};
+
+/*
+ * Depending on processed distances, some of them are already squared (e.g. L2)
+ * and some are not (e.g.Hamming). In KMeans++ for instance we want to be sure
+ * we are working on ^2 distances, thus following templates to ensure that.
+ */
+template <typename Distance, typename ElementType>
+struct squareDistance
+{
+ typedef typename Distance::ResultType ResultType;
+ ResultType operator()( ResultType dist ) { return dist*dist; }
+};
+
+
+template <typename ElementType>
+struct squareDistance<L2_Simple<ElementType>, ElementType>
+{
+ typedef typename L2_Simple<ElementType>::ResultType ResultType;
+ ResultType operator()( ResultType dist ) { return dist; }
+};
+
+template <typename ElementType>
+struct squareDistance<L2<ElementType>, ElementType>
+{
+ typedef typename L2<ElementType>::ResultType ResultType;
+ ResultType operator()( ResultType dist ) { return dist; }
+};
+
+
+template <typename ElementType>
+struct squareDistance<MinkowskiDistance<ElementType>, ElementType>
+{
+ typedef typename MinkowskiDistance<ElementType>::ResultType ResultType;
+ ResultType operator()( ResultType dist ) { return dist; }
+};
+
+template <typename ElementType>
+struct squareDistance<HellingerDistance<ElementType>, ElementType>
+{
+ typedef typename HellingerDistance<ElementType>::ResultType ResultType;
+ ResultType operator()( ResultType dist ) { return dist; }
+};
+
+template <typename ElementType>
+struct squareDistance<ChiSquareDistance<ElementType>, ElementType>
+{
+ typedef typename ChiSquareDistance<ElementType>::ResultType ResultType;
+ ResultType operator()( ResultType dist ) { return dist; }
+};
+
+
+template <typename Distance>
+typename Distance::ResultType ensureSquareDistance( typename Distance::ResultType dist )
+{
+ typedef typename Distance::ElementType ElementType;
+
+ squareDistance<Distance, ElementType> dummy;
+ return dummy( dist );
+}
+
}
#endif //OPENCV_FLANN_DIST_H_
// far from previous centers (and this complies to "k-means++: the advantages of careful seeding" article)
for (int i = 0; i < n; i++) {
closestDistSq[i] = distance(dataset[dsindices[i]], dataset[dsindices[index]], dataset.cols);
- closestDistSq[i] *= closestDistSq[i];
+ closestDistSq[i] = ensureSquareDistance<Distance>( closestDistSq[i] );
currentPot += closestDistSq[i];
}
double newPot = 0;
for (int i = 0; i < n; i++) {
DistanceType dist = distance(dataset[dsindices[i]], dataset[dsindices[index]], dataset.cols);
- newPot += std::min( dist*dist, closestDistSq[i] );
+ newPot += std::min( ensureSquareDistance<Distance>(dist), closestDistSq[i] );
}
// Store the best result
currentPot = bestNewPot;
for (int i = 0; i < n; i++) {
DistanceType dist = distance(dataset[dsindices[i]], dataset[dsindices[bestNewIndex]], dataset.cols);
- closestDistSq[i] = std::min( dist*dist, closestDistSq[i] );
+ closestDistSq[i] = std::min( ensureSquareDistance<Distance>(dist), closestDistSq[i] );
}
}
namespace cvflann
{
-template <typename Distance, typename ElementType>
-struct squareDistance
-{
- typedef typename Distance::ResultType ResultType;
- ResultType operator()( ResultType dist ) { return dist*dist; }
-};
-
-
-template <typename ElementType>
-struct squareDistance<L2_Simple<ElementType>, ElementType>
-{
- typedef typename L2_Simple<ElementType>::ResultType ResultType;
- ResultType operator()( ResultType dist ) { return dist; }
-};
-
-template <typename ElementType>
-struct squareDistance<L2<ElementType>, ElementType>
-{
- typedef typename L2<ElementType>::ResultType ResultType;
- ResultType operator()( ResultType dist ) { return dist; }
-};
-
-
-template <typename ElementType>
-struct squareDistance<MinkowskiDistance<ElementType>, ElementType>
-{
- typedef typename MinkowskiDistance<ElementType>::ResultType ResultType;
- ResultType operator()( ResultType dist ) { return dist; }
-};
-
-template <typename ElementType>
-struct squareDistance<HellingerDistance<ElementType>, ElementType>
-{
- typedef typename HellingerDistance<ElementType>::ResultType ResultType;
- ResultType operator()( ResultType dist ) { return dist; }
-};
-
-template <typename ElementType>
-struct squareDistance<ChiSquareDistance<ElementType>, ElementType>
-{
- typedef typename ChiSquareDistance<ElementType>::ResultType ResultType;
- ResultType operator()( ResultType dist ) { return dist; }
-};
-
-
-template <typename Distance>
-typename Distance::ResultType ensureSquareDistance( typename Distance::ResultType dist )
-{
- typedef typename Distance::ElementType ElementType;
-
- squareDistance<Distance, ElementType> dummy;
- return dummy( dist );
-}
-
-
-
struct KMeansIndexParams : public IndexParams
{
KMeansIndexParams(int branching = 32, int iterations = 11,