Fitting: Tweaks to F# linear combination fitting

src/FSharp/LeastSquares.fs

@@ -50,6 +50,7 @@ module Fit =
         |> List.map (fun f -> List.init (Array.length x) (fun i -> f x.[i]))
         |> DenseMatrix.ofColumnsList (Array.length x) (List.length functions)
         |> fun m -> m.QR(QRMethod.Thin).Solve(DenseVector(y)).ToArray()
+        |> List.ofArray
     let linearf functions x y =
-        let parameters = linear functions x y |> List.ofArray
+        let parts = linear functions x y |> List.zip functions
-        in fun z -> functions |> List.zip parameters |> List.fold (fun s (p,f) -> s+p*(f z)) 0.0
+        in fun z -> parts |> List.fold (fun s (f,p) -> s+p*(f z)) 0.0

src/FSharpUnitTests/CurveFittingTests.fs

@@ -34,7 +34,7 @@ module CurveFittingTests =
 
         // LeastSquares.FitToLinearCombination(x, y, (fun z -> 1.0), (fun z -> Math.Sin(z)), (fun z -> Math.Cos(z)))
         (x,y) ||> Fit.linear [(fun _ -> 1.0); (Math.Sin); (Math.Cos) ]
-        |> should (equalWithin 1.0e-4) [| -0.287476; 4.02159; -1.46962 |]
+        |> should (equalWithin 1.0e-4) [ -0.287476; 4.02159; -1.46962 ]
 
         let fres = LeastSquares.FitToLinearCombinationFunc(x, y, (fun z -> 1.0), (fun z -> Math.Sin(z)), (fun z -> Math.Cos(z))) |> tofs
         in x |> Array.iter (fun x -> fres x |> should (equalWithin 1.0e-4) (4.02159*Math.Sin(x) - 1.46962*Math.Cos(x) - 0.287476))