cuda編程之atomicAdd

以下內容來源於cuda c programming guide

注意：函數運算完之後，會將運算結果保存在第一個參數指針指定的空間位置，返回的是old值。

B.12.1.1. atomicAdd() 

int atomicAdd(int* address, int val);
unsigned int atomicAdd(unsigned int* address,

                       unsigned int val);
unsigned long long int atomicAdd(unsigned long long int* address,

                                 unsigned long long int val);
float atomicAdd(float* address, float val);

double atomicAdd(double* address, double val);

reads the 32-bit or 64-bit word old located at the address address in global or shared memory, computes (old + val), and stores the result back to memory at the same address. These three operations are performed in one atomic transaction. The function returns old.

The 32-bit floating-point version of atomicAdd() is only supported by devices ofcompute capability 2.x and higher.

The 64-bit floating-point version of atomicAdd() is only supported by devices ofcompute capability 6.x and higher.