The Computer Language
Benchmarks Game

mandelbrot C# .NET Core #4 program

source code

/* The Computer Language Benchmarks Game
   http://benchmarksgame.alioth.debian.org/
    
   started with Java #2 program (Krause/Whipkey/Bennet/AhnTran/Enotus/Stalcup)
   adapted for C# by Jan de Vaan
   simplified and optimised to use TPL by Anthony Lloyd
*/

using System;
using System.Threading.Tasks;
using System.IO;
using System.Runtime.CompilerServices;

public class MandelBrot
{
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     static byte getByte(double[] Crb, double Ciby, int x, int y)
     {
        int res=0;
        for(int i=0;i<8;i+=2)
        {
            double Crbx=Crb[x+i], Crbx1=Crb[x+i+1]; 
            double Zr1=Crbx, Zr2=Crbx1;
            double Zi1=Ciby, Zi2=Ciby;

            int b=0;
            int j=49;
            do
            {
                double nZr1=Zr1*Zr1-Zi1*Zi1+Crbx;
                Zi1=Zr1*Zi1+Zr1*Zi1+Ciby;
                Zr1=nZr1;

                double nZr2=Zr2*Zr2-Zi2*Zi2+Crbx1;
                Zi2=Zr2*Zi2+Zr2*Zi2+Ciby;
                Zr2=nZr2;

                if(Zr1*Zr1+Zi1*Zi1>4){b|=2;if(b==3)break;}
                if(Zr2*Zr2+Zi2*Zi2>4){b|=1;if(b==3)break;}
            } while(--j>0);
            res=(res<<2)+b;
        }
        return (byte)(res^-1);
    }

    public static void Main (String[] args)
    {
        var n = args.Length > 0 ? Int32.Parse(args[0]) : 200;
        double invN=2.0/n;
        var Crb = new double[n+7];
        for(int i=0;i<n;i++){ Crb[i]=i*invN-1.5; }
        int lineLen = (n-1)/8 + 1;
        var data = new byte[n*lineLen];
        Parallel.For(0, n, y =>
        {
            var Ciby = y*invN-1.0;
            var offset = y*lineLen;
            for(int x=0; x<lineLen; x++)
                data[offset+x] = getByte(Crb, Ciby, x*8, y);
        });
        Console.Out.WriteLine("P4\n{0} {0}", n);        
        Console.OpenStandardOutput().Write(data, 0, data.Length);        
    }
}
    

notes, command-line, and program output

NOTES:
64-bit Ubuntu quad core
2.0.0-preview2-006497
"System.GC.Server": true


Thu, 29 Jun 2017 00:43:18 GMT

MAKE:
cp mandelbrot.csharpcore-4.csharpcore Program.cs
cp Include/csharpcore/tmp.csproj .
cp Include/csharpcore/runtimeconfig.template.json .
mkdir obj
cp Include/csharpcore/tmp.csproj.nuget.g.props ./obj
cp Include/csharpcore/tmp.csproj.nuget.g.targets ./obj
/usr/bin/dotnet build -c Release
Microsoft (R) Build Engine version 15.3.388.41745 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

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

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

Time Elapsed 00:00:04.23

7.44s to complete and log all make actions

COMMAND LINE:
/usr/bin/dotnet ./bin/Release/netcoreapp2.0/tmp.dll 16000

(BINARY) PROGRAM OUTPUT NOT SHOWN