rocm-systems/samples/0_Intro/hcc_dialects/vadd_hc_array.cpp

// Simple test showing how to use HC syntax with array.
// Array provides a type-safe C++ mechanism to allocate accelerator memory.  
// Like array_view, hc::array provides multi-dimensional indexing capability,
// and is typed.  However, unlike array_view, hc::array does not provide
// automatic data management capabilities - instead the programmer
// takes the reins and controls when copies are executed.

#include <hc.hpp>

int main(int argc, char *argv[])
{
    int sizeElements = 1000000;
    size_t sizeBytes = sizeElements * sizeof(float);
    bool pass = true;

    // Allocate host memory
    float *A_h = (float*)malloc(sizeBytes);
    float *B_h = (float*)malloc(sizeBytes);
    float *C_h = (float*)malloc(sizeBytes);

    // Allocate device arrays<>
    // Unlike array_view, these must be explicitly managed by user:
    hc::array<float> A_d(sizeElements);
    hc::array<float> B_d(sizeElements);
    hc::array<float> C_d(sizeElements);

    // Initialize host data
    for (int i=0; i<sizeElements; i++) {
        A_h[i] = 1.618f * i; 
        B_h[i] = 3.142f * i;
    }

    hc::copy(A_h, A_d); // C++ copy H2D
    hc::copy(B_h, B_d); // C++ copy H2D

    // Launch kernel onto default accelerator:
    // array<> types are not implicitly copied, so we performed copies above.
    hc::parallel_for_each(hc::extent<1> (sizeElements),
      [&] (hc::index<1> idx) [[hc]] { 
        int i = idx[0];
        C_d[i] = A_d[i] + B_d[i];
    });

    // HCC runtime knows that C_d depends on previous PFE and will force the copy to wait for the PFE to complte.
    hc::copy(C_d, C_h); // C++ copy D2H


    for (int i=0; i<sizeElements; i++) {
        float ref= 1.618f * i + 3.142f * i;
        if (C_h[i] != ref) {
            printf ("error:%d computed=%6.2f, reference=%6.2f\n", i, C_h[i], ref);
            pass = false;
        }
    };
    if (pass) printf ("PASSED!\n");
}