several improvements

src/fann.c

@@ -900,6 +900,7 @@ FANN_EXTERNAL struct fann* FANN_API fann_copy(struct fann* orig)
 
     copy->learning_rate = orig->learning_rate;
     copy->learning_momentum = orig->learning_momentum;
+    copy->learning_l2_norm = orig->learning_l2_norm;
     copy->connection_rate = orig->connection_rate;
     copy->network_type = orig->network_type;
     copy->num_MSE = orig->num_MSE;
@@ -1288,6 +1289,7 @@ FANN_EXTERNAL void FANN_API fann_print_parameters(struct fann *ann)
 	printf("Bit fail limit                       :%8.3f\n", ann->bit_fail_limit);
 	printf("Learning rate                        :%8.3f\n", ann->learning_rate);
 	printf("Learning momentum                    :%8.3f\n", ann->learning_momentum);
+	printf("Learning l2 norm                     :%8.3f\n", ann->learning_l2_norm);
 	printf("Quickprop decay                      :%11.6f\n", ann->quickprop_decay);
 	printf("Quickprop mu                         :%8.3f\n", ann->quickprop_mu);
 	printf("RPROP increase factor                :%8.3f\n", ann->rprop_increase_factor);
@@ -1647,6 +1649,7 @@ struct fann *fann_allocate_structure(unsigned int num_layers)
 	ann->errstr = NULL;
 	ann->learning_rate = 0.7f;
 	ann->learning_momentum = 0.0;
+	ann->learning_l2_norm = 0.0;
 	ann->total_neurons = 0;
 	ann->total_connections = 0;
 	ann->num_input = 0;

src/fann_io.c

@@ -181,6 +181,7 @@ int fann_save_internal_fd(struct fann *ann, FILE * conf, const char *configurati
 	fprintf(conf, "network_type=%u\n", ann->network_type);
 
 	fprintf(conf, "learning_momentum=%f\n", ann->learning_momentum);
+	fprintf(conf, "learning_l2_norm=%f\n", ann->learning_l2_norm);
 	fprintf(conf, "training_algorithm=%u\n", ann->training_algorithm);
 	fprintf(conf, "train_error_function=%u\n", ann->train_error_function);
 	fprintf(conf, "train_stop_function=%u\n", ann->train_stop_function);
@@ -443,6 +444,7 @@ struct fann *fann_create_from_fd(FILE * conf, const char *configuration_file)
 	fann_scanf("%u", "network_type", &tmpVal);
 	ann->network_type = (enum fann_nettype_enum)tmpVal;
 	fann_scanf("%f", "learning_momentum", &ann->learning_momentum);
+	fann_scanf("%f", "learning_l2_norm", &ann->learning_l2_norm);
 	fann_scanf("%u", "training_algorithm", &tmpVal);
 	ann->training_algorithm = (enum fann_train_enum)tmpVal;
 	fann_scanf("%u", "train_error_function", &tmpVal);

src/fann_train.c

@@ -978,7 +978,7 @@ void fann_update_weights_irpropm(struct fann *ann, unsigned int first_weight, un
 	for(; i != past_end; i++)
 	{
 		prev_step = fann_max(prev_steps[i], (fann_type) 0.0001);	/* prev_step may not be zero because then the training will stop */
-		slope = train_slopes[i];
+		slope = train_slopes[i] - ann->learning_l2_norm * weights[i];
 		prev_slope = prev_train_slopes[i];
 
 		same_sign = prev_slope * slope;
@@ -1294,3 +1294,5 @@ FANN_GET_SET(float, sarprop_temperature)
 FANN_GET_SET(enum fann_stopfunc_enum, train_stop_function)
 FANN_GET_SET(fann_type, bit_fail_limit)
 FANN_GET_SET(float, learning_momentum)
+FANN_GET_SET(float, learning_l2_norm)
+

src/include/fann_cpp.h

@@ -2686,6 +2686,23 @@ namespace FANN
             }
         }
 
+	float get_learning_l2_norm()
+	{
+	        float learning_l2_norm = 0.0f;
+	        if (ann != NULL)
+	        {
+	        	learning_l2_norm = fann_get_learning_l2_norm(ann);
+	        }
+		return learning_l2_norm;
+	}
+
+	void set_learning_l2_norm(float learning_l2_norm)
+	{
+		if (ann != NULL)
+		{
+			fann_set_learning_l2_norm(ann, learning_l2_norm);
+		}
+	}
         /* Method: get_train_stop_function
 
            Returns the the stop function used during training.

src/include/fann_data.h

@@ -491,6 +491,7 @@ struct fann
 
 	/* The learning momentum used for backpropagation algorithm. */
 	float learning_momentum;
+	float learning_l2_norm;
 
 	/* the connection rate of the network
 	 * between 0 and 1, 1 meaning fully connected

src/include/fann_train.h

@@ -769,7 +769,8 @@ FANN_EXTERNAL float FANN_API fann_get_learning_momentum(struct fann *ann);
    This function appears in FANN >= 2.0.0.   	
  */ 
 FANN_EXTERNAL void FANN_API fann_set_learning_momentum(struct fann *ann, float learning_momentum);
-
+FANN_EXTERNAL float FANN_API fann_get_learning_l2_norm(struct fann *ann);
+FANN_EXTERNAL void FANN_API fann_set_learning_l2_norm(struct fann *ann, float learning_l2_norm);
 
 /* Function: fann_get_activation_function