#include
#include
#include
#include
#include
#include
#include
#include
using?namespace?std;
pthread_mutex_t?mutex?=?PTHREAD_MUTEX_INITIALIZER;/*初始化互斥鎖*/
pthread_cond_t?cond?=?PTHREAD_COND_INITIALIZER;/*初始化條件變量*/
long?long??maxn?;????//計算規模
double?ans?=?0;??????//結果
long?long??pnum?=?10;//線程數
long?long?maxn2;?????//
long?long?over;??????//線程結束數
struct?node{?????????//保存每個線程計算的起點和終點
????long?long??beginend;
};
void?*thread（void*xx）?//線程執行指令
{
????double?x?=?0yy;
????node?y?=?*（node*）xx;
????long?long?maxn1?=?（long?long）maxn*maxn;
????for（long?long??i?=?y.begin;i?????{
????????x?+=?1.0/（maxn1+（i+0.5）*（i+0.5））;
????}
????pthread_mutex_lock（&mutex）;?//加鎖更新總結果以及更新線程結束的個數
????ans?+=?x;
????over++;
????pthread_mutex_unlock（&mutex）;//解鎖
????void?*statu;
????pthread_exit（&statu）;//結束線程
}
int?main（int?argc?char*argv[]）
{
???struct?timeval?tv;
???gettimeofday（&tv?NULL）;
???double?time_start?time_end;?//保存程序開始時間和結束時間
???//獲取當前開始時間
???time_start?=?（double）tv.tv_sec?+?（double）tv.tv_usec?/?1000000.0;
???pnum?=?atoi（argv[1]）;????????//獲取線程數
???maxn?=?atoi（argv[2]）;????????//獲取數據規模
???pthread_t?pid[1000];?????????//保存線程id
???node?xx[1000];
???maxn2=?（long?long?）maxn*maxn;
???over?=?0;
???//給每個線程分配計算的開始和結束位置，并創建線程
???long?long??begin?=?0?length?=?（maxn+pnum-1）/pnum;
???for（long?long??i?=?0;i????{
????????xx[i].begin?=?begin;
????????xx[i].end?=?min（（long?long）maxnbegin+length）;
????????begin?=?begin+length;
????????pthread_create（&pid[i]NULLthread&xx[i]）;
???}
???while（over?!=?pnum）?{usleep（5）;}?//查看是否所有線程完成任務
???ans??=?4.0*ans*maxn;
???pthread_mutex_destroy（&mutex）;
???gettimeofday（&tv?NULL）;????????//獲取當前結束時間
???time_end?=?（double）tv.tv_sec?+?（double）tv.tv_usec?/?1000000.0;
???//輸出結果
???printf（“pnum:%lld?scale:%lld?the?pi?result:%0.10lf???thetimecost:%lf\n“pnummaxnanstime_end-time_start）;
???return?0;
}

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件??????154624??2014-03-28?20:49??1_多線程求pi?-?副本.doc
?????文件?????1350144??2014-03-28?20:49??2_多線程求卷積?-?副本.doc
?????目錄???????????0??2014-03-20?09:29??test1\
?????文件?????????371??2014-03-18?10:41??test1\shell1.txt
?????文件????????2188??2014-03-20?08:50??test1\test1.cpp
?????目錄???????????0??2014-03-20?09:29??test2\
?????文件??????????71??2014-03-20?13:26??test2\2.txt
?????文件??????525798??2014-03-21?12:37??test2\dataout0.txt
?????文件??????526769??2014-03-21?12:37??test2\dataout1.txt
?????文件??????527484??2014-03-21?12:37??test2\dataout2.txt
?????文件??????527492??2014-03-21?12:37??test2\dataout3.txt
?????文件??????527501??2014-03-21?12:37??test2\dataout4.txt
?????文件?????3096826??2014-03-21?14:10??test2\dataout5.txt
?????文件????????2691??2014-03-21?15:06??test2\test2.cpp