TEST: add test for shark relabelling function

Modules/Learning/LearningBase/otb-module.cmake

@@ -28,7 +28,10 @@ otb_module(OTBLearningBase
     OTBImageBase
     OTBITK
 
-  TEST_DEPENDS
+    OPTIONAL_DEPENDS
+    OTBShark
+
+    TEST_DEPENDS
     OTBTestKernel
     OTBImageIO
 

Modules/Learning/LearningBase/test/CMakeLists.txt

@@ -30,9 +30,12 @@ otbSEMClassifierNew.cxx
 otbDecisionTreeNew.cxx
 otbKMeansImageClassificationFilterNew.cxx
 otbMachineLearningModelTemplates.cxx
-otbSharkUtilsTests.cxx
 )
 
+if(OTB_USE_SHARK)
+  set(OTBLearningBaseTests ${OTBLearningBaseTests} otbSharkUtilsTests.cxx)
+endif()
+
 add_executable(otbLearningBaseTestDriver ${OTBLearningBaseTests})
 target_link_libraries(otbLearningBaseTestDriver ${OTBLearningBase-Test_LIBRARIES})
 otb_module_target_label(otbLearningBaseTestDriver)
@@ -69,5 +72,7 @@ otb_add_test(NAME leTuDecisionTreeNew COMMAND otbLearningBaseTestDriver
 otb_add_test(NAME leTuKMeansImageClassificationFilterNew COMMAND otbLearningBaseTestDriver
   otbKMeansImageClassificationFilterNew)
 
-otb_add_test(NAME leTuSharkNormalizeLabels COMMAND otbLearningBaseTestDriver 
-  otbSharkNormalizeLabels)
+if(OTB_USE_SHARK)
+  otb_add_test(NAME leTuSharkNormalizeLabels COMMAND otbLearningBaseTestDriver
+    otbSharkNormalizeLabels)
+endif()

Modules/Learning/LearningBase/test/otbLearningBaseTestDriver.cxx

@@ -29,5 +29,7 @@ void RegisterTests()
   REGISTER_TEST(otbSEMClassifierNew);
   REGISTER_TEST(otbDecisionTreeNew);
   REGISTER_TEST(otbKMeansImageClassificationFilterNew);
+#ifdef OTB_USE_SHARK
   REGISTER_TEST(otbSharkNormalizeLabels);
+#endif
 }

Modules/ThirdParty/Shark/include/otbSharkUtils.h

@@ -23,6 +23,7 @@
 
 #include <stdexcept>
 #include <string>
+#include <unordered_map>
 
 #if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic push
@@ -127,6 +128,27 @@ template <class T> void ListSampleToSharkVector(const T * listSample, std::vecto
   assert(listSample != nullptr);
   ListSampleRangeToSharkVector(listSample,output,0, static_cast<unsigned int>(listSample->Size()));
 }
+
+/** Shark assumes that labels are 0 ... (nbClasses-1). This function modifies the labels contained in the input vector and returns a vector with size = nbClasses which allows the translation from the normalised labels to the new ones oldLabel = dictionary[newLabel].
+*/
+template <typename T> void NormalizeLabelsAndGetDictionary(std::vector<T>& labels, 
+                                                           std::vector<T>& dictionary)
+{
+  std::unordered_map<T, T> dictMap;
+  T labelCount{0};
+  for(const auto& l : labels)
+    {
+    if(dictMap.find(l)==dictMap.end())
+      dictMap.insert({l, labelCount++});
+    }
+  dictionary.resize(labelCount);
+  for(auto& l : labels)
+    {
+    auto newLabel = dictMap[l];
+    dictionary[newLabel] = l;
+    l = newLabel;
+    }
+}
   
 }
 }