4 files changed, 163 insertions, 0 deletions
diff --git a/src/Alpha_complex/example/Alpha_complex_from_off.cpp b/src/Alpha_complex/example/Alpha_complex_from_off.cpp
new file mode 100644
index 00000000..e140fe3d
--- /dev/null
+++ b/src/Alpha_complex/example/Alpha_complex_from_off.cpp
@@ -0,0 +1,48 @@
+#include <iostream>
+#include <string>
+
+// to construct a Delaunay_triangulation from a OFF file
+#include <gudhi/Delaunay_triangulation_off_io.h>
+#include <gudhi/Alpha_complex.h>
+
+void usage(char * const progName) {
+  std::cerr << "Usage: " << progName << " filename.off alpha_square_max_value" << std::endl;
+  std::cerr << "       i.e.: " << progName << " ../../data/points/alphacomplexdoc.off 60.0" << std::endl;
+  exit(-1); // ----- >>
+}
+
+int main(int argc, char **argv) {
+  if (argc != 3) {
+    std::cerr << "Error: Number of arguments (" << argc << ") is not correct" << std::endl;
+    usage(argv[0]);
+  }
+
+  std::string off_file_name(argv[1]);
+  double alpha_square_max_value = atof(argv[2]);
+
+  // ----------------------------------------------------------------------------
+  // Init of an alpha complex from an OFF file
+  // ----------------------------------------------------------------------------
+  typedef CGAL::Epick_d< CGAL::Dynamic_dimension_tag > Kernel;
+  Gudhi::alphacomplex::Alpha_complex<Kernel> alpha_complex_from_file(off_file_name, alpha_square_max_value);
+
+  // ----------------------------------------------------------------------------
+  // Display information about the alpha complex
+  // ----------------------------------------------------------------------------
+  std::cout << "Alpha complex is of dimension " << alpha_complex_from_file.dimension() <<
+      " - " << alpha_complex_from_file.num_simplices() << " simplices - " <<
+      alpha_complex_from_file.num_vertices() << " vertices." << std::endl;
+
+  std::cout << "Iterator on alpha complex simplices in the filtration order, with [filtration value]:" << std::endl;
+  for (auto f_simplex : alpha_complex_from_file.filtration_simplex_range()) {
+    if (alpha_complex_from_file.filtration(f_simplex) <= alpha_complex_from_file.filtration()) {
+      std::cout << "   ( ";
+      for (auto vertex : alpha_complex_from_file.simplex_vertex_range(f_simplex)) {
+        std::cout << vertex << " ";
+      }
+      std::cout << ") -> " << "[" << alpha_complex_from_file.filtration(f_simplex) << "] ";
+      std::cout << std::endl;
+    }
+  }
+  return 0;
+}
diff --git a/src/Alpha_complex/example/Alpha_complex_from_points.cpp b/src/Alpha_complex/example/Alpha_complex_from_points.cpp
new file mode 100644
index 00000000..b160d702
--- /dev/null
+++ b/src/Alpha_complex/example/Alpha_complex_from_points.cpp
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <CGAL/Delaunay_triangulation.h>
+#include <CGAL/Epick_d.h>
+
+#include <string>
+#include <vector>
+
+// to construct a Delaunay_triangulation from a OFF file
+#include "gudhi/Delaunay_triangulation_off_io.h"
+#include "gudhi/Alpha_complex.h"
+
+typedef CGAL::Epick_d< CGAL::Dynamic_dimension_tag > Kernel;
+typedef Kernel::Point_d Point;
+typedef std::vector<Point> Vector_of_points;
+
+int main(int argc, char **argv) {
+  // ----------------------------------------------------------------------------
+  // Init of a list of points
+  // ----------------------------------------------------------------------------
+  Vector_of_points points;
+
+  std::vector<double> coords = { 0.0, 0.0, 0.0, 1.0 };
+  points.push_back(Point(coords.begin(), coords.end()));
+  coords = { 0.0, 0.0, 1.0, 0.0 };
+  points.push_back(Point(coords.begin(), coords.end()));
+  coords = { 0.0, 1.0, 0.0, 0.0 };
+  points.push_back(Point(coords.begin(), coords.end()));
+  coords = { 1.0, 0.0, 0.0, 0.0 };
+  points.push_back(Point(coords.begin(), coords.end()));
+
+  // ----------------------------------------------------------------------------
+  // Init of an alpha complex from the list of points
+  // ----------------------------------------------------------------------------
+  double max_alpha_square_value = 1e10;
+  Gudhi::alphacomplex::Alpha_complex<Kernel> alpha_complex_from_points(3, points.size(), points.begin(), points.end(),
+                                                                       max_alpha_square_value);
+
+  // ----------------------------------------------------------------------------
+  // Display information about the alpha complex
+  // ----------------------------------------------------------------------------
+  std::cout << "Alpha complex is of dimension " << alpha_complex_from_points.dimension() <<
+      " - " << alpha_complex_from_points.num_simplices() << " simplices - " <<
+      alpha_complex_from_points.num_vertices() << " vertices." << std::endl;
+
+  std::cout << "Iterator on alpha complex simplices in the filtration order, with [filtration value]:" << std::endl;
+  for (auto f_simplex : alpha_complex_from_points.filtration_simplex_range()) {
+    std::cout << "   ( ";
+    for (auto vertex : alpha_complex_from_points.simplex_vertex_range(f_simplex)) {
+      std::cout << vertex << " ";
+    }
+    std::cout << ") -> " << "[" << alpha_complex_from_points.filtration(f_simplex) << "] ";
+    std::cout << std::endl;
+  }
+  return 0;
+}
diff --git a/src/Alpha_complex/example/CMakeLists.txt b/src/Alpha_complex/example/CMakeLists.txt
new file mode 100644
index 00000000..04fc34af
--- /dev/null
+++ b/src/Alpha_complex/example/CMakeLists.txt
@@ -0,0 +1,32 @@
+cmake_minimum_required(VERSION 2.6)
+project(GUDHIAlphaShapesExample)
+
+# need CGAL 4.7
+# cmake -DCGAL_DIR=~/workspace/CGAL-4.7-Ic-41 ../../..
+if(CGAL_FOUND)
+  if (NOT CGAL_VERSION VERSION_LESS 4.7.0)
+    message(STATUS "CGAL version: ${CGAL_VERSION}.")
+
+    include( ${CGAL_USE_FILE} )
+ 
+    find_package(Eigen3 3.1.0)
+    if (EIGEN3_FOUND)
+      message(STATUS "Eigen3 version: ${EIGEN3_VERSION}.")
+      include( ${EIGEN3_USE_FILE} )
+      if (CMAKE_BUILD_TYPE MATCHES Debug)
+        # For programs to be more verbose
+        add_definitions(-DDEBUG_TRACES)
+      endif()
+      
+      add_executable ( alphaoffreader Alpha_complex_from_off.cpp )
+      target_link_libraries(alphaoffreader  ${Boost_SYSTEM_LIBRARY} ${CGAL_LIBRARY})
+
+      add_executable ( alphapoints Alpha_complex_from_points.cpp )
+      target_link_libraries(alphapoints  ${Boost_SYSTEM_LIBRARY} ${CGAL_LIBRARY})
+    else()
+      message(WARNING "Eigen3 not found. Version 3.1.0 is required for Alpha shapes feature.")
+    endif()
+  else()
+    message(WARNING "CGAL version: ${CGAL_VERSION} is too old to compile Alpha shapes feature. Version 4.6.0 is required.")
+  endif ()
+endif()
diff --git a/src/Alpha_complex/example/alphaoffreader_for_doc.txt b/src/Alpha_complex/example/alphaoffreader_for_doc.txt
new file mode 100644
index 00000000..71f29a00
--- /dev/null
+++ b/src/Alpha_complex/example/alphaoffreader_for_doc.txt
@@ -0,0 +1,27 @@
+Alpha complex is of dimension 2 - 25 simplices - 7 vertices.
+Iterator on alpha complex simplices in the filtration order, with [filtration value]:
+   ( 0 ) -> [0] 
+   ( 1 ) -> [0] 
+   ( 2 ) -> [0] 
+   ( 3 ) -> [0] 
+   ( 4 ) -> [0] 
+   ( 5 ) -> [0] 
+   ( 6 ) -> [0] 
+   ( 3 2 ) -> [6.25] 
+   ( 5 4 ) -> [7.25] 
+   ( 2 0 ) -> [8.5] 
+   ( 1 0 ) -> [9.25] 
+   ( 3 1 ) -> [10] 
+   ( 2 1 ) -> [11.25] 
+   ( 3 2 1 ) -> [12.5] 
+   ( 2 1 0 ) -> [12.9959] 
+   ( 6 5 ) -> [13.25] 
+   ( 4 2 ) -> [20] 
+   ( 6 4 ) -> [22.7367] 
+   ( 6 5 4 ) -> [22.7367] 
+   ( 6 3 ) -> [30.25] 
+   ( 6 2 ) -> [36.5] 
+   ( 6 3 2 ) -> [36.5] 
+   ( 6 4 2 ) -> [37.2449] 
+   ( 4 0 ) -> [59.7107] 
+   ( 4 2 0 ) -> [59.7107]