Added boost header

test/external/boost/graph/circle_layout.hpp

@@ -0,0 +1,58 @@
+// Copyright 2004 The Trustees of Indiana University.
+
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+//  Authors: Douglas Gregor
+//           Andrew Lumsdaine
+#ifndef BOOST_GRAPH_CIRCLE_LAYOUT_HPP
+#define BOOST_GRAPH_CIRCLE_LAYOUT_HPP
+#include <boost/config/no_tr1/cmath.hpp>
+#include <boost/math/constants/constants.hpp>
+#include <utility>
+#include <boost/graph/graph_traits.hpp>
+#include <boost/graph/iteration_macros.hpp>
+#include <boost/graph/topology.hpp>
+#include <boost/static_assert.hpp>
+
+namespace boost {
+  /** 
+   * \brief Layout the graph with the vertices at the points of a regular
+   * n-polygon. 
+   *
+   * The distance from the center of the polygon to each point is
+   * determined by the @p radius parameter. The @p position parameter
+   * must be an Lvalue Property Map whose value type is a class type
+   * containing @c x and @c y members that will be set to the @c x and
+   * @c y coordinates.
+   */
+  template<typename VertexListGraph, typename PositionMap, typename Radius>
+  void 
+  circle_graph_layout(const VertexListGraph& g, PositionMap position,
+                      Radius radius)
+  {
+    BOOST_STATIC_ASSERT (property_traits<PositionMap>::value_type::dimensions >= 2);
+    const double pi = boost::math::constants::pi<double>();
+
+#ifndef BOOST_NO_STDC_NAMESPACE
+    using std::sin;
+    using std::cos;
+#endif // BOOST_NO_STDC_NAMESPACE
+
+    typedef typename graph_traits<VertexListGraph>::vertices_size_type 
+      vertices_size_type;
+
+    vertices_size_type n = num_vertices(g);
+    
+    vertices_size_type i = 0;
+    double two_pi_over_n = 2. * pi / n;
+    BGL_FORALL_VERTICES_T(v, g, VertexListGraph) {
+      position[v][0] = radius * cos(i * two_pi_over_n);
+      position[v][1] = radius * sin(i * two_pi_over_n);
+      ++i;
+    }
+  }
+} // end namespace boost
+
+#endif // BOOST_GRAPH_CIRCLE_LAYOUT_HPP