CUDA : Global unique thread index in a 3D Grid

Question

正如问题所述，如果我有一个 3D 网格 block ，那么获取一个线程的全局唯一索引的公式是什么？

让 block 本身保持一维。

Answer 1

// unique block index inside a 3D block grid
const unsigned long long int blockId = blockIdx.x //1D
        + blockIdx.y * gridDim.x //2D
        + gridDim.x * gridDim.y * blockIdx.z; //3D

// global unique thread index, block dimension uses only x-coordinate
const unsigned long long int threadId = blockId * blockDim.x + threadIdx.x;