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,
36: PetscInt *qsize, PetscInt *qlink, PetscInt *marker, PetscInt *deg0,
37: PetscInt *nhdsze, PetscInt *nbrhd, PetscInt *rchset, PetscInt *ovrlp)
38: {
39: /* System generated locals */
40: PetscInt i__1, i__2, i__3;
42: /* Local variables */
43: PetscInt head, inhd, irch, node, mark, ilink, root, j, lnode, nabor,
44: jstop, jstrt, rchsze, mrgsze, novrlp, iov, deg1;
46: /* Parameter adjustments */
47: --ovrlp;
48: --rchset;
49: --nbrhd;
50: --marker;
51: --qlink;
52: --qsize;
53: --deg;
54: --adjncy;
55: --xadj;
57: if (*nhdsze <= 0) return 0;
58: i__1 = *nhdsze;
59: for (inhd = 1; inhd <= i__1; ++inhd) {
60: root = nbrhd[inhd];
61: marker[root] = 0;
62: }
63: /* LOOP THROUGH EACH ELIMINATED SUPERNODE IN THE SET */
64: /* (NHDSZE, NBRHD). */
65: i__1 = *nhdsze;
66: for (inhd = 1; inhd <= i__1; ++inhd) {
67: root = nbrhd[inhd];
68: marker[root] = -1;
69: rchsze = 0;
70: novrlp = 0;
71: deg1 = 0;
72: L200:
73: jstrt = xadj[root];
74: jstop = xadj[root + 1] - 1;
75: /* DETERMINE THE REACHABLE SET AND ITS PETSCINTERSECT- */
76: /* ION WITH THE INPUT REACHABLE SET. */
77: i__2 = jstop;
78: for (j = jstrt; j <= i__2; ++j) {
79: nabor = adjncy[j];
80: root = -nabor;
81: if (nabor < 0) goto L200;
82: else if (!nabor) goto L700;
83: else goto L300;
84: L300:
85: mark = marker[nabor];
86: if (mark < 0) goto L600;
87: else if (!mark) goto L400;
88: else goto L500;
89: L400:
90: ++rchsze;
91: rchset[rchsze] = nabor;
92: deg1 += qsize[nabor];
93: marker[nabor] = 1;
94: goto L600;
95: L500:
96: if (mark > 1) goto L600;
97: ++novrlp;
98: ovrlp[novrlp] = nabor;
99: marker[nabor] = 2;
100: L600:
101: ;
102: }
103: /* FROM THE OVERLAPPED SET, DETERMINE THE NODES */
104: /* THAT CAN BE MERGED TOGETHER. */
105: L700:
106: head = 0;
107: mrgsze = 0;
108: i__2 = novrlp;
109: for (iov = 1; iov <= i__2; ++iov) {
110: node = ovrlp[iov];
111: jstrt = xadj[node];
112: jstop = xadj[node + 1] - 1;
113: i__3 = jstop;
114: for (j = jstrt; j <= i__3; ++j) {
115: nabor = adjncy[j];
116: if (marker[nabor] != 0) goto L800;
117: marker[node] = 1;
118: goto L1100;
119: L800:
120: ;
121: }
122: /* NODE BELONGS TO THE NEW MERGED SUPERNODE. */
123: /* UPDATE THE VECTORS QLINK AND QSIZE. */
124: mrgsze += qsize[node];
125: marker[node] = -1;
126: lnode = node;
127: L900:
128: ilink = qlink[lnode];
129: if (ilink <= 0) goto L1000;
130: lnode = ilink;
131: goto L900;
132: L1000:
133: qlink[lnode] = head;
134: head = node;
135: L1100:
136: ;
137: }
138: if (head <= 0) goto L1200;
139: qsize[head] = mrgsze;
140: deg[head] = *deg0 + deg1 - 1;
141: marker[head] = 2;
142: /* RESET MARKER VALUES. */
143: L1200:
144: root = nbrhd[inhd];
145: marker[root] = 0;
146: if (rchsze <= 0) goto L1400;
147: i__2 = rchsze;
148: for (irch = 1; irch <= i__2; ++irch) {
149: node = rchset[irch];
150: marker[node] = 0;
151: }
152: L1400:
153: ;
154: }
155: return 0;
156: }