CUDA--Thrust--带参数自定义函数(6)
Thrust自定义函数非常灵活,给编写程序带来方便,上次的自定义函数没有带参数,这次
笔者写一个带参数的自定义函数。通过这次写带参数的自定义函数,我对如何用transformation
调用函数有了更深的理解。
代码:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <thrust/device_vector.h> #include <thrust/transform.h> #include <thrust/sequence.h> #include <thrust/copy.h> #include <thrust/fill.h> #include <thrust/replace.h> #include <thrust/functional.h> #include <iostream> #define D_SW 1 struct saxpy_functor { const float a; saxpy_functor(float _a) : a(_a) {} __host__ __device__ float operator()(const float& x, const float& y) const { return a * x + y; } }; void saxpy_fast(float A, thrust::device_vector<float>&X, thrust::device_vector<float>&Y) { //Y<- A*X+Y thrust::transform(X.begin(), X.end(), Y.begin(), Y.begin(), saxpy_functor(A)); } void saxpy_slow(float A, thrust::device_vector<float>&X, thrust::device_vector<float>&Y) { thrust::device_vector<float>temp(X.size()); //temp=A thrust::fill(temp.begin(), temp.end(),A); //temp=A*X thrust::transform(X.begin(), X.end(), temp.begin(), temp.begin(), thrust::multiplies<float>()); //Y=A*X+Y thrust::transform(temp.begin(), temp.end(), Y.begin(), Y.begin(), thrust::plus<float>()); } int main(void) { float a = -1.0f; thrust::device_vector<float>x(10); thrust::device_vector<float>y(10); thrust::sequence(x.begin(), x.end()); thrust::sequence(y.begin(), y.end()); /*for (int i = 0; i < y.size(); ++i) { std::cout << y[i] << std::endl; }*/ #if D_SW saxpy_fast(a, x, y); #else saxpy_slow(a, x, y); #endif for (int i = 0; i < y.size(); ++i) { std::cout << y[i] << std::endl; } return 0; }