README.md

rocFFT

rocFFT is a software library for computing Fast Fourier Transforms (FFT) written in HIP. It is part of AMD's software ecosystem based on ROCm. In addition to AMD GPU devices, the library can also be compiled with the CUDA compiler using HIP tools for running on Nvidia GPU devices.

API design

Please refer to the API design documentation for current documentation. Work in progress.

Example

The following is a simple example code that shows how to use rocFFT to compute a 1D single precision 16-point complex forward transform.

#include <iostream>
#include <vector>
#include "hip/hip_runtime_api.h"
#include "hip/hip_vector_types.h"
#include "rocfft.h"

int main()
{
        // rocFFT gpu compute
        // ========================================

        size_t N = 16;
        size_t Nbytes = N * sizeof(float2);

        // Create HIP device buffer
        float2 *x;
        hipMalloc(&x, Nbytes);

        // Initialize data
        std::vector<float2> cx(N);
        for (size_t i = 0; i < N; i++)
        {
                cx[i].x = 1;
                cx[i].y = -1;
        }

        //  Copy data to device
        hipMemcpy(x, cx.data(), Nbytes, hipMemcpyHostToDevice);

        // Create rocFFT plan
        rocfft_plan plan = NULL;
        size_t length = N;
        rocfft_plan_create(&plan, rocfft_placement_inplace, rocfft_transform_type_complex_forward, rocfft_precision_single, 1, &length, 1, NULL);

        // Execute plan
        rocfft_execute(plan, (void**) &x, NULL, NULL);

        // Wait for execution to finish
        hipDeviceSynchronize();

        // Destroy plan
        rocfft_plan_destroy(plan);

        // Copy result back to host
        std::vector<float2> y(N);
        hipMemcpy(y.data(), x, Nbytes, hipMemcpyDeviceToHost);

        // Print results
        for (size_t i = 0; i < N; i++)
        {
                std::cout << y[i].x << ", " << y[i].y << std::endl;
        }

        // Free device buffer
        hipFree(x);

        return 0;
}