3 files changed, 64 insertions, 11 deletions

diff --git a/src/common/include/gudhi/Debug_utils.h b/src/common/include/gudhi/Debug_utils.h
index 8ed3b7b3..90d3cf47 100644
--- a/src/common/include/gudhi/Debug_utils.h
+++ b/src/common/include/gudhi/Debug_utils.h
@@ -4,7 +4,7 @@
  *
  *    Author(s):       David Salinas
  *
- *    Copyright (C) 2014  INRIA Sophia Antipolis-Mediterranee (France)
+ *    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
@@ -32,7 +32,7 @@
 // GUDHI_CHECK throw an exception if expression is false in debug mode, but does nothing in release mode
 // Could assert in release mode, but cmake sets NDEBUG (for "NO DEBUG") in this mode, means assert does nothing.
 #ifdef GUDHI_DEBUG
-  #define GUDHI_CHECK(expression, excpt) if ((expression) == 0) throw excpt
+  #define GUDHI_CHECK(expression, excpt) ((expression) ? (void) 0 : (throw excpt))
   #define GUDHI_CHECK_code(CODE) CODE
 #else
   #define GUDHI_CHECK(expression, excpt) (void) 0
diff --git a/src/common/include/gudhi/Unitary_tests_utils.h b/src/common/include/gudhi/Unitary_tests_utils.h
new file mode 100644
index 00000000..8394a062
--- /dev/null
+++ b/src/common/include/gudhi/Unitary_tests_utils.h
@@ -0,0 +1,40 @@
+/*    This file is part of the Gudhi Library. The Gudhi library
+ *    (Geometric Understanding in Higher Dimensions) is a generic C++
+ *    library for computational topology.
+ *
+ *    Author(s):       Vincent Rouvreau
+ *
+ *    Copyright (C) 2017  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
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef UNITARY_TESTS_UTILS_H_
+#define UNITARY_TESTS_UTILS_H_
+
+#include <boost/test/unit_test.hpp>
+
+#include <iostream>
+#include <limits>  // for std::numeric_limits<>
+
+template<typename FloatingType >
+void GUDHI_TEST_FLOAT_EQUALITY_CHECK(FloatingType a, FloatingType b,
+                                     FloatingType epsilon = std::numeric_limits<FloatingType>::epsilon()) {
+#ifdef DEBUG_TRACES
+  std::cout << "GUDHI_TEST_FLOAT_EQUALITY_CHECK - " << a << " versus " << b
+            << " | diff = " << std::fabs(a - b) << " - epsilon = " << epsilon << std::endl;
+#endif
+  BOOST_CHECK(std::fabs(a - b) < epsilon);
+}
+
+#endif  // UNITARY_TESTS_UTILS_H_
diff --git a/src/common/include/gudhi/distance_functions.h b/src/common/include/gudhi/distance_functions.h
index c556155e..3a5d1fd5 100644
--- a/src/common/include/gudhi/distance_functions.h
+++ b/src/common/include/gudhi/distance_functions.h
@@ -23,6 +23,10 @@
 #ifndef DISTANCE_FUNCTIONS_H_
 #define DISTANCE_FUNCTIONS_H_
 
+#include <gudhi/Debug_utils.h>
+
+#include <boost/range/metafunctions.hpp>
+
 #include <cmath>  // for std::sqrt
 #include <type_traits>  // for std::decay
 #include <iterator>  // for std::begin, std::end
@@ -38,20 +42,29 @@ namespace Gudhi {
  * have the same dimension. */
 class Euclidean_distance {
  public:
+  // boost::range_value is not SFINAE-friendly so we cannot use it in the return type
   template< typename Point >
-  auto operator()(const Point& p1, const Point& p2) const -> typename std::decay<decltype(*std::begin(p1))>::type {
-    auto it1 = p1.begin();
-    auto it2 = p2.begin();
-    typename Point::value_type dist = 0.;
-    for (; it1 != p1.end(); ++it1, ++it2) {
-      typename Point::value_type tmp = (*it1) - (*it2);
+  typename std::iterator_traits<typename boost::range_iterator<Point>::type>::value_type
+  operator()(const Point& p1, const Point& p2) const {
+    auto it1 = std::begin(p1);
+    auto it2 = std::begin(p2);
+    typedef typename boost::range_value<Point>::type NT;
+    NT dist = 0;
+    for (; it1 != std::end(p1); ++it1, ++it2) {
+      GUDHI_CHECK(it2 != std::end(p2), "inconsistent point dimensions");
+      NT tmp = *it1 - *it2;
       dist += tmp*tmp;
     }
-    return std::sqrt(dist);
+    GUDHI_CHECK(it2 == std::end(p2), "inconsistent point dimensions");
+    using std::sqrt;
+    return sqrt(dist);
   }
   template< typename T >
-  T operator() (const std::pair< T, T >& f, const std::pair< T, T >& s) {
-    return  sqrt((f.first-s.first)*(f.first-s.first) + (f.second-s.second)*(f.second-s.second));
+  T operator() (const std::pair< T, T >& f, const std::pair< T, T >& s) const {
+    T dx = f.first - s.first;
+    T dy = f.second - s.second;
+    using std::sqrt;
+    return sqrt(dx*dx + dy*dy);
   }
 };