Actual source code: qmdmrg.c
2: /* qmdmrg.f -- translated by f2c (version 19931217).*/
4: #include <petscsys.h>
5: #include <petsc/private/matorderimpl.h>
7: /******************************************************************/
8: /*********** QMDMRG ..... QUOT MIN DEG MERGE ************/
9: /******************************************************************/
10: /* PURPOSE - THIS ROUTINE MERGES INDISTINGUISHABLE NODES IN */
11: /* THE MINIMUM DEGREE ORDERING ALGORITHM. */
12: /* IT ALSO COMPUTES THE NEW DEGREES OF THESE */
13: /* NEW SUPERNODES. */
14: /* */
15: /* INPUT PARAMETERS - */
16: /* (XADJ, ADJNCY) - THE ADJACENCY STRUCTURE. */
17: /* DEG0 - THE NUMBER OF NODES IN THE GIVEN SET. */
18: /* (NHDSZE, NBRHD) - THE SET OF ELIMINATED SUPERNODES */
19: /* ADJACENT TO SOME NODES IN THE SET. */
20: /* */
21: /* UPDATED PARAMETERS - */
22: /* DEG - THE DEGREE VECTOR. */
23: /* QSIZE - SIZE OF INDISTINGUISHABLE NODES. */
24: /* QLINK - LINKED LIST FOR INDISTINGUISHABLE NODES. */
25: /* MARKER - THE GIVEN SET IS GIVEN BY THOSE NODES WITH */
26: /* MARKER VALUE SET TO 1. THOSE NODES WITH DEGREE */
27: /* UPDATED WILL HAVE MARKER VALUE SET TO 2. */
28: /* */
29: /* WORKING PARAMETERS - */
30: /* RCHSET - THE REACHABLE SET. */
31: /* OVRLP - TEMP VECTOR TO STORE THE INTERSECTION OF TWO */
32: /* REACHABLE SETS. */
33: /* */
34: /*****************************************************************/
35: PetscErrorCode SPARSEPACKqmdmrg(const PetscInt *xadj, const PetscInt *adjncy, PetscInt *deg, PetscInt *qsize, PetscInt *qlink, PetscInt *marker, PetscInt *deg0, PetscInt *nhdsze, PetscInt *nbrhd, PetscInt *rchset, PetscInt *ovrlp)
36: {
37: /* System generated locals */
38: PetscInt i__1, i__2, i__3;
40: /* Local variables */
41: PetscInt head, inhd, irch, node, mark, ilink, root, j, lnode, nabor, jstop, jstrt, rchsze, mrgsze, novrlp, iov, deg1;
43: /* Parameter adjustments */
44: --ovrlp;
45: --rchset;
46: --nbrhd;
47: --marker;
48: --qlink;
49: --qsize;
50: --deg;
51: --adjncy;
52: --xadj;
54: if (*nhdsze <= 0) return 0;
55: i__1 = *nhdsze;
56: for (inhd = 1; inhd <= i__1; ++inhd) {
57: root = nbrhd[inhd];
58: marker[root] = 0;
59: }
60: /* LOOP THROUGH EACH ELIMINATED SUPERNODE IN THE SET */
61: /* (NHDSZE, NBRHD). */
62: i__1 = *nhdsze;
63: for (inhd = 1; inhd <= i__1; ++inhd) {
64: root = nbrhd[inhd];
65: marker[root] = -1;
66: rchsze = 0;
67: novrlp = 0;
68: deg1 = 0;
69: L200:
70: jstrt = xadj[root];
71: jstop = xadj[root + 1] - 1;
72: /* DETERMINE THE REACHABLE SET AND ITS PETSCINTERSECT- */
73: /* ION WITH THE INPUT REACHABLE SET. */
74: i__2 = jstop;
75: for (j = jstrt; j <= i__2; ++j) {
76: nabor = adjncy[j];
77: root = -nabor;
78: if (nabor < 0) goto L200;
79: else if (!nabor) goto L700;
80: else goto L300;
81: L300:
82: mark = marker[nabor];
83: if (mark < 0) goto L600;
84: else if (!mark) goto L400;
85: else goto L500;
86: L400:
87: ++rchsze;
88: rchset[rchsze] = nabor;
89: deg1 += qsize[nabor];
90: marker[nabor] = 1;
91: goto L600;
92: L500:
93: if (mark > 1) goto L600;
94: ++novrlp;
95: ovrlp[novrlp] = nabor;
96: marker[nabor] = 2;
97: L600:;
98: }
99: /* FROM THE OVERLAPPED SET, DETERMINE THE NODES */
100: /* THAT CAN BE MERGED TOGETHER. */
101: L700:
102: head = 0;
103: mrgsze = 0;
104: i__2 = novrlp;
105: for (iov = 1; iov <= i__2; ++iov) {
106: node = ovrlp[iov];
107: jstrt = xadj[node];
108: jstop = xadj[node + 1] - 1;
109: i__3 = jstop;
110: for (j = jstrt; j <= i__3; ++j) {
111: nabor = adjncy[j];
112: if (marker[nabor] != 0) goto L800;
113: marker[node] = 1;
114: goto L1100;
115: L800:;
116: }
117: /* NODE BELONGS TO THE NEW MERGED SUPERNODE. */
118: /* UPDATE THE VECTORS QLINK AND QSIZE. */
119: mrgsze += qsize[node];
120: marker[node] = -1;
121: lnode = node;
122: L900:
123: ilink = qlink[lnode];
124: if (ilink <= 0) goto L1000;
125: lnode = ilink;
126: goto L900;
127: L1000:
128: qlink[lnode] = head;
129: head = node;
130: L1100:;
131: }
132: if (head <= 0) goto L1200;
133: qsize[head] = mrgsze;
134: deg[head] = *deg0 + deg1 - 1;
135: marker[head] = 2;
136: /* RESET MARKER VALUES. */
137: L1200:
138: root = nbrhd[inhd];
139: marker[root] = 0;
140: if (rchsze <= 0) goto L1400;
141: i__2 = rchsze;
142: for (irch = 1; irch <= i__2; ++irch) {
143: node = rchset[irch];
144: marker[node] = 0;
145: }
146: L1400:;
147: }
148: return 0;
149: }