or copy this program for any
    purpose, provided the above notices are retained on all copies.
    Permission to modify the code and to distribute modified code is
    granted, provided the above notices are retained, and a notice that
    the code was modified is included with the above copyright notice.
  */
  /*
    This file has been modified to be compatible with the HYPRE
    linear solver
  */
  
  #include "slu_ddefs.h"
  
  #ifndef HYPRE_USING_HYPRE_BLAS
  #define USE_VENDOR_BLAS
  #endif
  
  /*
   * Function prototypes
   */
  void sludusolve(int, int, double*, double*);
  void sludlsolve(int, int, double*, double*);
  void sludmatvec(int, int, int, double*, double*, double*);
  
  void
  dgstrs (trans_t trans, SuperMatrix *L, SuperMatrix *U,
          int *perm_c, int *perm_r, SuperMatrix *B,
          SuperLUStat_t *stat, int *info)
  {
  /*
   * Purpose
   * =======
   *
   * DGSTRS solves a system of linear equations A*X=B or A'*X=B
   * with A sparse and B dense, using the LU factorization computed by
   * DGSTRF.
   *
   * See supermatrix.h for the definition of 'SuperMatrix' structure.
   *
   * Arguments
   * =========
   *
   * trans   (input) trans_t
   *          Specifies the form of the system of equations:
   *          = NOTRANS: A * X = B  (No transpose)
   *          = TRANS:   A'* X = B  (Transpose)
   *          = CONJ:    A**H * X = B  (Conjugate transpose)
   *
   * L       (input) SuperMatrix*
   *         The factor L from the factorization Pr*A*Pc=L*U as computed by
   *         dgstrf(). Use compressed row subscripts storage for supernodes,
   *         i.e., L has types: Stype = SLU_SC, Dtype = SLU_D, Mtype = SLU_TRLU.
   *
   * U       (input) SuperMatrix*
   *         The factor U from the factorization Pr*A*Pc=L*U as computed by
   *         dgstrf(). Use column-wise storage scheme, i.e., U has types:
   *         Stype = SLU_NC, Dtype = SLU_D, Mtype = SLU_TRU.
   *
   * perm_c  (input) int*, dimension (L->ncol)
   *	   Column permutation vector, which defines the 
   *         permutation matrix Pc; perm_c[i] = j means column i of A is 
   *         in position j in A*Pc.
   *
   * perm_r  (input) int*, dimension (L->nrow)
   *         Row permutation vector, which defines the permutation matrix Pr; 
   *         perm_r[i] = j means row i of A is in position j in Pr*A.
   *
   * B       (input/output) SuperMatrix*
   *         B has types: Stype = SLU_DN, Dtype = SLU_D, Mtype = SLU_GE.
   *         On entry, the right hand side matrix.
   *         On exit, the solution matrix if info = 0;
   *
   * stat     (output) SuperLUStat_t*
   *          Record the statistics on runtime and floating-point operation count.
   *          See util.h for the definition of 'SuperLUStat_t'.
   *
   * info    (output) int*
   * 	   = 0: successful exit
   *	   < 0: if info = -i, the i-th argument had an illegal value
   *
   */
  #ifdef _CRAY
      _fcd ftcs1, ftcs2, ftcs3, ftcs4;
  #endif
  #if 0
      int      incx = 1, incy = 1;
  #endif
  #ifdef USE_VENDOR_BLAS
      double   alpha = 1.0, beta = 1.0;
      double   *work_col;
  #endif
      DNformat *Bstore;
      double   *Bmat;
      SCformat *Lstore;
      NCformat *Ustore;
      double   *Lval, *Uval;
      int      fsupc, nrow, nsupr, nsupc, luptr, istart, irow;
      int      i, j, k, iptr, jcol, n, ldb, nrhs;
      double   *work, *rhs_work, *soln;
      flops_t  solve_ops;
      void dprint_soln();
  
      /* Test input parameters ... */
      *info = 0;
      Bstore = (DNformat*) B->Store;
      ldb = Bstore->lda;
      nrhs = B->ncol;
      if ( trans != NOTRANS && trans != TRANS && trans != CONJ ) *info = -1;
      else if ( L->nrow != L->ncol || L->nrow < 0 ||
  	      L->Stype != SLU_SC || L->Dtype != SLU_D || L->Mtype != SLU_TRLU )
  	*info = -2;
      else if ( U->nrow != U->ncol || U->nrow < 0 ||
  	      U->Stype != SLU_NC || U->Dtype != SLU_D || U->Mtype != SLU_TRU )
  	*info = -3;
      else if ( ldb < SUPERLU_MAX(0, L->nrow) ||
  	      B->Stype != SLU_DN || B->Dtype != SLU_D || B->Mtype != SLU_GE )
  	*info = -6;
      if ( *info ) {
  	i = -(*info);
  	superlu_xerbla("dgstrs", &i);
  	return;
      }
  
      n = L->nrow;
      work = doubleCalloc(n * nrhs);
      if ( !work ) ABORT("Malloc fails for local work[].");
      soln = doubleMalloc(n);
      if ( !soln ) ABORT("Malloc fails for local soln[].");
  
      Bmat = (double*) Bstore->nzval;
      Lstore = (SCformat*) L->Store;
      Lval = (double*)Lstore->nzval;
      Ustore = (NCformat*) U->Store;
      Uval = (double*)Ustore->nzval;
      solve_ops = 0;
      
      if ( trans == NOTRANS ) {
  	/* Permute right hand sides to form Pr*B */
  	for (i = 0; i < nrhs; i++) {
  	    rhs_work = &Bmat[i*ldb];
  	    for (k = 0; k < n; k++) soln[perm_r[k]] = rhs_work[k];
  	    for (k = 0; k < n; k++) rhs_work[k] = soln[k];
  	}
  	
  	/* Forward solve PLy=Pb. */
  	for (k = 0; k <= Lstore->nsuper; k++) {
  	    fsupc = L_FST_SUPC(k);
  	    istart = L_SUB_START(fsupc);
  	    nsupr = L_SUB_START(fsupc+1) - istart;
  	    nsupc = L_FST_SUPC(k+1) - fsupc;
  	    nrow = nsupr - nsupc;
  
  	    solve_ops += nsupc * (nsupc - 1) * nrhs;
  	    solve_ops += 2 * nrow * nsupc * nrhs;
  	    
  	    if ( nsupc == 1 ) {
  		for (j = 0; j < nrhs; j++) {
  		    rhs_work = &Bmat[j*ldb];
  	    	    luptr = L_NZ_START(fsupc);
  		    for (iptr=istart+1; iptr < L_SUB_START(fsupc+1); iptr++){
  			irow = L_SUB(iptr);
  			++luptr;
  			rhs_work[irow] -= rhs_work[fsupc] * Lval[luptr];
  		    }
  		}
  	    } else {
  	    	luptr = L_NZ_START(fsupc);
  #ifdef USE_VENDOR_BLAS
  #ifdef _CRAY
  		ftcs1 = _cptofcd("L", strlen("L"));
  		ftcs2 = _cptofcd("N", strlen("N"));
  		ftcs3 = _cptofcd("U", strlen("U"));
  		STRSM( ftcs1, ftcs1, ftcs2, ftcs3, &nsupc, &nrhs, &alpha,
  		       &Lval[luptr], &nsupr, &Bmat[fsupc], &ldb);
  		
  		SGEMM( ftcs2, ftcs2, &nrow, &nrhs, &nsupc, &alpha, 
  			&Lval[luptr+nsupc], &nsupr, &Bmat[fsupc], &ldb, 
  			&beta, &work[0], &n );
  #else
                  hypre_F90_NAME_BLAS(dtrsm,DTRSM)("L","L","N","U",&nsupc,
                         &nrhs, &alpha, &Lval[luptr], &nsupr, &Bmat[fsupc], 
                         &ldb);
                  hypre_F90_NAME_BLAS(dgemm,DGEMM)("N","N",&nrow,&nrhs,&nsupc, 
                         &alpha, &Lval[luptr+nsupc], &nsupr, &Bmat[fsupc], &ldb,
                         &beta, &work[0], &n );
  #endif
  		for (j = 0; j < nrhs; j++) {
  		    rhs_work = &Bmat[j*ldb];
  		    work_col = &work[j*n];
  		    iptr = istart + nsupc;
  		    for (i = 0; i < nrow; i++) {
  			irow = L_SUB(iptr);
  			rhs_work[irow] -= work_col[i]; /* Scatter */
  			work_col[i] = 0.0;
  			iptr++;
  		    }
  		}
  #else		
  		for (j = 0; j < nrhs; j++) {
  		    rhs_work = &Bmat[j*ldb];
  		    sludlsolve (nsupr, nsupc, &Lval[luptr], &rhs_work[fsupc]);
  		    sludmatvec (nsupr, nrow, nsupc, &Lval[luptr+nsupc],
  			    &rhs_work[fsupc], &work[0] );
  
  		    iptr = istart + nsupc;
  		    for (i = 0; i < nrow; i++) {
  			irow = L_SUB(iptr);
  			rhs_work[irow] -= work[i];
  			work[i] = 0.0;
  			iptr++;
  		    }
  		}
  #endif		    
  	    } /* else ... */
  	} /* for L-solve */
  
  #ifdef DEBUG
    	printf("After L-solve: y=\n");
  	dprint_soln(n, nrhs, Bmat);
  #endif
  
  	/*
  	 * Back solve Ux=y.
  	 */
  	for (k = Lstore->nsuper; k >= 0; k--) {
  	    fsupc = L_FST_SUPC(k);
  	    istart = L_SUB_START(fsupc);
  	    nsupr = L_SUB_START(fsupc+1) - istart;
  	    nsupc = L_FST_SUPC(k+1) - fsupc;
  	    luptr = L_NZ_START(fsupc);
  
  	    solve_ops += nsupc * (nsupc + 1) * nrhs;
  
  	    if ( nsupc == 1 ) {
  		rhs_work = &Bmat[0];
  		for (j = 0; j < nrhs; j++) {
  		    rhs_work[fsupc] /= Lval[luptr];
  		    rhs_work += ldb;
  		}
  	    } else {
  #ifdef USE_VENDOR_BLAS
  #ifdef _CRAY
  		ftcs1 = _cptofcd("L", strlen("L"));
  		ftcs2 = _cptofcd("U", strlen("U"));
  		ftcs3 = _cptofcd("N", strlen("N"));
  		STRSM( ftcs1, ftcs2, ftcs3, ftcs3, &nsupc, &nrhs, &alpha,
  		       &Lval[luptr], &nsupr, &Bmat[fsupc], &ldb);
  #else
                  hypre_F90_NAME_BLAS(dtrsm,DTRSM)("L","U","N","N", &nsupc, 
                         &nrhs, &alpha, &Lval[luptr], &nsupr, &Bmat[fsupc], 
                         &ldb);
  #endif
  #else		
  		for (j = 0; j < nrhs; j++)
  		    sludusolve ( nsupr, nsupc, &Lval[luptr], &Bmat[fsupc+j*ldb] );
  #endif		
  	    }
  
  	    for (j = 0; j < nrhs; ++j) {
  		rhs_work = &Bmat[j*ldb];
  		for (jcol = fsupc; jcol < fsupc + nsupc; jcol++) {
  		    solve_ops += 2*(U_NZ_START(jcol+1) - U_NZ_START(jcol));
  		    for (i = U_NZ_START(jcol); i < U_NZ_START(jcol+1); i++ ){
  			irow = U_SUB(i);
  			rhs_work[irow] -= rhs_work[jcol] * Uval[i];
  		    }
  		}
  	    }
  	    
  	} /* for U-solve */
  
  #ifdef DEBUG
    	printf("After U-solve: x=\n");
  	dprint_soln(n, nrhs, Bmat);
  #endif
  
  	/* Compute the final solution X := Pc*X. */
  	for (i = 0; i < nrhs; i++) {
  	    rhs_work = &Bmat[i*ldb];
  	    for (k = 0; k < n; k++) soln[k] = rhs_work[perm_c[k]];
  	    for (k = 0; k < n; k++) rhs_work[k] = soln[k];
  	}
  	
          stat->ops[SOLVE] = solve_ops;
  
      } else { /* Solve A'*X=B or CONJ(A)*X=B */
  	/* Permute right hand sides to form Pc'*B. */
  	for (i = 0; i < nrhs; i++) {
  	    rhs_work = &Bmat[i*ldb];
  	    for (k = 0; k < n; k++) soln[perm_c[k]] = rhs_work[k];
  	    for (k = 0; k < n; k++) rhs_work[k] = soln[k];
  	}
  
  	stat->ops[SOLVE] = 0;
  	for (k = 0; k < nrhs; ++k) {
  	    
  	    /* Multiply by inv(U'). */
  	    sp_dtrsv("U", "T", "N", L, U, &Bmat[k*ldb], stat, info);
  	    
  	    /* Multiply by inv(L'). */
  	    sp_dtrsv("L", "T", "U", L, U, &Bmat[k*ldb], stat, info);
  	    
  	}
  	/* Compute the final solution X := Pr'*X (=inv(Pr)*X) */
  	for (i = 0; i < nrhs; i++) {
  	    rhs_work = &Bmat[i*ldb];
  	    for (k = 0; k < n; k++) soln[k] = rhs_work[perm_r[k]];
  	    for (k = 0; k < n; k++) rhs_work[k] = soln[k];
  	}
  
      }
  
      SUPERLU_FREE(work);
      SUPERLU_FREE(soln);
  }
  
  /*
   * Diagnostic print of the solution vector 
   */
  void
  dprint_soln(int n, int nrhs, double *soln)
  {
      int i;
  
      for (i = 0; i < n; i++) 
    	printf("\t%d: %.4f\n", i, soln[i]);
  }
  