Demonstrating dotnet/fsharp#7422

Author: manofstick

src/Cistern.Linq.FSharp/Linq.fs

@@ -7,7 +7,8 @@ open System
 open System.Runtime.CompilerServices
 
 type Linq =
-    [<MethodImpl(MethodImplOptions.NoInlining)>]
+    // Uncomment this to make this code work
+    //[<MethodImpl(MethodImplOptions.NoInlining)>]
     static member unfold (f:'State->option<'T*'State>) (seed:'State) : seq<'T> = Consumables.Unfold (f, seed, Links.Identity.Instance) :> seq<'T>
 
     static member inline map (f:'a->'b) (e:seq<'a>)           = Enumerable.Select (e, f)

src/Cistern.Linq.Playground.FSharp/Program.fs

@@ -1,70 +1,46 @@
 // Learn more about F# at http://fsharp.org
 
-open System
 open Cistern.Linq.FSharp
 open System.Diagnostics
 
 [<EntryPoint>]
-let main argv =
+let main _ =
     Register.RegisterFSharpCollections ()
 
-    let listSize = 10000
-    let iterations = 1
-    let repetitions = 5
-
-    let x = Random 42
-    let test = List.init listSize (fun n -> x.NextDouble ())
+    let iterations = 1000000
+    let repetitions = 3
 
     for _i = 1 to repetitions do
         let sw = Stopwatch.StartNew ()
 
-        let mutable total = 0.
         for i = 1 to iterations do
-            let triangleNumber(n:int64) = [1L..n] |> Seq.sum
- 
-            let findFactorsOf(n:int64) =
-                let upperBound = int64(Math.Sqrt(double(n)))
-                [1L..upperBound] 
-                |> Seq.filter (fun x -> n % x = 0L) 
-                |> Seq.collect (fun x -> [x; n/x])
- 
-            let naturalNumbers = Seq.unfold (fun x -> Some(x, x+1L)) 1L
+            let fibonacciLinq = Linq.unfold (fun (current, next) -> Some(current, (next, current + next))) (0, 1)
 
-            let answer =
-                naturalNumbers
-                |> Seq.map (fun x -> triangleNumber(x))
-                |> Seq.filter (fun x -> Seq.length(findFactorsOf(x)) >= 500)
-                |> Seq.head
+            let fibTotal =
+                fibonacciLinq
+                |> Linq.takeWhile (fun n -> n < 4000000)
+                |> Linq.filter (fun n -> n % 2 = 0)
+                |> Linq.sum
 
-            total <- total  + float answer
+            burning_monk_euler.Helpers.validate 4613732 fibTotal
 
-        printfn "Seq %d (%f)" sw.ElapsedMilliseconds total
+        printfn "Cistern %dms" sw.ElapsedMilliseconds
 
     for _i = 1 to repetitions do
         let sw = Stopwatch.StartNew ()
 
         let mutable total = 0.
         for i = 1 to iterations do
-            let triangleNumber(n:int64) = [1L..n] |> Linq.sum
+            let fibonacciSeq = Seq.unfold (fun (current, next) -> Some(current, (next, current + next))) (0, 1)
 
-            let findFactorsOf(n:int64) =
-                let upperBound = int64(Math.Sqrt(double(n)))
-                [1L..upperBound] 
-                |> Linq.filter (fun x -> n % x = 0L) 
-                |> Linq.collect (fun x -> [x; n/x])
- 
-            let naturalNumbers = Linq.unfold (fun x -> Some(x, x+1L)) 1L
- 
-            let answer =
-                naturalNumbers
-                |> Linq.map (fun x -> triangleNumber(x))
-                |> Linq.filter (fun x -> Linq.length(findFactorsOf(x)) >= 500)
-                |> Linq.head
-
-            total <- total  + float answer
-
-        printfn "Cistern %d (%f)" sw.ElapsedMilliseconds total
+            let fibTotal =
+                fibonacciSeq
+                |> Seq.takeWhile (fun n -> n < 4000000)
+                |> Seq.filter (fun n -> n % 2 = 0)
+                |> Seq.sum
 
+            burning_monk_euler.Helpers.validate 4613732 fibTotal
 
+        printfn "Seq %dms" sw.ElapsedMilliseconds
 
     0 // return an integer exit code