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vf2.c
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vf2.c
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/* -*- mode: C -*- */
/*
IGraph library.
Copyright (C) 2006-2012 Gabor Csardi <csardi.gabor@gmail.com>
334 Harvard street, Cambridge, MA 02139 USA
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "igraph_topology.h"
#include "igraph_adjlist.h"
#include "igraph_interface.h"
#include "igraph_stack.h"
#include "igraph_structural.h"
#include "core/interruption.h"
/**
* \section about_vf2
*
* <para>
* The VF2 algorithm can search for a subgraph in a larger graph, or check if two
* graphs are isomorphic. See P. Foggia, C. Sansone, M. Vento, An Improved algorithm for
* matching large graphs, Proc. of the 3rd IAPR-TC-15 International
* Workshop on Graph-based Representations, Italy, 2001.
* </para>
*
* <para>
* VF2 supports both vertex and edge-colored graphs, as well as custom vertex or edge
* compatibility functions.
* </para>
*
* <para>
* VF2 works with both directed and undirected graphs. Only simple graphs are supported.
* Self-loops or multi-edges must not be present in the graphs. Currently, the VF2
* functions do not check that the input graph is simple: it is the responsibility
* of the user to pass in valid input.
* </para>
*/
static igraph_error_t igraph_i_perform_vf2_pre_checks(
const igraph_t* graph1, const igraph_t* graph2
) {
igraph_bool_t has_loops;
if (igraph_is_directed(graph1) != igraph_is_directed(graph2)) {
IGRAPH_ERROR("Cannot compare directed and undirected graphs",
IGRAPH_EINVAL);
}
IGRAPH_CHECK(igraph_has_loop(graph1, &has_loops));
if (!has_loops) {
IGRAPH_CHECK(igraph_has_loop(graph2, &has_loops));
}
if (has_loops) {
IGRAPH_ERROR("The VF2 algorithm does not support graphs with loop edges.",
IGRAPH_EINVAL);
}
/* TODO: VF2 does not support graphs with multiple edges either, but we
* don't check for this as the check would be complex, comparable to
* the runtime of the algorithm itself */
return IGRAPH_SUCCESS;
}
/**
* \function igraph_get_isomorphisms_vf2_callback
* The generic VF2 interface
*
* </para><para>
* This function is an implementation of the VF2 isomorphism algorithm,
* see P. Foggia, C. Sansone, M. Vento, An Improved algorithm for
* matching large graphs, Proc. of the 3rd IAPR-TC-15 International
* Workshop on Graph-based Representations, Italy, 2001.</para>
*
* <para>For using it you need to define a callback function of type
* \ref igraph_isohandler_t. This function will be called whenever VF2
* finds an isomorphism between the two graphs. The mapping between
* the two graphs will be also provided to this function. If the
* callback returns \c IGRAPH_SUCCESS, then the search is continued,
* otherwise it stops. \c IGRAPH_STOP as a return value can be used to
* indicate normal premature termination; any other return value will be
* treated as an igraph error code, making the caller function return the
* same error code as well. The callback function must not destroy the
* mapping vectors that are passed to it.
* \param graph1 The first input graph.
* \param graph2 The second input graph.
* \param vertex_color1 An optional color vector for the first graph. If
* color vectors are given for both graphs, then the isomorphism is
* calculated on the colored graphs; i.e. two vertices can match
* only if their color also matches. Supply a null pointer here if
* your graphs are not colored.
* \param vertex_color2 An optional color vector for the second graph. See
* the previous argument for explanation.
* \param edge_color1 An optional edge color vector for the first
* graph. The matching edges in the two graphs must have matching
* colors as well. Supply a null pointer here if your graphs are not
* edge-colored.
* \param edge_color2 The edge color vector for the second graph.
* \param map12 Pointer to an initialized vector or \c NULL. If not \c
* NULL and the supplied graphs are isomorphic then the permutation
* taking \p graph1 to \p graph is stored here. If not \c NULL and the
* graphs are not isomorphic then a zero-length vector is returned.
* \param map21 This is the same as \p map12, but for the permutation
* taking \p graph2 to \p graph1.
* \param isohandler_fn The callback function to be called if an
* isomorphism is found. See also \ref igraph_isohandler_t.
* \param node_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two nodes are compatible.
* \param edge_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two edges are compatible.
* \param arg Extra argument to supply to functions \p isohandler_fn, \p
* node_compat_fn and \p edge_compat_fn.
* \return Error code.
*
* Time complexity: exponential.
*/
igraph_error_t igraph_get_isomorphisms_vf2_callback(
const igraph_t *graph1, const igraph_t *graph2,
const igraph_vector_int_t *vertex_color1, const igraph_vector_int_t *vertex_color2,
const igraph_vector_int_t *edge_color1, const igraph_vector_int_t *edge_color2,
igraph_vector_int_t *map12, igraph_vector_int_t *map21,
igraph_isohandler_t *isohandler_fn, igraph_isocompat_t *node_compat_fn,
igraph_isocompat_t *edge_compat_fn, void *arg
) {
igraph_integer_t no_of_nodes = igraph_vcount(graph1);
igraph_integer_t no_of_edges = igraph_ecount(graph1);
igraph_vector_int_t mycore_1, mycore_2, *core_1 = &mycore_1, *core_2 = &mycore_2;
igraph_vector_int_t in_1, in_2, out_1, out_2;
igraph_integer_t in_1_size = 0, in_2_size = 0, out_1_size = 0, out_2_size = 0;
igraph_vector_int_t *inneis_1, *inneis_2, *outneis_1, *outneis_2;
igraph_integer_t matched_nodes = 0;
igraph_integer_t depth;
igraph_integer_t cand1, cand2;
igraph_integer_t last1, last2;
igraph_stack_int_t path;
igraph_lazy_adjlist_t inadj1, inadj2, outadj1, outadj2;
igraph_vector_int_t indeg1, indeg2, outdeg1, outdeg2;
igraph_integer_t vsize;
IGRAPH_CHECK(igraph_i_perform_vf2_pre_checks(graph1, graph2));
if ( (vertex_color1 && !vertex_color2) || (!vertex_color1 && vertex_color2) ) {
IGRAPH_WARNING("Only one graph is vertex-colored, vertex colors will be ignored");
vertex_color1 = vertex_color2 = 0;
}
if ( (edge_color1 && !edge_color2) || (!edge_color1 && edge_color2)) {
IGRAPH_WARNING("Only one graph is edge-colored, edge colors will be ignored");
edge_color1 = edge_color2 = 0;
}
if (no_of_nodes != igraph_vcount(graph2) ||
no_of_edges != igraph_ecount(graph2)) {
return IGRAPH_SUCCESS;
}
if (vertex_color1) {
if (igraph_vector_int_size(vertex_color1) != no_of_nodes ||
igraph_vector_int_size(vertex_color2) != no_of_nodes) {
IGRAPH_ERROR("Invalid vertex color vector length", IGRAPH_EINVAL);
}
}
if (edge_color1) {
if (igraph_vector_int_size(edge_color1) != no_of_edges ||
igraph_vector_int_size(edge_color2) != no_of_edges) {
IGRAPH_ERROR("Invalid edge color vector length", IGRAPH_EINVAL);
}
}
/* Check color distribution */
if (vertex_color1) {
igraph_bool_t ret = false;
igraph_vector_int_t tmp1, tmp2;
IGRAPH_CHECK(igraph_vector_int_init_copy(&tmp1, vertex_color1));
IGRAPH_FINALLY(igraph_vector_int_destroy, &tmp1);
IGRAPH_CHECK(igraph_vector_int_init_copy(&tmp2, vertex_color2));
IGRAPH_FINALLY(igraph_vector_int_destroy, &tmp2);
igraph_vector_int_sort(&tmp1);
igraph_vector_int_sort(&tmp2);
ret = !igraph_vector_int_all_e(&tmp1, &tmp2);
igraph_vector_int_destroy(&tmp1);
igraph_vector_int_destroy(&tmp2);
IGRAPH_FINALLY_CLEAN(2);
if (ret) {
return IGRAPH_SUCCESS;
}
}
/* Check edge color distribution */
if (edge_color1) {
igraph_bool_t ret = false;
igraph_vector_int_t tmp1, tmp2;
IGRAPH_CHECK(igraph_vector_int_init_copy(&tmp1, edge_color1));
IGRAPH_FINALLY(igraph_vector_int_destroy, &tmp1);
IGRAPH_CHECK(igraph_vector_int_init_copy(&tmp2, edge_color2));
IGRAPH_FINALLY(igraph_vector_int_destroy, &tmp2);
igraph_vector_int_sort(&tmp1);
igraph_vector_int_sort(&tmp2);
ret = !igraph_vector_int_all_e(&tmp1, &tmp2);
igraph_vector_int_destroy(&tmp1);
igraph_vector_int_destroy(&tmp2);
IGRAPH_FINALLY_CLEAN(2);
if (ret) {
return IGRAPH_SUCCESS;
}
}
if (map12) {
core_1 = map12;
IGRAPH_CHECK(igraph_vector_int_resize(core_1, no_of_nodes));
} else {
IGRAPH_VECTOR_INT_INIT_FINALLY(core_1, no_of_nodes);
}
igraph_vector_int_fill(core_1, -1);
if (map21) {
core_2 = map21;
IGRAPH_CHECK(igraph_vector_int_resize(core_2, no_of_nodes));
igraph_vector_int_null(core_2);
} else {
IGRAPH_VECTOR_INT_INIT_FINALLY(core_2, no_of_nodes);
}
igraph_vector_int_fill(core_2, -1);
IGRAPH_VECTOR_INT_INIT_FINALLY(&in_1, no_of_nodes);
IGRAPH_VECTOR_INT_INIT_FINALLY(&in_2, no_of_nodes);
IGRAPH_VECTOR_INT_INIT_FINALLY(&out_1, no_of_nodes);
IGRAPH_VECTOR_INT_INIT_FINALLY(&out_2, no_of_nodes);
IGRAPH_CHECK(igraph_stack_int_init(&path, 0));
IGRAPH_FINALLY(igraph_stack_int_destroy, &path);
IGRAPH_CHECK(igraph_lazy_adjlist_init(graph1, &inadj1, IGRAPH_IN, IGRAPH_NO_LOOPS, IGRAPH_NO_MULTIPLE));
IGRAPH_FINALLY(igraph_lazy_adjlist_destroy, &inadj1);
IGRAPH_CHECK(igraph_lazy_adjlist_init(graph1, &outadj1, IGRAPH_OUT, IGRAPH_NO_LOOPS, IGRAPH_NO_MULTIPLE));
IGRAPH_FINALLY(igraph_lazy_adjlist_destroy, &outadj1);
IGRAPH_CHECK(igraph_lazy_adjlist_init(graph2, &inadj2, IGRAPH_IN, IGRAPH_NO_LOOPS, IGRAPH_NO_MULTIPLE));
IGRAPH_FINALLY(igraph_lazy_adjlist_destroy, &inadj2);
IGRAPH_CHECK(igraph_lazy_adjlist_init(graph2, &outadj2, IGRAPH_OUT, IGRAPH_NO_LOOPS, IGRAPH_NO_MULTIPLE));
IGRAPH_FINALLY(igraph_lazy_adjlist_destroy, &outadj2);
IGRAPH_VECTOR_INT_INIT_FINALLY(&indeg1, 0);
IGRAPH_VECTOR_INT_INIT_FINALLY(&indeg2, 0);
IGRAPH_VECTOR_INT_INIT_FINALLY(&outdeg1, 0);
IGRAPH_VECTOR_INT_INIT_FINALLY(&outdeg2, 0);
IGRAPH_CHECK(igraph_stack_int_reserve(&path, no_of_nodes * 2));
IGRAPH_CHECK(igraph_degree(graph1, &indeg1, igraph_vss_all(),
IGRAPH_IN, IGRAPH_LOOPS));
IGRAPH_CHECK(igraph_degree(graph2, &indeg2, igraph_vss_all(),
IGRAPH_IN, IGRAPH_LOOPS));
IGRAPH_CHECK(igraph_degree(graph1, &outdeg1, igraph_vss_all(),
IGRAPH_OUT, IGRAPH_LOOPS));
IGRAPH_CHECK(igraph_degree(graph2, &outdeg2, igraph_vss_all(),
IGRAPH_OUT, IGRAPH_LOOPS));
depth = 0; last1 = -1; last2 = -1;
while (depth >= 0) {
igraph_integer_t i;
IGRAPH_ALLOW_INTERRUPTION();
cand1 = -1; cand2 = -1;
/* Search for the next pair to try */
if ((in_1_size != in_2_size) ||
(out_1_size != out_2_size)) {
/* step back, nothing to do */
} else if (out_1_size > 0 && out_2_size > 0) {
/**************************************************************/
/* cand2, search not always needed */
if (last2 >= 0) {
cand2 = last2;
} else {
i = 0;
while (cand2 < 0 && i < no_of_nodes) {
if (VECTOR(out_2)[i] > 0 && VECTOR(*core_2)[i] < 0) {
cand2 = i;
}
i++;
}
}
/* search for cand1 now, it should be bigger than last1 */
i = last1 + 1;
while (cand1 < 0 && i < no_of_nodes) {
if (VECTOR(out_1)[i] > 0 && VECTOR(*core_1)[i] < 0) {
cand1 = i;
}
i++;
}
} else if (in_1_size > 0 && in_2_size > 0) {
/**************************************************************/
/* cand2, search not always needed */
if (last2 >= 0) {
cand2 = last2;
} else {
i = 0;
while (cand2 < 0 && i < no_of_nodes) {
if (VECTOR(in_2)[i] > 0 && VECTOR(*core_2)[i] < 0) {
cand2 = i;
}
i++;
}
}
/* search for cand1 now, should be bigger than last1 */
i = last1 + 1;
while (cand1 < 0 && i < no_of_nodes) {
if (VECTOR(in_1)[i] > 0 && VECTOR(*core_1)[i] < 0) {
cand1 = i;
}
i++;
}
} else {
/**************************************************************/
/* cand2, search not always needed */
if (last2 >= 0) {
cand2 = last2;
} else {
i = 0;
while (cand2 < 0 && i < no_of_nodes) {
if (VECTOR(*core_2)[i] < 0) {
cand2 = i;
}
i++;
}
}
/* search for cand1, should be bigger than last1 */
i = last1 + 1;
while (cand1 < 0 && i < no_of_nodes) {
if (VECTOR(*core_1)[i] < 0) {
cand1 = i;
}
i++;
}
}
/* Ok, we have cand1, cand2 as candidates. Or not? */
if (cand1 < 0 || cand2 < 0) {
/**************************************************************/
/* dead end, step back, if possible. Otherwise we'll terminate */
if (depth >= 1) {
last2 = igraph_stack_int_pop(&path);
last1 = igraph_stack_int_pop(&path);
matched_nodes -= 1;
VECTOR(*core_1)[last1] = -1;
VECTOR(*core_2)[last2] = -1;
if (VECTOR(in_1)[last1] != 0) {
in_1_size += 1;
}
if (VECTOR(out_1)[last1] != 0) {
out_1_size += 1;
}
if (VECTOR(in_2)[last2] != 0) {
in_2_size += 1;
}
if (VECTOR(out_2)[last2] != 0) {
out_2_size += 1;
}
inneis_1 = igraph_lazy_adjlist_get(&inadj1, last1);
IGRAPH_CHECK_OOM(inneis_1, "Failed to query neighbors.");
vsize = igraph_vector_int_size(inneis_1);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*inneis_1)[i];
if (VECTOR(in_1)[node] == depth) {
VECTOR(in_1)[node] = 0;
in_1_size -= 1;
}
}
outneis_1 = igraph_lazy_adjlist_get(&outadj1, last1);
IGRAPH_CHECK_OOM(outneis_1, "Failed to query neighbors.");
vsize = igraph_vector_int_size(outneis_1);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*outneis_1)[i];
if (VECTOR(out_1)[node] == depth) {
VECTOR(out_1)[node] = 0;
out_1_size -= 1;
}
}
inneis_2 = igraph_lazy_adjlist_get(&inadj2, last2);
IGRAPH_CHECK_OOM(inneis_2, "Failed to query neighbors.");
vsize = igraph_vector_int_size(inneis_2);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*inneis_2)[i];
if (VECTOR(in_2)[node] == depth) {
VECTOR(in_2)[node] = 0;
in_2_size -= 1;
}
}
outneis_2 = igraph_lazy_adjlist_get(&outadj2, last2);
IGRAPH_CHECK_OOM(outneis_2, "Failed to query neighbors.");
vsize = igraph_vector_int_size(outneis_2);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*outneis_2)[i];
if (VECTOR(out_2)[node] == depth) {
VECTOR(out_2)[node] = 0;
out_2_size -= 1;
}
}
} /* end of stepping back */
depth -= 1;
} else {
/**************************************************************/
/* step forward if worth, check if worth first */
igraph_integer_t xin1 = 0, xin2 = 0, xout1 = 0, xout2 = 0;
igraph_bool_t end = false;
inneis_1 = igraph_lazy_adjlist_get(&inadj1, cand1);
outneis_1 = igraph_lazy_adjlist_get(&outadj1, cand1);
inneis_2 = igraph_lazy_adjlist_get(&inadj2, cand2);
outneis_2 = igraph_lazy_adjlist_get(&outadj2, cand2);
IGRAPH_CHECK_OOM(inneis_1, "Failed to query neighbors.");
IGRAPH_CHECK_OOM(outneis_1, "Failed to query neighbors.");
IGRAPH_CHECK_OOM(inneis_2, "Failed to query neighbors.");
IGRAPH_CHECK_OOM(outneis_2, "Failed to query neighbors.");
if (VECTOR(indeg1)[cand1] != VECTOR(indeg2)[cand2] ||
VECTOR(outdeg1)[cand1] != VECTOR(outdeg2)[cand2]) {
end = true;
}
if (vertex_color1 && VECTOR(*vertex_color1)[cand1] != VECTOR(*vertex_color2)[cand2]) {
end = true;
}
if (node_compat_fn && !node_compat_fn(graph1, graph2, cand1, cand2, arg)) {
end = true;
}
vsize = igraph_vector_int_size(inneis_1);
for (i = 0; !end && i < vsize; i++) {
igraph_integer_t node = VECTOR(*inneis_1)[i];
if (VECTOR(*core_1)[node] >= 0) {
igraph_integer_t node2 = VECTOR(*core_1)[node];
/* check if there is a node2->cand2 edge */
if (!igraph_vector_int_binsearch2(inneis_2, node2)) {
end = true;
} else if (edge_color1 || edge_compat_fn) {
igraph_integer_t eid1, eid2;
igraph_get_eid(graph1, &eid1, node, cand1, IGRAPH_DIRECTED,
/*error=*/ true);
igraph_get_eid(graph2, &eid2, node2, cand2, IGRAPH_DIRECTED,
/*error=*/ true);
if (edge_color1 && VECTOR(*edge_color1)[eid1] !=
VECTOR(*edge_color2)[eid2]) {
end = true;
}
if (edge_compat_fn && !edge_compat_fn(graph1, graph2,
eid1, eid2, arg)) {
end = true;
}
}
} else {
if (VECTOR(in_1)[node] != 0) {
xin1++;
}
if (VECTOR(out_1)[node] != 0) {
xout1++;
}
}
}
vsize = igraph_vector_int_size(outneis_1);
for (i = 0; !end && i < vsize; i++) {
igraph_integer_t node = VECTOR(*outneis_1)[i];
if (VECTOR(*core_1)[node] >= 0) {
igraph_integer_t node2 = VECTOR(*core_1)[node];
/* check if there is a cand2->node2 edge */
if (!igraph_vector_int_binsearch2(outneis_2, node2)) {
end = true;
} else if (edge_color1 || edge_compat_fn) {
igraph_integer_t eid1, eid2;
igraph_get_eid(graph1, &eid1, cand1, node, IGRAPH_DIRECTED,
/*error=*/ true);
igraph_get_eid(graph2, &eid2, cand2, node2, IGRAPH_DIRECTED,
/*error=*/ true);
if (edge_color1 && VECTOR(*edge_color1)[eid1] !=
VECTOR(*edge_color2)[eid2]) {
end = true;
}
if (edge_compat_fn && !edge_compat_fn(graph1, graph2,
eid1, eid2, arg)) {
end = true;
}
}
} else {
if (VECTOR(in_1)[node] != 0) {
xin1++;
}
if (VECTOR(out_1)[node] != 0) {
xout1++;
}
}
}
vsize = igraph_vector_int_size(inneis_2);
for (i = 0; !end && i < vsize; i++) {
igraph_integer_t node = VECTOR(*inneis_2)[i];
if (VECTOR(*core_2)[node] >= 0) {
igraph_integer_t node2 = VECTOR(*core_2)[node];
/* check if there is a node2->cand1 edge */
if (!igraph_vector_int_binsearch2(inneis_1, node2)) {
end = true;
} else if (edge_color1 || edge_compat_fn) {
igraph_integer_t eid1, eid2;
igraph_get_eid(graph1, &eid1, node2, cand1, IGRAPH_DIRECTED,
/*error=*/ true);
igraph_get_eid(graph2, &eid2, node, cand2, IGRAPH_DIRECTED,
/*error=*/ true);
if (edge_color1 && VECTOR(*edge_color1)[eid1] !=
VECTOR(*edge_color2)[eid2]) {
end = true;
}
if (edge_compat_fn && !edge_compat_fn(graph1, graph2,
eid1, eid2, arg)) {
end = true;
}
}
} else {
if (VECTOR(in_2)[node] != 0) {
xin2++;
}
if (VECTOR(out_2)[node] != 0) {
xout2++;
}
}
}
vsize = igraph_vector_int_size(outneis_2);
for (i = 0; !end && i < vsize; i++) {
igraph_integer_t node = VECTOR(*outneis_2)[i];
if (VECTOR(*core_2)[node] >= 0) {
igraph_integer_t node2 = VECTOR(*core_2)[node];
/* check if there is a cand1->node2 edge */
if (!igraph_vector_int_binsearch2(outneis_1, node2)) {
end = true;
} else if (edge_color1 || edge_compat_fn) {
igraph_integer_t eid1, eid2;
igraph_get_eid(graph1, &eid1, cand1, node2, IGRAPH_DIRECTED,
/*error=*/ true);
igraph_get_eid(graph2, &eid2, cand2, node, IGRAPH_DIRECTED,
/*error=*/ true);
if (edge_color1 && VECTOR(*edge_color1)[eid1] !=
VECTOR(*edge_color2)[eid2]) {
end = true;
}
if (edge_compat_fn && !edge_compat_fn(graph1, graph2,
eid1, eid2, arg)) {
end = true;
}
}
} else {
if (VECTOR(in_2)[node] != 0) {
xin2++;
}
if (VECTOR(out_2)[node] != 0) {
xout2++;
}
}
}
if (!end && (xin1 == xin2 && xout1 == xout2)) {
/* Ok, we add the (cand1, cand2) pair to the mapping */
depth += 1;
IGRAPH_CHECK(igraph_stack_int_push(&path, cand1));
IGRAPH_CHECK(igraph_stack_int_push(&path, cand2));
matched_nodes += 1;
VECTOR(*core_1)[cand1] = cand2;
VECTOR(*core_2)[cand2] = cand1;
/* update in_*, out_* */
if (VECTOR(in_1)[cand1] != 0) {
in_1_size -= 1;
}
if (VECTOR(out_1)[cand1] != 0) {
out_1_size -= 1;
}
if (VECTOR(in_2)[cand2] != 0) {
in_2_size -= 1;
}
if (VECTOR(out_2)[cand2] != 0) {
out_2_size -= 1;
}
inneis_1 = igraph_lazy_adjlist_get(&inadj1, cand1);
IGRAPH_CHECK_OOM(inneis_1, "Failed to query neighbors.");
vsize = igraph_vector_int_size(inneis_1);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*inneis_1)[i];
if (VECTOR(in_1)[node] == 0 && VECTOR(*core_1)[node] < 0) {
VECTOR(in_1)[node] = depth;
in_1_size += 1;
}
}
outneis_1 = igraph_lazy_adjlist_get(&outadj1, cand1);
IGRAPH_CHECK_OOM(outneis_1, "Failed to query neighbors.");
vsize = igraph_vector_int_size(outneis_1);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*outneis_1)[i];
if (VECTOR(out_1)[node] == 0 && VECTOR(*core_1)[node] < 0) {
VECTOR(out_1)[node] = depth;
out_1_size += 1;
}
}
inneis_2 = igraph_lazy_adjlist_get(&inadj2, cand2);
IGRAPH_CHECK_OOM(inneis_2, "Failed to query neighbors.");
vsize = igraph_vector_int_size(inneis_2);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*inneis_2)[i];
if (VECTOR(in_2)[node] == 0 && VECTOR(*core_2)[node] < 0) {
VECTOR(in_2)[node] = depth;
in_2_size += 1;
}
}
outneis_2 = igraph_lazy_adjlist_get(&outadj2, cand2);
IGRAPH_CHECK_OOM(outneis_2, "Failed to query neighbors.");
vsize = igraph_vector_int_size(outneis_2);
for (i = 0; i < vsize; i++) {
igraph_integer_t node = VECTOR(*outneis_2)[i];
if (VECTOR(out_2)[node] == 0 && VECTOR(*core_2)[node] < 0) {
VECTOR(out_2)[node] = depth;
out_2_size += 1;
}
}
last1 = -1; last2 = -1; /* this the first time here */
} else {
last1 = cand1;
last2 = cand2;
}
}
if (matched_nodes == no_of_nodes && isohandler_fn) {
igraph_error_t ret;
IGRAPH_CHECK_CALLBACK(isohandler_fn(core_1, core_2, arg), &ret);
if (ret == IGRAPH_STOP) {
break;
}
}
}
igraph_vector_int_destroy(&outdeg2);
igraph_vector_int_destroy(&outdeg1);
igraph_vector_int_destroy(&indeg2);
igraph_vector_int_destroy(&indeg1);
igraph_lazy_adjlist_destroy(&outadj2);
igraph_lazy_adjlist_destroy(&inadj2);
igraph_lazy_adjlist_destroy(&outadj1);
igraph_lazy_adjlist_destroy(&inadj1);
igraph_stack_int_destroy(&path);
igraph_vector_int_destroy(&out_2);
igraph_vector_int_destroy(&out_1);
igraph_vector_int_destroy(&in_2);
igraph_vector_int_destroy(&in_1);
IGRAPH_FINALLY_CLEAN(13);
if (!map21) {
igraph_vector_int_destroy(core_2);
IGRAPH_FINALLY_CLEAN(1);
}
if (!map12) {
igraph_vector_int_destroy(core_1);
IGRAPH_FINALLY_CLEAN(1);
}
return IGRAPH_SUCCESS;
}
/**
* \function igraph_isomorphic_function_vf2
* \brief The generic VF2 interface (deprecated alias).
*
* \deprecated-by igraph_get_isomorphisms_vf2_callback 0.10.0
*/
igraph_error_t igraph_isomorphic_function_vf2(
const igraph_t *graph1, const igraph_t *graph2,
const igraph_vector_int_t *vertex_color1, const igraph_vector_int_t *vertex_color2,
const igraph_vector_int_t *edge_color1, const igraph_vector_int_t *edge_color2,
igraph_vector_int_t *map12, igraph_vector_int_t *map21,
igraph_isohandler_t *isohandler_fn, igraph_isocompat_t *node_compat_fn,
igraph_isocompat_t *edge_compat_fn, void *arg
) {
return igraph_get_isomorphisms_vf2_callback(
graph1, graph2, vertex_color1, vertex_color2, edge_color1, edge_color2,
map12, map21, isohandler_fn, node_compat_fn, edge_compat_fn, arg
);
}
typedef struct {
igraph_isocompat_t *node_compat_fn, *edge_compat_fn;
void *arg, *carg;
} igraph_i_iso_cb_data_t;
static igraph_bool_t igraph_i_isocompat_node_cb(
const igraph_t *graph1,
const igraph_t *graph2,
const igraph_integer_t g1_num,
const igraph_integer_t g2_num,
void *arg) {
igraph_i_iso_cb_data_t *data = arg;
return data->node_compat_fn(graph1, graph2, g1_num, g2_num, data->carg);
}
static igraph_bool_t igraph_i_isocompat_edge_cb(
const igraph_t *graph1,
const igraph_t *graph2,
const igraph_integer_t g1_num,
const igraph_integer_t g2_num,
void *arg) {
igraph_i_iso_cb_data_t *data = arg;
return data->edge_compat_fn(graph1, graph2, g1_num, g2_num, data->carg);
}
static igraph_error_t igraph_i_isomorphic_vf2_cb(
const igraph_vector_int_t *map12, const igraph_vector_int_t *map21,
void *arg
) {
igraph_i_iso_cb_data_t *data = arg;
igraph_bool_t *iso = data->arg;
IGRAPH_UNUSED(map12); IGRAPH_UNUSED(map21);
*iso = 1;
return IGRAPH_STOP;
}
/**
* \function igraph_isomorphic_vf2
* \brief Isomorphism via VF2.
*
* </para><para>
* This function performs the VF2 algorithm via calling \ref
* igraph_get_isomorphisms_vf2_callback().
*
* </para><para> Note that this function cannot be used for
* deciding subgraph isomorphism, use \ref igraph_subisomorphic_vf2()
* for that.
* \param graph1 The first graph, may be directed or undirected.
* \param graph2 The second graph. It must have the same directedness
* as \p graph1, otherwise an error is reported.
* \param vertex_color1 An optional color vector for the first graph. If
* color vectors are given for both graphs, then the isomorphism is
* calculated on the colored graphs; i.e. two vertices can match
* only if their color also matches. Supply a null pointer here if
* your graphs are not colored.
* \param vertex_color2 An optional color vector for the second graph. See
* the previous argument for explanation.
* \param edge_color1 An optional edge color vector for the first
* graph. The matching edges in the two graphs must have matching
* colors as well. Supply a null pointer here if your graphs are not
* edge-colored.
* \param edge_color2 The edge color vector for the second graph.
* \param iso Pointer to a logical constant, the result of the
* algorithm will be placed here.
* \param map12 Pointer to an initialized vector or a NULL pointer. If not
* a NULL pointer then the mapping from \p graph1 to \p graph2 is
* stored here. If the graphs are not isomorphic then the vector is
* cleared (i.e. has zero elements).
* \param map21 Pointer to an initialized vector or a NULL pointer. If not
* a NULL pointer then the mapping from \p graph2 to \p graph1 is
* stored here. If the graphs are not isomorphic then the vector is
* cleared (i.e. has zero elements).
* \param node_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two nodes are compatible.
* \param edge_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two edges are compatible.
* \param arg Extra argument to supply to functions \p node_compat_fn
* and \p edge_compat_fn.
* \return Error code.
*
* \sa \ref igraph_subisomorphic_vf2(),
* \ref igraph_count_isomorphisms_vf2(),
* \ref igraph_get_isomorphisms_vf2(),
*
* Time complexity: exponential, what did you expect?
*
* \example examples/simple/igraph_isomorphic_vf2.c
*/
igraph_error_t igraph_isomorphic_vf2(const igraph_t *graph1, const igraph_t *graph2,
const igraph_vector_int_t *vertex_color1,
const igraph_vector_int_t *vertex_color2,
const igraph_vector_int_t *edge_color1,
const igraph_vector_int_t *edge_color2,
igraph_bool_t *iso, igraph_vector_int_t *map12,
igraph_vector_int_t *map21,
igraph_isocompat_t *node_compat_fn,
igraph_isocompat_t *edge_compat_fn,
void *arg) {
igraph_i_iso_cb_data_t data = { node_compat_fn, edge_compat_fn, iso, arg };
igraph_isocompat_t *ncb = node_compat_fn ? igraph_i_isocompat_node_cb : 0;
igraph_isocompat_t *ecb = edge_compat_fn ? igraph_i_isocompat_edge_cb : 0;
*iso = 0;
IGRAPH_CHECK(igraph_get_isomorphisms_vf2_callback(graph1, graph2,
vertex_color1, vertex_color2,
edge_color1, edge_color2,
map12, map21,
(igraph_isohandler_t*) igraph_i_isomorphic_vf2_cb,
ncb, ecb, &data));
if (! *iso) {
if (map12) {
igraph_vector_int_clear(map12);
}
if (map21) {
igraph_vector_int_clear(map21);
}
}
return IGRAPH_SUCCESS;
}
static igraph_error_t igraph_i_count_isomorphisms_vf2_cb(
const igraph_vector_int_t *map12, const igraph_vector_int_t *map21,
void *arg
) {
igraph_i_iso_cb_data_t *data = arg;
igraph_integer_t *count = data->arg;
IGRAPH_UNUSED(map12); IGRAPH_UNUSED(map21);
*count += 1;
return IGRAPH_SUCCESS;
}
/**
* \function igraph_count_isomorphisms_vf2
* \brief Number of isomorphisms via VF2.
*
* This function counts the number of isomorphic mappings between two
* graphs. It uses the generic \ref igraph_get_isomorphisms_vf2_callback()
* function.
* \param graph1 The first input graph, may be directed or undirected.
* \param graph2 The second input graph, it must have the same
* directedness as \p graph1, or an error will be reported.
* \param vertex_color1 An optional color vector for the first graph. If
* color vectors are given for both graphs, then the isomorphism is
* calculated on the colored graphs; i.e. two vertices can match
* only if their color also matches. Supply a null pointer here if
* your graphs are not colored.
* \param vertex_color2 An optional color vector for the second graph. See
* the previous argument for explanation.
* \param edge_color1 An optional edge color vector for the first
* graph. The matching edges in the two graphs must have matching
* colors as well. Supply a null pointer here if your graphs are not
* edge-colored.
* \param edge_color2 The edge color vector for the second graph.
* \param count Point to an integer, the result will be stored here.
* \param node_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two nodes are compatible.
* \param edge_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two edges are compatible.
* \param arg Extra argument to supply to functions \p node_compat_fn and
* \p edge_compat_fn.
* \return Error code.
*
* Time complexity: exponential.
*/
igraph_error_t igraph_count_isomorphisms_vf2(const igraph_t *graph1, const igraph_t *graph2,
const igraph_vector_int_t *vertex_color1,
const igraph_vector_int_t *vertex_color2,
const igraph_vector_int_t *edge_color1,
const igraph_vector_int_t *edge_color2,
igraph_integer_t *count,
igraph_isocompat_t *node_compat_fn,
igraph_isocompat_t *edge_compat_fn,
void *arg) {
igraph_i_iso_cb_data_t data = { node_compat_fn, edge_compat_fn,
count, arg
};
igraph_isocompat_t *ncb = node_compat_fn ? igraph_i_isocompat_node_cb : 0;
igraph_isocompat_t *ecb = edge_compat_fn ? igraph_i_isocompat_edge_cb : 0;
*count = 0;
IGRAPH_CHECK(igraph_get_isomorphisms_vf2_callback(graph1, graph2,
vertex_color1, vertex_color2,
edge_color1, edge_color2,
0, 0,
(igraph_isohandler_t*) igraph_i_count_isomorphisms_vf2_cb,
ncb, ecb, &data));
return IGRAPH_SUCCESS;
}
static igraph_error_t igraph_i_store_mapping_vf2_cb(
const igraph_vector_int_t *map12, const igraph_vector_int_t *map21,
void *arg
) {
igraph_i_iso_cb_data_t *data = arg;
igraph_vector_int_list_t *ptrvector = data->arg;
IGRAPH_UNUSED(map12);
return igraph_vector_int_list_push_back_copy(ptrvector, map21);
}
/**
* \function igraph_get_isomorphisms_vf2
* \brief Collect all isomorphic mappings of two graphs.
*
* This function finds all the isomorphic mappings between two simple
* graphs. It uses the \ref igraph_get_isomorphisms_vf2_callback()
* function. Call the function with the same graph as \p graph1 and \p
* graph2 to get automorphisms.
* \param graph1 The first input graph, may be directed or undirected.
* \param graph2 The second input graph, it must have the same
* directedness as \p graph1, or an error will be reported.
* \param vertex_color1 An optional color vector for the first graph. If
* color vectors are given for both graphs, then the isomorphism is
* calculated on the colored graphs; i.e. two vertices can match
* only if their color also matches. Supply a null pointer here if
* your graphs are not colored.
* \param vertex_color2 An optional color vector for the second graph. See
* the previous argument for explanation.
* \param edge_color1 An optional edge color vector for the first
* graph. The matching edges in the two graphs must have matching
* colors as well. Supply a null pointer here if your graphs are not
* edge-colored.
* \param edge_color2 The edge color vector for the second graph.
* \param maps Pointer to a list of integer vectors. On return it is empty if
* the input graphs are not isomorphic. Otherwise it contains pointers to
* \ref igraph_vector_int_t objects, each vector is an
* isomorphic mapping of \p graph2 to \p graph1.
* \param node_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two nodes are compatible.
* \param edge_compat_fn A pointer to a function of type \ref
* igraph_isocompat_t. This function will be called by the algorithm to
* determine whether two edges are compatible.
* \param arg Extra argument to supply to functions \p node_compat_fn
* and \p edge_compat_fn.
* \return Error code.
*
* Time complexity: exponential.
*/
igraph_error_t igraph_get_isomorphisms_vf2(const igraph_t *graph1,
const igraph_t *graph2,
const igraph_vector_int_t *vertex_color1,
const igraph_vector_int_t *vertex_color2,
const igraph_vector_int_t *edge_color1,
const igraph_vector_int_t *edge_color2,
igraph_vector_int_list_t *maps,
igraph_isocompat_t *node_compat_fn,
igraph_isocompat_t *edge_compat_fn,
void *arg) {
igraph_i_iso_cb_data_t data = { node_compat_fn, edge_compat_fn, maps, arg };
igraph_isocompat_t *ncb = node_compat_fn ? igraph_i_isocompat_node_cb : NULL;
igraph_isocompat_t *ecb = edge_compat_fn ? igraph_i_isocompat_edge_cb : NULL;
igraph_vector_int_list_clear(maps);
IGRAPH_CHECK(igraph_get_isomorphisms_vf2_callback(graph1, graph2,
vertex_color1, vertex_color2,
edge_color1, edge_color2,
NULL, NULL,
(igraph_isohandler_t*) igraph_i_store_mapping_vf2_cb,
ncb, ecb, &data));
return IGRAPH_SUCCESS;
}
/**
* \function igraph_get_subisomorphisms_vf2_callback
* \brief Generic VF2 function for subgraph isomorphism problems.
*
* This function is the pair of \ref igraph_get_isomorphisms_vf2_callback(),
* for subgraph isomorphism problems. It searches for subgraphs of \p
* graph1 which are isomorphic to \p graph2. When it founds an
* isomorphic mapping it calls the supplied callback \p isohandler_fn.
* The mapping (and its inverse) and the additional \p arg argument
* are supplied to the callback.
* \param graph1 The first input graph, may be directed or