NUP-2504: fix clang link optimization issue on private template function

src/nupic/algorithms/SDRClassifier.cpp

@@ -230,15 +230,14 @@ vector<Real64> SDRClassifier::calculateError_(const vector<UInt> &bucketIdxList,
   return likelihoods;
 }
 
-template <typename Iterator>
-void SDRClassifier::softmax_(Iterator begin, Iterator end) {
-  Iterator maxItr = max_element(begin, end);
+void SDRClassifier::softmax_(vector<Real64>::iterator begin,
+                             vector<Real64>::iterator end) {
+  vector<Real64>::iterator maxItr = max_element(begin, end);
   for (auto itr = begin; itr != end; ++itr) {
     *itr -= *maxItr;
   }
   range_exp(1.0, begin, end);
-  typename std::iterator_traits<Iterator>::value_type sum =
-      accumulate(begin, end, 0.0);
+  Real64 sum = accumulate(begin, end, 0.0);
   for (auto itr = begin; itr != end; ++itr) {
     *itr /= sum;
   }

src/nupic/algorithms/SDRClassifier.hpp

@@ -168,7 +168,7 @@ class SDRClassifier : public Serializable<SdrClassifierProto> {
                                  const vector<UInt> patternNZ, UInt step);
 
   // softmax function
-  template <typename Iterator> void softmax_(Iterator begin, Iterator end);
+  void softmax_(vector<Real64>::iterator begin, vector<Real64>::iterator end);
 
   // The list of prediction steps to learn and infer.
   vector<UInt> steps_;

src/test/unit/algorithms/SDRClassifierTest.cpp

@@ -432,9 +432,9 @@ TEST_F(SDRClassifierTest, WriteRead) {
 
 TEST_F(SDRClassifierTest, testSoftmaxOverflow) {
   SDRClassifier c = SDRClassifier({1}, 0.5, 0.5, 0);
-  std::vector<double> values = {numeric_limits<double>::max()};
+  std::vector<Real64> values = {numeric_limits<Real64>::max()};
   softmax_(&c, values.begin(), values.end());
-  double result = values[0];
+  Real64 result = values[0];
   ASSERT_FALSE(std::isnan(result));
 }