ENH: add a method to export centroids in a text file

Modules/Applications/AppClassification/include/otbTrainSharkKMeans.hxx

@@ -48,7 +48,7 @@ void LearningApplicationBase<TInputValue, TOutputValue>::InitSharkKMeansParams()
   SetMinimumParameterIntValue("classifier.sharkkm.k", 2);
 
   // Input centroids
-  AddParameter(ParameterType_InputFilename, "classifier.sharkkm.centroids", "input centroids");
+  AddParameter(ParameterType_InputFilename, "classifier.sharkkm.centroids", "User definied input centroids");
   SetParameterDescription("classifier.sharkkm.centroids", "Text file containing input centroids.");
   MandatoryOff("classifier.sharkkm.centroids");
 
@@ -58,6 +58,11 @@ void LearningApplicationBase<TInputValue, TOutputValue>::InitSharkKMeansParams()
     "and reduce the centroids before the KMeans algorithm, produced by ComputeImagesStatistics application.");
   MandatoryOff("classifier.sharkkm.centroidstats");
   
+  // output centroids
+  AddParameter(ParameterType_OutputFilename, "classifier.sharkkm.outcentroids", "Output centroids text file");
+  SetParameterDescription("classifier.sharkkm.outcentroids", "Output text file containing centroids after the kmean algorithm.");
+  MandatoryOff("classifier.sharkkm.outcentroids");
+  
 }
 
 template<class TInputValue, class TOutputValue>
@@ -109,6 +114,9 @@ void LearningApplicationBase<TInputValue, TOutputValue>::TrainSharkKMeans(
   classifier->SetMaximumNumberOfIterations( nbMaxIter );
   classifier->Train();
   classifier->Save( modelPath );
+  
+  if( HasValue( "classifier.sharkkm.outcentroids"))
+    classifier->ExportCentroids( GetParameterString( "classifier.sharkkm.outcentroids" ));
 }
 
 } //end namespace wrapper

Modules/Learning/Unsupervised/include/otbSharkKMeansMachineLearningModel.h

@@ -131,6 +131,8 @@ public:
     this->Modified();
   }
   
+  void ExportCentroids(const std::string & filename);
+  
 protected:
   /** Constructor */
   SharkKMeansMachineLearningModel();

Modules/Learning/Unsupervised/include/otbSharkKMeansMachineLearningModel.hxx

@@ -241,6 +241,14 @@ SharkKMeansMachineLearningModel<TInputValue, TOutputValue>
   return true;
 }
 
+template<class TInputValue, class TOutputValue>
+void
+SharkKMeansMachineLearningModel<TInputValue, TOutputValue>
+::ExportCentroids(const std::string & filename)
+{
+  shark::exportCSV(m_Centroids.centroids(), filename, ' ');
+}
+
 template<class TInputValue, class TOutputValue>
 void
 SharkKMeansMachineLearningModel<TInputValue, TOutputValue>