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