diff --git a/build/macosx/ml.xcodeproj/xcshareddata/xcschemes/ml.mlp pd.xcscheme b/build/macosx/ml.xcodeproj/xcshareddata/xcschemes/ml.mlp pd.xcscheme
index a6b14df..5e9b113 100644
--- a/build/macosx/ml.xcodeproj/xcshareddata/xcschemes/ml.mlp pd.xcscheme	
+++ b/build/macosx/ml.xcodeproj/xcshareddata/xcschemes/ml.mlp pd.xcscheme	
@@ -40,7 +40,6 @@
       buildConfiguration = "Development"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -60,7 +59,6 @@
       buildConfiguration = "Development"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
@@ -86,7 +84,7 @@
             isEnabled = "YES">
          </CommandLineArgument>
          <CommandLineArgument
-            argument = "~/Documents/ml-lib/ml.mlp/ml.mlp-help.pd"
+            argument = "~/Documents/ml-lib/help/pd/ml.mlp-help.pd"
             isEnabled = "YES">
          </CommandLineArgument>
       </CommandLineArguments>
diff --git a/sources/ml_ml.h b/sources/ml_ml.h
index ab22c42..4de0a3a 100644
--- a/sources/ml_ml.h
+++ b/sources/ml_ml.h
@@ -73,6 +73,7 @@ namespace ml
         
         data_type get_data_type() const;
         void set_data_type(data_type type);
+        void set_num_inputs(uint16_t num_inputs);
         
         virtual GRT::MLBase &get_MLBase_instance() = 0;
         virtual const GRT::MLBase &get_MLBase_instance() const = 0;
@@ -103,7 +104,6 @@ namespace ml
     private:
         
         void record_(bool state);
-        void set_num_inputs(uint16_t num_inputs);
         
         // Flext method wrappers
         FLEXT_CALLBACK_A(any);
diff --git a/sources/regression/ml_mlp.cpp b/sources/regression/ml_mlp.cpp
index 1469e99..2d273ab 100644
--- a/sources/regression/ml_mlp.cpp
+++ b/sources/regression/ml_mlp.cpp
@@ -19,6 +19,8 @@
 #include "ml_ml.h"
 #include "ml_defaults.h"
 
+#include <unordered_map>
+
 namespace ml
 {
     const std::string object_name = ML_NAME_PREFIX "mlp";
@@ -111,6 +113,7 @@ namespace ml
             DefineHelp(c, object_name.c_str());
         }
         
+        void add(int argc, const t_atom *argv);
         void clear();
         void train();
         void map(int argc, const t_atom *argv);
@@ -166,6 +169,9 @@ namespace ml
         
     private:
         void set_activation_function(int activation_function, mlp_layer layer);
+        int get_index_for_class(int classID);
+        int get_class_id_for_index(int index);
+        void clear_index_maps();
         
         // Flext method wrappers
         FLEXT_CALLBACK(error);
@@ -199,6 +205,8 @@ namespace ml
         GRT::Neuron::Type input_activation_function;
         GRT::Neuron::Type hidden_activation_function;
         GRT::Neuron::Type output_activation_function;
+        std::unordered_map<int, int> classLabelToIndex;
+        std::unordered_map<int, int> indexToClassLabel;
         
         bool probs;
     };
@@ -374,6 +382,47 @@ namespace ml
         post("activation function set to " + grt_mlp.activationFunctionToString(activation_function_));
     }
     
+    // adds index if it doesn't exist
+    int mlp::get_index_for_class(int classLabel)
+    {
+        const int count = classLabelToIndex.count(classLabel);
+        
+        if (count == 1)
+        {
+            return classLabelToIndex.at(classLabel);
+        }
+        else if (count != 0)
+        {
+            assert(false);
+        }
+        
+        const int index = classLabelToIndex.size() + 1; // GRT labels (i.e. index) must start from 1
+        classLabelToIndex[classLabel] = index;
+        indexToClassLabel[index] = classLabel;
+        
+        return index;
+    }
+    
+    // assumes index exists and returns -1 as a failsafe
+    int mlp::get_class_id_for_index(int index)
+    {
+        const int count = indexToClassLabel.count(index);
+
+        if (count == 0)
+        {
+            assert(false);
+            return -1;
+        }
+        
+        return indexToClassLabel.at(index);
+    }
+    
+    void mlp::clear_index_maps()
+    {
+        indexToClassLabel.clear();
+        classLabelToIndex.clear();
+    }
+    
     void mlp::set_input_activation_function(int activation_function)
     {
         set_activation_function(activation_function, LAYER_INPUT);
@@ -591,10 +640,79 @@ namespace ml
         ToOutAnything(1, get_s_train(), 1, &a_success);
     }
     
+    void mlp::add(int argc, const t_atom *argv)
+    {
+        if (get_data_type() != data_type::LABELLED_CLASSIFICATION)
+        {
+            ml::add(argc, argv);
+            return;
+        }
+        
+        // work around a bug in GRT where class labels must be contigious
+        if (argc < 2)
+        {
+            flext::error("invalid input length, must contain at least 2 values");
+            return;
+        }
+        
+        GRT::UINT numInputDimensions = classification_data.getNumDimensions();
+        GRT::UINT numOutputDimensions = 1;
+        GRT::UINT combinedVectorSize = numInputDimensions + numOutputDimensions;
+        
+        if ((unsigned)argc != combinedVectorSize)
+        {
+            numInputDimensions = argc - numOutputDimensions;
+            
+            if (numInputDimensions < 1)
+            {
+                flext::error(std::string("invalid input length, expected at least " + std::to_string(numOutputDimensions + 1)).c_str());
+                return;
+            }
+            post("new input vector size, adjusting num_inputs to " + std::to_string(numInputDimensions));
+            set_num_inputs(numInputDimensions);
+        }
+        
+        GRT::VectorDouble inputVector(numInputDimensions);
+        GRT::VectorDouble targetVector(numOutputDimensions);
+        
+        for (uint32_t index = 0; index < (unsigned)argc; ++index)
+        {
+            float value = GetAFloat(argv[index]);
+            
+            if (index < numOutputDimensions)
+            {
+                targetVector[index] = value;
+            }
+            else
+            {
+                inputVector[index - numOutputDimensions] = value;
+            }
+        }
+        
+        GRT::UINT label = get_index_for_class((GRT::UINT)targetVector[0]);
+        
+        assert(label > 0);
+        
+//        if ((double)label != targetVector[0])
+//        {
+//            flext::error("class label must be a positive integer");
+//            return;
+//        }
+//
+//        if (label == 0)
+//        {
+//            flext::error("class label must be non-zero");
+//            return;
+//        }
+        
+        classification_data.addSample(label, inputVector);
+    }
+
     void mlp::clear()
     {
         grt_mlp.clear();
         ml::clear();
+        clear_index_maps();
     }
         
     void mlp::map(int argc, const t_atom *argv)
@@ -639,9 +757,10 @@ namespace ml
         
         if (grt_mlp.getClassificationModeActive())
         {
-            GRT::VectorDouble likelihoods = grt_mlp.getClassLikelihoods();
-            GRT::Vector<GRT::UINT> labels = classification_data.getClassLabels();
-            GRT::UINT classification = grt_mlp.getPredictedClassLabel();
+            const GRT::VectorDouble likelihoods = grt_mlp.getClassLikelihoods();
+            const GRT::Vector<GRT::UINT> labels = classification_data.getClassLabels();
+            const GRT::UINT predicted = grt_mlp.getPredictedClassLabel();
+            const GRT::UINT classification = predicted == 0 ? 0 : get_class_id_for_index(predicted);
             
             if (likelihoods.size() != labels.size())
             {
@@ -657,7 +776,7 @@ namespace ml
                     t_atom likelihood_a;
                     
                     SetFloat(likelihood_a, static_cast<float>(likelihoods[count]));
-                    SetInt(label_a, labels[count]);
+                    SetInt(label_a, get_class_id_for_index(labels[count]));
                     
                     probs_list.Append(label_a);
                     probs_list.Append(likelihood_a);