[ML] Rename outlier detection method values (#598)

Closes #597

Author: dimitris-athanasiou

docs/CHANGELOG.asciidoc

@@ -28,6 +28,13 @@
 
 //=== Regressions
 
+== {es} version 7.4.0
+
+=== Bug Fixes
+
+* Rename outlier detection method values knn and tnn to distance_kth_nn and distance_knn
+respectively to match the API. (See {ml-pull}598[#598].)
+
 == {es} version 7.3.1
 
 === Bug Fixes

lib/api/CDataFrameOutliersRunner.cc

@@ -37,8 +37,8 @@ const std::string OUTLIER_FRACTION{"outlier_fraction"};
 const CDataFrameAnalysisConfigReader PARAMETER_READER{[] {
     const std::string lof{"lof"};
     const std::string ldof{"ldof"};
-    const std::string knn{"knn"};
-    const std::string tnn{"tnn"};
+    const std::string knn{"distance_kth_nn"};
+    const std::string tnn{"distance_knn"};
     CDataFrameAnalysisConfigReader theReader;
     theReader.addParameter(STANDARDIZE_COLUMNS,
                            CDataFrameAnalysisConfigReader::E_OptionalParameter);

lib/api/unittest/CDataFrameAnalyzerTest.cc

@@ -464,7 +464,7 @@ void CDataFrameAnalyzerTest::testRunOutlierDetectionWithParams() {
     // Test the method and number of neighbours parameters are correctly
     // propagated to the analysis runner.
 
-    TStrVec methods{"lof", "ldof", "knn", "tnn"};
+    TStrVec methods{"lof", "ldof", "distance_kth_nn", "distance_knn"};
 
     for (const auto& method :
          {maths::COutliers::E_Lof, maths::COutliers::E_Ldof,