diff --git a/src/shogun/mathematics/ajd/ApproxJointDiagonalizer.h b/src/shogun/mathematics/ajd/ApproxJointDiagonalizer.h
index 2f6fc115c09..3d84d71c3a9 100644
--- a/src/shogun/mathematics/ajd/ApproxJointDiagonalizer.h
+++ b/src/shogun/mathematics/ajd/ApproxJointDiagonalizer.h
@@ -54,8 +54,8 @@ class CApproxJointDiagonalizer : public CSGObject
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		virtual SGMatrix<float64_t> compute(const SGNDArray<float64_t> &C,
-						   SGMatrix<float64_t> V0= SGMatrix<float64_t>(NULL,0,0),
+		virtual SGMatrix<float64_t> compute(SGNDArray<float64_t> C,
+						   SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 						   double eps=CMath::MACHINE_EPSILON,
 						   int itermax=200) = 0;
 
diff --git a/src/shogun/mathematics/ajd/FFDiag.cpp b/src/shogun/mathematics/ajd/FFDiag.cpp
index 1adc82702a4..365ede1d0a4 100644
--- a/src/shogun/mathematics/ajd/FFDiag.cpp
+++ b/src/shogun/mathematics/ajd/FFDiag.cpp
@@ -16,7 +16,7 @@ using namespace shogun;
 
 void getW(double *C, int *ptN, int *ptK, double *W);
 
-SGMatrix<float64_t> CFFDiag::diagonalize(const SGNDArray<float64_t> &C0, SGMatrix<float64_t> V0,
+SGMatrix<float64_t> CFFDiag::diagonalize(SGNDArray<float64_t> C0, SGMatrix<float64_t> V0,
 						double eps, int itermax)
 {
 	int n = C0.dims[0];
diff --git a/src/shogun/mathematics/ajd/FFDiag.h b/src/shogun/mathematics/ajd/FFDiag.h
index ddb1e392e94..85d27679b79 100644
--- a/src/shogun/mathematics/ajd/FFDiag.h
+++ b/src/shogun/mathematics/ajd/FFDiag.h
@@ -53,8 +53,8 @@ class CFFDiag : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		static SGMatrix<float64_t> diagonalize(const SGNDArray<float64_t> &C,
-       							SGMatrix<float64_t> V0= SGMatrix<float64_t>(NULL,0,0),
+		static SGMatrix<float64_t> diagonalize(SGNDArray<float64_t> C,
+       							SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 							double eps=CMath::MACHINE_EPSILON,
 							int itermax=200);
 
@@ -65,8 +65,8 @@ class CFFDiag : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		virtual SGMatrix<float64_t> compute(const SGNDArray<float64_t> &C,
-						   SGMatrix<float64_t> V0= SGMatrix<float64_t>(NULL,0,0),
+		virtual SGMatrix<float64_t> compute(SGNDArray<float64_t> C,
+						   SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 						   double eps=CMath::MACHINE_EPSILON,
 						   int itermax=200)
 		{
diff --git a/src/shogun/mathematics/ajd/JADiag.cpp b/src/shogun/mathematics/ajd/JADiag.cpp
index 47268b3af05..256cb975ddd 100644
--- a/src/shogun/mathematics/ajd/JADiag.cpp
+++ b/src/shogun/mathematics/ajd/JADiag.cpp
@@ -17,7 +17,7 @@ using namespace shogun;
 void jadiagw(double c[], double w[], int *ptn, int *ptm, double a[],
 	         double *logdet, double *decr, double *result);
 
-SGMatrix<float64_t> CJADiag::diagonalize(const SGNDArray<float64_t> &C, SGMatrix<float64_t> V0,
+SGMatrix<float64_t> CJADiag::diagonalize(SGNDArray<float64_t> C, SGMatrix<float64_t> V0,
 						double eps, int itermax)
 {
 	int d = C.dims[0];
diff --git a/src/shogun/mathematics/ajd/JADiag.h b/src/shogun/mathematics/ajd/JADiag.h
index 73dc1159850..db36337cfda 100644
--- a/src/shogun/mathematics/ajd/JADiag.h
+++ b/src/shogun/mathematics/ajd/JADiag.h
@@ -53,8 +53,8 @@ class CJADiag : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		static SGMatrix<float64_t> diagonalize(const SGNDArray<float64_t> &C,
-       							SGMatrix<float64_t> V0= SGMatrix<float64_t>(NULL,0,0),
+		static SGMatrix<float64_t> diagonalize(SGNDArray<float64_t> C,
+       							SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 							double eps=CMath::MACHINE_EPSILON,
 							int itermax=200);
 
@@ -65,8 +65,8 @@ class CJADiag : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		virtual SGMatrix<float64_t> compute(const SGNDArray<float64_t> &C,
-						   SGMatrix<float64_t> V0= SGMatrix<float64_t>(NULL,0,0),
+		virtual SGMatrix<float64_t> compute(SGNDArray<float64_t> C,
+						   SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 						   double eps=CMath::MACHINE_EPSILON,
 						   int itermax=200)
 		{
diff --git a/src/shogun/mathematics/ajd/JADiagOrth.cpp b/src/shogun/mathematics/ajd/JADiagOrth.cpp
index 565d27e7556..fc60180d82c 100644
--- a/src/shogun/mathematics/ajd/JADiagOrth.cpp
+++ b/src/shogun/mathematics/ajd/JADiagOrth.cpp
@@ -19,18 +19,11 @@ void left_rot_stack(double *A, int M, int N, int K, int p, int q, double c, doub
 void right_rot_stack(double *A, int M, int N, int K, int p, int q, double c, double s);
 void left_rot_simple(double *A, int m, int n, int p, int q, double c, double s);
 
-SGMatrix<float64_t> CJADiagOrth::diagonalize(const SGNDArray<float64_t> &C0, SGMatrix<float64_t> V0,
+SGMatrix<float64_t> CJADiagOrth::diagonalize(SGNDArray<float64_t> C, SGMatrix<float64_t> V0,
 						double eps, int itermax)
 {	
-	int m = C0.dims[0];
-	int L = C0.dims[2];	
-
-	index_t * C_dims = SG_MALLOC(index_t, 3);
-	C_dims[0] = C0.dims[0];
-	C_dims[1] = C0.dims[1];
-	C_dims[2] = C0.dims[2];
-	SGNDArray<float64_t> C(C_dims,3);
-	memcpy(C.array, C0.array, C0.dims[0]*C0.dims[1]*C0.dims[2]*sizeof(float64_t));
+	int m = C.dims[0];
+	int L = C.dims[2];
 
 	SGMatrix<float64_t> V;
 	if (V0.num_rows != 0)
diff --git a/src/shogun/mathematics/ajd/JADiagOrth.h b/src/shogun/mathematics/ajd/JADiagOrth.h
index 1a2c6b4136e..e1a8ce78a3d 100644
--- a/src/shogun/mathematics/ajd/JADiagOrth.h
+++ b/src/shogun/mathematics/ajd/JADiagOrth.h
@@ -53,7 +53,7 @@ class CJADiagOrth : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		static SGMatrix<float64_t> diagonalize(const SGNDArray<float64_t> &C,
+		static SGMatrix<float64_t> diagonalize(SGNDArray<float64_t> C,
 							SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 							double eps=CMath::MACHINE_EPSILON,
 							int itermax=200);
@@ -65,7 +65,7 @@ class CJADiagOrth : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		virtual SGMatrix<float64_t> compute(const SGNDArray<float64_t> &C,
+		virtual SGMatrix<float64_t> compute(SGNDArray<float64_t> C,
 						   SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 						   double eps=CMath::MACHINE_EPSILON,
 						   int itermax=200)
diff --git a/src/shogun/mathematics/ajd/UWedge.cpp b/src/shogun/mathematics/ajd/UWedge.cpp
index ee2f69e6c70..629894fc846 100644
--- a/src/shogun/mathematics/ajd/UWedge.cpp
+++ b/src/shogun/mathematics/ajd/UWedge.cpp
@@ -14,7 +14,7 @@ typedef Matrix< float64_t, Dynamic, Dynamic, ColMajor > EMatrix;
 
 using namespace shogun;
 
-SGMatrix<float64_t> CUWedge::diagonalize(const SGNDArray<float64_t> &C, SGMatrix<float64_t> V0,
+SGMatrix<float64_t> CUWedge::diagonalize(SGNDArray<float64_t> C, SGMatrix<float64_t> V0,
 					double eps, int itermax)
 {
 	int d = C.dims[0];
diff --git a/src/shogun/mathematics/ajd/UWedge.h b/src/shogun/mathematics/ajd/UWedge.h
index 5f4fc9799c2..c0443be8472 100644
--- a/src/shogun/mathematics/ajd/UWedge.h
+++ b/src/shogun/mathematics/ajd/UWedge.h
@@ -52,8 +52,8 @@ class CUWedge : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		static SGMatrix<float64_t> diagonalize(const SGNDArray<float64_t> &C,
-       							SGMatrix<float64_t> V0= SGMatrix<float64_t>(NULL,0,0),
+		static SGMatrix<float64_t> diagonalize(SGNDArray<float64_t> C,
+       							SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 							double eps=1e-12,
 							int itermax=200);
 
@@ -64,8 +64,8 @@ class CUWedge : public CApproxJointDiagonalizer
 		 * @param itermax maximum number of iterations
 		 * @return V the matrix that best diagonalizes C 
 		 */
-		virtual SGMatrix<float64_t> compute(const SGNDArray<float64_t> &C,
-						   SGMatrix<float64_t> V0= SGMatrix<float64_t>(NULL,0,0),
+		virtual SGMatrix<float64_t> compute(SGNDArray<float64_t> C,
+						   SGMatrix<float64_t> V0 = SGMatrix<float64_t>(NULL,0,0),
 						   double eps=1e-12,
 						   int itermax=200)
 		{