Implement predecessor_tree()

src/graph/generation/Makefile.am

@@ -16,7 +16,8 @@ libgraph_tool_generation_la_LDFLAGS = $(MOD_LDFLAGS)
 
 libgraph_tool_generation_la_SOURCES = \
     graph_generation.cc \
-    graph_rewiring.cc
+    graph_rewiring.cc \
+    graph_predecessor.cc
 
 libgraph_tool_generation_la_include_HEADERS = \
     graph_generation.hh \

src/graph/generation/graph_generation.cc

@@ -96,6 +96,8 @@ void generate_random_graph(GraphInterface& gi, size_t N,
 
 void random_rewire(GraphInterface& gi, string strat, bool self_loops,
                    bool parallel_edges, size_t seed);
+void predecessor_graph(GraphInterface& gi, GraphInterface& gpi,
+                       boost::any pred_map);
 
 using namespace boost::python;
 
@@ -103,4 +105,5 @@ BOOST_PYTHON_MODULE(libgraph_tool_generation)
 {
     def("gen_random_graph", &generate_random_graph);
     def("random_rewire", &random_rewire);
+    def("predecessor_graph", &predecessor_graph);
 }

src/graph/generation/graph_predecessor.cc

+// graph-tool -- a general graph modification and manipulation thingy
+//
+// Copyright (C) 2007  Tiago de Paula Peixoto <tiago@forked.de>
+//
+// 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 3
+// 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, see <http://www.gnu.org/licenses/>.
+
+#include <boost/lambda/bind.hpp>
+
+#include "graph.hh"
+#include "graph_filtering.hh"
+
+#include "graph_predecessor.hh"
+
+using namespace graph_tool;
+using namespace boost;
+using namespace boost::lambda;
+
+void predecessor_graph(GraphInterface& gi, GraphInterface& gpi,
+                       boost::any pred_map)
+{
+     run_action<>()(gi, bind<void>(get_predecessor_graph(), _1,
+                                   gi.GetVertexIndex(), ref(gpi.GetGraph()),
+                                   _2),
+                    vertex_scalar_properties())(pred_map);
+}

src/graph/generation/graph_predecessor.hh

+// graph-tool -- a general graph modification and manipulation thingy
+//
+// Copyright (C) 2007  Tiago de Paula Peixoto <tiago@forked.de>
+//
+// 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 3
+// 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, see <http://www.gnu.org/licenses/>.
+
+#ifndef GRAPH_PREDECESSOR_HH
+#define GRAPH_PREDECESSOR_HH
+
+#include "graph.hh"
+#include "graph_filtering.hh"
+#include "graph_util.hh"
+
+namespace graph_tool
+{
+using namespace std;
+using namespace boost;
+
+struct get_predecessor_graph
+{
+    template <class Graph, class IndexMap, class PredGraph, class PredMap>
+    void operator()(Graph& g, IndexMap vertex_index, PredGraph& pg,
+                    PredMap pred_map) const
+    {
+        unchecked_vector_property_map<size_t,IndexMap>
+            index_map(vertex_index, num_vertices(g));
+
+        size_t count = 0;
+        typename graph_traits<Graph>::vertex_iterator v,v_end;
+        for (tie(v,v_end) = vertices(g); v != v_end; ++v)
+        {
+            index_map[*v] = count++;
+            add_vertex(pg);
+        }
+
+        for (tie(v,v_end) = vertices(g); v != v_end; ++v)
+        {
+            size_t pred_i = get(pred_map, *v);
+            if (pred_i >= num_vertices(g))
+                continue;
+
+            typename graph_traits<Graph>::vertex_descriptor pred =
+                vertex(pred_i, g);
+            if (pred == graph_traits<Graph>::null_vertex())
+                continue;
+
+            if (pred != *v)
+            {
+                typename graph_traits<PredGraph>::vertex_descriptor s, t;
+                s = vertex(index_map[pred], pg);
+                t = vertex(index_map[*v], pg);
+                add_edge(s, t, pg);
+            }
+        }
+    }
+};
+
+} // graph_tool namespace
+
+#endif // GRAPH_PREDECESSOR_HH

src/graph_tool/generation/__init__.py

@@ -24,10 +24,10 @@
 from .. dl_import import dl_import
 dl_import("import libgraph_tool_generation")
 
-from .. core import Graph
+from .. core import Graph, _check_prop_scalar, _prop
 import sys, numpy
 
-__all__ = ["random_graph", "random_rewire"]
+__all__ = ["random_graph", "random_rewire", "predecessor_tree"]
 
 def _corr_wrap(i, j, corr):
     return corr(i[1], j[1])
@@ -376,3 +376,14 @@ def random_rewire(g, strat= "uncorrelated", parallel_edges = False,
     libgraph_tool_generation.random_rewire(g._Graph__graph, strat, self_loops,
                                            parallel_edges, seed)
     g.pop_filter(reversed=True)
+
+def predecessor_tree(g, pred_map):
+    """Return a graph from a list of predecessors given by
+    the 'pred_map' vertex property."""
+
+    _check_prop_scalar(pred_map, "pred_map")
+    pg = Graph()
+    libgraph_tool_generation.predecessor_graph(g._Graph__graph,
+                                               pg._Graph__graph,
+                                               _prop("v", g, pred_map))
+    return pg