Made feature block logistic regression outputs use sigmoid

shogun-toolbox · Jul 10, 2012 · 2aba715 · 2aba715
1 parent 80adbb4
commit 2aba715
Show file tree

Hide file tree

Showing 3 changed files with 35 additions and 2 deletions.
diff --git a/src/shogun/classifier/FeatureBlockLogisticRegression.cpp b/src/shogun/classifier/FeatureBlockLogisticRegression.cpp
@@ -138,4 +138,33 @@ bool CFeatureBlockLogisticRegression::train_machine(CFeatures* data)
 	return true;
 }
 
+float64_t CFeatureBlockLogisticRegression::apply_one(int32_t vec_idx)
+{
+	return CMath::exp(-(features->dense_dot(vec_idx, w.vector, w.vlen) + bias));
+}
+
+SGVector<float64_t> CFeatureBlockLogisticRegression::apply_get_outputs(CFeatures* data)
+{
+	if (data)
+	{
+		if (!data->has_property(FP_DOT))
+			SG_ERROR("Specified features are not of type CDotFeatures\n");
+
+		set_features((CDotFeatures*) data);
+	}
+
+	if (!features)
+		return SGVector<float64_t>();
+
+	int32_t num=features->get_num_vectors();
+	ASSERT(num>0);
+	ASSERT(w.vlen==features->get_dim_feature_space());
+
+	float64_t* out=SG_MALLOC(float64_t, num);
+	features->dense_dot_range(out, 0, num, NULL, w.vector, w.vlen, bias);
+	for (int32_t i=0; i<num; i++)
+		out[i] = 2.0/(1.0+CMath::exp(-out[i])) - 1.0;//*CMath::exp(-CMath::sign(out[i])*out[i]);
+	return SGVector<float64_t>(out,num);
+}
+
 }
diff --git a/src/shogun/classifier/FeatureBlockLogisticRegression.h b/src/shogun/classifier/FeatureBlockLogisticRegression.h
@@ -55,8 +55,12 @@ class CFeatureBlockLogisticRegression : public CSLEPMachine
 		 * @param feature_tree feature tree
 		 */
 		void set_feature_relation(CIndexBlockRelation* feature_relation);
-
+
+		virtual float64_t apply_one(int32_t vec_idx);
+
 	protected:
+
+		virtual SGVector<float64_t> apply_get_outputs(CFeatures* data);
 
 		/** train machine */
 		virtual bool train_machine(CFeatures* data=NULL);

diff --git a/src/shogun/machine/LinearMachine.h b/src/shogun/machine/LinearMachine.h
@@ -150,7 +150,7 @@ class CLinearMachine : public CMachine
 
 	protected:
 
-		SGVector<float64_t> apply_get_outputs(CFeatures* data);
+		virtual SGVector<float64_t> apply_get_outputs(CFeatures* data);
 
 		/** Stores feature data of underlying model. Does nothing because
 		 * Linear machines store the normal vector of the separating hyperplane