/*
Copyright (c) 2003, The Regents of the University of California, through
Lawrence Berkeley National Laboratory (subject to receipt of any required 
approvals from U.S. Dept. of Energy) 

All rights reserved. 

The source code is distributed under BSD license, see the file License.txt
at the top-level directory.
*/

/*
 * -- SuperLU routine (version 5.0) --
 * Univ. of California Berkeley, Xerox Palo Alto Research Center,
 * and Lawrence Berkeley National Lab.
 * October 15, 2003
 *
 * Last update: July 10, 2015
 *
 */

/*! \file
 * \brief DGSSVX to solve systems with the same matrix but different right-hand side.
 *
 * \ingroup Example
 */

#include <getopt.h>
#include "slu_ddefs.h"

void parse_command_line(int argc, char *argv[], int_t *lwork,
                        double *u, yes_no_t *equil, trans_t *trans);
			
int main(int argc, char *argv[])
{
/*!
 * \brief The driver program DLINSOLX1.
 *
 * This example illustrates how to use DGSSVX to solve systems with the same
 * A but different right-hand side.
 * In this case, we factorize A only once in the first call to DGSSVX,
 * and reuse the following data structures in the subsequent call to DGSSVX:
 *     perm_c, perm_r, R, C, L, U.
 * 
 */
    char           equed[1];
    yes_no_t       equil;
    trans_t        trans;
    SuperMatrix    A, L, U;
    SuperMatrix    B, X;
    NCformat       *Astore;
    NCformat       *Ustore;
    SCformat       *Lstore;
    GlobalLU_t	   Glu; /* facilitate multiple factorizations with 
                           SamePattern_SameRowPerm                  */
    double         *a;
    int_t          *asub, *xa;
    int            *perm_c; /* column permutation vector */
    int            *perm_r; /* row permutations from partial pivoting */
    int            *etree;
    void           *work = NULL;
    int            m, n, nrhs, ldx;
    int_t          info, lwork, nnz;
    double         *rhsb, *rhsx, *xact;
    double         *R, *C;
    double         *ferr, *berr;
    double         u, rpg, rcond;
    mem_usage_t    mem_usage;
    superlu_options_t options;
    SuperLUStat_t stat;
    FILE           *fp = stdin;

#if ( DEBUGlevel>=1 )
    CHECK_MALLOC("Enter main()");
#endif

    /* Defaults */
    lwork = 0;
    nrhs  = 1;
    equil = YES;	
    u     = 1.0;
    trans = NOTRANS;

    /* Set the default values for options argument:
	options.Fact = DOFACT;
        options.Equil = YES;
    	options.ColPerm = COLAMD;
	options.DiagPivotThresh = 1.0;
    	options.Trans = NOTRANS;
    	options.IterRefine = NOREFINE;
    	options.SymmetricMode = NO;
    	options.PivotGrowth = NO;
    	options.ConditionNumber = NO;
    	options.PrintStat = YES;
    */
    set_default_options(&options);

    /* Can use command line input to modify the defaults. */
    parse_command_line(argc, argv, &lwork, &u, &equil, &trans);
    options.Equil = equil;
    options.DiagPivotThresh = u;
    options.Trans = trans;
    
    if ( lwork > 0 ) {
	work = SUPERLU_MALLOC(lwork);
	if ( !work ) {
	    ABORT("DLINSOLX: cannot allocate work[]");
	}
    }

    /* Read matrix A from a file in Harwell-Boeing format.*/
    dreadhb(fp, &m, &n, &nnz, &a, &asub, &xa);
    
    dCreate_CompCol_Matrix(&A, m, n, nnz, a, asub, xa, SLU_NC, SLU_D, SLU_GE);
    Astore = A.Store;
    printf("Dimension %dx%d; # nonzeros %d\n", (int)A.nrow, (int)A.ncol, (int)Astore->nnz);
    
    if ( !(rhsb = doubleMalloc(m * nrhs)) ) ABORT("Malloc fails for rhsb[].");
    if ( !(rhsx = doubleMalloc(m * nrhs)) ) ABORT("Malloc fails for rhsx[].");
    dCreate_Dense_Matrix(&B, m, nrhs, rhsb, m, SLU_DN, SLU_D, SLU_GE);
    dCreate_Dense_Matrix(&X, m, nrhs, rhsx, m, SLU_DN, SLU_D, SLU_GE);
    xact = doubleMalloc(n * nrhs);
    ldx = n;
    dGenXtrue(n, nrhs, xact, ldx);
    dFillRHS(trans, nrhs, xact, ldx, &A, &B);
    
    if ( !(etree = int32Malloc(n)) ) ABORT("Malloc fails for etree[].");
    if ( !(perm_r = int32Malloc(m)) ) ABORT("Malloc fails for perm_r[].");
    if ( !(perm_c = int32Malloc(n)) ) ABORT("Malloc fails for perm_c[].");
    if ( !(R = (double *) SUPERLU_MALLOC(A.nrow * sizeof(double))) ) 
        ABORT("SUPERLU_MALLOC fails for R[].");
    if ( !(C = (double *) SUPERLU_MALLOC(A.ncol * sizeof(double))) )
        ABORT("SUPERLU_MALLOC fails for C[].");
    if ( !(ferr = (double *) SUPERLU_MALLOC(nrhs * sizeof(double))) )
        ABORT("SUPERLU_MALLOC fails for ferr[].");
    if ( !(berr = (double *) SUPERLU_MALLOC(nrhs * sizeof(double))) ) 
        ABORT("SUPERLU_MALLOC fails for berr[].");

    /* Initialize the statistics variables. */
    StatInit(&stat);
    
    /* ONLY PERFORM THE LU DECOMPOSITION */
    B.ncol = 0;  /* Indicate not to solve the system */
    dgssvx(&options, &A, perm_c, perm_r, etree, equed, R, C,
           &L, &U, work, lwork, &B, &X, &rpg, &rcond, ferr, berr,
           &Glu, &mem_usage, &stat, &info);

    printf("LU factorization: dgssvx() returns info %lld\n", (long long)info);

    if ( info == 0 || info == n+1 ) {

	if ( options.PivotGrowth ) printf("Recip. pivot growth = %e\n", rpg);
	if ( options.ConditionNumber )
	    printf("Recip. condition number = %e\n", rcond);
        Lstore = (SCformat *) L.Store;
        Ustore = (NCformat *) U.Store;
	printf("No of nonzeros in factor L = %lld\n", (long long) Lstore->nnz);
    	printf("No of nonzeros in factor U = %lld\n", (long long) Ustore->nnz);
    	printf("No of nonzeros in L+U = %lld\n", (long long) Lstore->nnz + Ustore->nnz - n);
    	printf("FILL ratio = %.1f\n", (float)(Lstore->nnz + Ustore->nnz - n)/nnz);

	printf("L\\U MB %.3f\ttotal MB needed %.3f\n",
	       mem_usage.for_lu/1e6, mem_usage.total_needed/1e6);
	fflush(stdout);

    } else if ( info > 0 && lwork == -1 ) {
        printf("** Estimated memory: %lld bytes\n", (long long)info - n);
    }

    if ( options.PrintStat ) StatPrint(&stat);
    StatFree(&stat);

    /* ------------------------------------------------------------
       NOW WE SOLVE THE LINEAR SYSTEM USING THE FACTORED FORM OF A.
       ------------------------------------------------------------*/
    options.Fact = FACTORED; /* Indicate the factored form of A is supplied. */
    B.ncol = nrhs;  /* Set the number of right-hand side */

    /* Initialize the statistics variables. */
    StatInit(&stat);

    dgssvx(&options, &A, perm_c, perm_r, etree, equed, R, C,
           &L, &U, work, lwork, &B, &X, &rpg, &rcond, ferr, berr,
           &Glu, &mem_usage, &stat, &info);

    printf("Triangular solve: dgssvx() returns info %lld\n", (long long)info);

    if ( info == 0 || info == n+1 ) {

        /* This is how you could access the solution matrix. */
        double *sol = (double*) ((DNformat*) X.Store)->nzval; 
        (void)sol;  // suppress unused variable warning

	if ( options.IterRefine ) {
            printf("Iterative Refinement:\n");
	    printf("%8s%8s%16s%16s\n", "rhs", "Steps", "FERR", "BERR");
	    for (int i = 0; i < nrhs; ++i)
	      printf("%8d%8d%16e%16e\n", i+1, stat.RefineSteps, ferr[i], berr[i]);
	}
	fflush(stdout);
    } else if ( info > 0 && lwork == -1 ) {
        printf("** Estimated memory: %lld bytes\n", (long long)info - n);
    }

    if ( options.PrintStat ) StatPrint(&stat);
    StatFree(&stat);

    SUPERLU_FREE (rhsb);
    SUPERLU_FREE (rhsx);
    SUPERLU_FREE (xact);
    SUPERLU_FREE (etree);
    SUPERLU_FREE (perm_r);
    SUPERLU_FREE (perm_c);
    SUPERLU_FREE (R);
    SUPERLU_FREE (C);
    SUPERLU_FREE (ferr);
    SUPERLU_FREE (berr);
    Destroy_CompCol_Matrix(&A);
    Destroy_SuperMatrix_Store(&B);
    Destroy_SuperMatrix_Store(&X);
    if ( lwork == 0 ) {
        Destroy_SuperNode_Matrix(&L);
        Destroy_CompCol_Matrix(&U);
    } else if ( lwork > 0 ) {
        SUPERLU_FREE(work);
    }


#if ( DEBUGlevel>=1 )
    CHECK_MALLOC("Exit main()");
#endif
    return EXIT_SUCCESS;
}

/*!
 * \brief Parse command line options to get relaxed snode size, panel size, etc.
 */
void
parse_command_line(int argc, char *argv[], int_t *lwork,
                   double *u, yes_no_t *equil, trans_t *trans )
{
    int c;
    extern char *optarg;

    while ( (c = getopt(argc, argv, "hl:u:e:t:")) != EOF ) {
	switch (c) {
	  case 'h':
	    printf("Options:\n");
	    printf("\t-l <int> - length of work[*] array\n");
	    printf("\t-u <int> - pivoting threshold\n");
	    printf("\t-e <0 or 1> - equilibrate or not\n");
	    printf("\t-t <0 or 1> - solve transposed system or not\n");
	    exit(1);
	    break;
	  case 'l': *lwork = atoi(optarg);
	            break;
	  case 'u': *u = atof(optarg); 
	            break;
	  case 'e': *equil = atoi(optarg); 
	            break;
	  case 't': *trans = atoi(optarg);
	            break;
  	}
    }
}