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/*
* Rips_contraction.cpp
*
* Created on: Nov 28, 2014
* Author: dsalinas
*/
#include <list>
#include <boost/timer/timer.hpp>
#include <iostream>
#include "gudhi/Edge_contraction.h"
#include "gudhi/Skeleton_blocker.h"
#include "gudhi/Off_reader.h"
using namespace std;
using namespace Gudhi;
using namespace skbl;
using namespace contraction;
struct Geometry_trait{
typedef std::vector<double> Point;
};
typedef Geometry_trait::Point Point;
typedef Skeleton_blocker_simple_geometric_traits<Geometry_trait> Complex_geometric_traits;
typedef Skeleton_blocker_geometric_complex< Complex_geometric_traits > Complex;
typedef Edge_profile<Complex> Profile;
typedef Skeleton_blocker_contractor<Complex> Complex_contractor;
template<typename Point>
double eucl_distance(const Point& a,const Point& b){
double res = 0;
auto a_coord = a.begin();
auto b_coord = b.begin();
for(; a_coord != a.end(); a_coord++, b_coord++){
res += (*a_coord - *b_coord) * (*a_coord - *b_coord);
}
return sqrt(res);
}
template<typename ComplexType>
void build_rips(ComplexType& complex, double offset){
if (offset<=0) return;
auto vertices = complex.vertex_range();
for (auto p = vertices.begin(); p != vertices.end(); ++p)
for (auto q = p; ++q != vertices.end(); /**/)
if (eucl_distance(complex.point(*p), complex.point(*q)) < 2 * offset)
complex.add_edge(*p,*q);
}
void test_contraction_rips(string name_file, double offset){
boost::timer::auto_cpu_timer t;
Complex complex;
// load the points
Skeleton_blocker_off_reader<Complex> off_reader(name_file,complex,true);
if(!off_reader.is_valid()){
std::cerr << "Unable to read file:"<<name_file<<std::endl;
return;
}
std::cerr << "build the Rips complex"<<std::endl;
build_rips(complex,offset);
std::cerr << "Initial complex has "<<
complex.num_vertices()<<" vertices, and "<<
complex.num_edges()<<" edges."<<std::endl;
Complex_contractor contractor(complex,
new Edge_length_cost<Profile>, //todo make_edge_length_cost
contraction::make_first_vertex_placement<Profile>(),
contraction::make_link_valid_contraction<Profile>(),
contraction::make_remove_popable_blockers_visitor<Profile>());
contractor.contract_edges();
std::cerr << "Resulting complex has "<<
complex.num_vertices()<<" vertices, "<<
complex.num_edges()<<"edges and "<<
complex.num_blockers()<<" blockers"<<std::endl;
}
int main (int argc, char *argv[])
{
if (argc!=3){
std::cerr << "Usage "<<argv[0]<<" GUDHIPATH/src/data/sphere3D.off 0.1 to load the file GUDHIPATH/src/data/sphere3D.off and contract the Rips complex built with paremeter 0.2.\n";
return -1;
}
std::string name_file(argv[1]);
test_contraction_rips(name_file,atof(argv[2]));
}
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