Fractals using MPI.NET and HPC

I updated my fractal example to support MPI.NET (Message Passing Interface with .NET) and parametric tasks in Windows HPC Server 2008. The example can be download from my ajcodekatas Google code:

http://code.google.com/p/ajcodekatas/source/browse/#svn/trunk/FractalExample

There are two solutions. Fractal.sln contains:

The Fractal.Console project is a console application that takes parameters from the command line. It uses that parameters to generate a serialized sector of the fractal, writing a file:

        static void Main(string[] args)
        {
            if (args[4].Equals("*"))
                args[4] = "0";

            SectorInfo sectorinfo = new SectorInfo()
            {
                RealMinimum = Convert.ToDouble(args[0]),
                ImgMinimum = Convert.ToDouble(args[1]),
                Delta = Convert.ToDouble(args[2]),
                FromX = Convert.ToInt32(args[3]),
                FromY = Convert.ToInt32(args[4]),
                Width = Convert.ToInt32(args[5]),
                Height = Convert.ToInt32(args[6]),
                MaxIterations = Convert.ToInt32(args[7]),
                MaxValue = Convert.ToInt32(args[8])
            };

            Calculator calculator = new Calculator();

            Sector sector = calculator.CalculateSector(sectorinfo);

            SectorSerializer serializer = new SectorSerializer();

            string filename = string.Format("{0}-{1}-{2}-{3}-{4}.bin", args[9], sectorinfo.FromX, sectorinfo.FromY, sectorinfo.Width, sectorinfo.Height);

            serializer.Serialize(sector, filename);
        }

You can run the project in Debug mode, with parameters:

Launch the new Fractal.GUIFiles project. It’s a winform application, with a new button Read:

Click Read button, and load the generated sector file located in the Fractal.Console bin\debug directory:

This is the result:

Creating the sectors with HPC

The console application can be used in a cluster. Suppose the application is installed in c:\FractalConsole in each node of a cluster. Suppose the name of the head node is HEAD-NODE, and that it has a shared directory named \shared. Then, we can submit a parametric job:

job submit /parametric:0-500:100 c:\FractalConsole\Fractal.Console.exe 0.3 0.3 0.01 0 * 1000 100 2000 4 \\HEAD-NODE\shared\sector

This command submit a parametric job to the cluster. The asterisk in the parameter lists will be replaced by the values 0,100,200,300,400 and 500 (this is the Y coordinate of the top left point of sector). Each execution will produce a file with a serialized sector in the shared directory, that you can read and show using the Fractal.GUIFiles app.

Using MPI.NET

There is a second solution Fractal.MPI:

This code uses MPI (Message Passing Interface). The rank 0 receives a sector, and then, the sector is partitioned between all ranks in execution. Each instance writes a file, representing a subsector of the original sector. 

To compile and run this example I installed the HPC Pack I downloaded from:

HPC Pack 2008 SDK download

and then, I installed MPI.NET Software

(I installed MPI.NET SDK.msi but I expanded MPI.NET-1.0.0.zip too: it has better examples, with VS solutions)

(note: if you want to run under XP Pro, you must download the previous version of the HPC SDK:
Microsoft Compute Cluster Pack SDK

The new SDK has an issue with XP. More info at:

http://social.microsoft.com/Forums/en-US/windowshpcdevs/thread/19deb181-15c2-40be-bb5e-2d4604b984a4
http://www.pluralsight.com/community/blogs/drjoe/archive/2008/10/10/32-bit-sdk-for-hpc-server-2008-fails-quot-the-procedure-entry-point-getprocessidofthread-could-not-be-located-quot.aspx
)

You can run the program using mpiexec utility, that launch many instances of the same program:

mpiexec -n 10 Fractal.Mpi.Exe 0 0 0.01 0 0 500 1000 2000 4 sector

The sectors will be produced by ten instances:

that you can read and show using the Fractal.GUIFiles.

You can run the above command in an HPC cluster, using:

job submit /numnodes=10 mpiexec c:\FractalMpi\Fractal.Mpi.Exe 0 0 0.01 0 0 500 1000 2000 4 \\HEAD-NODE\shared\sector

(assuming you had deployed the application in each node, inside c:\FractalMpi folder)

You have a more complete example at:

Learning Parallel Programming — from shared-memory multi-threading to distributed-memory multi-processing

Angel “Java” Lopez
http://www.ajlopez.com/en
http://twitter/ajlopez