Actual source code: dsm.c

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

     4:  #include petsc.h
     5:  #include src/mat/color/color.h

      7: static PetscInt c_n1 = -1;

     11: PetscErrorCode MINPACKdsm(PetscInt *m,PetscInt *n,PetscInt *npairs,PetscInt *indrow,PetscInt *indcol,PetscInt *ngrp,PetscInt *maxgrp,
     12:                           PetscInt *mingrp,PetscInt *info,PetscInt *ipntr,PetscInt *jpntr,PetscInt *iwa,PetscInt *liwa)
     13: {
     14:     /* System generated locals */
     15:     PetscInt i__1,i__2,i__3;

     17:     /* Local variables */
     18:     PetscInt i,j,maxclq,numgrp;

     20: /*     Given the sparsity pattern of an m by n matrix A, this */
     21: /*     subroutine determines a partition of the columns of A */
     22: /*     consistent with the direct determination of A. */
     23: /*     The sparsity pattern of the matrix A is specified by */
     24: /*     the arrays indrow and indcol. On input the indices */
     25: /*     for the non-zero elements of A are */
     26: /*           indrow(k),indcol(k), k = 1,2,...,npairs. */
     27: /*     The (indrow,indcol) pairs may be specified in any order. */
     28: /*     Duplicate input pairs are permitted, but the subroutine */
     29: /*     eliminates them. */
     30: /*     The subroutine partitions the columns of A into groups */
     31: /*     such that columns in the same group do not have a */
     32: /*     non-zero in the same row position. A partition of the */
     33: /*     columns of A with this property is consistent with the */
     34: /*     direct determination of A. */
     35: /*     The subroutine statement is */
     36: /*       subroutine dsm(m,n,npairs,indrow,indcol,ngrp,maxgrp,mingrp, */
     37: /*                      info,ipntr,jpntr,iwa,liwa) */
     38: /*     where */
     39: /*       m is a positive integer input variable set to the number */
     40: /*         of rows of A. */
     41: /*       n is a positive integer input variable set to the number */
     42: /*         of columns of A. */
     43: /*       npairs is a positive integer input variable set to the */
     44: /*         number of (indrow,indcol) pairs used to describe the */
     45: /*         sparsity pattern of A. */
     46: /*       indrow is an integer array of length npairs. On input indrow */
     47: /*         must contain the row indices of the non-zero elements of A. */
     48: /*         On output indrow is permuted so that the corresponding */
     49: /*         column indices are in non-decreasing order. The column */
     50: /*         indices can be recovered from the array jpntr. */
     51: /*       indcol is an integer array of length npairs. On input indcol */
     52: /*         must contain the column indices of the non-zero elements of */
     53: /*         A. On output indcol is permuted so that the corresponding */
     54: /*         row indices are in non-decreasing order. The row indices */
     55: /*         can be recovered from the array ipntr. */
     56: /*       ngrp is an integer output array of length n which specifies */
     57: /*         the partition of the columns of A. Column jcol belongs */
     58: /*         to group ngrp(jcol). */
     59: /*       maxgrp is an integer output variable which specifies the */
     60: /*         number of groups in the partition of the columns of A. */
     61: /*       mingrp is an integer output variable which specifies a lower */
     62: /*         bound for the number of groups in any consistent partition */
     63: /*         of the columns of A. */
     64: /*       info is an integer output variable set as follows. For */
     65: /*         normal termination info = 1. If m, n, or npairs is not */
     66: /*         positive or liwa is less than max(m,6*n), then info = 0. */
     67: /*         If the k-th element of indrow is not an integer between */
     68: /*         1 and m or the k-th element of indcol is not an integer */
     69: /*         between 1 and n, then info = -k. */
     70: /*       ipntr is an integer output array of length m + 1 which */
     71: /*         specifies the locations of the column indices in indcol. */
     72: /*         The column indices for row i are */
     73: /*               indcol(k), k = ipntr(i),...,ipntr(i+1)-1. */
     74: /*         Note that ipntr(m+1)-1 is then the number of non-zero */
     75: /*         elements of the matrix A. */
     76: /*       jpntr is an integer output array of length n + 1 which */
     77: /*         specifies the locations of the row indices in indrow. */
     78: /*         The row indices for column j are */
     79: /*               indrow(k), k = jpntr(j),...,jpntr(j+1)-1. */
     80: /*         Note that jpntr(n+1)-1 is then the number of non-zero */
     81: /*         elements of the matrix A. */
     82: /*       iwa is an integer work array of length liwa. */
     83: /*       liwa is a positive integer input variable not less than */
     84: /*         max(m,6*n). */
     85: /*     Subprograms called */
     86: /*       MINPACK-supplied ... degr,ido,numsrt,seq,setr,slo,srtdat */
     87: /*       FORTRAN-supplied ... max */
     88: /*     Argonne National Laboratory. MINPACK Project. December 1984. */
     89: /*     Thomas F. Coleman, Burton S. Garbow, Jorge J. More' */

     92:     /* Parameter adjustments */
     93:     --iwa;
     94:     --jpntr;
     95:     --ipntr;
     96:     --ngrp;
     97:     --indcol;
     98:     --indrow;

    100:     *info = 0;

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

    104:     *mingrp = 0;
    105:     i__1 = *m;
    106:     for (i = 1; i <= i__1; ++i) {
    107: /* Computing MAX */
    108:         i__2 = *mingrp,i__3 = ipntr[i + 1] - ipntr[i];
    109:         *mingrp = PetscMax(i__2,i__3);
    110:     }

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

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

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

    121:     MINPACKslo(n,&indrow[1],&jpntr[1],&indcol[1],&ipntr[1],&iwa[*n * 5 + 1],&
    122:             iwa[(*n << 2) + 1],&maxclq,&iwa[1],&iwa[*n + 1],&iwa[(*n << 1)
    123:              + 1],&iwa[*n * 3 + 1]);
    124:     MINPACKseq(n,&indrow[1],&jpntr[1],&indcol[1],&ipntr[1],&iwa[(*n << 2) + 1],
    125:              &ngrp[1],maxgrp,&iwa[*n + 1]);
    126:     *mingrp = PetscMax(*mingrp,maxclq);

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

    130:     if (*maxgrp == *mingrp) {
    131:         return(0);
    132:     }

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

    137:     MINPACKido(m,n,&indrow[1],&jpntr[1],&indcol[1],&ipntr[1],&iwa[*n * 5 + 1],
    138:              &iwa[(*n << 2) + 1],&maxclq,&iwa[1],&iwa[*n + 1],&iwa[(*n <<
    139:             1) + 1],&iwa[*n * 3 + 1]);
    140:     MINPACKseq(n,&indrow[1],&jpntr[1],&indcol[1],&ipntr[1],&iwa[(*n << 2) + 1],
    141:              &iwa[1],&numgrp,&iwa[*n + 1]);
    142:     *mingrp = PetscMax(*mingrp,maxclq);

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

    146:     if (numgrp < *maxgrp) {
    147:         *maxgrp = numgrp;
    148:         i__1 = *n;
    149:         for (j = 1; j <= i__1; ++j) {
    150:             ngrp[j] = iwa[j];
    151:         }

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

    155:         if (*maxgrp == *mingrp) {
    156:             return(0);
    157:         }
    158:     }

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

    163:     i__1 = *n - 1;
    164:     MINPACKnumsrt(n,&i__1,&iwa[*n * 5 + 1],&c_n1,&iwa[(*n << 2) + 1],&iwa[(*n
    165:             << 1) + 1],&iwa[*n + 1]);
    166:     MINPACKseq(n,&indrow[1],&jpntr[1],&indcol[1],&ipntr[1],&iwa[(*n << 2) + 1],
    167:              &iwa[1],&numgrp,&iwa[*n + 1]);

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

    171:     if (numgrp < *maxgrp) {
    172:         *maxgrp = numgrp;
    173:         i__1 = *n;
    174:         for (j = 1; j <= i__1; ++j) {
    175:             ngrp[j] = iwa[j];
    176:         }
    177:     }
    178:     return(0);
    179: }