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使用推力生成具有均匀分布的随机数

更新时间:2023-02-10 13:56:59

推力具有可用于生成的随机生成器随机数序列。要与设备向量一起使用它们,您将需要创建一个函子,该函子返回随机生成器序列的另一个元素。最简单的方法是使用计数迭代器的转换。示例(在这种情况下,生成1.0和2.0之间的随机单精度数字)可能像这样:

Thrust has random generators you can use to produce sequences of random numbers. To use them with a device vector you will need to create a functor which returns a different element of the random generator sequence. The most straightforward way to do this is using a transformation of a counting iterator. A very simple complete example (in this case generating random single precision numbers between 1.0 and 2.0) could look like:

#include <thrust/random.h>
#include <thrust/device_vector.h>
#include <thrust/transform.h>
#include <thrust/iterator/counting_iterator.h>
#include <iostream>

struct prg
{
    float a, b;

    __host__ __device__
    prg(float _a=0.f, float _b=1.f) : a(_a), b(_b) {};

    __host__ __device__
        float operator()(const unsigned int n) const
        {
            thrust::default_random_engine rng;
            thrust::uniform_real_distribution<float> dist(a, b);
            rng.discard(n);

            return dist(rng);
        }
};


int main(void)
{
    const int N = 20;

    thrust::device_vector<float> numbers(N);
    thrust::counting_iterator<unsigned int> index_sequence_begin(0);

    thrust::transform(index_sequence_begin,
            index_sequence_begin + N,
            numbers.begin(),
            prg(1.f,2.f));

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

    return 0;
}

在此示例中,函子 prg 将随机数的上限和下限作为参数,默认值为(0.f,1.f)。请注意,为了使每次调用转换操作都具有不同的向量,应使用初始化为不同起始值的计数迭代器。

In this example, the functor prg takes the lower and upper bounds of the random number as an argument, with (0.f,1.f) as the default. Note that in order to have a different vector each time you call the transform operation, you should used a counting iterator initialised to a different starting value.