From f527cde6342c5b8109a20f0a6b483327c6569844 Mon Sep 17 00:00:00 2001
From: salinasd <salinasd@636b058d-ea47-450e-bf9e-a15bfbe3eedb>
Date: Tue, 27 Jan 2015 10:20:13 +0000
Subject: Merge GudhUI, a UI for gudhi based on Qt

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/trunk@427 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: 17fedd974f14a8225b27d94361e835964eeb5cba
---
 src/GudhUI/utils/Lloyd_builder.h | 78 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 src/GudhUI/utils/Lloyd_builder.h

(limited to 'src/GudhUI/utils/Lloyd_builder.h')

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_ */
-- 
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