anchor.diff:      let rowRange (a:Matrix<_>) = (0,a.NumRows - 1)
       let colRange (a:Matrix<_>) = (0,a.NumCols - 1)
       let wholeRegion a = (colRange a, rowRange a)
  -    let foldByRow f (z:Vector<'T>) (a:matrix) = 
  +    let foldByRow f (z:Vector<'T>) (a:matrix) =
           colRange a |> GU.foldR (fun z j -> MS.mapiV (fun i z -> f z (get a i j)) z) z
  -    let foldByCol f (z:RowVector<'T>) (a:matrix) = 
  +    let foldByCol f (z:RowVector<'T>) (a:matrix) =
           rowRange a |> GU.foldR (fun z i -> MS.mapiRV (fun j z -> f z (get a i j)) z) z
  -    let foldRow f (z:'T) (a:matrix) i = 
  +    let foldRow f (z:'T) (a:matrix) i =
           colRange a |> GU.foldR (fun (z:'T) j -> f z (get a i j)) z
  -    let foldCol f (z:'T) (a:matrix) j = 
  +    let foldCol f (z:'T) (a:matrix) j =
           rowRange a |> GU.foldR (fun (z:'T) i -> f z (get a i j)) z
       let sum (a:matrix)  = MS.sumM a
       let prod (a:matrix)  = MS.prodM a
  
positive.code:                 for rowi=0 to m.NumRows-1 do
                      yield f rowi (getRow m rowi)
              ]
                  
          // TM
          /// Applies function f along colúmn axis 
          let enumerateColumnWise f (m:Matrix<'a>) =
              seq [ 
                  for coli=0 to m.NumCols-1 do 
                  yield f (seq [for rowi=0 to m.NumRows-1 do yield m.[rowi,coli]])
              ]
    
          /// Maps every matrix column using the position dependant function
          let mapiCols (f: int -> Vector<'a> -> 'b) (m:Matrix<'a>) =
              seq [
  
negative.code: 
      // Accessors
      let get (a:matrix) i j   = MG.get a i j
      let set (a:matrix) i j x = MG.set a i j x
      // Creation
      ///returns a dense matrix with m rows and n rows, applying the init function with the two indices as arguments
      let init  m n f = DS.initDenseMatrixDS  m n f |> MS.dense
      ///returns a dense matrix with the inner lists of the input jagged list as its rows
      let ofJaggedList     xss   = DS.listDenseMatrixDS    xss |> MS.dense
      ///returns a dense matrix with the inner lists of the input jagged list as its columns
  