/* dsm.f -- translated by f2c (version of 25 March 1992  12:58:56). */

#include <../src/mat/color/impls/minpack/color.h>

static PetscInt c_n1 = -1;

PetscErrorCode MINPACKdsm(PetscInt *m, PetscInt *n, PetscInt *npairs, PetscInt *indrow, PetscInt *indcol, PetscInt *ngrp, PetscInt *maxgrp, PetscInt *mingrp, PetscInt *info, PetscInt *ipntr, PetscInt *jpntr, PetscInt *iwa, PetscInt *liwa)
{
  /* System generated locals */
  PetscInt i__1, i__2, i__3;

  /* Local variables */
  PetscInt i, j, maxclq, numgrp;

  /*     Given the sparsity pattern of an m by n matrix A, this */
  /*     subroutine determines a partition of the columns of A */
  /*     consistent with the direct determination of A. */
  /*     The sparsity pattern of the matrix A is specified by */
  /*     the arrays indrow and indcol. On input the indices */
  /*     for the non-zero elements of A are */
  /*           indrow(k),indcol(k), k = 1,2,...,npairs. */
  /*     The (indrow,indcol) pairs may be specified in any order. */
  /*     Duplicate input pairs are permitted, but the subroutine */
  /*     eliminates them. */
  /*     The subroutine partitions the columns of A into groups */
  /*     such that columns in the same group do not have a */
  /*     non-zero in the same row position. A partition of the */
  /*     columns of A with this property is consistent with the */
  /*     direct determination of A. */
  /*     The subroutine statement is */
  /*       subroutine dsm(m,n,npairs,indrow,indcol,ngrp,maxgrp,mingrp, */
  /*                      info,ipntr,jpntr,iwa,liwa) */
  /*     where */
  /*       m is a positive integer input variable set to the number */
  /*         of rows of A. */
  /*       n is a positive integer input variable set to the number */
  /*         of columns of A. */
  /*       npairs is a positive integer input variable set to the */
  /*         number of (indrow,indcol) pairs used to describe the */
  /*         sparsity pattern of A. */
  /*       indrow is an integer array of length npairs. On input indrow */
  /*         must contain the row indices of the non-zero elements of A. */
  /*         On output indrow is permuted so that the corresponding */
  /*         column indices are in non-decreasing order. The column */
  /*         indices can be recovered from the array jpntr. */
  /*       indcol is an integer array of length npairs. On input indcol */
  /*         must contain the column indices of the non-zero elements of */
  /*         A. On output indcol is permuted so that the corresponding */
  /*         row indices are in non-decreasing order. The row indices */
  /*         can be recovered from the array ipntr. */
  /*       ngrp is an integer output array of length n which specifies */
  /*         the partition of the columns of A. Column jcol belongs */
  /*         to group ngrp(jcol). */
  /*       maxgrp is an integer output variable which specifies the */
  /*         number of groups in the partition of the columns of A. */
  /*       mingrp is an integer output variable which specifies a lower */
  /*         bound for the number of groups in any consistent partition */
  /*         of the columns of A. */
  /*       info is an integer output variable set as follows. For */
  /*         normal termination info = 1. If m, n, or npairs is not */
  /*         positive or liwa is less than max(m,6*n), then info = 0. */
  /*         If the k-th element of indrow is not an integer between */
  /*         1 and m or the k-th element of indcol is not an integer */
  /*         between 1 and n, then info = -k. */
  /*       ipntr is an integer output array of length m + 1 which */
  /*         specifies the locations of the column indices in indcol. */
  /*         The column indices for row i are */
  /*               indcol(k), k = ipntr(i),...,ipntr(i+1)-1. */
  /*         Note that ipntr(m+1)-1 is then the number of non-zero */
  /*         elements of the matrix A. */
  /*       jpntr is an integer output array of length n + 1 which */
  /*         specifies the locations of the row indices in indrow. */
  /*         The row indices for column j are */
  /*               indrow(k), k = jpntr(j),...,jpntr(j+1)-1. */
  /*         Note that jpntr(n+1)-1 is then the number of non-zero */
  /*         elements of the matrix A. */
  /*       iwa is an integer work array of length liwa. */
  /*       liwa is a positive integer input variable not less than */
  /*         max(m,6*n). */
  /*     Subprograms called */
  /*       MINPACK-supplied ... degr,ido,numsrt,seq,setr,slo,srtdat */
  /*       FORTRAN-supplied ... max */
  /*     Argonne National Laboratory. MINPACK Project. December 1984. */
  /*     Thomas F. Coleman, Burton S. Garbow, Jorge J. More' */

  PetscFunctionBegin;
  /* Parameter adjustments */
  --iwa;
  --jpntr;
  --ipntr;
  --ngrp;
  --indcol;
  --indrow;

  *info = 0;

  /*     Determine a lower bound for the number of groups. */

  *mingrp = 0;
  i__1    = *m;
  for (i = 1; i <= i__1; ++i) {
    /* Computing MAX */
    i__2    = *mingrp;
    i__3    = ipntr[i + 1] - ipntr[i];
    *mingrp = PetscMax(i__2, i__3);
  }

  /*     Determine the degree sequence for the intersection */
  /*     graph of the columns of A. */

  PetscCall(MINPACKdegr(n, &indrow[1], &jpntr[1], &indcol[1], &ipntr[1], &iwa[*n * 5 + 1], &iwa[*n + 1]));

  /*     Color the intersection graph of the columns of A */
  /*     with the smallest-last (SL) ordering. */

  PetscCall(MINPACKslo(n, &indrow[1], &jpntr[1], &indcol[1], &ipntr[1], &iwa[*n * 5 + 1], &iwa[(*n << 2) + 1], &maxclq, &iwa[1], &iwa[*n + 1], &iwa[(*n << 1) + 1], &iwa[*n * 3 + 1]));
  PetscCall(MINPACKseq(n, &indrow[1], &jpntr[1], &indcol[1], &ipntr[1], &iwa[(*n << 2) + 1], &ngrp[1], maxgrp, &iwa[*n + 1]));
  *mingrp = PetscMax(*mingrp, maxclq);

  /*     Exit if the smallest-last ordering is optimal. */

  if (*maxgrp == *mingrp) PetscFunctionReturn(PETSC_SUCCESS);

  /*     Color the intersection graph of the columns of A */
  /*     with the incidence-degree (ID) ordering. */

  PetscCall(MINPACKido(m, n, &indrow[1], &jpntr[1], &indcol[1], &ipntr[1], &iwa[*n * 5 + 1], &iwa[(*n << 2) + 1], &maxclq, &iwa[1], &iwa[*n + 1], &iwa[(*n << 1) + 1], &iwa[*n * 3 + 1]));
  PetscCall(MINPACKseq(n, &indrow[1], &jpntr[1], &indcol[1], &ipntr[1], &iwa[(*n << 2) + 1], &iwa[1], &numgrp, &iwa[*n + 1]));
  *mingrp = PetscMax(*mingrp, maxclq);

  /*     Retain the better of the two orderings so far. */

  if (numgrp < *maxgrp) {
    *maxgrp = numgrp;
    i__1    = *n;
    for (j = 1; j <= i__1; ++j) ngrp[j] = iwa[j];

    /*        Exit if the incidence-degree ordering is optimal. */

    if (*maxgrp == *mingrp) PetscFunctionReturn(PETSC_SUCCESS);
  }

  /*     Color the intersection graph of the columns of A */
  /*     with the largest-first (LF) ordering. */

  i__1 = *n - 1;
  PetscCall(MINPACKnumsrt(n, &i__1, &iwa[*n * 5 + 1], &c_n1, &iwa[(*n << 2) + 1], &iwa[(*n << 1) + 1], &iwa[*n + 1]));
  PetscCall(MINPACKseq(n, &indrow[1], &jpntr[1], &indcol[1], &ipntr[1], &iwa[(*n << 2) + 1], &iwa[1], &numgrp, &iwa[*n + 1]));

  /*     Retain the best of the three orderings and exit. */

  if (numgrp < *maxgrp) {
    *maxgrp = numgrp;
    i__1    = *n;
    for (j = 1; j <= i__1; ++j) ngrp[j] = iwa[j];
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}
