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