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Diffstat (limited to 'src/GudhUI/utils/Lloyd_builder.h')
-rw-r--r-- | src/GudhUI/utils/Lloyd_builder.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/src/GudhUI/utils/Lloyd_builder.h b/src/GudhUI/utils/Lloyd_builder.h new file mode 100644 index 00000000..db2a7973 --- /dev/null +++ b/src/GudhUI/utils/Lloyd_builder.h @@ -0,0 +1,78 @@ +/* + * Lloyd.h + * + * Created on: Sep 25, 2014 + * Author: dsalinas + */ + +#ifndef LLOYD_H_ +#define LLOYD_H_ + + +#include <vector> + +/** + * Iteratively puts every vertex at the center of its neighbors + */ +template<typename SkBlComplex> class Lloyd_builder{ +private: + SkBlComplex& complex_; + int dim; +public: + typedef typename SkBlComplex::Vertex_handle Vertex_handle; + /** + * @brief Modify complex to be the expansion of the k-nearest neighbor + * symetric graph. + */ + Lloyd_builder(SkBlComplex& complex,unsigned num_iterations):complex_(complex),dim(-1){ + if(!complex_.empty()){ + dim = get_dimension(); + while(num_iterations--){ + std::list<Point> new_points; + for(auto v : complex.vertex_range()) + new_points.push_back(barycenter_neighbors(v)); + + auto new_points_it = new_points.begin(); + for(auto v : complex.vertex_range()) + complex_.point(v) = *(new_points_it++); + } + } + } + +private: + + int get_dimension(){ + assert(!complex_.empty()); + for(auto v : complex_.vertex_range()) + return complex_.point(v).dimension(); + return -1; + } + + Point barycenter_neighbors(Vertex_handle v) const{ + if(complex_.degree(v)==0) + return complex_.point(v); + + std::vector<double> res(dim,0); + unsigned num_points = 0; + for(auto nv : complex_.vertex_range(v)){ + ++num_points; + const Point& point = complex_.point(nv); + assert(point.dimension() == dim); + for(int i = 0; i < point.dimension() ; ++i) + res[i] += point[i]; + } + for(auto& x : res) + x/= num_points; + return Point(dim,res.begin(),res.end()); + } + + + + double squared_eucl_distance(const Point& p1,const Point& p2) const{ + return Geometry_trait::Squared_distance_d()(p1,p2); + } + +}; + + +#endif /* LLOYD_H_ */ |