mandelbrot C# .NET Core #5 program

 
/* The Computer Language Benchmarks Game
   https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
    
   started with Java #2 program (Krause/Whipkey/Bennet/AhnTran/Enotus/Stalcup)
   adapted for C# by Jan de Vaan
*/

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

public class MandelBrot
{
    private static int n = 200;
    private static byte[][] data;
    private static int lineCount = -1;

    private static double[] Crb;
    private static double[] Cib;

     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     static int getByte(int x, int y){
      int res=0;
      for(int i=0;i<8;i+=2){
         double Zr1=Crb[x+i];
         double Zi1=Cib[y];

         double Zr2=Crb[x+i+1];
         double Zi2=Cib[y];

         int b=0;
         int j=49;do{
            double nZr1=Zr1*Zr1-Zi1*Zi1+Crb[x+i];
            double nZi1=Zr1*Zi1+Zr1*Zi1+Cib[y];
            Zr1=nZr1;Zi1=nZi1;

            double nZr2=Zr2*Zr2-Zi2*Zi2+Crb[x+i+1];
            double nZi2=Zr2*Zi2+Zr2*Zi2+Cib[y];
            Zr2=nZr2;Zi2=nZi2;

            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 res^-1;
    }

    public static void Main (String[] args)
    {
        if (args.Length > 0) n = Int32.Parse(args[0]);
       
        int lineLen = (n-1)/8 + 1;
        data = new byte[n][];
           
        Crb=new double[n+7];
        Cib =new double[n+7];
        
        double invN=2.0/n; for(int i=0;i<n;i++){ Cib[i]=i*invN-1.0; Crb[i]=i*invN-1.5; }
        
        var threads = new Thread[Environment.ProcessorCount]; 
        for (int i = 0; i < threads.Length; i++)
        {   
            threads[i] = new Thread(() => {
                                               int y;
                                               while ((y = Interlocked.Increment(ref lineCount)) < n)
                                               {
                                                   var buffer = new byte[lineLen];                    
                                                   for (int x = 0; x < lineLen; x++)
                                                   {
                                                       buffer[x] = (byte) getByte(x*8, y);
                                                   }
                                                   data[y] = buffer; 
                                               }
            });
            threads[i].Start();
        }

        foreach (var t in threads) t.Join();
        
        Console.Out.WriteLine("P4\n{0} {0}", n);        
        var s = Console.OpenStandardOutput();
        for (int y = 0; y < n; y++) s.Write(data[y], 0, lineLen);        
    }  
}
   
    

NOTES:
64-bit Ubuntu quad core
.NET Core SDK   3.1.201
Host Version: 3.1.3; Commit: 4a9f85e9f8
<ServerGarbageCollection>true
<ConcurrentGarbageCollection>true


Thu, 07 May 2020 20:56:31 GMT

MAKE:
cp mandelbrot.csharpcore-5.csharpcore Program.cs
cp Include/csharpcore/tmp.csproj .
mkdir obj
cp Include/csharpcore/project.assets.json ./obj
/usr/bin/dotnet build -c Release --no-restore
Microsoft (R) Build Engine version 16.5.0+d4cbfca49 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

  tmp -> /home/dunham/benchmarksgame_quadcore/mandelbrot/tmp/bin/Release/netcoreapp3.1/tmp.dll

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

Time Elapsed 00:00:04.69

7.55s to complete and log all make actions

COMMAND LINE:
/usr/bin/dotnet ./bin/Release/netcoreapp3.1/tmp.dll 16000

(BINARY) PROGRAM OUTPUT NOT SHOWN