1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at https://graphviz.org
*************************************************************************/
#include "config.h"
#include <limits.h>
#include <ortho/sgraph.h>
#include <ortho/fPQ.h>
#include <util/alloc.h>
void
gsave (sgraph* G)
{
int i;
G->save_nnodes = G->nnodes;
G->save_nedges = G->nedges;
for (i = 0; i < G->nnodes; i++)
G->nodes[i].save_n_adj = G->nodes[i].n_adj;
}
void
reset(sgraph* G)
{
int i;
G->nnodes = G->save_nnodes;
G->nedges = G->save_nedges;
for (i = 0; i < G->nnodes; i++)
G->nodes[i].n_adj = G->nodes[i].save_n_adj;
for (; i < G->nnodes+2; i++)
G->nodes[i].n_adj = 0;
}
void initSEdges(sgraph *g, size_t maxdeg) {
int i;
int* adj = gv_calloc(6 * g->nnodes + 2 * maxdeg, sizeof(int));
g->edges = gv_calloc(3 * g->nnodes + maxdeg, sizeof(sedge));
for (i = 0; i < g->nnodes; i++) {
g->nodes[i].adj_edge_list = adj;
adj += 6;
}
for (; i < g->nnodes+2; i++) {
g->nodes[i].adj_edge_list = adj;
adj += maxdeg;
}
}
sgraph *createSGraph(size_t nnodes) {
sgraph* g = gv_alloc(sizeof(sgraph));
/* create the nodes vector in the search graph */
g->nnodes = 0;
g->nodes = gv_calloc(nnodes, sizeof(snode));
return g;
}
snode*
createSNode (sgraph* g)
{
snode* np = g->nodes+g->nnodes;
np->index = g->nnodes;
g->nnodes++;
return np;
}
static void
addEdgeToNode (snode* np, int idx)
{
np->adj_edge_list[np->n_adj] = idx;
np->n_adj++;
}
sedge*
createSEdge (sgraph* g, snode* v1, snode* v2, double wt)
{
sedge* e;
int idx = g->nedges++;
e = g->edges + idx;
e->v1 = v1->index;
e->v2 = v2->index;
e->weight = wt;
e->cnt = 0;
addEdgeToNode (v1, idx);
addEdgeToNode (v2, idx);
return e;
}
void
freeSGraph (sgraph* g)
{
free (g->nodes[0].adj_edge_list);
free (g->nodes);
free (g->edges);
free (g);
}
#include <ortho/fPQ.h>
/* shortest path:
* Constructs the path of least weight between from and to.
*
* Assumes graph, node and edge type, and that nodes
* have associated values N_VAL, N_IDX, and N_DAD, the first two
* being ints, the last being a node*. Edges have a E_WT function
* to specify the edge length or weight.
*
* Assumes there are functions:
* agnnodes: graph -> int number of nodes in the graph
* agfstnode, agnxtnode : iterators over the nodes in the graph
* agfstedge, agnxtedge : iterators over the edges attached to a node
* adjacentNode : given an edge e and an endpoint n of e, returns the
* other endpoint.
*
* The path is given by
* to, N_DAD(to), N_DAD(N_DAD(to)), ..., from
*/
#define UNSEEN INT_MIN
static snode*
adjacentNode(sgraph* g, sedge* e, snode* n)
{
if (e->v1==n->index)
return &g->nodes[e->v2];
else
return &g->nodes[e->v1];
}
int
shortPath (sgraph* g, snode* from, snode* to)
{
snode* n;
sedge* e;
snode* adjn;
int d;
int x, y;
for (x = 0; x<g->nnodes; x++) {
snode* temp = &g->nodes[x];
N_VAL(temp) = UNSEEN;
}
PQinit();
if (PQ_insert (from)) return 1;
N_DAD(from) = NULL;
N_VAL(from) = 0;
while ((n = PQremove())) {
#ifdef DEBUG
fprintf (stderr, "process %d\n", n->index);
#endif
N_VAL(n) *= -1;
if (n == to) break;
for (y=0; y<n->n_adj; y++) {
e = &g->edges[n->adj_edge_list[y]];
adjn = adjacentNode(g, e, n);
if (N_VAL(adjn) < 0) {
d = -(N_VAL(n) + E_WT(e));
if (N_VAL(adjn) == UNSEEN) {
#ifdef DEBUG
fprintf (stderr, "new %d (%d)\n", adjn->index, -d);
#endif
N_VAL(adjn) = d;
if (PQ_insert(adjn)) return 1;
N_DAD(adjn) = n;
N_EDGE(adjn) = e;
}
else {
if (N_VAL(adjn) < d) {
#ifdef DEBUG
fprintf (stderr, "adjust %d (%d)\n", adjn->index, -d);
#endif
PQupdate(adjn, d);
N_DAD(adjn) = n;
N_EDGE(adjn) = e;
}
}
}
}
}
return 0;
}
|
