diff --git a/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs
index 4f9a26ab..395c6fa1 100644
--- a/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs
@@ -505,7 +505,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
             var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
             if (diagonalOther != null)
             {
-                Storage.CopyToUnchecked(result.Storage);
+                Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
                 for (int i = 0; i < diagonal.Length; i++)
                 {
diff --git a/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs
index dd812358..bbca65e9 100644
--- a/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs
@@ -500,7 +500,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
             var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
             if (diagonalOther != null)
             {
-                Storage.CopyToUnchecked(result.Storage);
+                Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
                 for (int i = 0; i < diagonal.Length; i++)
                 {
diff --git a/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs
index 3d576fc3..cde8bb12 100644
--- a/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs
@@ -482,7 +482,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             var diagonalOther = other.Storage as DiagonalMatrixStorage<double>;
             if (diagonalOther != null)
             {
-                Storage.CopyToUnchecked(result.Storage);
+                Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
                 for (int i = 0; i < diagonal.Length; i++)
                 {
diff --git a/src/Numerics/LinearAlgebra/Matrix.cs b/src/Numerics/LinearAlgebra/Matrix.cs
index 4e936026..cf8b7a7d 100644
--- a/src/Numerics/LinearAlgebra/Matrix.cs
+++ b/src/Numerics/LinearAlgebra/Matrix.cs
@@ -261,7 +261,7 @@ namespace MathNet.Numerics.LinearAlgebra
             }
 
             var ret = Vector<T>.Build.SameAs(this, ColumnCount);
-            Storage.CopySubRowToUnchecked(ret.Storage, index, 0, 0, ColumnCount);
+            Storage.CopySubRowToUnchecked(ret.Storage, index, 0, 0, ColumnCount, ExistingData.AssumeZeros);
             return ret;
         }
 
@@ -346,7 +346,7 @@ namespace MathNet.Numerics.LinearAlgebra
             }
 
             var ret = Vector<T>.Build.SameAs(this, RowCount);
-            Storage.CopySubColumnToUnchecked(ret.Storage, index, 0, 0, RowCount);
+            Storage.CopySubColumnToUnchecked(ret.Storage, index, 0, 0, RowCount, ExistingData.AssumeZeros);
             return ret;
         }
 
@@ -1121,8 +1121,8 @@ namespace MathNet.Numerics.LinearAlgebra
                 throw new ArgumentException(Resources.ArgumentMatrixSameColumnDimension);
             }
 
-            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount);
-            right.Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, right.RowCount, 0, ColumnCount, right.ColumnCount);
+            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount, ExistingData.Clear);
+            right.Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, right.RowCount, 0, ColumnCount, right.ColumnCount, ExistingData.Clear);
         }
 
         /// <summary>
@@ -1183,8 +1183,8 @@ namespace MathNet.Numerics.LinearAlgebra
                 throw DimensionsDontMatch<ArgumentException>(this, result, "result");
             }
 
-            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount);
-            lower.Storage.CopySubMatrixToUnchecked(result.Storage, 0, RowCount, lower.RowCount, 0, 0, lower.ColumnCount);
+            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount, ExistingData.Clear);
+            lower.Storage.CopySubMatrixToUnchecked(result.Storage, 0, RowCount, lower.RowCount, 0, 0, lower.ColumnCount, ExistingData.Clear);
         }
 
         /// <summary>
@@ -1205,8 +1205,8 @@ namespace MathNet.Numerics.LinearAlgebra
             }
 
             var result = Build.SameAs(this, lower, RowCount + lower.RowCount, ColumnCount + lower.ColumnCount, RowCount != ColumnCount);
-            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount);
-            lower.Storage.CopySubMatrixToUnchecked(result.Storage, 0, RowCount, lower.RowCount, 0, ColumnCount, lower.ColumnCount);
+            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount, ExistingData.AssumeZeros);
+            lower.Storage.CopySubMatrixToUnchecked(result.Storage, 0, RowCount, lower.RowCount, 0, ColumnCount, lower.ColumnCount, ExistingData.AssumeZeros);
             return result;
         }
 
@@ -1237,8 +1237,8 @@ namespace MathNet.Numerics.LinearAlgebra
                 throw DimensionsDontMatch<ArgumentException>(this, result, "result");
             }
 
-            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount);
-            lower.Storage.CopySubMatrixToUnchecked(result.Storage, 0, RowCount, lower.RowCount, 0, ColumnCount, lower.ColumnCount);
+            Storage.CopySubMatrixToUnchecked(result.Storage, 0, 0, RowCount, 0, 0, ColumnCount, ExistingData.Clear);
+            lower.Storage.CopySubMatrixToUnchecked(result.Storage, 0, RowCount, lower.RowCount, 0, ColumnCount, lower.ColumnCount, ExistingData.Clear);
         }
 
         /// <summary>
diff --git a/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs
index bc488a59..23b37382 100644
--- a/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs
@@ -482,7 +482,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
             var diagonalOther = other.Storage as DiagonalMatrixStorage<float>;
             if (diagonalOther != null)
             {
-                Storage.CopyToUnchecked(result.Storage);
+                Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
                 for (int i = 0; i < diagonal.Length; i++)
                 {
diff --git a/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs b/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs
index 381fe52a..d6b8e5c1 100644
--- a/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs
@@ -376,7 +376,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // MATRIX COPY
 
-        internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -405,7 +405,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopySubMatrixToUnchecked(MatrixStorage<T> target,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -442,7 +442,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // ROW COPY
 
         internal override void CopySubRowToUnchecked(VectorStorage<T> target, int rowIndex, int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            ExistingData existingData)
         {
             var targetDense = target as DenseVectorStorage<T>;
             if (targetDense != null)
@@ -465,7 +465,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // COLUMN COPY
 
         internal override void CopySubColumnToUnchecked(VectorStorage<T> target, int columnIndex, int sourceRowIndex, int targetRowIndex, int rowCount,
-            ExistingData existingData = ExistingData.Clear)
+            ExistingData existingData)
         {
             var targetDense = target as DenseVectorStorage<T>;
             if (targetDense != null)
@@ -485,7 +485,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // TRANSPOSE
 
-        internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -782,7 +782,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal override void MapToUnchecked<TU>(MatrixStorage<TU> target, Func<T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<TU>;
             if (denseTarget != null)
@@ -810,7 +810,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal override void MapIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<TU>;
             if (denseTarget != null)
@@ -845,7 +845,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void MapSubMatrixIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<TU>;
             if (denseTarget != null)
@@ -881,7 +881,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // FUNCTIONAL COMBINATORS: FOLD
 
-        internal override void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal override void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             for (int i = 0; i < RowCount; i++)
             {
@@ -894,7 +894,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
         }
 
-        internal override void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal override void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             for (int j = 0; j < ColumnCount; j++)
             {
diff --git a/src/Numerics/LinearAlgebra/Storage/DenseVectorStorage.cs b/src/Numerics/LinearAlgebra/Storage/DenseVectorStorage.cs
index 59913410..2cbaaee1 100644
--- a/src/Numerics/LinearAlgebra/Storage/DenseVectorStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/DenseVectorStorage.cs
@@ -181,7 +181,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // VECTOR COPY
 
-        internal override void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData)
         {
             var denseTarget = target as DenseVectorStorage<T>;
             if (denseTarget != null)
@@ -226,7 +226,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // ROW COPY
 
-        internal override void CopyToRowUnchecked(MatrixStorage<T> target, int rowIndex, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToRowUnchecked(MatrixStorage<T> target, int rowIndex, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -248,7 +248,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // COLUMN COPY
 
-        internal override void CopyToColumnUnchecked(MatrixStorage<T> target, int columnIndex, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToColumnUnchecked(MatrixStorage<T> target, int columnIndex, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -268,8 +268,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // SUB-VECTOR COPY
 
         internal override void CopySubVectorToUnchecked(VectorStorage<T> target,
-            int sourceIndex, int targetIndex, int count,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceIndex, int targetIndex, int count, ExistingData existingData)
         {
             var denseTarget = target as DenseVectorStorage<T>;
             if (denseTarget != null)
@@ -286,8 +285,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // SUB-ROW COPY
 
         internal override void CopyToSubRowUnchecked(MatrixStorage<T> target, int rowIndex,
-            int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceColumnIndex, int targetColumnIndex, int columnCount, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -310,8 +308,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // SUB-COLUMN COPY
 
         internal override void CopyToSubColumnUnchecked(MatrixStorage<T> target, int columnIndex,
-            int sourceRowIndex, int targetRowIndex, int rowCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceRowIndex, int targetRowIndex, int rowCount, ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -358,8 +355,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // FUNCTIONAL COMBINATORS
 
-        internal override void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f, Zeros zeros, ExistingData existingData)
         {
             var denseTarget = target as DenseVectorStorage<TU>;
             if (denseTarget != null)
@@ -382,8 +378,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
         }
 
-        internal override void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f, Zeros zeros, ExistingData existingData)
         {
             var denseTarget = target as DenseVectorStorage<TU>;
             if (denseTarget != null)
@@ -406,7 +401,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
         }
 
-        internal override void Map2ToUnchecked(VectorStorage<T> target, VectorStorage<T> other, Func<T, T, T> f, Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void Map2ToUnchecked(VectorStorage<T> target, VectorStorage<T> other, Func<T, T, T> f, Zeros zeros, ExistingData existingData)
         {
             if (target is SparseVectorStorage<T>)
             {
@@ -461,7 +456,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             base.Map2ToUnchecked(target, other, f, zeros, existingData);
         }
 
-        internal override TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros = Zeros.AllowSkip)
+        internal override TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
         {
             var denseOther = other as DenseVectorStorage<TOther>;
             if (denseOther != null)
diff --git a/src/Numerics/LinearAlgebra/Storage/DiagonalMatrixStorage.cs b/src/Numerics/LinearAlgebra/Storage/DiagonalMatrixStorage.cs
index 09a182bd..891e5249 100644
--- a/src/Numerics/LinearAlgebra/Storage/DiagonalMatrixStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/DiagonalMatrixStorage.cs
@@ -252,7 +252,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // MATRIX COPY
 
-        internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             var diagonalTarget = target as DiagonalMatrixStorage<T>;
             if (diagonalTarget != null)
@@ -323,7 +323,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopySubMatrixToUnchecked(MatrixStorage<T> target,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            ExistingData existingData)
         {
             var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
             if (denseTarget != null)
@@ -453,8 +453,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // ROW COPY
 
         internal override void CopySubRowToUnchecked(VectorStorage<T> target, int rowIndex,
-            int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceColumnIndex, int targetColumnIndex, int columnCount, ExistingData existingData)
         {
             if (existingData == ExistingData.Clear)
             {
@@ -470,8 +469,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // COLUMN COPY
 
         internal override void CopySubColumnToUnchecked(VectorStorage<T> target, int columnIndex,
-            int sourceRowIndex, int targetRowIndex, int rowCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceRowIndex, int targetRowIndex, int rowCount, ExistingData existingData)
         {
             if (existingData == ExistingData.Clear)
             {
@@ -486,7 +484,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // TRANSPOSE
 
-        internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             CopyToUnchecked(target, existingData);
         }
@@ -763,7 +761,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal override void MapToUnchecked<TU>(MatrixStorage<TU> target, Func<T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(Zero));
 
@@ -812,7 +810,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal override void MapIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(0, 1, Zero));
 
@@ -863,7 +861,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void MapSubMatrixIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
         {
             var diagonalTarget = target as DiagonalMatrixStorage<TU>;
             if (diagonalTarget != null)
@@ -1034,7 +1032,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // FUNCTIONAL COMBINATORS: FOLD
 
-        internal override void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal override void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             if (zeros == Zeros.AllowSkip)
             {
@@ -1062,7 +1060,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
         }
 
-        internal override void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal override void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             if (zeros == Zeros.AllowSkip)
             {
diff --git a/src/Numerics/LinearAlgebra/Storage/MatrixStorage.cs b/src/Numerics/LinearAlgebra/Storage/MatrixStorage.cs
index e2799e54..7d83e0f6 100644
--- a/src/Numerics/LinearAlgebra/Storage/MatrixStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/MatrixStorage.cs
@@ -320,7 +320,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             CopyToUnchecked(target, existingData);
         }
 
-        internal virtual void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal virtual void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             for (int j = 0; j < ColumnCount; j++)
             {
@@ -362,7 +362,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal virtual void CopySubMatrixToUnchecked(MatrixStorage<T> target,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            ExistingData existingData)
         {
             for (int j = sourceColumnIndex, jj = targetColumnIndex; j < sourceColumnIndex + columnCount; j++, jj++)
             {
@@ -405,8 +405,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal virtual void CopySubRowToUnchecked(VectorStorage<T> target, int rowIndex,
-            int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceColumnIndex, int targetColumnIndex, int columnCount, ExistingData existingData)
         {
             for (int j = sourceColumnIndex, jj = targetColumnIndex; j < sourceColumnIndex + columnCount; j++, jj++)
             {
@@ -446,8 +445,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal virtual void CopySubColumnToUnchecked(VectorStorage<T> target, int columnIndex,
-            int sourceRowIndex, int targetRowIndex, int rowCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceRowIndex, int targetRowIndex, int rowCount, ExistingData existingData)
         {
             for (int i = sourceRowIndex, ii = targetRowIndex; i < sourceRowIndex + rowCount; i++, ii++)
             {
@@ -478,7 +476,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             TransposeToUnchecked(target, existingData);
         }
 
-        internal virtual void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal virtual void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             for (int j = 0; j < ColumnCount; j++)
             {
@@ -711,8 +709,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             MapToUnchecked(target, f, zeros, existingData);
         }
 
-        internal virtual void MapToUnchecked<TU>(MatrixStorage<TU> target, Func<T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal virtual void MapToUnchecked<TU>(MatrixStorage<TU> target, Func<T, TU> f, Zeros zeros, ExistingData existingData)
             where TU : struct, IEquatable<TU>, IFormattable
         {
             for (int i = 0; i < RowCount; i++)
@@ -742,8 +739,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             MapIndexedToUnchecked(target, f, zeros, existingData);
         }
 
-        internal virtual void MapIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal virtual void MapIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f, Zeros zeros, ExistingData existingData)
             where TU : struct, IEquatable<TU>, IFormattable
         {
             for (int j = 0; j < ColumnCount; j++)
@@ -786,7 +782,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal virtual void MapSubMatrixIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
             where TU : struct, IEquatable<TU>, IFormattable
         {
             for (int j = sourceColumnIndex, jj = targetColumnIndex; j < sourceColumnIndex + columnCount; j++, jj++)
@@ -825,7 +821,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         /// <remarks>The state array will not be modified, unless it is the same instance as the target array (which is allowed).</remarks>
-        internal virtual void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal virtual void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             for (int i = 0; i < RowCount; i++)
             {
@@ -863,7 +859,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         /// <remarks>The state array will not be modified, unless it is the same instance as the target array (which is allowed).</remarks>
-        internal virtual void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal virtual void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             for (int j = 0; j < ColumnCount; j++)
             {
diff --git a/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs b/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs
index 2f6f280c..9e037bab 100644
--- a/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs
@@ -816,7 +816,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // MATRIX COPY
 
-        internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             var sparseTarget = target as SparseCompressedRowMatrixStorage<T>;
             if (sparseTarget != null)
@@ -892,7 +892,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopySubMatrixToUnchecked(MatrixStorage<T> target,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            ExistingData existingData)
         {
             if (target == null)
             {
@@ -1007,8 +1007,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // ROW COPY
 
         internal override void CopySubRowToUnchecked(VectorStorage<T> target, int rowIndex,
-            int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceColumnIndex, int targetColumnIndex, int columnCount, ExistingData existingData)
         {
             if (existingData == ExistingData.Clear)
             {
@@ -1034,7 +1033,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // TRANSPOSE
 
-        internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
             var sparseTarget = target as SparseCompressedRowMatrixStorage<T>;
             if (sparseTarget != null)
@@ -1576,8 +1575,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
         }
 
-        internal override void MapToUnchecked<TU>(MatrixStorage<TU> target, Func<T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void MapToUnchecked<TU>(MatrixStorage<TU> target, Func<T, TU> f, Zeros zeros, ExistingData existingData)
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(Zero));
 
@@ -1671,8 +1669,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
         }
 
-        internal override void MapIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void MapIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f, Zeros zeros, ExistingData existingData)
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(0, 1, Zero));
 
@@ -1769,7 +1766,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void MapSubMatrixIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
             int sourceRowIndex, int targetRowIndex, int rowCount,
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+            Zeros zeros, ExistingData existingData)
         {
             var sparseTarget = target as SparseCompressedRowMatrixStorage<TU>;
             if (sparseTarget != null)
@@ -1978,7 +1975,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // FUNCTIONAL COMBINATORS: FOLD
 
-        internal override void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal override void FoldByRowUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             if (zeros == Zeros.AllowSkip)
             {
@@ -2018,7 +2015,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
         }
 
-        internal override void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros = Zeros.AllowSkip)
+        internal override void FoldByColumnUnchecked<TU>(TU[] target, Func<TU, T, TU> f, Func<TU, int, TU> finalize, TU[] state, Zeros zeros)
         {
             if (!ReferenceEquals(state, target))
             {
diff --git a/src/Numerics/LinearAlgebra/Storage/SparseVectorStorage.cs b/src/Numerics/LinearAlgebra/Storage/SparseVectorStorage.cs
index 94b13f68..0f383cb3 100644
--- a/src/Numerics/LinearAlgebra/Storage/SparseVectorStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/SparseVectorStorage.cs
@@ -417,7 +417,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // VECTOR COPY
 
-        internal override void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData)
         {
             var sparseTarget = target as SparseVectorStorage<T>;
             if (sparseTarget != null)
@@ -468,7 +468,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // Row COPY
 
-        internal override void CopyToRowUnchecked(MatrixStorage<T> target, int rowIndex, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToRowUnchecked(MatrixStorage<T> target, int rowIndex, ExistingData existingData)
         {
             if (existingData == ExistingData.Clear)
             {
@@ -488,7 +488,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // COLUMN COPY
 
-        internal override void CopyToColumnUnchecked(MatrixStorage<T> target, int columnIndex, ExistingData existingData = ExistingData.Clear)
+        internal override void CopyToColumnUnchecked(MatrixStorage<T> target, int columnIndex, ExistingData existingData)
         {
             if (existingData == ExistingData.Clear)
             {
@@ -509,8 +509,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         // SUB-VECTOR COPY
 
         internal override void CopySubVectorToUnchecked(VectorStorage<T> target,
-            int sourceIndex, int targetIndex, int count,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceIndex, int targetIndex, int count, ExistingData existingData)
         {
             var sparseTarget = target as SparseVectorStorage<T>;
             if (sparseTarget != null)
@@ -648,8 +647,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         // FUNCTIONAL COMBINATORS
 
-        internal override void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f, Zeros zeros, ExistingData existingData)
         {
             var sparseTarget = target as SparseVectorStorage<TU>;
             if (sparseTarget != null)
@@ -723,8 +721,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             base.MapToUnchecked(target, f, zeros, existingData);
         }
 
-        internal override void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f, Zeros zeros, ExistingData existingData)
         {
             var sparseTarget = target as SparseVectorStorage<TU>;
             if (sparseTarget != null)
@@ -798,7 +795,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             base.MapIndexedToUnchecked(target, f, zeros, existingData);
         }
 
-        internal override void Map2ToUnchecked(VectorStorage<T> target, VectorStorage<T> other, Func<T, T, T> f, Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal override void Map2ToUnchecked(VectorStorage<T> target, VectorStorage<T> other, Func<T, T, T> f, Zeros zeros, ExistingData existingData)
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(Zero, Zero));
 
@@ -948,7 +945,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             base.Map2ToUnchecked(target, other, f, zeros, existingData);
         }
 
-        internal override TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros = Zeros.AllowSkip)
+        internal override TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
         {
             var sparseOther = other as SparseVectorStorage<TOther>;
             if (sparseOther != null)
diff --git a/src/Numerics/LinearAlgebra/Storage/VectorStorage.cs b/src/Numerics/LinearAlgebra/Storage/VectorStorage.cs
index 87993f59..04077836 100644
--- a/src/Numerics/LinearAlgebra/Storage/VectorStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/VectorStorage.cs
@@ -207,7 +207,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             CopyToUnchecked(target, existingData);
         }
 
-        internal virtual void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData = ExistingData.Clear)
+        internal virtual void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData)
         {
             for (int i = 0; i < Length; i++)
             {
@@ -233,7 +233,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             CopyToRowUnchecked(target, rowIndex, existingData);
         }
 
-        internal virtual void CopyToRowUnchecked(MatrixStorage<T> target, int rowIndex, ExistingData existingData = ExistingData.Clear)
+        internal virtual void CopyToRowUnchecked(MatrixStorage<T> target, int rowIndex, ExistingData existingData)
         {
             for (int j = 0; j < Length; j++)
             {
@@ -259,7 +259,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             CopyToColumnUnchecked(target, columnIndex, existingData);
         }
 
-        internal virtual void CopyToColumnUnchecked(MatrixStorage<T> target, int columnIndex, ExistingData existingData = ExistingData.Clear)
+        internal virtual void CopyToColumnUnchecked(MatrixStorage<T> target, int columnIndex, ExistingData existingData)
         {
             for (int i = 0; i < Length; i++)
             {
@@ -288,8 +288,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal virtual void CopySubVectorToUnchecked(VectorStorage<T> target,
-            int sourceIndex, int targetIndex, int count,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceIndex, int targetIndex, int count, ExistingData existingData)
         {
             if (ReferenceEquals(this, target))
             {
@@ -333,8 +332,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal virtual void CopyToSubRowUnchecked(MatrixStorage<T> target, int rowIndex,
-            int sourceColumnIndex, int targetColumnIndex, int columnCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceColumnIndex, int targetColumnIndex, int columnCount, ExistingData existingData)
         {
             for (int j = sourceColumnIndex, jj = targetColumnIndex; j < sourceColumnIndex + columnCount; j++, jj++)
             {
@@ -363,8 +361,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         }
 
         internal virtual void CopyToSubColumnUnchecked(MatrixStorage<T> target, int columnIndex,
-            int sourceRowIndex, int targetRowIndex, int rowCount,
-            ExistingData existingData = ExistingData.Clear)
+            int sourceRowIndex, int targetRowIndex, int rowCount, ExistingData existingData)
         {
             for (int i = sourceRowIndex, ii = targetRowIndex; i < sourceRowIndex + rowCount; i++, ii++)
             {
@@ -433,8 +430,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             MapToUnchecked(target, f, zeros, existingData);
         }
 
-        internal virtual void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal virtual void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f, Zeros zeros, ExistingData existingData)
             where TU : struct, IEquatable<TU>, IFormattable
         {
             for (int i = 0; i < Length; i++)
@@ -460,8 +456,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             MapIndexedToUnchecked(target, f, zeros, existingData);
         }
 
-        internal virtual void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal virtual void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f, Zeros zeros, ExistingData existingData)
             where TU : struct, IEquatable<TU>, IFormattable
         {
             for (int i = 0; i < Length; i++)
@@ -496,8 +491,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             Map2ToUnchecked(target, other, f, zeros, existingData);
         }
 
-        internal virtual void Map2ToUnchecked(VectorStorage<T> target, VectorStorage<T> other, Func<T, T, T> f,
-            Zeros zeros = Zeros.AllowSkip, ExistingData existingData = ExistingData.Clear)
+        internal virtual void Map2ToUnchecked(VectorStorage<T> target, VectorStorage<T> other, Func<T, T, T> f, Zeros zeros, ExistingData existingData)
         {
             for (int i = 0; i < Length; i++)
             {
@@ -521,7 +515,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return Fold2Unchecked(other, f, state, zeros);
         }
 
-        internal virtual TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros = Zeros.AllowSkip)
+        internal virtual TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
             where TOther : struct, IEquatable<TOther>, IFormattable
         {
             for (int i = 0; i < Length; i++)