diff --git a/src/FSharp/Fit.fs b/src/FSharp/Fit.fs
index 4497b7ad..686449a2 100644
--- a/src/FSharp/Fit.fs
+++ b/src/FSharp/Fit.fs
@@ -62,7 +62,7 @@ module Fit =
     let linear functions (x:_[]) (y:float[]) =
         functions
         |> List.map (fun f -> List.init (Array.length x) (fun i -> f x.[i]))
-        |> DenseMatrix.ofColumnList (Array.length x) (List.length functions)
+        |> DenseMatrix.ofColumnList
         |> fun m -> m.QR(QRMethod.Thin).Solve(DenseVector(y)).ToArray()
         |> List.ofArray
 
diff --git a/src/FSharp/LinearAlgebra.Double.Matrix.fs b/src/FSharp/LinearAlgebra.Double.Matrix.fs
index 6ad192b4..55a35dc3 100644
--- a/src/FSharp/LinearAlgebra.Double.Matrix.fs
+++ b/src/FSharp/LinearAlgebra.Double.Matrix.fs
@@ -61,6 +61,7 @@ module Matrix =
             v.At(k, macc)
         v :> _ Vector
 
+
 /// A module which implements functional dense vector operations.
 [<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
 module DenseMatrix =
@@ -78,7 +79,7 @@ module DenseMatrix =
     let inline create (rows: int) (cols: int) x = DenseMatrix.Create(rows, cols, fun i j -> x) :> _ Matrix
 
     /// Create a matrix with the given dimension and set all diagonal values to x. All other values are zero.
-    let inline createDiag (rows: int) (cols: int) x =
+    let createDiag (rows: int) (cols: int) x =
         let A = DenseMatrix(rows,cols)
         for i=0 to min (rows-1) (cols-1) do A.At(i,i,x)
         A :> _ Matrix
@@ -86,8 +87,14 @@ module DenseMatrix =
     /// Initialize a matrix by calling a construction function for every element.
     let inline init (rows: int) (cols: int) (f: int -> int -> float) = DenseMatrix.Create(rows, cols, fun i j -> f i j) :> _ Matrix
 
+    /// Initialize a matrix by calling a construction function for every row.
+    let inline initRows (rows: int) (f: int -> Vector<float>) = DenseMatrix.OfRowVectors(Array.init rows f) :> _ Matrix
+
+    /// Initialize a matrix by calling a construction function for every column.
+    let inline initColumns (cols: int) (f: int -> Vector<float>) = DenseMatrix.OfColumnVectors(Array.init cols f) :> _ Matrix
+
     /// Initialize a matrix by calling a construction function for every diagonal element. All other values are zero.
-    let inline initDiag (rows: int) (cols: int) (f: int -> float) =
+    let initDiag (rows: int) (cols: int) (f: int -> float) =
         let A = DenseMatrix(rows,cols)
         for i=0 to min (rows-1) (cols-1) do A.At(i,i,f i)
         A :> _ Matrix
@@ -95,67 +102,54 @@ module DenseMatrix =
     /// Create an identity matrix with the given dimension.
     let inline identity (rows: int) (cols: int) = createDiag rows cols 1.0
 
-
     /// Create a matrix from a 2D array of floating point numbers.
     let inline ofArray2 array = DenseMatrix.OfArray(array) :> _ Matrix
 
-    /// Create a matrix from a list of float lists. Every list in the master list specifies a row.
-    /// If the dimensions are known, consider to use ofRowList instead to avoid multiple enumeration.
-    let inline ofList (fll: float list list) =
-        let n = List.length fll
-        let m = List.length (List.head fll)
-        DenseMatrix.OfRowsCovariant(n, m, fll) :> _ Matrix
-
-    /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a row.
-    /// If the dimensions are known, consider to use ofRowSeq instead to avoid multiple enumeration.
-    let inline ofSeq (fss: #seq<#seq<float>>) =
-        let n = Seq.length fss
-        let m = Seq.length (Seq.head fss)
-        DenseMatrix.OfRowsCovariant(n, m, fss) :> _ Matrix
-
-
     /// Create a matrix from a list of row vectors.
-    let inline ofRows (vectors: #Vector<float> list) = DenseMatrix.OfRowVectors(vectors |> Array.ofList |> box |> unbox) :> _ Matrix
+    let inline ofRows (rows: Vector<float> list) = DenseMatrix.OfRowVectors(Array.ofList rows) :> _ Matrix
+
+    /// Create a matrix from a list of row arrays.
+    let inline ofRowArrays (rows: float[][]) = DenseMatrix.OfRowArrays(rows) :> _ Matrix
 
     /// Create a matrix from a list of float lists. Every list in the master list specifies a row.
-    let inline ofRowList (rows: int) (cols: int) (fll: float list list) = DenseMatrix.OfRowsCovariant(rows, cols, fll) :> _ Matrix
+    let inline ofRowList (rows: float list list) = DenseMatrix.OfRowArrays(rows |> List.map List.toArray |> List.toArray) :> _ Matrix
+
+    /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a row.
+    let inline ofRowSeq (rows: #seq<#seq<float>>) = DenseMatrix.OfRowArrays(rows |> Seq.map Seq.toArray |> Seq.toArray) :> _ Matrix
 
     /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a row.
-    let inline ofRowSeq (rows: int) (cols: int) (fss: #seq<#seq<float>>) = DenseMatrix.OfRowsCovariant(rows, cols, fss) :> _ Matrix
+    let inline ofRowSeq2 (rows: int) (cols: int) (seqOfRows: #seq<seq<float>>) = DenseMatrix.OfRows(rows, cols, seqOfRows) :> _ Matrix
 
     /// Create a matrix from a list of column vectors.
-    let inline ofColumns (vectors: #Vector<float> list) = DenseMatrix.OfColumnVectors(vectors |> Array.ofList |> box |> unbox) :> _ Matrix
+    let inline ofColumns (columns: Vector<float> list) = DenseMatrix.OfColumnVectors(Array.ofList columns) :> _ Matrix
+
+    /// Create a matrix from a list of column arrays.
+    let inline ofColumnArrays (columns: float[][]) = DenseMatrix.OfColumnArrays(columns) :> _ Matrix
 
     /// Create a matrix from a list of float lists. Every list in the master list specifies a column.
-    let inline ofColumnList (rows: int) (cols: int) (fll: float list list) = DenseMatrix.OfColumnsCovariant(rows, cols, fll) :> _ Matrix
+    let inline ofColumnList (columns: float list list) = DenseMatrix.OfColumnArrays(columns |> List.map List.toArray |> List.toArray) :> _ Matrix
+
+    /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a column.
+    let inline ofColumnSeq (columns: #seq<#seq<float>>) = DenseMatrix.OfColumnArrays(columns |> Seq.map Seq.toArray |> Seq.toArray) :> _ Matrix
 
     /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a column.
-    let inline ofColumnSeq (rows: int) (cols: int) (fss: #seq<#seq<float>>) = DenseMatrix.OfColumnsCovariant(rows, cols, fss) :> _ Matrix
+    let inline ofColumnSeq2 (rows: int) (cols: int) (seqOfCols: #seq<seq<float>>) = DenseMatrix.OfColumns(rows, cols, seqOfCols) :> _ Matrix
 
     /// Create a matrix with a given dimension from an indexed list of row, column, value tuples.
-    let inline ofListi (rows: int) (cols: int) (fl: list<int * int * float>) = DenseMatrix.OfIndexed(rows, cols, Seq.ofList fl) :> _ Matrix
+    let inline ofListi (rows: int) (cols: int) (indexed: list<int * int * float>) = DenseMatrix.OfIndexed(rows, cols, Seq.ofList indexed) :> _ Matrix
 
     /// Create a matrix with a given dimension from an indexed sequences of row, column, value tuples.
-    let inline ofSeqi (rows: int) (cols: int) (fs: #seq<int * int * float>) = DenseMatrix.OfIndexed(rows, cols, fs) :> _ Matrix
+    let inline ofSeqi (rows: int) (cols: int) (indexed: #seq<int * int * float>) = DenseMatrix.OfIndexed(rows, cols, indexed) :> _ Matrix
 
-    /// Create a square matrix with the vector elements on the diagonal.
-    let inline ofDiag (v: #Vector<float>) =
-        let n = v.Count
-        let A = DenseMatrix(n,n)
+    /// Create a matrix with the vector elements on the diagonal.
+    let ofDiag2 (rows: int) (cols: int) (v: Vector<float>) =
+        let A = DenseMatrix(rows,cols)
         A.SetDiagonal(v)
         A :> _ Matrix
 
-    /// Initialize a matrix by calling a construction function for every row.
-    let inline initRow (rows: int) (cols: int) (f: int -> #Vector<float>) =
-        let A = DenseMatrix(rows,cols)
-        for i=0 to rows-1 do A.SetRow(i, f i)
-        A :> _ Matrix
+    /// Create a square matrix with the vector elements on the diagonal.
+    let inline ofDiag (v: Vector<float>) = ofDiag2 v.Count v.Count v
 
-    /// Initialize a matrix by calling a construction function for every column.
-    let inline initCol (rows: int) (cols: int) (f: int -> #Vector<float>) =
-        let A = DenseMatrix(rows,cols)
-        for i=0 to cols-1 do A.SetColumn(i, f i)
-        A :> _ Matrix
 
 /// A module which implements functional sparse vector operations.
 [<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
@@ -165,7 +159,7 @@ module SparseMatrix =
     let inline zeroCreate (rows: int) (cols: int) = SparseMatrix(rows, cols) :> _ Matrix
 
     /// Create a matrix with the given dimension and set all diagonal values to x. All other values are zero.
-    let inline createDiag (rows: int) (cols: int) x =
+    let createDiag (rows: int) (cols: int) x =
         let A = SparseMatrix(rows,cols)
         for i=0 to min (rows-1) (cols-1) do A.At(i,i,x)
         A :> _ Matrix
@@ -173,8 +167,14 @@ module SparseMatrix =
     /// Initialize a matrix by calling a construction function for every element.
     let inline init (rows: int) (cols: int) (f: int -> int -> float) = SparseMatrix.Create(rows, cols, fun n m -> f n m) :> _ Matrix
 
+    /// Initialize a matrix by calling a construction function for every row.
+    let inline initRows (rows: int) (f: int -> Vector<float>) = SparseMatrix.OfRowVectors(Array.init rows f) :> _ Matrix
+
+    /// Initialize a matrix by calling a construction function for every column.
+    let inline initColumns (cols: int) (f: int -> Vector<float>) = SparseMatrix.OfColumnVectors(Array.init cols f) :> _ Matrix
+
     /// Initialize a matrix by calling a construction function for every diagonal element. All other values are zero.
-    let inline initDiag (rows: int) (cols: int) (f: int -> float) =
+    let initDiag (rows: int) (cols: int) (f: int -> float) =
         let A = SparseMatrix(rows,cols)
         for i=0 to min (rows-1) (cols-1) do A.At(i,i,f i)
         A :> _ Matrix
@@ -182,58 +182,50 @@ module SparseMatrix =
     /// Create an identity matrix with the given dimension.
     let inline identity (rows: int) (cols: int) = createDiag rows cols 1.0
 
-
     /// Create a matrix from a 2D array of floating point numbers.
     let inline ofArray2 array = SparseMatrix.OfArray(array) :> _ Matrix
 
-    /// Create a matrix with a given dimension from an indexed sequences of row, column, value tuples.
-    [<System.ObsoleteAttribute("Use ofSeqi instead. Will be changed to expect a non-indexed seq in a future version.")>]
-    let inline ofSeq (rows: int) (cols: int) (fs: #seq<int * int * float>) = SparseMatrix.OfIndexed(rows, cols, fs) :> _ Matrix
-
-    /// Create a matrix with a given dimension from an indexed list of row, column, value tuples.
-    [<System.ObsoleteAttribute("Use ofListi instead. Will be changed to expect a non-indexed list in a future version.")>]
-    let inline ofList (rows: int) (cols: int) (fl: list<int * int * float>) = SparseMatrix.OfIndexed(rows, cols, Seq.ofList fl) :> _ Matrix
-
-
     /// Create a matrix from a list of row vectors.
-    let inline ofRows (vectors: #Vector<float> list) = SparseMatrix.OfRowVectors(vectors |> Array.ofList |> box |> unbox) :> _ Matrix
+    let inline ofRows (rows: Vector<float> list) = SparseMatrix.OfRowVectors(Array.ofList rows) :> _ Matrix
+
+    /// Create a matrix from a list of row arrays.
+    let inline ofRowArrays (rows: float[][]) = SparseMatrix.OfRowArrays(rows) :> _ Matrix
 
     /// Create a matrix from a list of float lists. Every list in the master list specifies a row.
-    let inline ofRowList (rows: int) (cols: int) (fll: float list list) = SparseMatrix.OfRowsCovariant(rows, cols, fll) :> _ Matrix
+    let inline ofRowList (rows: float list list) = SparseMatrix.OfRowArrays(rows |> List.map List.toArray |> List.toArray) :> _ Matrix
+
+    /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a row.
+    let inline ofRowSeq (rows: #seq<#seq<float>>) = SparseMatrix.OfRowArrays(rows |> Seq.map Seq.toArray |> Seq.toArray) :> _ Matrix
 
     /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a row.
-    let inline ofRowSeq (rows: int) (cols: int) (fss: #seq<#seq<float>>) = SparseMatrix.OfRowsCovariant(rows, cols, fss) :> _ Matrix
+    let inline ofRowSeq2 (rows: int) (cols: int) (seqOfRows: #seq<seq<float>>) = SparseMatrix.OfRows(rows, cols, seqOfRows) :> _ Matrix
 
     /// Create a matrix from a list of column vectors.
-    let inline ofColumns (vectors: #Vector<float> list) = SparseMatrix.OfColumnVectors(vectors |> Array.ofList |> box |> unbox) :> _ Matrix
+    let inline ofColumns (columns: Vector<float> list) = SparseMatrix.OfColumnVectors(Array.ofList columns) :> _ Matrix
+
+    /// Create a matrix from a list of column arrays.
+    let inline ofColumnArrays (columns: float[][]) = SparseMatrix.OfColumnArrays(columns) :> _ Matrix
 
     /// Create a matrix from a list of float lists. Every list in the master list specifies a column.
-    let inline ofColumnList (rows: int) (cols: int) (fll: float list list) = SparseMatrix.OfColumnsCovariant(rows, cols, fll) :> _ Matrix
+    let inline ofColumnList (columns: float list list) = SparseMatrix.OfColumnArrays(columns |> List.map List.toArray |> List.toArray) :> _ Matrix
+
+    /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a column.
+    let inline ofColumnSeq (columns: #seq<#seq<float>>) = SparseMatrix.OfColumnArrays(columns |> Seq.map Seq.toArray |> Seq.toArray) :> _ Matrix
 
     /// Create a matrix from a list of sequences. Every sequence in the master sequence specifies a column.
-    let inline ofColumnSeq (rows: int) (cols: int) (fss: #seq<#seq<float>>) = SparseMatrix.OfColumnsCovariant(rows, cols, fss) :> _ Matrix
+    let inline ofColumnSeq2 (rows: int) (cols: int) (seqOfCols: #seq<seq<float>>) = SparseMatrix.OfColumns(rows, cols, seqOfCols) :> _ Matrix
 
     /// Create a matrix with a given dimension from an indexed list of row, column, value tuples.
-    let inline ofListi (rows: int) (cols: int) (fl: list<int * int * float>) = SparseMatrix.OfIndexed(rows, cols, Seq.ofList fl) :> _ Matrix
+    let inline ofListi (rows: int) (cols: int) (indexed: list<int * int * float>) = SparseMatrix.OfIndexed(rows, cols, Seq.ofList indexed) :> _ Matrix
 
     /// Create a matrix with a given dimension from an indexed sequences of row, column, value tuples.
-    let inline ofSeqi (rows: int) (cols: int) (fs: #seq<int * int * float>) = SparseMatrix.OfIndexed(rows, cols, fs) :> _ Matrix
-
-    /// Create a square matrix with the vector elements on the diagonal.
-    let inline ofDiag (v: #Vector<float>) =
-        let n = v.Count
-        let A = SparseMatrix(n,n)
-        A.SetDiagonal(v)
-        A :> _ Matrix
+    let inline ofSeqi (rows: int) (cols: int) (indexed: #seq<int * int * float>) = SparseMatrix.OfIndexed(rows, cols, indexed) :> _ Matrix
 
-    /// Initialize a matrix by calling a construction function for every row.
-    let inline initRow (rows: int) (cols: int) (f: int -> #Vector<float>) =
+    /// Create a matrix with the vector elements on the diagonal.
+    let ofDiag2 (rows: int) (cols: int) (v: Vector<float>) =
         let A = SparseMatrix(rows,cols)
-        for i=0 to rows-1 do A.SetRow(i, f i)
+        A.SetDiagonal(v)
         A :> _ Matrix
 
-    /// Initialize a matrix by calling a construction function for every column.
-    let inline initCol (rows: int) (cols: int) (f: int -> #Vector<float>) =
-        let A = SparseMatrix(rows,cols)
-        for i=0 to cols-1 do A.SetColumn(i, f i)
-        A :> _ Matrix
+    /// Create a square matrix with the vector elements on the diagonal.
+    let inline ofDiag (v: Vector<float>) = ofDiag2 v.Count v.Count v
diff --git a/src/FSharp/LinearAlgebra.Double.Vector.fs b/src/FSharp/LinearAlgebra.Double.Vector.fs
index 202c4b8c..e7f61568 100644
--- a/src/FSharp/LinearAlgebra.Double.Vector.fs
+++ b/src/FSharp/LinearAlgebra.Double.Vector.fs
@@ -97,10 +97,10 @@ module SparseVector =
     let inline init (n: int) (f: int -> float) = SparseVector.Create(n, fun i -> f i) :> _ Vector
 
     /// Create a sparse vector from a float list.
-    let inline ofList (n: int) (fl: float list) = SparseVector.OfEnumerable(Seq.ofList fl) :> _ Vector
+    let inline ofList (fl: float list) = SparseVector.OfEnumerable(Seq.ofList fl) :> _ Vector
 
     /// Create a sparse vector from a float sequence.
-    let inline ofSeq (n: int) (fs: #seq<float>) = SparseVector.OfEnumerable(fs) :> _ Vector
+    let inline ofSeq (fs: #seq<float>) = SparseVector.OfEnumerable(fs) :> _ Vector
 
     /// Create a sparse vector with a given dimension from an indexed list of index, value pairs.
     let inline ofListi (n: int) (fl: list<int * float>) = SparseVector.OfIndexedEnumerable(n, Seq.ofList fl) :> _ Vector
diff --git a/src/FSharp/LinearAlgebra.Double.fs b/src/FSharp/LinearAlgebra.Double.fs
index 5f3adb33..827d2821 100644
--- a/src/FSharp/LinearAlgebra.Double.fs
+++ b/src/FSharp/LinearAlgebra.Double.fs
@@ -36,8 +36,8 @@ open MathNet.Numerics.LinearAlgebra
 [<AutoOpen>]
 module Utility =
 
-    /// Construct a dense matrix from a list of floating point numbers.
-    let inline matrix (lst: list<list<float>>) = DenseMatrix.ofList lst
+    /// Construct a dense matrix from a nested list of floating point numbers.
+    let inline matrix (lst: list<list<float>>) = DenseMatrix.ofRowList lst
 
     /// Construct a dense vector from a list of floating point numbers.
     let inline vector (lst: list<float>) = DenseVector.ofList lst
diff --git a/src/FSharpExamples/Matrices.fsx b/src/FSharpExamples/Matrices.fsx
index 8dec98b1..883f90ff 100644
--- a/src/FSharpExamples/Matrices.fsx
+++ b/src/FSharpExamples/Matrices.fsx
@@ -53,21 +53,25 @@ let d1 = DenseMatrix.init 3 4 (fun i j -> float i / 100.0 + float j)
 let d2 = SparseMatrix.init 3 4 (fun i j -> if i=j then float i / 100.0 + float j else 0.0)
 
 // Matrices can also be constructed from sequences of rows or of columns
-let e1 = DenseMatrix.ofRowSeq 20 10 (seq { for i in 1 .. 20 do yield Array.init 10 (fun j -> float j + 100.0 * float i) })
-let e2 = SparseMatrix.ofRowSeq 20 10 (seq { for i in 1 .. 20 do yield Array.init 10 (fun j -> if i%5 = 0 then float j + 100.0 * float i else 0.0) })
-let e3 = DenseMatrix.ofColumnSeq 20 10 (seq { for j in 1 .. 10 do yield Array.init 20 (fun i -> float j + 100.0 * float i) })
-let e4 = SparseMatrix.ofColumnSeq 20 10 (seq { for j in 1 .. 10 do yield Array.init 20 (fun i -> if i%5 = 0 then float j + 100.0 * float i else 0.0) })
+let e1 = DenseMatrix.ofRowSeq (seq { for i in 1 .. 20 do yield Array.init 10 (fun j -> float j + 100.0 * float i) })
+let e2 = SparseMatrix.ofRowSeq (seq { for i in 1 .. 20 do yield Array.init 10 (fun j -> if i%5 = 0 then float j + 100.0 * float i else 0.0) })
+let e3 = DenseMatrix.ofColumnSeq (seq { for j in 1 .. 10 do yield Array.init 20 (fun i -> float j + 100.0 * float i) })
+let e4 = SparseMatrix.ofColumnSeq (seq { for j in 1 .. 10 do yield Array.init 20 (fun i -> if i%5 = 0 then float j + 100.0 * float i else 0.0) })
 
 // Or from F# lists
-let f1 = DenseMatrix.ofRowList 20 10 [ for i in 1 .. 20 -> List.init 10 (fun j -> float j + 100.0 * float i) ]
-let f2 = SparseMatrix.ofRowList 20 10 [ for i in 1 .. 20 -> List.init 10 (fun j -> if i%5 = 0 then float j + 100.0 * float i else 0.0) ]
-let f3 = DenseMatrix.ofColumnList 20 10 [ for j in 1 .. 10 -> List.init 20 (fun i -> float j + 100.0 * float i) ]
-let f4 = SparseMatrix.ofColumnList 20 10 [ for j in 1 .. 10 -> List.init 20 (fun i -> if i%5 = 0 then float j + 100.0 * float i else 0.0) ]
+let f1 = DenseMatrix.ofRowList [ for i in 1 .. 20 -> List.init 10 (fun j -> float j + 100.0 * float i) ]
+let f2 = SparseMatrix.ofRowList [ for i in 1 .. 20 -> List.init 10 (fun j -> if i%5 = 0 then float j + 100.0 * float i else 0.0) ]
+let f3 = DenseMatrix.ofColumnList [ for j in 1 .. 10 -> List.init 20 (fun i -> float j + 100.0 * float i) ]
+let f4 = SparseMatrix.ofColumnList [ for j in 1 .. 10 -> List.init 20 (fun i -> if i%5 = 0 then float j + 100.0 * float i else 0.0) ]
 
 // Or from row or column vectors
 let m1 = DenseMatrix.ofRows [DenseVector.create 3 1.0; DenseVector.create 3 2.0]
 let m2 = DenseMatrix.ofColumns [DenseVector.create 3 1.0; DenseVector.create 3 2.0]
 
+// Or from row or column arrays
+let n1 = DenseMatrix.ofRowArrays [| Array.create 3 1.0; Array.create 3 2.0 |]
+let n2 = DenseMatrix.ofColumnArrays [| Array.create 3 1.0; Array.create 3 2.0 |]
+
 // Or from indexed lists or sequences where all other values are zero (useful mostly for sparse data)
 let g1 = DenseMatrix.ofListi 20 10 [(4,3,20.0); (18,9,3.0); (2,1,100.0)]
 let g2 = SparseMatrix.ofListi 20 10 [(4,3,20.0); (18,9,3.0); (2,1,100.0)]
diff --git a/src/FSharpUnitTests/DenseMatrixTests.fs b/src/FSharpUnitTests/DenseMatrixTests.fs
index f27a5f33..1964b6ec 100644
--- a/src/FSharpUnitTests/DenseMatrixTests.fs
+++ b/src/FSharpUnitTests/DenseMatrixTests.fs
@@ -44,21 +44,13 @@ module DenseMatrixTests =
         DenseMatrix.ofArray2 (Array2D.create 3 2 0.3) |> should equal smallM
         DenseMatrix.ofArray2 (Array2D.init 100 120 (fun i j -> float i * 100.0 + float j)) |> should equal largeM
 
-    [<Test>]
-    let ``DenseMatrix.ofSeq`` () =
-        DenseMatrix.ofSeq (Seq.ofList [[0.3;0.3];[0.3;0.3];[0.3;0.3]]) |> should equal smallM
-
-    [<Test>]
-    let ``DenseMatrix.ofList`` () =
-        DenseMatrix.ofList [[0.3;0.3];[0.3;0.3];[0.3;0.3]] |> should equal smallM
-
     [<Test>]
     let ``DenseMatrix.ofRowSeq`` () =
-        DenseMatrix.ofRowSeq 3 2 (Seq.ofList [[0.3;0.3];[0.3;0.3];[0.3;0.3]]) |> should equal smallM
+        DenseMatrix.ofRowSeq (Seq.ofList [[0.3;0.3];[0.3;0.3];[0.3;0.3]]) |> should equal smallM
 
     [<Test>]
     let ``DenseMatrix.ofRowList`` () =
-        DenseMatrix.ofRowList 3 2 [[0.3;0.3];[0.3;0.3];[0.3;0.3]] |> should equal smallM
+        DenseMatrix.ofRowList [[0.3;0.3];[0.3;0.3];[0.3;0.3]] |> should equal smallM
 
     [<Test>]
     let ``DenseMatrix.ofRows`` () =
@@ -66,11 +58,11 @@ module DenseMatrixTests =
 
     [<Test>]
     let ``DenseMatrix.ofColumnSeq`` () =
-        DenseMatrix.ofColumnSeq 3 2 (Seq.ofList [[0.3;0.3;0.3];[0.3;0.3;0.3]]) |> should equal smallM
+        DenseMatrix.ofColumnSeq (Seq.ofList [[0.3;0.3;0.3];[0.3;0.3;0.3]]) |> should equal smallM
 
     [<Test>]
     let ``DenseMatrix.ofColumnList`` () =
-        DenseMatrix.ofColumnList 3 2 [[0.3;0.3;0.3];[0.3;0.3;0.3]] |> should equal smallM
+        DenseMatrix.ofColumnList [[0.3;0.3;0.3];[0.3;0.3;0.3]] |> should equal smallM
 
     [<Test>]
     let ``DenseMatrix.ofColumns`` () =
@@ -96,8 +88,8 @@ module DenseMatrixTests =
 
     [<Test>]
     let ``DenseMatrix.initRow`` () =
-        DenseMatrix.initRow 100 120 (fun i -> (DenseVector.init 120 (fun j -> float i * 100.0 + float j))) |> should equal largeM
+        DenseMatrix.initRows 100 (fun i -> (DenseVector.init 120 (fun j -> float i * 100.0 + float j))) |> should equal largeM
 
     [<Test>]
     let ``DenseMatrix.initCol`` () =
-        DenseMatrix.initCol 100 120 (fun j -> (DenseVector.init 100 (fun i -> float i * 100.0 + float j))) |> should equal largeM
+        DenseMatrix.initColumns 120 (fun j -> (DenseVector.init 100 (fun i -> float i * 100.0 + float j))) |> should equal largeM
diff --git a/src/FSharpUnitTests/SparseMatrixTests.fs b/src/FSharpUnitTests/SparseMatrixTests.fs
index 86e0fb79..eb6b48b0 100644
--- a/src/FSharpUnitTests/SparseMatrixTests.fs
+++ b/src/FSharpUnitTests/SparseMatrixTests.fs
@@ -26,19 +26,19 @@ module SparseMatrixTests =
 
     [<Test>]
     let ``SparseMatrix.ofRowSeq`` () =
-        SparseMatrix.ofRowSeq 4 6 (Seq.ofList [[0.;0.;0.;0.;0.;0.];[0.;0.;1.;0.;0.;0.];[0.;0.;0.;0.;0.;0.];[0.;0.;0.;0.;0.;0.]]) |> should equal smallM
+        SparseMatrix.ofRowSeq (Seq.ofList [[0.;0.;0.;0.;0.;0.];[0.;0.;1.;0.;0.;0.];[0.;0.;0.;0.;0.;0.];[0.;0.;0.;0.;0.;0.]]) |> should equal smallM
 
     [<Test>]
     let ``SparseMatrix.ofRowList`` () =
-        SparseMatrix.ofRowList 4 6 [[0.;0.;0.;0.;0.;0.];[0.;0.;1.;0.;0.;0.];[0.;0.;0.;0.;0.;0.];[0.;0.;0.;0.;0.;0.]] |> should equal smallM
+        SparseMatrix.ofRowList [[0.;0.;0.;0.;0.;0.];[0.;0.;1.;0.;0.;0.];[0.;0.;0.;0.;0.;0.];[0.;0.;0.;0.;0.;0.]] |> should equal smallM
 
     [<Test>]
     let ``SparseMatrix.ofColumnSeq`` () =
-        SparseMatrix.ofColumnSeq 4 6 (Seq.ofList [[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;1.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.]]) |> should equal smallM
+        SparseMatrix.ofColumnSeq (Seq.ofList [[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;1.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.]]) |> should equal smallM
 
     [<Test>]
     let ``SparseMatrix.ofColumnList`` () =
-        SparseMatrix.ofColumnList 4 6 [[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;1.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.]] |> should equal smallM
+        SparseMatrix.ofColumnList [[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;1.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.];[0.;0.;0.;0.]] |> should equal smallM
 
     [<Test>]
     let ``SparseMatrix.ofSeqi`` () =
@@ -53,13 +53,13 @@ module SparseMatrixTests =
         SparseMatrix.createDiag 100 100 2.0 |> should equal (2.0 * (SparseMatrix.Identity 100))
 
     [<Test>]
-    let ``SparseMatrix.diag`` () =
+    let ``SparseMatrix.ofDiag`` () =
         SparseMatrix.ofDiag (DenseVector.Create(100, fun i -> 2.0)) |> should equal (2.0 * (SparseMatrix.Identity 100))
 
     [<Test>]
     let ``SparseMatrix.init_row`` () =
-        SparseMatrix.initRow 4 6 (fun i -> if i=1 then DenseVector.raw [|0.;0.;1.;0.;0.;0.|] else DenseVector.zeroCreate 6) |> should equal smallM
+        SparseMatrix.initRows 4 (fun i -> if i=1 then DenseVector.raw [|0.;0.;1.;0.;0.;0.|] else DenseVector.zeroCreate 6) |> should equal smallM
 
     [<Test>]
     let ``SparseMatrix.init_col`` () =
-        SparseMatrix.initCol 4 6 (fun j -> if j=2 then DenseVector.raw [|0.;1.;0.;0.|] else DenseVector.zeroCreate 4) |> should equal smallM
+        SparseMatrix.initColumns 6 (fun j -> if j=2 then DenseVector.raw [|0.;1.;0.;0.|] else DenseVector.zeroCreate 4) |> should equal smallM
diff --git a/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs
index 4fc9e4ec..34bca505 100644
--- a/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs
@@ -173,6 +173,16 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
             return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new dense matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static DenseMatrix OfColumnArrays(params Complex[][] columns)
+        {
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new dense matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -189,26 +199,24 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            where TColumn : IEnumerable<Complex>
+        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex>> data)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfColumnEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new dense matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex>> data)
+        public static DenseMatrix OfRowArrays(params Complex[][] rows)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfRowEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -226,18 +234,6 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
             return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static DenseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            where TRow : IEnumerable<Complex>
-        {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new dense matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs b/src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs
index fc316714..0294873f 100644
--- a/src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs
@@ -162,6 +162,16 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
             return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new sparse matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static SparseMatrix OfColumnArrays(params Complex[][] columns)
+        {
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new sparse matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -178,27 +188,24 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TColumn : IEnumerable<Complex>
+        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex>> data)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfColumnEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new sparse matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex>> data)
+        public static SparseMatrix OfRowArrays(params Complex[][] rows)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfRowEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -216,19 +223,6 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
             return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static SparseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TRow : IEnumerable<Complex>
-        {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new sparse matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs
index 540964a5..76f912e0 100644
--- a/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs
@@ -168,6 +168,16 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
             return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new dense matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static DenseMatrix OfColumnArrays(params Complex32[][] columns)
+        {
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new dense matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -184,26 +194,24 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            where TColumn : IEnumerable<Complex32>
+        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex32>> data)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfColumnEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new dense matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex32>> data)
+        public static DenseMatrix OfRowArrays(params Complex32[][] rows)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfRowEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -221,18 +229,6 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
             return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static DenseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            where TRow : IEnumerable<Complex32>
-        {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<Complex32>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new dense matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs b/src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs
index 9a62af35..be1eafe9 100644
--- a/src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs
@@ -157,6 +157,16 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
             return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new sparse matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static SparseMatrix OfColumnArrays(params Complex32[][] columns)
+        {
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new sparse matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -173,27 +183,24 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TColumn : IEnumerable<Complex32>
+        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex32>> data)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfColumnEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new sparse matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<Complex32>> data)
+        public static SparseMatrix OfRowArrays(params Complex32[][] rows)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfRowEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -211,19 +218,6 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
             return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static SparseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TRow : IEnumerable<Complex32>
-        {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<Complex32>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new sparse matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs
index 4fe6c565..f5ed2cdc 100644
--- a/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Double/DenseMatrix.cs
@@ -166,6 +166,16 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new dense matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static DenseMatrix OfColumnArrays(params double[][] columns)
+        {
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new dense matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -182,26 +192,24 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            where TColumn : IEnumerable<double>
+        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<double>> data)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfColumnEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new dense matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<double>> data)
+        public static DenseMatrix OfRowArrays(params double[][] rows)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfRowEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -219,18 +227,6 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static DenseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            where TRow : IEnumerable<double>
-        {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<double>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new dense matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Double/SparseMatrix.cs b/src/Numerics/LinearAlgebra/Double/SparseMatrix.cs
index 5e5a703e..e16865ee 100644
--- a/src/Numerics/LinearAlgebra/Double/SparseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Double/SparseMatrix.cs
@@ -155,6 +155,16 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new sparse matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static SparseMatrix OfColumnArrays(params double[][] columns)
+        {
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new sparse matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -171,27 +181,24 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TColumn : IEnumerable<double>
+        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<double>> data)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfColumnEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new sparse matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<double>> data)
+        public static SparseMatrix OfRowArrays(params double[][] rows)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfRowEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -209,19 +216,6 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static SparseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TRow : IEnumerable<double>
-        {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<double>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new sparse matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs b/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs
index 179a8954..209c6778 100644
--- a/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Single/DenseMatrix.cs
@@ -166,6 +166,16 @@ namespace MathNet.Numerics.LinearAlgebra.Single
             return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new dense matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static DenseMatrix OfColumnArrays(params float[][] columns)
+        {
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new dense matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -182,26 +192,24 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            where TColumn : IEnumerable<float>
+        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<float>> data)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfColumnEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new dense matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static DenseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<float>> data)
+        public static DenseMatrix OfRowArrays(params float[][] rows)
         {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfRowEnumerables(rows, columns, data));
+            return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -219,18 +227,6 @@ namespace MathNet.Numerics.LinearAlgebra.Single
             return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new dense matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static DenseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            where TRow : IEnumerable<float>
-        {
-            return new DenseMatrix(DenseColumnMajorMatrixStorage<float>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new dense matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Single/SparseMatrix.cs b/src/Numerics/LinearAlgebra/Single/SparseMatrix.cs
index 0ce2ae3c..ce426e54 100644
--- a/src/Numerics/LinearAlgebra/Single/SparseMatrix.cs
+++ b/src/Numerics/LinearAlgebra/Single/SparseMatrix.cs
@@ -155,6 +155,16 @@ namespace MathNet.Numerics.LinearAlgebra.Single
             return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfColumnEnumerables(rows, columns, data));
         }
 
+        /// <summary>
+        /// Create a new sparse matrix as a copy of the given column arrays.
+        /// This new matrix will be independent from the arrays.
+        /// A new memory block will be allocated for storing the matrix.
+        /// </summary>
+        public static SparseMatrix OfColumnArrays(params float[][] columns)
+        {
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfColumnArrays(columns));
+        }
+
         /// <summary>
         /// Create a new sparse matrix as a copy of the given column vectors.
         /// This new matrix will be independent from the vectors.
@@ -171,27 +181,24 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable columns.
-        /// Each enumerable in the master enumerable specifies a column.
+        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
+        /// Each enumerable in the master enumerable specifies a row.
         /// This new matrix will be independent from the enumerables.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfColumnsCovariant<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TColumn : IEnumerable<float>
+        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<float>> data)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfColumnEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfRowEnumerables(rows, columns, data));
         }
 
         /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
+        /// Create a new sparse matrix as a copy of the given row arrays.
+        /// This new matrix will be independent from the arrays.
         /// A new memory block will be allocated for storing the matrix.
         /// </summary>
-        public static SparseMatrix OfRows(int rows, int columns, IEnumerable<IEnumerable<float>> data)
+        public static SparseMatrix OfRowArrays(params float[][] rows)
         {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfRowEnumerables(rows, columns, data));
+            return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfRowArrays(rows));
         }
 
         /// <summary>
@@ -209,19 +216,6 @@ namespace MathNet.Numerics.LinearAlgebra.Single
             return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfRowVectors(storage));
         }
 
-        /// <summary>
-        /// Create a new sparse matrix as a copy of the given enumerable of enumerable rows.
-        /// Each enumerable in the master enumerable specifies a row.
-        /// This new matrix will be independent from the enumerables.
-        /// A new memory block will be allocated for storing the matrix.
-        /// </summary>
-        public static SparseMatrix OfRowsCovariant<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TRow : IEnumerable<float>
-        {
-            return new SparseMatrix(SparseCompressedRowMatrixStorage<float>.OfRowEnumerables(rows, columns, data));
-        }
-
         /// <summary>
         /// Create a new sparse matrix and initialize each value using the provided init function.
         /// </summary>
diff --git a/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs b/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs
index d9cb7b1d..ce4f0dd5 100644
--- a/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs
@@ -110,34 +110,62 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return storage;
         }
 
-        public static DenseColumnMajorMatrixStorage<T> OfArray(T[,] array)
+        public static DenseColumnMajorMatrixStorage<T> OfInit(int rows, int columns, Func<int, int, T> init)
         {
-            var storage = new DenseColumnMajorMatrixStorage<T>(array.GetLength(0), array.GetLength(1));
+            var storage = new DenseColumnMajorMatrixStorage<T>(rows, columns);
             int index = 0;
             for (var j = 0; j < storage.ColumnCount; j++)
             {
                 for (var i = 0; i < storage.RowCount; i++)
                 {
-                    storage.Data[index++] = array[i, j];
+                    storage.Data[index++] = init(i, j);
                 }
             }
             return storage;
         }
 
-        public static DenseColumnMajorMatrixStorage<T> OfInit(int rows, int columns, Func<int, int, T> init)
+        public static DenseColumnMajorMatrixStorage<T> OfArray(T[,] array)
         {
-            var storage = new DenseColumnMajorMatrixStorage<T>(rows, columns);
+            var storage = new DenseColumnMajorMatrixStorage<T>(array.GetLength(0), array.GetLength(1));
             int index = 0;
             for (var j = 0; j < storage.ColumnCount; j++)
             {
                 for (var i = 0; i < storage.RowCount; i++)
                 {
-                    storage.Data[index++] = init(i, j);
+                    storage.Data[index++] = array[i, j];
                 }
             }
             return storage;
         }
 
+        public static DenseColumnMajorMatrixStorage<T> OfColumnArrays(T[][] data)
+        {
+            int columns = data.Length;
+            int rows = data[0].Length;
+            var array = new T[rows * columns];
+            for (int j = 0; j < data.Length; j++)
+            {
+                Array.Copy(data[j], 0, array, j*rows, rows);
+            }
+            return new DenseColumnMajorMatrixStorage<T>(rows, columns, array);
+        }
+
+        public static DenseColumnMajorMatrixStorage<T> OfRowArrays(T[][] data)
+        {
+            int rows = data.Length;
+            int columns = data[0].Length;
+            var array = new T[rows * columns];
+            for (int j = 0; j < columns; j++)
+            {
+                int offset = j * rows;
+                for (int i = 0; i < rows; i++)
+                {
+                    array[offset + i] = data[i][j];
+                }
+            }
+            return new DenseColumnMajorMatrixStorage<T>(rows, columns, array);
+        }
+
         public static DenseColumnMajorMatrixStorage<T> OfColumnVectors(VectorStorage<T>[] data)
         {
             int columns = data.Length;
@@ -200,13 +228,10 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return new DenseColumnMajorMatrixStorage<T>(rows, columns, copy);
             }
 
-            var array = System.Linq.Enumerable.ToArray(data);
-            return new DenseColumnMajorMatrixStorage<T>(rows, columns, array);
+            return new DenseColumnMajorMatrixStorage<T>(rows, columns, data.ToArray());
         }
 
-        public static DenseColumnMajorMatrixStorage<T> OfColumnEnumerables<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TColumn : IEnumerable<T>
+        public static DenseColumnMajorMatrixStorage<T> OfColumnEnumerables(int rows, int columns, IEnumerable<IEnumerable<T>> data)
         {
             var array = new T[rows*columns];
             using (var columnIterator = data.GetEnumerator())
@@ -238,9 +263,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return new DenseColumnMajorMatrixStorage<T>(rows, columns, array);
         }
 
-        public static DenseColumnMajorMatrixStorage<T> OfRowEnumerables<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TRow : IEnumerable<T>
+        public static DenseColumnMajorMatrixStorage<T> OfRowEnumerables(int rows, int columns, IEnumerable<IEnumerable<T>> data)
         {
             var array = new T[rows*columns];
             using (var rowIterator = data.GetEnumerator())
diff --git a/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs b/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs
index 7dfed791..9ea86671 100644
--- a/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs
+++ b/src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs
@@ -372,6 +372,33 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return storage;
         }
 
+        public static SparseCompressedRowMatrixStorage<T> OfInit(int rows, int columns, Func<int, int, T> init)
+        {
+            var storage = new SparseCompressedRowMatrixStorage<T>(rows, columns);
+            var rowPointers = storage.RowPointers;
+            var columnIndices = new List<int>();
+            var values = new List<T>();
+
+            for (int row = 0; row < rows; row++)
+            {
+                rowPointers[row] = values.Count;
+                for (int col = 0; col < columns; col++)
+                {
+                    var item = init(row, col);
+                    if (!Zero.Equals(item))
+                    {
+                        values.Add(item);
+                        columnIndices.Add(col);
+                    }
+                }
+            }
+
+            storage.ColumnIndices = columnIndices.ToArray();
+            storage.Values = values.ToArray();
+            storage.ValueCount = values.Count;
+            return storage;
+        }
+
         public static SparseCompressedRowMatrixStorage<T> OfArray(T[,] array)
         {
             var storage = new SparseCompressedRowMatrixStorage<T>(array.GetLength(0), array.GetLength(1));
@@ -398,22 +425,49 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return storage;
         }
 
-        public static SparseCompressedRowMatrixStorage<T> OfInit(int rows, int columns, Func<int, int, T> init)
+        public static SparseCompressedRowMatrixStorage<T> OfRowArrays(T[][] data)
         {
-            var storage = new SparseCompressedRowMatrixStorage<T>(rows, columns);
+            var storage = new SparseCompressedRowMatrixStorage<T>(data.Length, data[0].Length);
             var rowPointers = storage.RowPointers;
             var columnIndices = new List<int>();
             var values = new List<T>();
 
-            for (int row = 0; row < rows; row++)
+            for (int row = 0; row < storage.RowCount; row++)
             {
                 rowPointers[row] = values.Count;
-                for (int col = 0; col < columns; col++)
+                for (int col = 0; col < storage.ColumnCount; col++)
                 {
-                    var item = init(row, col);
-                    if (!Zero.Equals(item))
+                    T x = data[row][col];
+                    if (!Zero.Equals(x))
                     {
-                        values.Add(item);
+                        values.Add(x);
+                        columnIndices.Add(col);
+                    }
+                }
+            }
+
+            storage.ColumnIndices = columnIndices.ToArray();
+            storage.Values = values.ToArray();
+            storage.ValueCount = values.Count;
+            return storage;
+        }
+
+        public static SparseCompressedRowMatrixStorage<T> OfColumnArrays(T[][] data)
+        {
+            var storage = new SparseCompressedRowMatrixStorage<T>(data[0].Length, data.Length);
+            var rowPointers = storage.RowPointers;
+            var columnIndices = new List<int>();
+            var values = new List<T>();
+
+            for (int row = 0; row < storage.RowCount; row++)
+            {
+                rowPointers[row] = values.Count;
+                for (int col = 0; col < storage.ColumnCount; col++)
+                {
+                    T x = data[col][row];
+                    if (!Zero.Equals(x))
+                    {
+                        values.Add(x);
                         columnIndices.Add(col);
                     }
                 }
@@ -522,9 +576,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return storage;
         }
 
-        public static SparseCompressedRowMatrixStorage<T> OfRowEnumerables<TRow>(int rows, int columns, IEnumerable<TRow> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TRow : IEnumerable<T>
+        public static SparseCompressedRowMatrixStorage<T> OfRowEnumerables(int rows, int columns, IEnumerable<IEnumerable<T>> data)
         {
             var storage = new SparseCompressedRowMatrixStorage<T>(rows, columns);
             var rowPointers = storage.RowPointers;
@@ -559,9 +611,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return storage;
         }
 
-        public static SparseCompressedRowMatrixStorage<T> OfColumnEnumerables<TColumn>(int rows, int columns, IEnumerable<TColumn> data)
-            // NOTE: flexible typing to 'backport' generic covariance.
-            where TColumn : IEnumerable<T>
+        public static SparseCompressedRowMatrixStorage<T> OfColumnEnumerables(int rows, int columns, IEnumerable<IEnumerable<T>> data)
         {
             var trows = new List<Tuple<int, T>>[rows];
             using (var columnIterator = data.GetEnumerator())