Passing a Struct to a kernel in cudafy.net

Question

I'm having some issues allocating a struct, which contains several arrays, to the GPU. In the 2nd code block im getting an error with:

SimpleDataStructure[] dev_SDS = _gpu.CopyToDevice(SDS);

Does anyone know why? From what i can see CopyToDevice() doesnt support a struct as an argument. I might be missing something though so would appreciate some assistance in any case.

Struct declaration:

[Cudafy]
public struct SimpleDataStructure
{
    public float[] AreaCode;
    public float[] Number; 

    public SimpleDataStructure(int x)
    {
        AreaCode = new float[x];
        Number = new float[x];
    }
}

Code in a method in my class:

Public class TaskManager
{
    private static GPGPU _gpu;

    private SimpleDataStructure SDS;

    public void PreparationForTasks()
    {
        DataRetrieval();

        SDS = new SimpleDataStructure(_entity.Data.Count - 1);

        CudafyModule km = CudafyTranslator.Cudafy();            
        _gpu = CudafyHost.GetDevice(eGPUType.Cuda);
        _gpu.LoadModule(km);

        //Loaded SimpleDataStructure into same module.
        km = CudafyTranslator.Cudafy(typeof(SimpleDataStructure));
        _gpu.LoadModule(km, false);

//Getting error on following line.
        SimpleDataStructure[] dev_SDS = _gpu.CopyToDevice(SDS);

        dim3 grid = new dim3(10, 10, 1);
        dim3 block = new dim3(8, 8, 1);
        _gpu.Launch(grid, block, "WorkerKernelOnGPU", dev_SDS);

        SimpleDataStructure result_SDS = new SimpleDataStructure(100);

        _gpu.CopyFromDevice(dev_SDS, result_SDS);
    }

    //.....
}

score 5 · Accepted Answer · answered Jun 18 '13 at 15:22

5

You can not have array references as members of your struct, that is not supported by cudafy. You can work around this by copying the arrays to the device yourself and store the device addresses as IntPtrs inside your struct. Alternatively if the size of the arrays is going to be fixed you could make your struct unsafe and use fixed-size arrays inside the struct.

answered Jun 18 '13 at 15:22

RoBiK

1,740
12
15

Could you write a quick example using ur second method with IntPtrs please? Regarding the 1st method, I would just be passing, in my example, AreaCode and Number as separate parameters to my kernel? Thanks for your help thus far. +1. – Hans Rudel Jun 18 '13 at 15:28
2

@HansRudel regarding the possible solutions for arrays inside struct i would refer you to this discussion: http://cudafy.codeplex.com/discussions/283527 Looking at your code, using a struct seems like overkill when you can simply pass two arrays instead and avoid the whole mess with the struct with arrays. – RoBiK Jun 18 '13 at 15:59
Thanks for your help + yeah ur probably right. I'll see about implementing the struct version when things become more complicated. – Hans Rudel Jun 18 '13 at 16:32

Passing a Struct to a kernel in cudafy.net

1 Answers1