2: /* seq.f -- translated by f2c (version of 25 March 1992 12:58:56).*/
4: #include <../src/mat/color/color.h>
8: PetscErrorCode MINPACKseq(PetscInt *n,PetscInt *indrow,PetscInt *jpntr,PetscInt *indcol,PetscInt *ipntr,PetscInt *list,PetscInt *ngrp, 9: PetscInt *maxgrp,PetscInt *iwa) 10: {
11: /* System generated locals */
12: PetscInt i__1, i__2, i__3;
14: /* Local variables */
15: PetscInt jcol, j, ic, ip, jp, ir;
17: /* Given the sparsity pattern of an m by n matrix A, this */
18: /* subroutine determines a consistent partition of the */
19: /* columns of A by a sequential algorithm. */
20: /* A consistent partition is defined in terms of the loopless */
21: /* graph G with vertices a(j), j = 1,2,...,n where a(j) is the */
22: /* j-th column of A and with edge (a(i),a(j)) if and only if */
23: /* columns i and j have a non-zero in the same row position. */
24: /* A partition of the columns of A into groups is consistent */
25: /* if the columns in any group are not adjacent in the graph G. */
26: /* In graph-theory terminology, a consistent partition of the */
27: /* columns of A corresponds to a coloring of the graph G. */
28: /* The subroutine examines the columns in the order specified */
29: /* by the array list, and assigns the current column to the */
30: /* group with the smallest possible number. */
31: /* Note that the value of m is not needed by seq and is */
32: /* therefore not present in the subroutine statement. */
33: /* The subroutine statement is */
34: /* subroutine seq(n,indrow,jpntr,indcol,ipntr,list,ngrp,maxgrp, */
35: /* iwa) */
36: /* where */
37: /* n is a positive integer input variable set to the number */
38: /* of columns of A. */
39: /* indrow is an integer input array which contains the row */
40: /* indices for the non-zeroes in the matrix A. */
41: /* jpntr is an integer input array of length n + 1 which */
42: /* specifies the locations of the row indices in indrow. */
43: /* The row indices for column j are */
44: /* indrow(k), k = jpntr(j),...,jpntr(j+1)-1. */
45: /* Note that jpntr(n+1)-1 is then the number of non-zero */
46: /* elements of the matrix A. */
47: /* indcol is an integer input array which contains the */
48: /* column indices for the non-zeroes in the matrix A. */
49: /* ipntr is an integer input array of length m + 1 which */
50: /* specifies the locations of the column indices in indcol. */
51: /* The column indices for row i are */
52: /* indcol(k), k = ipntr(i),...,ipntr(i+1)-1. */
53: /* Note that ipntr(m+1)-1 is then the number of non-zero */
54: /* elements of the matrix A. */
55: /* list is an integer input array of length n which specifies */
56: /* the order to be used by the sequential algorithm. */
57: /* The j-th column in this order is list(j). */
58: /* ngrp is an integer output array of length n which specifies */
59: /* the partition of the columns of A. Column jcol belongs */
60: /* to group ngrp(jcol). */
61: /* maxgrp is an integer output variable which specifies the */
62: /* number of groups in the partition of the columns of A. */
63: /* iwa is an integer work array of length n. */
64: /* Argonne National Laboratory. MINPACK Project. July 1983. */
65: /* Thomas F. Coleman, Burton S. Garbow, Jorge J. More' */
68: /* Parameter adjustments */
69: --iwa;
70: --ngrp;
71: --list;
72: --ipntr;
73: --indcol;
74: --jpntr;
75: --indrow;
77: /* Function Body */
78: *maxgrp = 0;
79: i__1 = *n;
80: for (jp = 1; jp <= i__1; ++jp) {
81: ngrp[jp] = *n;
82: iwa[jp] = 0;
83: }
85: /* Beginning of iteration loop. */
87: i__1 = *n;
88: for (j = 1; j <= i__1; ++j) {
89: jcol = list[j];
91: /* Find all columns adjacent to column jcol. */
93: /* Determine all positions (ir,jcol) which correspond */
94: /* to non-zeroes in the matrix. */
96: i__2 = jpntr[jcol + 1] - 1;
97: for (jp = jpntr[jcol]; jp <= i__2; ++jp) {
98: ir = indrow[jp];
100: /* For each row ir, determine all positions (ir,ic) */
101: /* which correspond to non-zeroes in the matrix. */
103: i__3 = ipntr[ir + 1] - 1;
104: for (ip = ipntr[ir]; ip <= i__3; ++ip) {
105: ic = indcol[ip];
107: /* Array iwa marks the group numbers of the */
108: /* columns which are adjacent to column jcol. */
110: iwa[ngrp[ic]] = j;
111: }
112: }
114: /* Assign the smallest un-marked group number to jcol. */
116: i__2 = *maxgrp;
117: for (jp = 1; jp <= i__2; ++jp) {
118: if (iwa[jp] != j) {
119: goto L50;
120: }
121: }
122: ++(*maxgrp);
123: L50:124: ngrp[jcol] = jp;
125: }
127: /* End of iteration loop. */
129: return(0);
130: }