anchor.diff:  An alternative is a robust simple linear regression like Theil's incomplete method or the Theil-Sen estimator, that are outlier resistant.
   
   *)
  -(*** do-not-eval***)
  +
   open FSharp.Stats
  +open FSharp.Plotly
   open FSharp.Stats.Fitting.LinearRegression
  -open FSharp.Plotly
   
   let x_Data = vector [|1.;2.;3.;|]
   let y_Data = vector [|4.;7.;9.;|]
   
   //Least squares simple linear regression
  -let coefficientsLinearLS = OrdinaryLeastSquares.Linear.Univariable.coefficient x_Data y_Data
  -let fittingFunctionLinearLS x = OrdinaryLeastSquares.Linear.Univariable.fit coefficientsLinearLS x
  +let coefficientsLinearLS = 
  +    OrdinaryLeastSquares.Linear.Univariable.coefficient x_Data y_Data
  +let fittingFunctionLinearLS x = 
  +    OrdinaryLeastSquares.Linear.Univariable.fit coefficientsLinearLS x
   
   //Robust simple linear regression
  -let coefficientsLinearRobust = RobustRegression.Linear.theilSenEstimator x_Data y_Data 
  -let fittingFunctionLinearRobust x = RobustRegression.Linear.fit coefficientsLinearRobust x
  +let coefficientsLinearRobust = 
  +    RobustRegression.Linear.theilSenEstimator x_Data y_Data 
  +let fittingFunctionLinearRobust x = 
  +    RobustRegression.Linear.fit coefficientsLinearRobust x
   
   //least squares simple linear regression through the origin
  -let coefficientsLinearRTO = OrdinaryLeastSquares.Linear.RTO.coefficientOfVector x_Data y_Data 
  -let fittingFunctionLinearRobust x = OrdinaryLeastSquares.Linear.RTO.fit coefficientsLinearRTO x
  +let coefficientsLinearRTO = 
  +    OrdinaryLeastSquares.Linear.RTO.coefficientOfVector x_Data y_Data 
  +let fittingFunctionLinearRTO x = 
  +    OrdinaryLeastSquares.Linear.RTO.fit coefficientsLinearRTO x
   
   
   let rawChart = 
  
positive.code:     |> Chart.withTraceName "raw data"
      
  let fittingLS = 
      let fit = [|0. .. 4.|] |> Array.map (fun x -> x,fittingFunctionLinearLS x)
      Chart.Line(fit)
      |> Chart.withTraceName "least squares"
  
  let fittingRobust = 
      let fit = [|0. .. 4.|] |> Array.map (fun x -> x,fittingFunctionLinearRobust x)
      Chart.Line(fit)
      |> Chart.withTraceName "TheilSen estimator"
  
  let fittingRTO = 
      let fit = [|0. .. 4.|] |> Array.map (fun x -> x,fittingFunctionLinearRobust x)
      Chart.Line(fit)
      |> Chart.withTraceName "through origin"
  
  [rawChart;fittingLS;fittingRobust;fittingRTO] 
  |> Chart.Combine
  |> Chart.Show
  
negative.code:     |> Chart.Line
      |> Chart.withTraceName (sprintf "lambda: %.2f" lambda)
  
  let rawChartS = Chart.Point(data)
  
  [
  rawChartS
  fit 0.001
  fit 0.1
  fit 10.
  