1 files changed, 51 insertions, 1 deletions
diff --git a/include/gudhi/distance_functions.h b/include/gudhi/distance_functions.h
index 3a5d1fd5..5ef12f2e 100644
--- a/include/gudhi/distance_functions.h
+++ b/include/gudhi/distance_functions.h
@@ -4,7 +4,7 @@
  *
  *    Author(s):       Clément Maria
  *
- *    Copyright (C) 2014  INRIA
+ *    Copyright (C) 2014 Inria
  *
  *    This program is free software: you can redistribute it and/or modify
  *    it under the terms of the GNU General Public License as published by
@@ -25,7 +25,10 @@
 
 #include <gudhi/Debug_utils.h>
 
+#include <gudhi/Miniball.hpp>
+
 #include <boost/range/metafunctions.hpp>
+#include <boost/range/size.hpp>
 
 #include <cmath>  // for std::sqrt
 #include <type_traits>  // for std::decay
@@ -68,6 +71,53 @@ class Euclidean_distance {
   }
 };
 
+/** @brief Compute the radius of the minimal enclosing ball between Points given by a range of coordinates.
+ * The points are assumed to have the same dimension. */
+class Minimal_enclosing_ball_radius {
+ public:
+  /** \brief Minimal_enclosing_ball_radius from two points.
+   *
+   * @param[in] point_1 First point.
+   * @param[in] point_2 second point.
+   * @return The minimal enclosing ball radius for the two points (aka. Euclidean distance / 2.).
+   *
+   * \tparam Point must be a range of Cartesian coordinates.
+   *
+   */
+  template< typename Point >
+  typename std::iterator_traits<typename boost::range_iterator<Point>::type>::value_type
+  operator()(const Point& point_1, const Point& point_2) const {
+    return Euclidean_distance()(point_1, point_2) / 2.;
+  }
+  /** \brief Minimal_enclosing_ball_radius from a point cloud.
+   *
+   * @param[in] point_cloud The points.
+   * @return The minimal enclosing ball radius for the points.
+   *
+   * \tparam Point_cloud must be a range of points with Cartesian coordinates.
+   * Point_cloud is a range over a range of Coordinate.
+   *
+   */
+  template< typename Point_cloud,
+            typename Point_iterator = typename boost::range_const_iterator<Point_cloud>::type,
+            typename Point = typename std::iterator_traits<Point_iterator>::value_type,
+            typename Coordinate_iterator = typename boost::range_const_iterator<Point>::type,
+            typename Coordinate = typename std::iterator_traits<Coordinate_iterator>::value_type>
+  Coordinate
+  operator()(const Point_cloud& point_cloud) const {
+    using Min_sphere = Miniball::Miniball<Miniball::CoordAccessor<Point_iterator, Coordinate_iterator>>;
+
+    Min_sphere ms(boost::size(*point_cloud.begin()), point_cloud.begin(), point_cloud.end());
+#ifdef DEBUG_TRACES
+    std::cout << "Minimal_enclosing_ball_radius = " << std::sqrt(ms.squared_radius()) << " | nb points = "
+              << boost::size(point_cloud) << " | dimension = "
+              << boost::size(*point_cloud.begin()) << std::endl;
+#endif  // DEBUG_TRACES
+
+    return std::sqrt(ms.squared_radius());
+  }
+};
+
 }  // namespace Gudhi
 
 #endif  // DISTANCE_FUNCTIONS_H_