2: /* seq.f -- translated by f2c (version of 25 March 1992 12:58:56).*/
4: #include <../src/mat/color/impls/minpack/color.h> 6: PetscErrorCode MINPACKseq(PetscInt *n,const PetscInt *indrow,const PetscInt *jpntr,const PetscInt *indcol,const PetscInt *ipntr,PetscInt *list,PetscInt *ngrp,PetscInt *maxgrp,PetscInt *iwa) 7: {
8: /* System generated locals */
9: PetscInt i__1, i__2, i__3;
11: /* Local variables */
12: PetscInt jcol, j, ic, ip, jp, ir;
14: /* Given the sparsity pattern of an m by n matrix A, this */
15: /* subroutine determines a consistent partition of the */
16: /* columns of A by a sequential algorithm. */
17: /* A consistent partition is defined in terms of the loopless */
18: /* graph G with vertices a(j), j = 1,2,...,n where a(j) is the */
19: /* j-th column of A and with edge (a(i),a(j)) if and only if */
20: /* columns i and j have a non-zero in the same row position. */
21: /* A partition of the columns of A into groups is consistent */
22: /* if the columns in any group are not adjacent in the graph G. */
23: /* In graph-theory terminology, a consistent partition of the */
24: /* columns of A corresponds to a coloring of the graph G. */
25: /* The subroutine examines the columns in the order specified */
26: /* by the array list, and assigns the current column to the */
27: /* group with the smallest possible number. */
28: /* Note that the value of m is not needed by seq and is */
29: /* therefore not present in the subroutine statement. */
30: /* The subroutine statement is */
31: /* subroutine seq(n,indrow,jpntr,indcol,ipntr,list,ngrp,maxgrp, */
32: /* iwa) */
33: /* where */
34: /* n is a positive integer input variable set to the number */
35: /* of columns of A. */
36: /* indrow is an integer input array which contains the row */
37: /* indices for the non-zeroes in the matrix A. */
38: /* jpntr is an integer input array of length n + 1 which */
39: /* specifies the locations of the row indices in indrow. */
40: /* The row indices for column j are */
41: /* indrow(k), k = jpntr(j),...,jpntr(j+1)-1. */
42: /* Note that jpntr(n+1)-1 is then the number of non-zero */
43: /* elements of the matrix A. */
44: /* indcol is an integer input array which contains the */
45: /* column indices for the non-zeroes in the matrix A. */
46: /* ipntr is an integer input array of length m + 1 which */
47: /* specifies the locations of the column indices in indcol. */
48: /* The column indices for row i are */
49: /* indcol(k), k = ipntr(i),...,ipntr(i+1)-1. */
50: /* Note that ipntr(m+1)-1 is then the number of non-zero */
51: /* elements of the matrix A. */
52: /* list is an integer input array of length n which specifies */
53: /* the order to be used by the sequential algorithm. */
54: /* The j-th column in this order is list(j). */
55: /* ngrp is an integer output array of length n which specifies */
56: /* the partition of the columns of A. Column jcol belongs */
57: /* to group ngrp(jcol). */
58: /* maxgrp is an integer output variable which specifies the */
59: /* number of groups in the partition of the columns of A. */
60: /* iwa is an integer work array of length n. */
61: /* Argonne National Laboratory. MINPACK Project. July 1983. */
62: /* Thomas F. Coleman, Burton S. Garbow, Jorge J. More' */
65: /* Parameter adjustments */
66: --iwa;
67: --ngrp;
68: --list;
69: --ipntr;
70: --indcol;
71: --jpntr;
72: --indrow;
74: /* Function Body */
75: *maxgrp = 0;
76: i__1 = *n;
77: for (jp = 1; jp <= i__1; ++jp) {
78: ngrp[jp] = *n;
79: iwa[jp] = 0;
80: }
82: /* Beginning of iteration loop. */
84: i__1 = *n;
85: for (j = 1; j <= i__1; ++j) {
86: jcol = list[j];
88: /* Find all columns adjacent to column jcol. */
90: /* Determine all positions (ir,jcol) which correspond */
91: /* to non-zeroes in the matrix. */
93: i__2 = jpntr[jcol + 1] - 1;
94: for (jp = jpntr[jcol]; jp <= i__2; ++jp) {
95: ir = indrow[jp];
97: /* For each row ir, determine all positions (ir,ic) */
98: /* which correspond to non-zeroes in the matrix. */
100: i__3 = ipntr[ir + 1] - 1;
101: for (ip = ipntr[ir]; ip <= i__3; ++ip) {
102: ic = indcol[ip];
104: /* Array iwa marks the group numbers of the */
105: /* columns which are adjacent to column jcol. */
107: iwa[ngrp[ic]] = j;
108: }
109: }
111: /* Assign the smallest un-marked group number to jcol. */
113: i__2 = *maxgrp;
114: for (jp = 1; jp <= i__2; ++jp) {
115: if (iwa[jp] != j) goto L50;
116: }
117: ++(*maxgrp);
118: L50:119: ngrp[jcol] = jp;
120: }
122: /* End of iteration loop. */
123: return(0);
124: }