out of place transform not working

[jglaser]

What is the expected behavior

complex-to-complex in-place transforms using hipfft with single precision produce incorrect results when performed out of place

What actually happens

I modified the sample script hipfft_3d_z2z.cpp to do the FFT out-of-place.

I get

output:
(-23.8431,-23.8431) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 

(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 

(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 

(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 

with out-of-place transform, but I expect the same result as for inplace, which is

output:
(1056,96) (-320,320) (-320,0) (-320,-320) 
(-32,-32) (0,0) (0,0) (0,0) 
(0,-32) (0,0) (0,0) (0,0) 
(32,-32) (0,0) (0,0) (0,0) 

(-32,32) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 

(-32,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 

(-32,-32) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 
(0,0) (0,0) (0,0) (0,0) 

How to reproduce

// Kernel for initializing the real-valued input data on the GPU.
__global__ void initdata(hipfftComplex* x, const int Nx, const int Ny, const int Nz)
{
    const int idx = blockIdx.x * blockDim.x + threadIdx.x;
    const int idy = blockIdx.y * blockDim.y + threadIdx.y;
    const int idz = blockIdx.z * blockDim.z + threadIdx.z;
    if(idx < Nx && idy < Ny && idz < Nz)
    {
        const int pos = (idx * Ny + idy) * Nz + idz;
        x[pos].x      = idx + 10 * idz;
        x[pos].y      = idy;
    }
}

// Helper function for determining grid dimensions
template <typename Tint1, typename Tint2>
Tint1 ceildiv(const Tint1 nominator, const Tint2 denominator)
{
    return (nominator + denominator - 1) / denominator;
}

int main()
{
    std::cout << "hipfft 3D single-precision complex-to-complex transform (out of place)\n";

    const int Nx        = 4;
    const int Ny        = 4;
    const int Nz        = 4;
    int       direction = HIPFFT_FORWARD; // forward=-1, backward=1

    std::vector<std::complex<float>> cdata(Nx * Ny * Nz);
    size_t complex_bytes = sizeof(decltype(cdata)::value_type) * cdata.size();

    // Create HIP device object and copy data to device:
    // hipfftComplex for single-precision
    hipfftComplex* x;
    hipMalloc(&x, complex_bytes);

    hipfftComplex* y;
    hipMalloc(&y, complex_bytes);

    // Inititalize the data on the device
    hipError_t rt;
    const dim3 blockdim(8, 8, 8);
    const dim3 griddim(ceildiv(Nx, blockdim.x), ceildiv(Ny, blockdim.y), ceildiv(Nz, blockdim.z));
    hipLaunchKernelGGL(initdata, blockdim, griddim, 0, 0, x, Nx, Ny, Nz);
    hipDeviceSynchronize();
    rt = hipGetLastError();
    assert(rt == hipSuccess);

    std::cout << "input:\n";
    hipMemcpy(cdata.data(), x, complex_bytes, hipMemcpyDefault);
    for(int i = 0; i < Nx; i++)
    {
        for(int j = 0; j < Ny; j++)
        {
            for(int k = 0; k < Nz; k++)
            {
                int pos = (i * Ny + j) * Nz + k;
                std::cout << cdata[pos] << " ";
            }
            std::cout << "\n";
        }
        std::cout << "\n";
    }
    std::cout << std::endl;

    // Create plan
    hipfftResult rc   = HIPFFT_SUCCESS;
    hipfftHandle plan = NULL;
    rc                = hipfftCreate(&plan);
    assert(rc == HIPFFT_SUCCESS);
    rc = hipfftPlan3d(&plan, // plan handle
                      Nx, // transform length
                      Ny, // transform length
                      Nz, // transform length
                      HIPFFT_C2C); // transform type (HIPFFT_C2C for single-precision)
    assert(rc == HIPFFT_SUCCESS);

    // Execute plan
    // hipfftExecZ2Z: single precision, hipfftExecC2C: for single-precision
    rc = hipfftExecC2C(plan, x, y, direction);
    assert(rc == HIPFFT_SUCCESS);

    std::cout << "output:\n";
    hipMemcpy(cdata.data(), y, complex_bytes, hipMemcpyDeviceToHost);
    for(int i = 0; i < Nx; i++)
    {
        for(int j = 0; j < Ny; j++)
        {
            for(int k = 0; k < Nz; k++)
            {
                int pos = (i * Ny + j) * Nz + k;
                std::cout << cdata[pos] << " ";
            }
            std::cout << "\n";
        }
        std::cout << "\n";
    }
    std::cout << std::endl;

    hipfftDestroy(plan);
    hipFree(x);
    hipFree(y);
    return 0;
}

Environment

Hardware	description
GPU	Vega 10 [Radeon Instinct MI25]
CPU	AMD EPYC 7601 32-Core

Software	version
HCC	10.0
Library	0.9.7.722-rocm-rel-2.9-6-e3055e1

[malcolmroberts]

Thank for bringing up this issue. It seems to be isolatd to the 3D complex-to-complex out-of-place transform.

[malcolmroberts]

I think that this is fixed in develop now; would you mind giving it a try?

[malcolmroberts]

I'm going to close this issue; if the problem presists, please re-open.