(done) openMP学习 (Day13: 线程私有数据和如何支持库(Pi again)，蒙特卡洛计算 Pi，线性同余法)

url: https://dazuozcy.github.io/posts/introdution-to-openmp-intel/#23-%E5%8F%AF%E6%80%95%E7%9A%84%E4%B8%9C%E8%A5%BF%E5%86%85%E5%AD%98%E6%A8%A1%E5%9E%8Batomicsflushpairwise%E5%90%8C%E6%AD%A5%20

视频：https://www.bilibili.com/video/BV1SW411s7ST?spm_id_from=333.788.videopod.episodes&vd_source=7a1a0bc74158c6993c7355c5490fc600&p=26

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先来回顾 threadprivate

threadprivate: makes global data private to a thread.

例子：

int counter = 0;
#pragma omp threadprivate(counter) //每个线程都有一个counter变量，并且被初始化为0

int increment_counter()
{
   
    counter++;
    return (counter);
}

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一个例子：蒙特卡洛法计算pi值

#include <random>

static long num_trails = 10000;

void calc_pi_montacalo()
{
   
    long i;
    long Ncircle =