diff --git a/Source/C/SMatrix_c.h b/Source/C/SMatrix_c.h
index d2629770..4a49f801 100644
--- a/Source/C/SMatrix_c.h
+++ b/Source/C/SMatrix_c.h
@@ -34,8 +34,7 @@ void PrintMatrix_lsr_wrp(const int *ih_this);
 void PrintMatrixF_lsr_wrp(const int *ih_this, const char *file_name,
                           const int *name_size);
 void MatrixToTripletList_lsr_wrp(const int *ih_this, int *ih_triplet_list);
-void DiagonalScale_lsr_wrp(int *ih_mat, const int *ih_tlist,
-                           const double *threhsold);
+void DiagonalScale_lsr_wrp(int *ih_mat, const int *ih_tlist);
 
 void ConstructMatrixFromFile_lsc_wrp(int *ih_this, const char *file_name,
                                      const int *name_size);
@@ -72,7 +71,6 @@ void PrintMatrix_lsc_wrp(const int *ih_this);
 void PrintMatrixF_lsc_wrp(const int *ih_this, const char *file_name,
                           const int *name_size);
 void MatrixToTripletList_lsc_wrp(const int *ih_this, int *ih_triplet_list);
-void DiagonalScale_lsc_wrp(int *ih_mat, const int *ih_tlist,
-                           const double *threhsold);
+void DiagonalScale_lsc_wrp(int *ih_mat, const int *ih_tlist);
 
 #endif
diff --git a/Source/CPlusPlus/SMatrix.cc b/Source/CPlusPlus/SMatrix.cc
index 68620ae4..48dbbe8d 100644
--- a/Source/CPlusPlus/SMatrix.cc
+++ b/Source/CPlusPlus/SMatrix.cc
@@ -176,13 +176,13 @@ void Matrix_lsc::Gemm(const Matrix_lsc &matA, const Matrix_lsc &matB,
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-void Matrix_lsr::DiagonalScale(const TripletList_r &tlist, double threshold) {
-  DiagonalScale_lsr_wrp(ih_this, tlist.ih_this, &threshold);
+void Matrix_lsr::DiagonalScale(const TripletList_r &tlist) {
+  DiagonalScale_lsr_wrp(ih_this, tlist.ih_this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void Matrix_lsc::DiagonalScale(const TripletList_c &tlist, double threshold) {
-  DiagonalScale_lsc_wrp(ih_this, tlist.ih_this, &threshold);
+  DiagonalScale_lsc_wrp(ih_this, tlist.ih_this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/Source/CPlusPlus/SMatrix.h b/Source/CPlusPlus/SMatrix.h
index 40984449..21f90116 100644
--- a/Source/CPlusPlus/SMatrix.h
+++ b/Source/CPlusPlus/SMatrix.h
@@ -79,7 +79,7 @@ class Matrix_lsr {
   //! Scale a matrix using a diagonal matrix (triplet list form).
   //!\param tlist the triplet list.
   //!\param threshold for flushing small values.
-  void DiagonalScale(const NTPoly::TripletList_r &tlist, double threshold);
+  void DiagonalScale(const NTPoly::TripletList_r &tlist);
 
 public:
   //! Transpose a sparse matrix.
diff --git a/Source/Fortran/SMatrixAlgebraModule.F90 b/Source/Fortran/SMatrixAlgebraModule.F90
index 1493a300..ace4bbc9 100644
--- a/Source/Fortran/SMatrixAlgebraModule.F90
+++ b/Source/Fortran/SMatrixAlgebraModule.F90
@@ -533,13 +533,11 @@ PURE SUBROUTINE PruneList_lsc(memorypool,alpha,threshold, &
   END SUBROUTINE PruneList_lsc
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   !> Scale a matrix using a diagonal matrix (triplet list form).
-  SUBROUTINE DiagonalScale_lsr(mat, tlist, threshold_in)
+  SUBROUTINE DiagonalScale_lsr(mat, tlist)
     !> The matrix to scale.
     TYPE(Matrix_lsr), INTENT(INOUT)  :: mat
     !> The diagonal matrix.
     TYPE(TripletList_r), INTENT(IN)  :: tlist
-    !> For flushing values to zero. Default value is 0.0.
-    REAL(NTREAL), OPTIONAL, INTENT(IN) :: threshold_in
     !! Intermediate Data
     REAL(NTREAL) :: val
 
@@ -547,13 +545,11 @@ SUBROUTINE DiagonalScale_lsr(mat, tlist, threshold_in)
   END SUBROUTINE DiagonalScale_lsr
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   !> Scale a matrix using a diagonal matrix (triplet list form).
-  SUBROUTINE DiagonalScale_lsc(mat, tlist, threshold_in)
+  SUBROUTINE DiagonalScale_lsc(mat, tlist)
     !> The matrix to scale.
     TYPE(Matrix_lsc), INTENT(INOUT)  :: mat
     !> The diagonal matrix.
     TYPE(TripletList_c), INTENT(IN)  :: tlist
-    !> For flushing values to zero. Default value is 0.0.
-    REAL(NTREAL), OPTIONAL, INTENT(IN) :: threshold_in
     !! Intermediate Data
     COMPLEX(NTCOMPLEX) :: val
 
diff --git a/Source/Wrapper/SMatrixAlgebraModule_wrp.F90 b/Source/Wrapper/SMatrixAlgebraModule_wrp.F90
index 55fec023..405bd326 100644
--- a/Source/Wrapper/SMatrixAlgebraModule_wrp.F90
+++ b/Source/Wrapper/SMatrixAlgebraModule_wrp.F90
@@ -114,18 +114,17 @@ SUBROUTINE MatrixMultiply_lsr_wrp(ih_matA, ih_matB, ih_matC, IsATransposed, &
   END SUBROUTINE MatrixMultiply_lsr_wrp
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   !> Scale a matrix using a diagonal matrix (triplet list form).
-  SUBROUTINE DiagonalScale_lsr_wrp(ih_mat, ih_tlist, threshold) &
+  SUBROUTINE DiagonalScale_lsr_wrp(ih_mat, ih_tlist) &
        & BIND(c,name="DiagonalScale_lsr_wrp")
     INTEGER(kind=c_int), INTENT(INOUT) :: ih_mat(SIZE_wrp)
     INTEGER(kind=c_int), INTENT(IN) :: ih_tlist(SIZE_wrp)
-    REAL(NTREAL), INTENT(in) :: threshold
     TYPE(Matrix_lsr_wrp) :: h_mat
     TYPE(TripletList_r_wrp) :: h_tlist
 
     h_mat = TRANSFER(ih_mat, h_mat)
     h_tlist = TRANSFER(ih_tlist, h_tlist)
 
-    CALL DiagonalScale(h_mat%DATA, h_tlist%DATA, threshold)
+    CALL DiagonalScale(h_mat%DATA, h_tlist%DATA)
   END SUBROUTINE DiagonalScale_lsr_wrp
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   !> Wrap the scale a sparse matrix by a constant routine.
@@ -220,18 +219,17 @@ SUBROUTINE MatrixMultiply_lsc_wrp(ih_matA, ih_matB, ih_matC, IsATransposed, &
   END SUBROUTINE MatrixMultiply_lsc_wrp
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   !> Scale a matrix using a diagonal matrix (triplet list form).
-  SUBROUTINE DiagonalScale_lsc_wrp(ih_mat, ih_tlist, threshold) &
+  SUBROUTINE DiagonalScale_lsc_wrp(ih_mat, ih_tlist) &
        & BIND(c,name="DiagonalScale_lsc_wrp")
     INTEGER(kind=c_int), INTENT(INOUT) :: ih_mat(SIZE_wrp)
     INTEGER(kind=c_int), INTENT(IN) :: ih_tlist(SIZE_wrp)
-    REAL(NTREAL), INTENT(in) :: threshold
     TYPE(Matrix_lsc_wrp) :: h_mat
     TYPE(TripletList_c_wrp) :: h_tlist
 
     h_mat = TRANSFER(ih_mat, h_mat)
     h_tlist = TRANSFER(ih_tlist, h_tlist)
 
-    CALL DiagonalScale(h_mat%DATA, h_tlist%DATA, threshold)
+    CALL DiagonalScale(h_mat%DATA, h_tlist%DATA)
   END SUBROUTINE DiagonalScale_lsc_wrp
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 END MODULE SMatrixAlgebraModule_wrp
diff --git a/UnitTests/test_matrix.py b/UnitTests/test_matrix.py
index 2d874988..90ee3d14 100644
--- a/UnitTests/test_matrix.py
+++ b/UnitTests/test_matrix.py
@@ -416,7 +416,7 @@ def test_scalediag(self):
                 tlist.Append(t)
                 CheckMat[:, i] *= i
             ntmatrix = self.SMatrix(self.file1)
-            ntmatrix.DiagonalScale(tlist, 0)
+            ntmatrix.DiagonalScale(tlist)
             ntmatrix.WriteToMatrixMarket(self.file2)
 
             ResultMat = mmread(self.file2)