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namespace stim{
namespace cuda{
template<typename T>
__global__ void cuda_add(T* ptr1, T* ptr2, T* sum, unsigned int N){
//calculate the 1D index for this thread
int idx = blockIdx.x * blockDim.x + threadIdx.x;
if(idx < N){
sum[idx] = ptr1[idx] + ptr2[idx];
}
}
template<typename T>
void gpu_add(T* ptr1, T* ptr2, T* sum, unsigned int N){
//get the maximum number of threads per block for the CUDA device
int threads = stim::maxThreadsPerBlock();
//calculate the number of blocks
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//call the kernel to do the multiplication
cuda_add <<< blocks, threads >>>(ptr1, ptr2, sum, N);
}
template<typename T>
void cpu_add(T* ptr1, T* ptr2, T* cpu_sum, unsigned int N){
//allocate memory on the GPU for the array
T* gpu_ptr1;
T* gpu_ptr2;
T* gpu_sum;
HANDLE_ERROR( cudaMalloc( &gpu_ptr1, N * sizeof(T) ) );
HANDLE_ERROR( cudaMalloc( &gpu_ptr2, N * sizeof(T) ) );
HANDLE_ERROR( cudaMalloc( &gpu_sum, N * sizeof(T) ) );
//copy the array to the GPU
HANDLE_ERROR( cudaMemcpy( gpu_ptr1, ptr1, N * sizeof(T), cudaMemcpyHostToDevice) );
HANDLE_ERROR( cudaMemcpy( gpu_ptr2, ptr2, N * sizeof(T), cudaMemcpyHostToDevice) );
//call the GPU version of this function
gpu_add<T>(gpu_ptr1, gpu_ptr2 ,gpu_sum, N);
//copy the array back to the CPU
HANDLE_ERROR( cudaMemcpy( cpu_sum, gpu_sum, N * sizeof(T), cudaMemcpyDeviceToHost) );
//free allocated memory
cudaFree(gpu_ptr1);
cudaFree(gpu_ptr2);
cudaFree(gpu_sum);
}
}
}
#endif
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change the header...