/* Erdos-Renyi : G(n,M)
*/
igraph_t *ggen_generate_erdos_gnm(gsl_rng *r, unsigned long n, unsigned long m)
{
igraph_matrix_t adj;
igraph_t *g = NULL;
int err;
unsigned long i,j;
unsigned long added_edges = 0;
ggen_error_start_stack();
if(r == NULL)
GGEN_SET_ERRNO(GGEN_EINVAL);
if(m > (n*(n-1)/2))
GGEN_SET_ERRNO(GGEN_EINVAL);
g = malloc(sizeof(igraph_t));
GGEN_CHECK_ALLOC(g);
GGEN_FINALLY3(free,g,1);
if(m == 0 || n <= 1)
{
GGEN_CHECK_IGRAPH(igraph_empty(g,n,1));
goto end;
}
if(m == (n*(n-1))/2)
{
GGEN_CHECK_IGRAPH(igraph_full_citation(g,n,1));
goto end;
}
GGEN_CHECK_IGRAPH(igraph_matrix_init(&adj,n,n));
GGEN_FINALLY(igraph_matrix_destroy,&adj);
igraph_matrix_null(&adj);
while(added_edges < m) {
GGEN_CHECK_GSL_DO(i = gsl_rng_uniform_int(r,n));
GGEN_CHECK_GSL_DO(j = gsl_rng_uniform_int(r,n));
if(i < j && igraph_matrix_e(&adj,i,j) == 0)
{
igraph_matrix_set(&adj,i,j,1);
added_edges++;
}
}
GGEN_CHECK_IGRAPH(igraph_adjacency(g,&adj,IGRAPH_ADJ_DIRECTED));
end:
ggen_error_clean(1);
return g;
ggen_error_label:
return NULL;
}
/* Erdos-Renyi : G(n,p)
*/
igraph_t *ggen_generate_erdos_gnp(gsl_rng *r, unsigned long n, double p)
{
igraph_matrix_t m;
igraph_t *g = NULL;
int err;
unsigned long i,j;
ggen_error_start_stack();
if(r == NULL)
GGEN_SET_ERRNO(GGEN_EINVAL);
if(p < 0.0 || p > 1.0)
GGEN_SET_ERRNO(GGEN_EINVAL);
g = malloc(sizeof(igraph_t));
GGEN_CHECK_ALLOC(g);
GGEN_FINALLY3(free,g,1);
if(p == 0.0)
{
GGEN_CHECK_IGRAPH(igraph_empty(g,n,1));
goto end;
}
if(p == 1.0)
{
GGEN_CHECK_IGRAPH(igraph_full_citation(g,n,1));
goto end;
}
GGEN_CHECK_IGRAPH(igraph_matrix_init(&m,n,n));
GGEN_FINALLY(igraph_matrix_destroy,&m);
for(i = 0; i < n; i++)
for(j = 0; j < n; j++)
if(i < j)
// coin flipping to determine if we add an edge or not
igraph_matrix_set(&m,i,j,gsl_ran_bernoulli(r,p));
else
igraph_matrix_set(&m,i,j,0);
GGEN_CHECK_IGRAPH(igraph_adjacency(g,&m,IGRAPH_ADJ_DIRECTED));
end:
ggen_error_clean(1);
return g;
ggen_error_label:
return NULL;
}
int main(int argc,char** argv)
{
igraph_vector_t *lp;
igraph_t g;
// all ggen methods should fail on incorrect arguments
assert(ggen_analyze_longest_path(NULL) == NULL);
// an empty graph as a longest path of zero
igraph_empty(&g,10,1);
lp = ggen_analyze_longest_path(&g);
assert(lp != NULL);
assert(igraph_vector_size(lp) == 0);
igraph_destroy(&g);
igraph_vector_destroy(lp);
free((void *)lp);
// a full dag as a longest path of containing all vertices
igraph_full_citation(&g,10,1);
lp = ggen_analyze_longest_path(&g);
assert(lp != NULL);
assert(igraph_vector_size(lp) == 10);
igraph_destroy(&g);
igraph_vector_destroy(lp);
free((void *)lp);
// a wrong graph (not dag) should fail
// graph is 0 -> 1 -> 2 and 2 -> 0
igraph_small(&g,10,1,0,1,1,2,2,0,-1);
assert(ggen_analyze_longest_path(&g) == NULL);
igraph_destroy(&g);
// a simple graph should work too
// graph is 0 -> 1 -> 2 and 0 -> 2
igraph_small(&g,10,1,0,1,1,2,0,2,-1);
lp = ggen_analyze_longest_path(&g);
assert(lp != NULL);
assert(igraph_vector_size(lp) == 3);
igraph_destroy(&g);
igraph_vector_destroy(lp);
free((void *)lp);
return 0;
}
igraph_t *ggen_generate_erdos_lbl(gsl_rng *r, unsigned long n, double p, unsigned long nbl)
{
igraph_t *g = NULL;
igraph_matrix_t m;
igraph_vector_t layers;
unsigned long i,j;
int err;
ggen_error_start_stack();
if(r == NULL)
GGEN_SET_ERRNO(GGEN_EINVAL);
if(p < 0.0 || p > 1.0)
GGEN_SET_ERRNO(GGEN_EINVAL);
if(nbl > n || nbl == 0)
GGEN_SET_ERRNO(GGEN_EINVAL);
g = malloc(sizeof(igraph_t));
GGEN_CHECK_ALLOC(g);
GGEN_FINALLY3(free,g,1);
if(p == 0.0)
{
GGEN_CHECK_IGRAPH(igraph_empty(g,n,1));
goto end;
}
if(p == 1.0 && nbl == n)
{
GGEN_CHECK_IGRAPH(igraph_full_citation(g,n,1));
goto end;
}
GGEN_CHECK_IGRAPH(igraph_matrix_init(&m,n,n));
GGEN_FINALLY(igraph_matrix_destroy,&m);
GGEN_CHECK_IGRAPH(igraph_vector_init(&layers,n));
GGEN_FINALLY(igraph_vector_destroy,&layers);
// asign to each vertex a layer
for(i = 0; i < n; i++)
{
GGEN_CHECK_GSL_DO(j = gsl_rng_uniform_int(r,nbl));
VECTOR(layers)[i] = j;
}
// create edges
for(i = 0; i < n; i++)
for(j = 0; j < n; j++)
// if the layer allocation allows the edge, we test for it
if(VECTOR(layers)[i]<VECTOR(layers)[j])
igraph_matrix_set(&m,i,j,gsl_ran_bernoulli(r,p));
else
igraph_matrix_set(&m,i,j,0);
//translate the matrix to a graph
GGEN_CHECK_IGRAPH(igraph_adjacency(g,&m,IGRAPH_ADJ_DIRECTED));
end:
ggen_error_clean(1);
return g;
ggen_error_label:
return NULL;
}
