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// Copyright Michael Drexl 2005, 2006.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://boost.org/LICENSE_1_0.txt)
// Example use of the resource-constrained shortest paths algorithm.
#include <boost/config.hpp>
#ifdef BOOST_MSVC
# pragma warning(disable: 4267)
#endif
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/r_c_shortest_paths.hpp>
#include <iostream>
using namespace boost;
struct SPPRC_Example_Graph_Vert_Prop
{
SPPRC_Example_Graph_Vert_Prop( int n = 0, int e = 0, int l = 0 )
: num( n ), eat( e ), lat( l ) {}
int num;
// earliest arrival time
int eat;
// latest arrival time
int lat;
};
struct SPPRC_Example_Graph_Arc_Prop
{
SPPRC_Example_Graph_Arc_Prop( int n = 0, int c = 0, int t = 0 )
: num( n ), cost( c ), time( t ) {}
int num;
// traversal cost
int cost;
// traversal time
int time;
};
typedef adjacency_list<vecS,
vecS,
directedS,
SPPRC_Example_Graph_Vert_Prop,
SPPRC_Example_Graph_Arc_Prop>
SPPRC_Example_Graph;
// data structures for spp without resource constraints:
// ResourceContainer model
struct spp_no_rc_res_cont
{
spp_no_rc_res_cont( int c = 0 ) : cost( c ) {};
spp_no_rc_res_cont& operator=( const spp_no_rc_res_cont& other )
{
if( this == &other )
return *this;
this->~spp_no_rc_res_cont();
new( this ) spp_no_rc_res_cont( other );
return *this;
}
int cost;
};
bool operator==( const spp_no_rc_res_cont& res_cont_1,
const spp_no_rc_res_cont& res_cont_2 )
{
return ( res_cont_1.cost == res_cont_2.cost );
}
bool operator<( const spp_no_rc_res_cont& res_cont_1,
const spp_no_rc_res_cont& res_cont_2 )
{
return ( res_cont_1.cost < res_cont_2.cost );
}
// ResourceExtensionFunction model
class ref_no_res_cont
{
public:
inline bool operator()( const SPPRC_Example_Graph& g,
spp_no_rc_res_cont& new_cont,
const spp_no_rc_res_cont& old_cont,
graph_traits
<SPPRC_Example_Graph>::edge_descriptor ed ) const
{
new_cont.cost = old_cont.cost + g[ed].cost;
return true;
}
};
// DominanceFunction model
class dominance_no_res_cont
{
public:
inline bool operator()( const spp_no_rc_res_cont& res_cont_1,
const spp_no_rc_res_cont& res_cont_2 ) const
{
// must be "<=" here!!!
// must NOT be "<"!!!
return res_cont_1.cost <= res_cont_2.cost;
// this is not a contradiction to the documentation
// the documentation says:
// "A label $l_1$ dominates a label $l_2$ if and only if both are resident
// at the same vertex, and if, for each resource, the resource consumption
// of $l_1$ is less than or equal to the resource consumption of $l_2$,
// and if there is at least one resource where $l_1$ has a lower resource
// consumption than $l_2$."
// one can think of a new label with a resource consumption equal to that
// of an old label as being dominated by that old label, because the new
// one will have a higher number and is created at a later point in time,
// so one can implicitly use the number or the creation time as a resource
// for tie-breaking
}
};
// end data structures for spp without resource constraints:
// data structures for shortest path problem with time windows (spptw)
// ResourceContainer model
struct spp_spptw_res_cont
{
spp_spptw_res_cont( int c = 0, int t = 0 ) : cost( c ), time( t ) {}
spp_spptw_res_cont& operator=( const spp_spptw_res_cont& other )
{
if( this == &other )
return *this;
this->~spp_spptw_res_cont();
new( this ) spp_spptw_res_cont( other );
return *this;
}
int cost;
int time;
};
bool operator==( const spp_spptw_res_cont& res_cont_1,
const spp_spptw_res_cont& res_cont_2 )
{
return ( res_cont_1.cost == res_cont_2.cost
&& res_cont_1.time == res_cont_2.time );
}
bool operator<( const spp_spptw_res_cont& res_cont_1,
const spp_spptw_res_cont& res_cont_2 )
{
if( res_cont_1.cost > res_cont_2.cost )
return false;
if( res_cont_1.cost == res_cont_2.cost )
return res_cont_1.time < res_cont_2.time;
return true;
}
// ResourceExtensionFunction model
class ref_spptw
{
public:
inline bool operator()( const SPPRC_Example_Graph& g,
spp_spptw_res_cont& new_cont,
const spp_spptw_res_cont& old_cont,
graph_traits
<SPPRC_Example_Graph>::edge_descriptor ed ) const
{
const SPPRC_Example_Graph_Arc_Prop& arc_prop =
get( edge_bundle, g )[ed];
const SPPRC_Example_Graph_Vert_Prop& vert_prop =
get( vertex_bundle, g )[target( ed, g )];
new_cont.cost = old_cont.cost + arc_prop.cost;
int& i_time = new_cont.time;
i_time = old_cont.time + arc_prop.time;
i_time < vert_prop.eat ? i_time = vert_prop.eat : 0;
return i_time <= vert_prop.lat ? true : false;
}
};
// DominanceFunction model
class dominance_spptw
{
public:
inline bool operator()( const spp_spptw_res_cont& res_cont_1,
const spp_spptw_res_cont& res_cont_2 ) const
{
// must be "<=" here!!!
// must NOT be "<"!!!
return res_cont_1.cost <= res_cont_2.cost
&& res_cont_1.time <= res_cont_2.time;
// this is not a contradiction to the documentation
// the documentation says:
// "A label $l_1$ dominates a label $l_2$ if and only if both are resident
// at the same vertex, and if, for each resource, the resource consumption
// of $l_1$ is less than or equal to the resource consumption of $l_2$,
// and if there is at least one resource where $l_1$ has a lower resource
// consumption than $l_2$."
// one can think of a new label with a resource consumption equal to that
// of an old label as being dominated by that old label, because the new
// one will have a higher number and is created at a later point in time,
// so one can implicitly use the number or the creation time as a resource
// for tie-breaking
}
};
// end data structures for shortest path problem with time windows (spptw)
// example graph structure and cost from
// http://www.boost.org/libs/graph/example/dijkstra-example.cpp
const int num_nodes = 5;
enum nodes { A, B, C, D, E };
char name[] = "ABCDE";
int main()
{
SPPRC_Example_Graph g;
add_vertex( SPPRC_Example_Graph_Vert_Prop( A, 0, 0 ), g );
add_vertex( SPPRC_Example_Graph_Vert_Prop( B, 5, 20 ), g );
add_vertex( SPPRC_Example_Graph_Vert_Prop( C, 6, 10 ), g );
add_vertex( SPPRC_Example_Graph_Vert_Prop( D, 3, 12 ), g );
add_vertex( SPPRC_Example_Graph_Vert_Prop( E, 0, 100 ), g );
add_edge( A, C, SPPRC_Example_Graph_Arc_Prop( 0, 1, 5 ), g );
add_edge( B, B, SPPRC_Example_Graph_Arc_Prop( 1, 2, 5 ), g );
add_edge( B, D, SPPRC_Example_Graph_Arc_Prop( 2, 1, 2 ), g );
add_edge( B, E, SPPRC_Example_Graph_Arc_Prop( 3, 2, 7 ), g );
add_edge( C, B, SPPRC_Example_Graph_Arc_Prop( 4, 7, 3 ), g );
add_edge( C, D, SPPRC_Example_Graph_Arc_Prop( 5, 3, 8 ), g );
add_edge( D, E, SPPRC_Example_Graph_Arc_Prop( 6, 1, 3 ), g );
add_edge( E, A, SPPRC_Example_Graph_Arc_Prop( 7, 1, 5 ), g );
add_edge( E, B, SPPRC_Example_Graph_Arc_Prop( 8, 1, 4 ), g );
// the unique shortest path from A to E in the dijkstra-example.cpp is
// A -> C -> D -> E
// its length is 5
// the following code also yields this result
// with the above time windows, this path is infeasible
// now, there are two shortest paths that are also feasible with respect to
// the vertex time windows:
// A -> C -> B -> D -> E and
// A -> C -> B -> E
// however, the latter has a longer total travel time and is therefore not
// pareto-optimal, i.e., it is dominated by the former path
// therefore, the code below returns only the former path
// spp without resource constraints
graph_traits<SPPRC_Example_Graph>::vertex_descriptor s = A;
graph_traits<SPPRC_Example_Graph>::vertex_descriptor t = E;
std::vector
<std::vector
<graph_traits<SPPRC_Example_Graph>::edge_descriptor> >
opt_solutions;
std::vector<spp_no_rc_res_cont> pareto_opt_rcs_no_rc;
r_c_shortest_paths
( g,
get( &SPPRC_Example_Graph_Vert_Prop::num, g ),
get( &SPPRC_Example_Graph_Arc_Prop::num, g ),
s,
t,
opt_solutions,
pareto_opt_rcs_no_rc,
spp_no_rc_res_cont( 0 ),
ref_no_res_cont(),
dominance_no_res_cont(),
std::allocator
<r_c_shortest_paths_label
<SPPRC_Example_Graph, spp_no_rc_res_cont> >(),
default_r_c_shortest_paths_visitor() );
std::cout << "SPP without resource constraints:" << std::endl;
std::cout << "Number of optimal solutions: ";
std::cout << static_cast<int>( opt_solutions.size() ) << std::endl;
for( int i = 0; i < static_cast<int>( opt_solutions.size() ); ++i )
{
std::cout << "The " << i << "th shortest path from A to E is: ";
std::cout << std::endl;
for( int j = static_cast<int>( opt_solutions[i].size() ) - 1; j >= 0; --j )
std::cout << name[source( opt_solutions[i][j], g )] << std::endl;
std::cout << "E" << std::endl;
std::cout << "Length: " << pareto_opt_rcs_no_rc[i].cost << std::endl;
}
std::cout << std::endl;
// spptw
std::vector
<std::vector
<graph_traits<SPPRC_Example_Graph>::edge_descriptor> >
opt_solutions_spptw;
std::vector<spp_spptw_res_cont> pareto_opt_rcs_spptw;
r_c_shortest_paths
( g,
get( &SPPRC_Example_Graph_Vert_Prop::num, g ),
get( &SPPRC_Example_Graph_Arc_Prop::num, g ),
s,
t,
opt_solutions_spptw,
pareto_opt_rcs_spptw,
spp_spptw_res_cont( 0, 0 ),
ref_spptw(),
dominance_spptw(),
std::allocator
<r_c_shortest_paths_label
<SPPRC_Example_Graph, spp_spptw_res_cont> >(),
default_r_c_shortest_paths_visitor() );
std::cout << "SPP with time windows:" << std::endl;
std::cout << "Number of optimal solutions: ";
std::cout << static_cast<int>( opt_solutions.size() ) << std::endl;
for( int i = 0; i < static_cast<int>( opt_solutions.size() ); ++i )
{
std::cout << "The " << i << "th shortest path from A to E is: ";
std::cout << std::endl;
for( int j = static_cast<int>( opt_solutions_spptw[i].size() ) - 1;
j >= 0;
--j )
std::cout << name[source( opt_solutions_spptw[i][j], g )] << std::endl;
std::cout << "E" << std::endl;
std::cout << "Length: " << pareto_opt_rcs_spptw[i].cost << std::endl;
std::cout << "Time: " << pareto_opt_rcs_spptw[i].time << std::endl;
}
// utility function check_r_c_path example
std::cout << std::endl;
bool b_is_a_path_at_all = false;
bool b_feasible = false;
bool b_correctly_extended = false;
spp_spptw_res_cont actual_final_resource_levels( 0, 0 );
graph_traits<SPPRC_Example_Graph>::edge_descriptor ed_last_extended_arc;
check_r_c_path( g,
opt_solutions_spptw[0],
spp_spptw_res_cont( 0, 0 ),
true,
pareto_opt_rcs_spptw[0],
actual_final_resource_levels,
ref_spptw(),
b_is_a_path_at_all,
b_feasible,
b_correctly_extended,
ed_last_extended_arc );
if( !b_is_a_path_at_all )
std::cout << "Not a path." << std::endl;
if( !b_feasible )
std::cout << "Not a feasible path." << std::endl;
if( !b_correctly_extended )
std::cout << "Not correctly extended." << std::endl;
if( b_is_a_path_at_all && b_feasible && b_correctly_extended )
{
std::cout << "Actual final resource levels:" << std::endl;
std::cout << "Length: " << actual_final_resource_levels.cost << std::endl;
std::cout << "Time: " << actual_final_resource_levels.time << std::endl;
std::cout << "OK." << std::endl;
}
return 0;
}