# HG changeset patch
# User athos
# Date 1084290131 0
# Node ID 327f7cf13843854e06213cbb88756cd8ea9ec541
# Parent 81a0c2f2f7c61ea4812222f0592b5ad02e26eb6f
Finished MinLengthPaths: a specialization of MinCostFlows.
diff -r 81a0c2f2f7c6 -r 327f7cf13843 src/work/athos/makefile
--- a/src/work/athos/makefile Tue May 11 14:58:09 2004 +0000
+++ b/src/work/athos/makefile Tue May 11 15:42:11 2004 +0000
@@ -1,4 +1,4 @@
-BINARIES = suurballe minlength_demo mincostflows_test
+BINARIES = minlengthpaths_test minlength_demo
INCLUDEDIRS= -I../.. -I.. -I../{athos,klao,marci,jacint,alpar,johanna,akos}
include ../makefile
diff -r 81a0c2f2f7c6 -r 327f7cf13843 src/work/athos/mincostflows.h
--- a/src/work/athos/mincostflows.h Tue May 11 14:58:09 2004 +0000
+++ b/src/work/athos/mincostflows.h Tue May 11 15:42:11 2004 +0000
@@ -8,7 +8,7 @@
#include <iostream>
#include <hugo/dijkstra.h>
-#include <graph_wrapper.h>
+#include <hugo/graph_wrapper.h>
#include <hugo/maps.h>
#include <vector>
#include <for_each_macros.h>
@@ -77,12 +77,14 @@
};//ModLengthMap
+ protected:
//Input
const Graph& G;
const LengthMap& length;
const CapacityMap& capacity;
+
//auxiliary variables
//To store the flow
@@ -98,6 +100,7 @@
Length total_length;
+
public :
@@ -110,6 +113,8 @@
///Runs the algorithm.
///Returns k if there are at least k edge-disjoint paths from s to t.
///Otherwise it returns the number of found edge-disjoint paths from s to t.
+ ///\todo May be it does make sense to be able to start with a nonzero
+ /// feasible primal-dual solution pair as well.
int run(Node s, Node t, int k) {
//Resetting variables from previous runs
@@ -185,10 +190,20 @@
return total_length;
}
- //This function checks, whether the given solution is optimal
- //Running after a \c run() should return with true
- //In this "state of the art" this only check optimality, doesn't bother with feasibility
- bool checkSolution(){
+ ///Returns a const reference to the EdgeMap \c flow. \pre \ref run() must
+ ///be called before using this function.
+ const EdgeIntMap &getFlow() const { return flow;}
+
+ ///Returns a const reference to the NodeMap \c potential (the dual solution).
+ /// \pre \ref run() must be called before using this function.
+ const EdgeIntMap &getPotential() const { return potential;}
+
+ ///This function checks, whether the given solution is optimal
+ ///Running after a \c run() should return with true
+ ///In this "state of the art" this only check optimality, doesn't bother with feasibility
+ ///
+ ///\todo Is this OK here?
+ bool checkComplementarySlackness(){
Length mod_pot;
Length fl_e;
FOR_EACH_LOC(typename Graph::EdgeIt, e, G){
diff -r 81a0c2f2f7c6 -r 327f7cf13843 src/work/athos/minlength_demo.cc
--- a/src/work/athos/minlength_demo.cc Tue May 11 14:58:09 2004 +0000
+++ b/src/work/athos/minlength_demo.cc Tue May 11 15:42:11 2004 +0000
@@ -2,8 +2,9 @@
#include <fstream>
#include <list_graph.h>
-#include <dimacs.h>
-#include <minlengthpaths.h>
+#include <hugo/dimacs.h>
+#include <hugo/time_measure.h>
+#include "minlengthpaths.h"
//#include <time_measure.h>
using namespace hugo;
@@ -19,9 +20,9 @@
Graph G;
Node s, t;
Graph::EdgeMap<int> cap(G);
- readDimacsMaxFlow(std::cin, G, s, t, cap);
+ readDimacs(std::cin, G, cap, s, t);
- std::cout << "preflow demo (ATHOS)..." << std::endl;
+ std::cout << "Minlengthpaths demo (ATHOS)..." << std::endl;
//Graph::EdgeMap<int> flow(G); //0 flow
// double pre_time=currTime();
@@ -31,8 +32,14 @@
k = atoi(argv[1]);
MinLengthPaths<Graph, Graph::EdgeMap<int> >
surb_test(G,cap);
- std::cout << surb_test.run(s,t,k) << std::endl;
- std::cout << surb_test.totalLength() << std::endl;
+ Timer ts;
+ ts.reset();
+ std::cout << "Number of found paths: " << surb_test.run(s,t,k) << std::endl;
+ std::cout << "elapsed time: " << ts << std::endl;
+
+ std::cout << "Total length of found paths: " << surb_test.totalLength() << std::endl;
+ //std::cout << (surb_test.checkComplementarySlackness() ? "OK (compl. slackn.)." : "Problem (compl. slackn.)!!!") << std::endl;
+
//preflow_push<Graph, int> max_flow_test(G, s, t, cap);
//int flow_value=max_flow_test.run();
diff -r 81a0c2f2f7c6 -r 327f7cf13843 src/work/athos/minlengthpaths.h
--- a/src/work/athos/minlengthpaths.h Tue May 11 14:58:09 2004 +0000
+++ b/src/work/athos/minlengthpaths.h Tue May 11 15:42:11 2004 +0000
@@ -7,11 +7,12 @@
///\brief An algorithm for finding k paths of minimal total length.
#include <iostream>
-#include <dijkstra.h>
-#include <graph_wrapper.h>
-#include <maps.h>
-#include <vector.h>
-
+//#include <hugo/dijkstra.h>
+//#include <hugo/graph_wrapper.h>
+#include <hugo/maps.h>
+#include <vector>
+#include <mincostflows.h>
+#include <for_each_macros.h>
namespace hugo {
@@ -26,9 +27,13 @@
/// from a given source node to a given target node in an
/// edge-weighted directed graph having minimal total weigth (length).
///
+ ///\warning It is assumed that the lengths are positive, since the
+ /// general flow-decomposition is not implemented yet.
+ ///
///\author Attila Bernath
template <typename Graph, typename LengthMap>
- class MinLengthPaths {
+ class MinLengthPaths{
+
typedef typename LengthMap::ValueType Length;
@@ -40,114 +45,50 @@
typedef ConstMap<Edge,int> ConstMap;
- typedef ResGraphWrapper<const Graph,int,ConstMap,EdgeIntMap> ResGraphType;
+ //Input
+ const Graph& G;
- class ModLengthMap {
- typedef typename ResGraphType::template NodeMap<Length> NodeMap;
- const ResGraphType& G;
- const EdgeIntMap& rev;
- const LengthMap &ol;
- const NodeMap &pot;
- public :
- typedef typename LengthMap::KeyType KeyType;
- typedef typename LengthMap::ValueType ValueType;
-
- ValueType operator[](typename ResGraphType::Edge e) const {
- //if ( (1-2*rev[e])*ol[e]-(pot[G.head(e)]-pot[G.tail(e)] ) <0 ){
- // std::cout<<"Negative length!!"<<std::endl;
- //}
- return (1-2*rev[e])*ol[e]-(pot[G.head(e)]-pot[G.tail(e)]);
- }
-
- ModLengthMap(const ResGraphType& _G, const EdgeIntMap& _rev,
- const LengthMap &o, const NodeMap &p) :
- G(_G), rev(_rev), ol(o), pot(p){};
- };//ModLengthMap
+ //Auxiliary variables
+ //This is the capacity map for the mincostflow problem
+ ConstMap const1map;
+ //This MinCostFlows instance will actually solve the problem
+ MinCostFlows<Graph, LengthMap, ConstMap> mincost_flow;
-
-
-
- const Graph& G;
- const LengthMap& length;
-
- //auxiliary variables
-
- //The value is 1 iff the edge is reversed.
- //If the algorithm has finished, the edges of the seeked paths are
- //exactly those that are reversed
- EdgeIntMap reversed;
-
//Container to store found paths
std::vector< std::vector<Edge> > paths;
- //typedef DirPath<Graph> DPath;
- //DPath paths;
-
-
- Length total_length;
public :
- MinLengthPaths(Graph& _G, LengthMap& _length) : G(_G),
- length(_length), reversed(_G)/*, dijkstra_dist(_G)*/{ }
+ MinLengthPaths(Graph& _G, LengthMap& _length) : G(_G),
+ const1map(1), mincost_flow(_G, _length, const1map){}
-
///Runs the algorithm.
///Runs the algorithm.
///Returns k if there are at least k edge-disjoint paths from s to t.
- ///Otherwise it returns the number of found edge-disjoint paths from s to t.
+ ///Otherwise it returns the number of found edge-disjoint paths from s to t.
int run(Node s, Node t, int k) {
- ConstMap const1map(1);
+ int i = mincost_flow.run(s,t,k);
+
- //We need a residual graph, in which some of the edges are reversed
- ResGraphType res_graph(G, const1map, reversed);
- //Initialize the copy of the Dijkstra potential to zero
- typename ResGraphType::template NodeMap<Length> dijkstra_dist(res_graph);
- ModLengthMap mod_length(res_graph, reversed, length, dijkstra_dist);
-
- Dijkstra<ResGraphType, ModLengthMap> dijkstra(res_graph, mod_length);
-
- int i;
- for (i=0; i<k; ++i){
- dijkstra.run(s);
- if (!dijkstra.reached(t)){
- //There are no k paths from s to t
- break;
- };
-
- {
- //We have to copy the potential
- typename ResGraphType::NodeIt n;
- for ( res_graph.first(n) ; res_graph.valid(n) ; res_graph.next(n) ) {
- dijkstra_dist[n] += dijkstra.distMap()[n];
- }
- }
-
-
- //Reversing the sortest path
- Node n=t;
- Edge e;
- while (n!=s){
- e = dijkstra.pred(n);
- n = dijkstra.predNode(n);
- reversed[e] = 1-reversed[e];
- }
-
-
- }
-
//Let's find the paths
//We put the paths into stl vectors (as an inner representation).
//In the meantime we lose the information stored in 'reversed'.
//We suppose the lengths to be positive now.
- //Meanwhile we put the total length of the found paths
- //in the member variable total_length
+ //We don't want to change the flow of mincost_flow, so we make a copy
+ //The name here suggests that the flow has only 0/1 values.
+ EdgeIntMap reversed(G);
+
+ FOR_EACH_LOC(typename Graph::EdgeIt, e, G){
+ reversed[e] = mincost_flow.getFlow()[e];
+ }
+
paths.clear();
- total_length=0;
+ //total_length=0;
paths.resize(k);
for (int j=0; j<i; ++j){
Node n=s;
@@ -163,27 +104,48 @@
}
n = G.head(e);
paths[j].push_back(e);
- total_length += length[e];
+ //total_length += length[e];
reversed[e] = 1-reversed[e];
}
}
-
return i;
}
+
///This function gives back the total length of the found paths.
///Assumes that \c run() has been run and nothing changed since then.
Length totalLength(){
- return total_length;
+ return mincost_flow.totalLength();
+ }
+
+ ///Returns a const reference to the EdgeMap \c flow. \pre \ref run() must
+ ///be called before using this function.
+ const EdgeIntMap &getFlow() const { return mincost_flow.flow;}
+
+ ///Returns a const reference to the NodeMap \c potential (the dual solution).
+ /// \pre \ref run() must be called before using this function.
+ const EdgeIntMap &getPotential() const { return mincost_flow.potential;}
+
+ ///This function checks, whether the given solution is optimal
+ ///Running after a \c run() should return with true
+ ///In this "state of the art" this only checks optimality, doesn't bother with feasibility
+ ///
+ ///\todo Is this OK here?
+ bool checkComplementarySlackness(){
+ return mincost_flow.checkComplementarySlackness();
}
///This function gives back the \c j-th path in argument p.
///Assumes that \c run() has been run and nothing changed since then.
- /// \warning It is assumed that \c p is constructed to be a path of graph \c G. If \c j is greater than the result of previous \c run, then the result here will be an empty path.
+ /// \warning It is assumed that \c p is constructed to be a path of graph \c G. If \c j is not less than the result of previous \c run, then the result here will be an empty path (\c j can be 0 as well).
template<typename DirPath>
- void getPath(DirPath& p, int j){
+ void getPath(DirPath& p, size_t j){
+
p.clear();
+ if (j>paths.size()-1){
+ return;
+ }
typename DirPath::Builder B(p);
for(typename std::vector<Edge>::iterator i=paths[j].begin();
i!=paths[j].end(); ++i ){
diff -r 81a0c2f2f7c6 -r 327f7cf13843 src/work/athos/minlengthpaths_test.cc
--- a/src/work/athos/minlengthpaths_test.cc Tue May 11 14:58:09 2004 +0000
+++ b/src/work/athos/minlengthpaths_test.cc Tue May 11 15:42:11 2004 +0000
@@ -69,6 +69,8 @@
check( surb_test.run(s,t,k) == 2 && surb_test.totalLength() == 46,"Two paths, total length should be 46");
+ check( surb_test.checkComplementarySlackness(), "Complementary slackness conditions are not met.");
+
typedef DirPath<ListGraph> DPath;
DPath P(graph);
@@ -80,6 +82,8 @@
k=1;
check( surb_test.run(s,t,k) == 1 && surb_test.totalLength() == 19,"One path, total length should be 19");
+
+ check( surb_test.checkComplementarySlackness(), "Complementary slackness conditions are not met.");
surb_test.getPath(P,0);
check(P.length() == 4, "First path should contain 4 edges.");
diff -r 81a0c2f2f7c6 -r 327f7cf13843 src/work/athos/old/minlengthpaths.h
--- a/src/work/athos/old/minlengthpaths.h Tue May 11 14:58:09 2004 +0000
+++ b/src/work/athos/old/minlengthpaths.h Tue May 11 15:42:11 2004 +0000
@@ -7,10 +7,10 @@
///\brief An algorithm for finding k paths of minimal total length.
#include <iostream>
-#include <dijkstra.h>
-#include <graph_wrapper.h>
-#include <maps.h>
-#include <vector.h>
+#include <hugo/dijkstra.h>
+#include <hugo/graph_wrapper.h>
+#include <hugo/maps.h>
+#include <vector>
namespace hugo {
diff -r 81a0c2f2f7c6 -r 327f7cf13843 src/work/klao/path.h
--- a/src/work/klao/path.h Tue May 11 14:58:09 2004 +0000
+++ b/src/work/klao/path.h Tue May 11 15:42:11 2004 +0000
@@ -11,8 +11,8 @@
#include <vector>
#include <algorithm>
-#include <invalid.h>
-#include <error.h>
+#include <hugo/invalid.h>
+#include <hugo/error.h>
#include <debug.h>
namespace hugo {