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using less space to store the used_edges and critical_nodes arrays

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fc_botelho
2005-01-03 20:47:21 +00:00
parent b3f008eb40
commit 77ce0aaddf
2 changed files with 37 additions and 25 deletions
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36
src/graph.c
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@@ -10,6 +10,11 @@
//#define DEBUG
#include "debug.h"
static const char bitmask[8] = { 1, 1 << 1, 1 << 2, 1 << 3, 1 << 4, 1 << 5, 1 << 6, 1 << 7 };
#define GETBIT(array, i) (array[(i) / 8] & bitmask[(i) % 8])
#define SETBIT(array, i) (array[(i) / 8] |= bitmask[(i) % 8])
#define UNSETBIT(array, i) (array[(i) / 8] &= (~(bitmask[(i) % 8])))
#define abs_edge(e, i) (e % g->nedges + i * g->nedges)
struct __graph_t
@@ -172,7 +177,7 @@ static int find_degree1_edge(graph_t *g, uint32 v, char *deleted, uint32 *e)
char found = 0;
DEBUGP("Checking degree of vertex %u\n", v);
if (edge == EMPTY) return 0;
else if (!deleted[abs_edge(edge, 0)])
else if (!(GETBIT(deleted, abs_edge(edge, 0))))
{
found = 1;
*e = edge;
@@ -181,7 +186,7 @@ static int find_degree1_edge(graph_t *g, uint32 v, char *deleted, uint32 *e)
{
edge = g->next[edge];
if (edge == EMPTY) break;
if (deleted[abs_edge(edge, 0)]) continue;
if (GETBIT(deleted, abs_edge(edge, 0))) continue;
if (found) return 0;
DEBUGP("Found first edge\n");
*e = edge;
@@ -203,7 +208,7 @@ static void cyclic_del_edge(graph_t *g, uint32 v, char *deleted)
while(1)
{
DEBUGP("Deleting edge %u (%u->%u)\n", e, g->edges[abs_edge(e, 0)], g->edges[abs_edge(e, 1)]);
deleted[abs_edge(e, 0)] = 1;
SETBIT(deleted, abs_edge(e, 0));
v2 = g->edges[abs_edge(e, 0)];
if (v2 == v1) v2 = g->edges[abs_edge(e, 1)];
@@ -223,8 +228,8 @@ int graph_is_cyclic(graph_t *g)
{
uint32 i;
uint32 v;
char *deleted = (char *)malloc(g->nedges*sizeof(char));
memset(deleted, 0, g->nedges);
char *deleted = (char *)malloc((g->nedges*sizeof(char))/8 + 1);
memset(deleted, 0, g->nedges/8 + 1);
DEBUGP("Looking for cycles in graph with %u vertices and %u edges\n", g->nnodes, g->nedges);
for (v = 0; v < g->nnodes; ++v)
@@ -233,7 +238,7 @@ int graph_is_cyclic(graph_t *g)
}
for (i = 0; i < g->nedges; ++i)
{
if (!(deleted[i]))
if (!(GETBIT(deleted, i)))
{
DEBUGP("Edge %u %u->%u was not deleted\n", i, g->edges[i], g->edges[i + g->nedges]);
free(deleted);
@@ -246,17 +251,16 @@ int graph_is_cyclic(graph_t *g)
uint8 graph_node_is_critical(graph_t * g, uint32 v) /* included -- Fabiano */
{
return g->critical_nodes[v];
return GETBIT(g->critical_nodes,v);
}
void graph_obtain_critical_nodes(graph_t *g) /* included -- Fabiano*/
{
uint32 i;
uint32 v;
char *deleted = (char *)malloc(g->nedges*sizeof(char));
memset(deleted, 0, g->nedges);
/* g->critical_nodes = (uint8 *)malloc((size_t)(ceil(g->nnodes*sizeof(uint8)/8.))); */
g->critical_nodes = (uint8 *)malloc(g->nnodes*sizeof(uint8));
char *deleted = (char *)malloc((g->nedges*sizeof(char))/8+1);
memset(deleted, 0, g->nedges/8 + 1);
g->critical_nodes = (uint8 *)malloc((g->nnodes*sizeof(uint8))/8 + 1);
g->ncritical_nodes = 0;
DEBUGP("Looking for the 2-core in graph with %u vertices and %u edges\n", g->nnodes, g->nedges);
for (v = 0; v < g->nnodes; ++v)
@@ -266,18 +270,18 @@ void graph_obtain_critical_nodes(graph_t *g) /* included -- Fabiano*/
for (i = 0; i < g->nedges; ++i)
{
if (!(deleted[i]))
if (!(GETBIT(deleted,i)))
{
DEBUGP("Edge %u %u->%u belongs to the 2-core\n", i, g->edges[i], g->edges[i + g->nedges]);
if(!(g->critical_nodes[g->edges[i]]))
if(!(GETBIT(g->critical_nodes,g->edges[i])))
{
g->ncritical_nodes ++;
g->critical_nodes[g->edges[i]] = 1;
SETBIT(g->critical_nodes,g->edges[i]);
}
if(!(g->critical_nodes[g->edges[i + g->nedges]]))
if(!(GETBIT(g->critical_nodes,g->edges[i + g->nedges])))
{
g->ncritical_nodes ++;
g->critical_nodes[g->edges[i + g->nedges]] = 1;
SETBIT(g->critical_nodes,g->edges[i + g->nedges]);
}
}
}