IF# Notebook

iPython provides a rich browser-based interactive notebook with support for code, text, mathematical expressions, inline plots and other rich media. IfSharp, developed by Bayard Rock, is an F# profile for iPython with IntelliSense and embedded FSharp.Charting. Thanks to its NuGet support it can load other packages like Math.NET Numerics on demand.

Installing IF# Notebook

Follow the instructions at IfSharp/Installation.

Essentially:

1. Install Anaconda

2. In a shell, run

   conda update conda conda update ipython

3. Install IfSharp.

Display Printers for Matrices and Vectors

By itself IfSharp does not know how to display matrices and vectors in a nice way, but we can tell it how to do so by providing our own display printers for them. Since v3.3 the Math.NET Numerics F# package includes a script MathNet.Numerics.IfSharp.fsx to do so. Unfortunately loading this script requires the exact version in the path - if you know a way to avoid this please let us know.

Alternatively you can also use the code below and adapt it to your needs, e.g. if you want it to show more rows.

open MathNet.Numerics.LinearAlgebra

let inline (|Float|_|) (v:obj) =
    if v :? float then Some(v :?> float) else None
let inline (|Float32|_|) (v:obj) =
    if v :? float32 then Some(v :?> float32) else None
let inline (|PositiveInfinity|_|) (v: ^T) =
    if (^T : (static member IsPositiveInfinity: 'T -> bool) (v))
    then Some PositiveInfinity else None
let inline (|NegativeInfinity|_|) (v: ^T) =
    if (^T : (static member IsNegativeInfinity: 'T -> bool) (v))
    then Some NegativeInfinity else None
let inline (|NaN|_|) (v: ^T) =
    if (^T : (static member IsNaN: 'T -> bool) (v))
    then Some NaN else None

let inline formatMathValue (floatFormat:string) = function
  | PositiveInfinity -> "\\infty"
  | NegativeInfinity -> "-\\infty"
  | NaN -> "\\times"
  | Float v -> v.ToString(floatFormat)
  | Float32 v -> v.ToString(floatFormat)
  | v -> v.ToString()

let inline formatMatrix (matrix: Matrix<'T>) =
  String.concat Environment.NewLine
    [ "\\begin{bmatrix}"
      matrix.ToMatrixString(10,4,7,2,"\\cdots","\\vdots","\\ddots",
        " & ", "\\\\ " + Environment.NewLine, (fun x -> formatMathValue "G4" x))
      "\\end{bmatrix}" ]

let inline formatVector (vector: Vector<'T>) =
  String.concat Environment.NewLine
    [ "\\begin{bmatrix}"
      vector.ToVectorString(12, 80, "\\vdots", " & ", "\\\\ " + Environment.NewLine,
        (fun x -> formatMathValue "G4" x))
      "\\end{bmatrix}" ]

App.AddDisplayPrinter (fun (x:Matrix<float>) ->
    { ContentType = "text/latex"; Data = formatMatrix x })
App.AddDisplayPrinter (fun (x:Matrix<float32>) ->
    { ContentType = "text/latex"; Data = formatMatrix x })
App.AddDisplayPrinter (fun (x:Vector<float>) ->
    { ContentType = "text/latex"; Data = formatVector x })
App.AddDisplayPrinter (fun (x:Vector<float32>) ->
    { ContentType = "text/latex"; Data = formatVector x })