[WIP] drop obtain_from and use either ctors or .as<>

src/shogun/features/CombinedDotFeatures.h

@@ -1,8 +1,8 @@
 /*
  * This software is distributed under BSD 3-clause license (see LICENSE file).
  *
- * Authors: Soeren Sonnenburg, Sergey Lisitsyn, Heiko Strathmann, 
- *          Vladislav Horbatiuk, Evgeniy Andreev, Yuyu Zhang, Evan Shelhamer, 
+ * Authors: Soeren Sonnenburg, Sergey Lisitsyn, Heiko Strathmann,
+ *          Vladislav Horbatiuk, Evgeniy Andreev, Yuyu Zhang, Evan Shelhamer,
  *          Björn Esser, Evangelos Anagnostopoulos
  */
 
@@ -147,6 +147,11 @@ class CCombinedDotFeatures : public CDotFeatures
 		 * @return feature class
 		 */
 		virtual EFeatureClass get_feature_class() const
+		{
+			return this->class_type();
+		}
+
+		static EFeatureClass class_type()
 		{
 			return C_COMBINED_DOT;
 		}

src/shogun/features/DenseFeatures.cpp

@@ -1,10 +1,10 @@
 /*
  * This software is distributed under BSD 3-clause license (see LICENSE file).
  *
- * Authors: Soeren Sonnenburg, Saurabh Mahindre, Soumyajit De, Heiko Strathmann, 
- *          Sergey Lisitsyn, Sanuj Sharma, Chiyuan Zhang, Viktor Gal, 
- *          Michele Mazzoni, Vladislav Horbatiuk, Kevin Hughes, Weijie Lin, 
- *          Fernando Iglesias, Björn Esser, Evgeniy Andreev, 
+ * Authors: Soeren Sonnenburg, Saurabh Mahindre, Soumyajit De, Heiko Strathmann,
+ *          Sergey Lisitsyn, Sanuj Sharma, Chiyuan Zhang, Viktor Gal,
+ *          Michele Mazzoni, Vladislav Horbatiuk, Kevin Hughes, Weijie Lin,
+ *          Fernando Iglesias, Björn Esser, Evgeniy Andreev,
  *          Christopher Goldsworthy
  */
 
@@ -61,6 +61,28 @@ template<class ST> CDenseFeatures<ST>::CDenseFeatures(CFile* loader) :
 	load(loader);
 }
 
+template<class ST> CDenseFeatures<ST>::CDenseFeatures(CDotFeatures* features) :
+		CDotFeatures()
+{
+	init();
+
+	auto num_feat = features->get_dim_feature_space();
+	auto num_vec = features->get_num_vectors();
+
+	ASSERT(num_feat>0 && num_vec>0)
+	feature_matrix = SGMatrix<ST>(num_feat, num_vec);
+	for (auto i = 0; i < num_vec; i++)
+	{
+		SGVector<float64_t> v = features->get_computed_dot_feature_vector(i);
+		ASSERT(num_feat==v.vlen)
+
+		for (auto j = 0; j < num_feat; j++)
+			feature_matrix.matrix[i * int64_t(num_feat) + j] = (ST) v.vector[j];
+	}
+	num_features = num_feat;
+	num_vectors = num_vec;
+}
+
 template<class ST> CFeatures* CDenseFeatures<ST>::duplicate() const
 {
 	return new CDenseFeatures<ST>(*this);
@@ -366,30 +388,6 @@ template<class ST> ST* CDenseFeatures<ST>::get_transposed(int32_t &num_feat, int
 	return fm;
 }
 
-template<class ST> void CDenseFeatures<ST>::obtain_from_dot(CDotFeatures* df)
-{
-	m_subset_stack->remove_all_subsets();
-
-	int32_t num_feat = df->get_dim_feature_space();
-	int32_t num_vec = df->get_num_vectors();
-
-	ASSERT(num_feat>0 && num_vec>0)
-
-	free_feature_matrix();
-	feature_matrix = SGMatrix<ST>(num_feat, num_vec);
-
-	for (int32_t i = 0; i < num_vec; i++)
-	{
-		SGVector<float64_t> v = df->get_computed_dot_feature_vector(i);
-		ASSERT(num_feat==v.vlen)
-
-		for (int32_t j = 0; j < num_feat; j++)
-			feature_matrix.matrix[i * int64_t(num_feat) + j] = (ST) v.vector[j];
-	}
-	num_features = num_feat;
-	num_vectors = num_vec;
-}
-
 template<class ST> bool CDenseFeatures<ST>::apply_preprocessor(bool force_preprocessing)
 {
 	if (m_subset_stack->has_subsets())
@@ -468,8 +466,6 @@ template<class ST> void CDenseFeatures<ST>::initialize_cache()
 	}
 }
 
-template<class ST> EFeatureClass CDenseFeatures<ST>::get_feature_class() const  { return C_DENSE; }
-
 template<class ST> bool CDenseFeatures<ST>::reshape(int32_t p_num_features, int32_t p_num_vectors)
 {
 	if (m_subset_stack->has_subsets())

src/shogun/features/DenseFeatures.h

@@ -1,8 +1,8 @@
 /*
  * This software is distributed under BSD 3-clause license (see LICENSE file).
  *
- * Authors: Soumyajit De, Heiko Strathmann, Saurabh Mahindre, Soeren Sonnenburg, 
- *          Vladislav Horbatiuk, Yuyu Zhang, Kevin Hughes, Evgeniy Andreev, 
+ * Authors: Soumyajit De, Heiko Strathmann, Saurabh Mahindre, Soeren Sonnenburg,
+ *          Vladislav Horbatiuk, Yuyu Zhang, Kevin Hughes, Evgeniy Andreev,
  *          Thoralf Klein, Fernando Iglesias, Björn Esser, Sergey Lisitsyn
  */
 
@@ -87,6 +87,12 @@ template<class ST> class CDenseFeatures: public CDotFeatures
 	 */
 	CDenseFeatures(ST* src, int32_t num_feat, int32_t num_vec);
 
+	/** constructor from DotFeatures
+	 *
+	 * @param features DotFeatures object
+	 */
+	CDenseFeatures(CDotFeatures* features);
+
 	/** constructor loading features from file
 	 *
 	 * @param loader File object via which to load data
@@ -255,14 +261,6 @@ template<class ST> class CDenseFeatures: public CDotFeatures
 	 */
 	ST* get_transposed(int32_t &num_feat, int32_t &num_vec);
 
-	/** obtain dense features from other dotfeatures
-	 *
-	 * removes any subset before
-	 *
-	 * @param df dotfeatures to obtain features from
-	 */
-	void obtain_from_dot(CDotFeatures* df);
-
 	/** apply preprocessor
 	 *
 	 * applies preprocessors to ALL features (subset removed before and
@@ -311,7 +309,15 @@ template<class ST> class CDenseFeatures: public CDotFeatures
 	 *
 	 * @return feature class DENSE
 	 */
-	virtual EFeatureClass get_feature_class() const;
+	virtual EFeatureClass get_feature_class() const
+	{
+		return this->class_type();
+	}
+
+	static EFeatureClass class_type()
+	{
+		return C_DENSE;
+	}
 
 	/** get feature type
 	 *

src/shogun/features/Features.h

@@ -1,8 +1,8 @@
 /*
  * This software is distributed under BSD 3-clause license (see LICENSE file).
  *
- * Authors: Heiko Strathmann, Soeren Sonnenburg, Sergey Lisitsyn, 
- *          Saurabh Mahindre, Evgeniy Andreev, Wu Lin, Vladislav Horbatiuk, 
+ * Authors: Heiko Strathmann, Soeren Sonnenburg, Sergey Lisitsyn,
+ *          Saurabh Mahindre, Evgeniy Andreev, Wu Lin, Vladislav Horbatiuk,
  *          Yuyu Zhang, Björn Esser, Soumyajit De
  */
 
@@ -335,19 +335,44 @@ class CFeatures : public CSGObject
 		 */
 		virtual bool support_compatible_class() const {return false;}
 
-		/** Given a class in right hand side, does this class support compatible computation? 
+		/** Given a class in right hand side, does this class support compatible computation?
 		 *
 		 * for example, is this->dot(rhs_prt) valid,
-		 * where rhs_prt is the class in right hand side 
+		 * where rhs_prt is the class in right hand side
 		 *
-		 * @param rhs the class in right hand side 
+		 * @param rhs the class in right hand side
 		 * @return whether this class supports compatible computation
 		 */
 		virtual bool get_feature_class_compatibility (EFeatureClass rhs) const;
 
 #ifndef SWIG // SWIG should skip this part
-		virtual CFeatures* shallow_subset_copy() 
-		{ 
+		/**
+		 * Utility method to specialize the feature to the required type.
+		 *
+		 * @param f CFeatures base type
+		 * @return The requested type if casting was successful.
+		 */
+		template<class T> static T* as(CFeatures* f)
+		{
+			return f->as<T>();
+		}
+
+		/**
+		 * Utility method to specialize the feature to the required type.
+		 *
+		 * @param f CFeatures base type
+		 * @return The requested type if casting was successful.
+		 */
+		template<class T> T* as()
+		{
+			REQUIRE(T::class_type() == this->get_feature_class(),
+				"Provided features (%s) is not of type %s!\n",
+				this->get_feature_class());
+			return (T*)this;
+		}
+
+		virtual CFeatures* shallow_subset_copy()
+		{
 			SG_SNOTIMPLEMENTED;
 			return NULL;
 		}

src/shogun/features/SparseFeatures.cpp

@@ -44,6 +44,21 @@ template<class ST> CSparseFeatures<ST>::CSparseFeatures(const CSparseFeatures &
 	m_subset_stack=orig.m_subset_stack;
 	SG_REF(m_subset_stack);
 }
+
+template<class ST> CSparseFeatures<ST>::CSparseFeatures(CDenseFeatures<ST>* dense)
+{
+	init();
+
+	SGMatrix<ST> fm=dense->get_feature_matrix();
+	ASSERT(fm.matrix && fm.num_cols>0 && fm.num_rows>0)
+	set_full_feature_matrix(fm);
+}
+
+template<> CSparseFeatures<complex128_t>::CSparseFeatures(CDenseFeatures<complex128_t>* dense)
+{
+	SG_NOTIMPLEMENTED;
+}
+
 template<class ST> CSparseFeatures<ST>::CSparseFeatures(CFile* loader)
 : CDotFeatures(), feature_cache(NULL)
 {
@@ -316,18 +331,6 @@ template<class ST> bool CSparseFeatures<ST>::apply_preprocessor(bool force_prepr
 	}
 }
 
-template<class ST> void CSparseFeatures<ST>::obtain_from_simple(CDenseFeatures<ST>* sf)
-{
-	SGMatrix<ST> fm=sf->get_feature_matrix();
-	ASSERT(fm.matrix && fm.num_cols>0 && fm.num_rows>0)
-	set_full_feature_matrix(fm);
-}
-
-template<> void CSparseFeatures<complex128_t>::obtain_from_simple(CDenseFeatures<complex128_t>* sf)
-{
-	SG_NOTIMPLEMENTED;
-}
-
 template<class ST> int32_t  CSparseFeatures<ST>::get_num_vectors() const
 {
 	return m_subset_stack->has_subsets() ? m_subset_stack->get_size() : sparse_feature_matrix.num_vectors;

src/shogun/features/SparseFeatures.h

@@ -1,8 +1,8 @@
 /*
  * This software is distributed under BSD 3-clause license (see LICENSE file).
  *
- * Authors: Heiko Strathmann, Soeren Sonnenburg, Sergey Lisitsyn, 
- *          Evgeniy Andreev, Vladislav Horbatiuk, Yuyu Zhang, Viktor Gal, 
+ * Authors: Heiko Strathmann, Soeren Sonnenburg, Sergey Lisitsyn,
+ *          Evgeniy Andreev, Vladislav Horbatiuk, Yuyu Zhang, Viktor Gal,
  *          Thoralf Klein, Björn Esser, Soumyajit De
  */
 
@@ -72,6 +72,9 @@ template <class ST> class CSparseFeatures : public CDotFeatures
 		/** copy constructor */
 		CSparseFeatures(const CSparseFeatures & orig);
 
+		/** copy constructor from DenseFeatures */
+		CSparseFeatures(CDenseFeatures<ST>* dense);
+
 		/** constructor loading features from file
 		 *
 		 * @param loader File object to load data from
@@ -249,14 +252,6 @@ template <class ST> class CSparseFeatures : public CDotFeatures
 		 */
 		virtual bool apply_preprocessor(bool force_preprocessing=false);
 
-		/** obtain sparse features from simple features
-		 *
-		 * subset on input is ignored, subset of this instance is removed
-		 *
-		 * @param sf simple features
-		 */
-		void obtain_from_simple(CDenseFeatures<ST>* sf);
-
 		/** get number of feature vectors, possibly of subset
 		 *
 		 * @return number of feature vectors

src/shogun/preprocessor/DimensionReductionPreprocessor.cpp

@@ -51,7 +51,7 @@ SGMatrix<float64_t> CDimensionReductionPreprocessor::apply_to_feature_matrix(CFe
 	else
 	{
 		SG_WARNING("Converter to process was not set.\n")
-		return ((CDenseFeatures<float64_t>*)features)->get_feature_matrix();
+		return features.as<CDenseFeatures<float64_t>>()->get_feature_matrix();
 	}
 }
 

src/shogun/preprocessor/PCA.cpp

@@ -1,7 +1,7 @@
 /*
  * This software is distributed under BSD 3-clause license (see LICENSE file).
  *
- * Authors: Soeren Sonnenburg, Sergey Lisitsyn, Heiko Strathmann, Viktor Gal, 
+ * Authors: Soeren Sonnenburg, Sergey Lisitsyn, Heiko Strathmann, Viktor Gal,
  *          Evan Shelhamer, Evgeniy Andreev, Marc Zimmermann, Björn Esser
  */
 #include <shogun/lib/config.h>
@@ -287,7 +287,7 @@ SGMatrix<float64_t> CPCA::apply_to_feature_matrix(CFeatures* features)
 {
 	ASSERT(m_initialized)
 	ASSERT(features != NULL)
-	SGMatrix<float64_t> m = ((CDenseFeatures<float64_t>*) features)->get_feature_matrix();
+	SGMatrix<float64_t> m = features->as<CDenseFeatures<float64_t>>()->get_feature_matrix();
 	int32_t num_vectors = m.num_cols;
 	int32_t num_features = m.num_rows;