CODEWITHSUNDEEP
gpustdvectorhpcnvccopenacc
carbonaraHPC
carbonaraHPC

Reputation: 11

Use std::vector with OpenACC

I’m trying to compute on GPU, using OpenACC, the sum between two vectors of std::vector. As compiler I’m using GCC+NVPTX with OpenACC support but when I compile the code with these flags: g++ -fopenacc -offload=nvptx-none -fopt-info-optimized-omp -g -std=c++17 But I got: “array_1 does not have pointer or array type” and “array_2 does not have pointer or array type”. Is there any way to use std::vector with OpenACC?

This a minimal reproducible example:

int main(int argc, char **argv) {
    std::vector<std::vector<float>> array1,array2;
    float result[1000]={0.0};

    for(int i=0; i<1000; i++){
        std::vector<float> accumulator1, accumulator2;
        for (int j=0; j<1000; j++){
            accumulator1.push_back(99.99);
            accumulator2.push_back(66.66);          
        }
        array1.push_back(accumulator1);
        array2.push_back(accumulator2);
    }

    #pragma acc data copyin(array1[:1000][:1000],array2[:1000][:1000])
    #pragma acc data copy(result[:1000])
    #pragma acc parallel loop
    for(int i=0; i<1000; i++){
        for (int j=0; j<1000; j++){
            result[i] += array1[i][j] + array2[i][j];       
        }
    }

    for(int i=0; i<10; i++){
        std::cout << result[i] << std::endl;
    }

    return 0;
}

Compiling with GCC+NVPTX is mandatory for me, but also trying to compile it with nvc++ returns:

main:
     18, Generating copyin(array1,array2) [if not already present]
         Generating copy(result[:]) [if not already present]
         Generating NVIDIA GPU code
         23, #pragma acc loop gang, vector(128) /* blockIdx.x threadIdx.x */
         24, #pragma acc loop seq
     24, Complex loop carried dependence of  prevents parallelization
         Loop carried dependence of result prevents parallelization
         Loop carried backward dependence of result prevents vectorization
std::vector<std::vector<float, std::allocator<float>>, std::allocator<std::vector<float, std::allocator<float>>>>::operator [](unsigned long):
      3, include "vector"
          64, include "stl_vector.h"
              771, Generating implicit acc routine seq
                   Generating acc routine seq
                   Generating NVIDIA GPU code
std::vector<float, std::allocator<float>>::operator [](unsigned long):
      3, include "vector"
          64, include "stl_vector.h"
              771, Generating implicit acc routine seq
                   Generating acc routine seq
                   Generating NVIDIA GPU code

And launching the application:

Failing in Thread:0
call to cuInit returned error 999: Unknown

Any advice? Thanks

Upvotes: 1

Views: 226

Answers (0)

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