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// 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_FRUCHTERMAN_REINGOLD_FORCE_DIRECTED_LAYOUT_HPP
#define BOOST_GRAPH_FRUCHTERMAN_REINGOLD_FORCE_DIRECTED_LAYOUT_HPP
#include <cmath>
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/named_function_params.hpp>
#include <boost/graph/simple_point.hpp>
#include <vector>
#include <list>
#include <algorithm> // for std::min and std::max
namespace boost {
struct square_distance_attractive_force {
template<typename Graph, typename T>
T
operator()(typename graph_traits<Graph>::edge_descriptor,
T k,
T d,
const Graph&) const
{
return d * d / k;
}
};
struct square_distance_repulsive_force {
template<typename Graph, typename T>
T
operator()(typename graph_traits<Graph>::vertex_descriptor,
typename graph_traits<Graph>::vertex_descriptor,
T k,
T d,
const Graph&) const
{
return k * k / d;
}
};
template<typename T>
struct linear_cooling {
typedef T result_type;
linear_cooling(std::size_t iterations)
: temp(T(iterations) / T(10)), step(0.1) { }
linear_cooling(std::size_t iterations, T temp)
: temp(temp), step(temp / T(iterations)) { }
T operator()()
{
T old_temp = temp;
temp -= step;
if (temp < T(0)) temp = T(0);
return old_temp;
}
private:
T temp;
T step;
};
struct all_force_pairs
{
template<typename Graph, typename ApplyForce >
void operator()(const Graph& g, ApplyForce apply_force)
{
typedef typename graph_traits<Graph>::vertex_iterator vertex_iterator;
vertex_iterator v, end;
for (tie(v, end) = vertices(g); v != end; ++v) {
vertex_iterator u = v;
for (++u; u != end; ++u) {
apply_force(*u, *v);
apply_force(*v, *u);
}
}
}
};
template<typename Dim, typename PositionMap>
struct grid_force_pairs
{
template<typename Graph>
explicit
grid_force_pairs(Dim width, Dim height, PositionMap position, const Graph& g)
: width(width), height(height), position(position)
{
#ifndef BOOST_NO_STDC_NAMESPACE
using std::sqrt;
#endif // BOOST_NO_STDC_NAMESPACE
two_k = Dim(2) * sqrt(width*height / num_vertices(g));
}
template<typename Graph, typename ApplyForce >
void operator()(const Graph& g, ApplyForce apply_force)
{
typedef typename graph_traits<Graph>::vertex_iterator vertex_iterator;
typedef typename graph_traits<Graph>::vertex_descriptor vertex_descriptor;
typedef std::list<vertex_descriptor> bucket_t;
typedef std::vector<bucket_t> buckets_t;
std::size_t columns = std::size_t(width / two_k + Dim(1));
std::size_t rows = std::size_t(height / two_k + Dim(1));
buckets_t buckets(rows * columns);
vertex_iterator v, v_end;
for (tie(v, v_end) = vertices(g); v != v_end; ++v) {
std::size_t column = std::size_t((position[*v].x + width / 2) / two_k);
std::size_t row = std::size_t((position[*v].y + height / 2) / two_k);
if (column >= columns) column = columns - 1;
if (row >= rows) row = rows - 1;
buckets[row * columns + column].push_back(*v);
}
for (std::size_t row = 0; row < rows; ++row)
for (std::size_t column = 0; column < columns; ++column) {
bucket_t& bucket = buckets[row * columns + column];
typedef typename bucket_t::iterator bucket_iterator;
for (bucket_iterator u = bucket.begin(); u != bucket.end(); ++u) {
// Repulse vertices in this bucket
bucket_iterator v = u;
for (++v; v != bucket.end(); ++v) {
apply_force(*u, *v);
apply_force(*v, *u);
}
std::size_t adj_start_row = row == 0? 0 : row - 1;
std::size_t adj_end_row = row == rows - 1? row : row + 1;
std::size_t adj_start_column = column == 0? 0 : column - 1;
std::size_t adj_end_column = column == columns - 1? column : column + 1;
for (std::size_t other_row = adj_start_row; other_row <= adj_end_row;
++other_row)
for (std::size_t other_column = adj_start_column;
other_column <= adj_end_column; ++other_column)
if (other_row != row || other_column != column) {
// Repulse vertices in this bucket
bucket_t& other_bucket
= buckets[other_row * columns + other_column];
for (v = other_bucket.begin(); v != other_bucket.end(); ++v)
apply_force(*u, *v);
}
}
}
}
private:
Dim width;
Dim height;
PositionMap position;
Dim two_k;
};
template<typename Dim, typename PositionMap, typename Graph>
inline grid_force_pairs<Dim, PositionMap>
make_grid_force_pairs(Dim width, Dim height, const PositionMap& position,
const Graph& g)
{ return grid_force_pairs<Dim, PositionMap>(width, height, position, g); }
template<typename Graph, typename PositionMap, typename Dim>
void
scale_graph(const Graph& g, PositionMap position,
Dim left, Dim top, Dim right, Dim bottom)
{
if (num_vertices(g) == 0) return;
if (bottom > top) {
using std::swap;
swap(bottom, top);
}
typedef typename graph_traits<Graph>::vertex_iterator vertex_iterator;
// Find min/max ranges
Dim minX = position[*vertices(g).first].x, maxX = minX;
Dim minY = position[*vertices(g).first].y, maxY = minY;
vertex_iterator vi, vi_end;
for (tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi) {
BOOST_USING_STD_MIN();
BOOST_USING_STD_MAX();
minX = min BOOST_PREVENT_MACRO_SUBSTITUTION (minX, position[*vi].x);
maxX = max BOOST_PREVENT_MACRO_SUBSTITUTION (maxX, position[*vi].x);
minY = min BOOST_PREVENT_MACRO_SUBSTITUTION (minY, position[*vi].y);
maxY = max BOOST_PREVENT_MACRO_SUBSTITUTION (maxY, position[*vi].y);
}
// Scale to bounding box provided
for (tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi) {
position[*vi].x = ((position[*vi].x - minX) / (maxX - minX))
* (right - left) + left;
position[*vi].y = ((position[*vi].y - minY) / (maxY - minY))
* (top - bottom) + bottom;
}
}
namespace detail {
template<typename PositionMap, typename DisplacementMap,
typename RepulsiveForce, typename Dim, typename Graph>
struct fr_apply_force
{
typedef typename graph_traits<Graph>::vertex_descriptor vertex_descriptor;
fr_apply_force(const PositionMap& position,
const DisplacementMap& displacement,
RepulsiveForce repulsive_force, Dim k, const Graph& g)
: position(position), displacement(displacement),
repulsive_force(repulsive_force), k(k), g(g)
{ }
void operator()(vertex_descriptor u, vertex_descriptor v)
{
#ifndef BOOST_NO_STDC_NAMESPACE
using std::sqrt;
#endif // BOOST_NO_STDC_NAMESPACE
if (u != v) {
Dim delta_x = position[v].x - position[u].x;
Dim delta_y = position[v].y - position[u].y;
Dim dist = sqrt(delta_x * delta_x + delta_y * delta_y);
Dim fr = repulsive_force(u, v, k, dist, g);
displacement[v].x += delta_x / dist * fr;
displacement[v].y += delta_y / dist * fr;
}
}
private:
PositionMap position;
DisplacementMap displacement;
RepulsiveForce repulsive_force;
Dim k;
const Graph& g;
};
} // end namespace detail
template<typename Graph, typename PositionMap, typename Dim,
typename AttractiveForce, typename RepulsiveForce,
typename ForcePairs, typename Cooling, typename DisplacementMap>
void
fruchterman_reingold_force_directed_layout
(const Graph& g,
PositionMap position,
Dim width,
Dim height,
AttractiveForce attractive_force,
RepulsiveForce repulsive_force,
ForcePairs force_pairs,
Cooling cool,
DisplacementMap displacement)
{
typedef typename graph_traits<Graph>::vertex_iterator vertex_iterator;
typedef typename graph_traits<Graph>::vertex_descriptor vertex_descriptor;
typedef typename graph_traits<Graph>::edge_iterator edge_iterator;
#ifndef BOOST_NO_STDC_NAMESPACE
using std::sqrt;
#endif // BOOST_NO_STDC_NAMESPACE
Dim area = width * height;
// assume positions are initialized randomly
Dim k = sqrt(area / num_vertices(g));
detail::fr_apply_force<PositionMap, DisplacementMap,
RepulsiveForce, Dim, Graph>
apply_force(position, displacement, repulsive_force, k, g);
Dim temp = cool();
if (temp) do {
// Calculate repulsive forces
vertex_iterator v, v_end;
for (tie(v, v_end) = vertices(g); v != v_end; ++v) {
displacement[*v].x = 0;
displacement[*v].y = 0;
}
force_pairs(g, apply_force);
// Calculate attractive forces
edge_iterator e, e_end;
for (tie(e, e_end) = edges(g); e != e_end; ++e) {
vertex_descriptor v = source(*e, g);
vertex_descriptor u = target(*e, g);
Dim delta_x = position[v].x - position[u].x;
Dim delta_y = position[v].y - position[u].y;
Dim dist = sqrt(delta_x * delta_x + delta_y * delta_y);
Dim fa = attractive_force(*e, k, dist, g);
displacement[v].x -= delta_x / dist * fa;
displacement[v].y -= delta_y / dist * fa;
displacement[u].x += delta_x / dist * fa;
displacement[u].y += delta_y / dist * fa;
}
// Update positions
for (tie(v, v_end) = vertices(g); v != v_end; ++v) {
BOOST_USING_STD_MIN();
BOOST_USING_STD_MAX();
Dim disp_size = sqrt(displacement[*v].x * displacement[*v].x
+ displacement[*v].y * displacement[*v].y);
position[*v].x += displacement[*v].x / disp_size
* min BOOST_PREVENT_MACRO_SUBSTITUTION (disp_size, temp);
position[*v].y += displacement[*v].y / disp_size
* min BOOST_PREVENT_MACRO_SUBSTITUTION (disp_size, temp);
position[*v].x = min BOOST_PREVENT_MACRO_SUBSTITUTION
(width / 2,
max BOOST_PREVENT_MACRO_SUBSTITUTION(-width / 2,
position[*v].x));
position[*v].y = min BOOST_PREVENT_MACRO_SUBSTITUTION
(height / 2,
max BOOST_PREVENT_MACRO_SUBSTITUTION(-height / 2,
position[*v].y));
}
} while (temp = cool());
}
namespace detail {
template<typename DisplacementMap>
struct fr_force_directed_layout
{
template<typename Graph, typename PositionMap, typename Dim,
typename AttractiveForce, typename RepulsiveForce,
typename ForcePairs, typename Cooling,
typename Param, typename Tag, typename Rest>
static void
run(const Graph& g,
PositionMap position,
Dim width,
Dim height,
AttractiveForce attractive_force,
RepulsiveForce repulsive_force,
ForcePairs force_pairs,
Cooling cool,
DisplacementMap displacement,
const bgl_named_params<Param, Tag, Rest>&)
{
fruchterman_reingold_force_directed_layout
(g, position, width, height, attractive_force, repulsive_force,
force_pairs, cool, displacement);
}
};
template<>
struct fr_force_directed_layout<error_property_not_found>
{
template<typename Graph, typename PositionMap, typename Dim,
typename AttractiveForce, typename RepulsiveForce,
typename ForcePairs, typename Cooling,
typename Param, typename Tag, typename Rest>
static void
run(const Graph& g,
PositionMap position,
Dim width,
Dim height,
AttractiveForce attractive_force,
RepulsiveForce repulsive_force,
ForcePairs force_pairs,
Cooling cool,
error_property_not_found,
const bgl_named_params<Param, Tag, Rest>& params)
{
std::vector<simple_point<Dim> > displacements(num_vertices(g));
fruchterman_reingold_force_directed_layout
(g, position, width, height, attractive_force, repulsive_force,
force_pairs, cool,
make_iterator_property_map
(displacements.begin(),
choose_const_pmap(get_param(params, vertex_index), g,
vertex_index),
simple_point<Dim>()));
}
};
} // end namespace detail
template<typename Graph, typename PositionMap, typename Dim, typename Param,
typename Tag, typename Rest>
void
fruchterman_reingold_force_directed_layout
(const Graph& g,
PositionMap position,
Dim width,
Dim height,
const bgl_named_params<Param, Tag, Rest>& params)
{
typedef typename property_value<bgl_named_params<Param,Tag,Rest>,
vertex_displacement_t>::type D;
detail::fr_force_directed_layout<D>::run
(g, position, width, height,
choose_param(get_param(params, attractive_force_t()),
square_distance_attractive_force()),
choose_param(get_param(params, repulsive_force_t()),
square_distance_repulsive_force()),
choose_param(get_param(params, force_pairs_t()),
make_grid_force_pairs(width, height, position, g)),
choose_param(get_param(params, cooling_t()),
linear_cooling<Dim>(100)),
get_param(params, vertex_displacement_t()),
params);
}
template<typename Graph, typename PositionMap, typename Dim>
void
fruchterman_reingold_force_directed_layout(const Graph& g,
PositionMap position,
Dim width,
Dim height)
{
fruchterman_reingold_force_directed_layout
(g, position, width, height,
attractive_force(square_distance_attractive_force()));
}
} // end namespace boost
#endif // BOOST_GRAPH_FRUCHTERMAN_REINGOLD_FORCE_DIRECTED_LAYOUT_HPP
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