The Computer Language
Benchmarks Game

spectral-norm F# .NET Core #3 program

// The Computer Language Benchmarks Game
// http://benchmarksgame.alioth.debian.org/
//
// Based on C version by Ledrug and F# version by Don Syme
// Contributed by Simon Dickson

open System
open System.Threading

let nthread = Environment.ProcessorCount

let inline A i j = 1. / float((i + j) * (i + j + 1) / 2 + i + 1)

let inline dot (v : float array) (u : float array) n =
   let mutable sum = 0.
   for i = 0 to n - 1 do
      sum <- sum + v.[i] * u.[i]
   sum

let inline multiplyAv (v : double[]) (Av : double[]) r1 r2 =
    for i = r1 to r2 - 1 do 
        let mutable sum = 0.
        for j = 0 to v.Length - 1 do 
            sum <- sum + A i j * v.[j]
        Av.[i] <- sum

let inline multiplyAtv (v : double[]) (atv : double[]) r1 r2 =
    for i = r1 to r2 - 1 do
        let mutable sum = 0.
        for j = 0 to v.Length - 1 do 
            sum <- sum + A j i * v.[j]
        atv.[i] <- sum

let current = ref nthread
let mutable handle = new ManualResetEvent (false)
let inline barrierHandle () =
    let h = handle
    if Interlocked.Decrement current > 0 then
        h.WaitOne() |> ignore
    else
        handle <- new ManualResetEvent (false)
        Interlocked.Exchange (current, nthread) |> ignore
        h.Set () |> ignore
        h.Dispose ()

let mutable tmp = null
let inline multiplyAtAv (v : double[]) (out : double[]) r1 r2 =
    multiplyAv v tmp r1 r2
    barrierHandle ()
    multiplyAtv tmp out r1 r2
    barrierHandle ()

[<EntryPoint>]
let main args =
    let n = if args.Length >= 1 then int args.[0] else 5500
    let u = Array.create n 1.0
    tmp <- Array.zeroCreate n 
    let v = Array.zeroCreate n
    let chunk = n / nthread

    [for i in 0 .. nthread - 1 do
        let r1 = i * chunk
        let r2 = if (i < (nthread - 1)) then r1 + chunk else n
        yield async {
            for i = 0 to 10 do
                multiplyAtAv u v r1 r2
                multiplyAtAv v u r1 r2
        }]
    |> Async.Parallel
    |> Async.Ignore
    |> Async.RunSynchronously

    let result = Math.Sqrt(dot u v n / dot v v n)

    Console.WriteLine("{0:f9}", result);
    0
    

NOTES:
64-bit Ubuntu quad core
2.0.2 a04b4bf512
"System.GC.Server": true


Thu, 09 Nov 2017 01:03:52 GMT

MAKE:
cp spectralnorm.fsharpcore-3.fsharpcore Program.fs
cp Include/fsharpcore/tmp.fsproj .
cp Include/fsharpcore/runtimeconfig.template.json .
mkdir obj
cp Include/fsharpcore/project.assets.json ./obj
cp Include/fsharpcore/tmp.fsproj.nuget.g.props ./obj
cp Include/fsharpcore/tmp.fsproj.nuget.g.targets ./obj
/usr/bin/dotnet build -c Release --no-restore
Microsoft (R) Build Engine version 15.4.8.50001 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

  tmp -> /home/dunham/benchmarksgame_quadcore/spectralnorm/tmp/bin/Release/netcoreapp2.0/tmp.dll

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 00:00:09.22

9.77s to complete and log all make actions

COMMAND LINE:
/usr/bin/dotnet ./bin/Release/netcoreapp2.0/tmp.dll 5500

PROGRAM OUTPUT:
1.274224153