/*

 * -- SuperLU routine (version 3.0) --

 * Univ. of California Berkeley, Xerox Palo Alto Research Center,

 * and Lawrence Berkeley National Lab.

 * October 15, 2003

 *

 */

#include "slu_sdefs.h"

#define HANDLE_SIZE  8

/* kind of integer to hold a pointer.  Use int.

   This might need to be changed on 64-bit systems. */

typedef int fptr;  /* 32-bit by default */

typedef struct {

    SuperMatrix *L;

    SuperMatrix *U;

    int *perm_c;

    int *perm_r;

} factors_t;

void

c_fortran_sgssv_(int *iopt, int *n, int *nnz, int *nrhs, 

                 float *values, int *rowind, int *colptr,

                 float *b, int *ldb,

		 fptr *f_factors, /* a handle containing the address

				     pointing to the factored matrices */

		 int *info)

{

/* 

 * This routine can be called from Fortran.

 *

 * iopt (input) int

 *      Specifies the operation:

 *      = 1, performs LU decomposition for the first time

 *      = 2, performs triangular solve

 *      = 3, free all the storage in the end

 *

 * f_factors (input/output) fptr* 

 *      If iopt == 1, it is an output and contains the pointer pointing to

 *                    the structure of the factored matrices.

 *      Otherwise, it it an input.

 *

 */

    SuperMatrix A, AC, B;

    SuperMatrix *L, *U;

    int *perm_r; /* row permutations from partial pivoting */

    int *perm_c; /* column permutation vector */

    int *etree;  /* column elimination tree */

    SCformat *Lstore;

    NCformat *Ustore;

    int      i, panel_size, permc_spec, relax;

    trans_t  trans;

    mem_usage_t   mem_usage;

    superlu_options_t options;

    SuperLUStat_t stat;

    factors_t *LUfactors;

    trans = NOTRANS;

    if ( *iopt == 1 ) { /* LU decomposition */

        /* Set the default input options. */

        set_default_options(&options);

	/* Initialize the statistics variables. */

	StatInit(&stat);

	/* Adjust to 0-based indexing */

	for (i = 0; i < *nnz; ++i) --rowind[i];

	for (i = 0; i <= *n; ++i) --colptr[i];

	sCreate_CompCol_Matrix(&A, *n, *n, *nnz, values, rowind, colptr,

			       SLU_NC, SLU_S, SLU_GE);

	L = (SuperMatrix *) SUPERLU_MALLOC( sizeof(SuperMatrix) );

	U = (SuperMatrix *) SUPERLU_MALLOC( sizeof(SuperMatrix) );

	if ( !(perm_r = intMalloc(*n)) ) ABORT("Malloc fails for perm_r[].");

	if ( !(perm_c = intMalloc(*n)) ) ABORT("Malloc fails for perm_c[].");

	if ( !(etree = intMalloc(*n)) ) ABORT("Malloc fails for etree[].");

	/*

	 * Get column permutation vector perm_c[], according to permc_spec:

	 *   permc_spec = 0: natural ordering 

	 *   permc_spec = 1: minimum degree on structure of A'*A

	 *   permc_spec = 2: minimum degree on structure of A'+A

	 *   permc_spec = 3: approximate minimum degree for unsymmetric matrices

	 */    	

	permc_spec = options.ColPerm;

	get_perm_c(permc_spec, &A, perm_c);

	sp_preorder(&options, &A, perm_c, etree, &AC);

	panel_size = sp_ienv(1);

	relax = sp_ienv(2);

	sgstrf(&options, &AC, relax, panel_size, etree,

                NULL, 0, perm_c, perm_r, L, U, &stat, info);

	if ( *info == 0 ) {

	    Lstore = (SCformat *) L->Store;

	    Ustore = (NCformat *) U->Store;

	    printf("No of nonzeros in factor L = %d\n", Lstore->nnz);

	    printf("No of nonzeros in factor U = %d\n", Ustore->nnz);

	    printf("No of nonzeros in L+U = %d\n", Lstore->nnz + Ustore->nnz);

	    sQuerySpace(L, U, &mem_usage);

	    printf("L\\U MB %.3f\ttotal MB needed %.3f\n",

		   mem_usage.for_lu/1e6, mem_usage.total_needed/1e6);

	} else {

	    printf("sgstrf() error returns INFO= %d\n", *info);

	    if ( *info <= *n ) { /* factorization completes */

		sQuerySpace(L, U, &mem_usage);

		printf("L\\U MB %.3f\ttotal MB needed %.3f\n",

		       mem_usage.for_lu/1e6, mem_usage.total_needed/1e6);

	    }

	}

	/* Restore to 1-based indexing */

	for (i = 0; i < *nnz; ++i) ++rowind[i];

	for (i = 0; i <= *n; ++i) ++colptr[i];

	/* Save the LU factors in the factors handle */

	LUfactors = (factors_t*) SUPERLU_MALLOC(sizeof(factors_t));

	LUfactors->L = L;

	LUfactors->U = U;

	LUfactors->perm_c = perm_c;

	LUfactors->perm_r = perm_r;

	*f_factors = (fptr) LUfactors;

	/* Free un-wanted storage */

	SUPERLU_FREE(etree);

	Destroy_SuperMatrix_Store(&A);

	Destroy_CompCol_Permuted(&AC);

	StatFree(&stat);

    } else if ( *iopt == 2 ) { /* Triangular solve */

	/* Initialize the statistics variables. */

	StatInit(&stat);

	/* Extract the LU factors in the factors handle */

	LUfactors = (factors_t*) *f_factors;

	L = LUfactors->L;

	U = LUfactors->U;

	perm_c = LUfactors->perm_c;

	perm_r = LUfactors->perm_r;

	sCreate_Dense_Matrix(&B, *n, *nrhs, b, *ldb, SLU_DN, SLU_S, SLU_GE);

        /* Solve the system A*X=B, overwriting B with X. */

        sgstrs (trans, L, U, perm_c, perm_r, &B, &stat, info);

	Destroy_SuperMatrix_Store(&B);

	StatFree(&stat);

    } else if ( *iopt == 3 ) { /* Free storage */

	/* Free the LU factors in the factors handle */

	LUfactors = (factors_t*) *f_factors;

	SUPERLU_FREE (LUfactors->perm_r);

	SUPERLU_FREE (LUfactors->perm_c);

	Destroy_SuperNode_Matrix(LUfactors->L);

	Destroy_CompCol_Matrix(LUfactors->U);

        SUPERLU_FREE (LUfactors->L);

        SUPERLU_FREE (LUfactors->U);

	SUPERLU_FREE (LUfactors);

    } else {

	fprintf(stderr,"Invalid iopt=%d passed to c_fortran_sgssv()\n",*iopt);

	exit(-1);

    }

}