如何在ubuntu 12.04中为openCV项目设置openMP多线程？ [英] How to set openMP for Multithreading in ubuntu 12.04 for an openCV project?

问题描述

我想使用 #pragma omp parallel 在我的 for循环之一中执行多线程。所以，我写了下面的代码：

  #pragma omp parallel for 
 for（int i = 0; i< ; square-> total; i ++）
 {
 ...... 
} 
  

我的项目有一个CMakeList.txt和Makefile。 我不明白，我如何告诉编译器和链接器使用openMP？

更新：我已经使用以下代码编辑了我的 CMakeList.txt

  find_package（OpenMP）
 if（OPENMP_FOUND）
 set（CMAKE_C_FLAGS$ {CMAKE_C_FLAGS} $ {OpenMP_C_FLAGS}）
 set（CMAKE_CXX_FLAGS$ {CMAKE_CXX_FLAGS} $ {OpenMP_CXX_FLAGS}）
 endif（）
  

<然后我做了 cmake .. 并在终端得到了以下结果：

- C编译器身份验证是GNU

- CXX编译器标识是GNU

- 检查工作的C编译器：/ usr / bin / gcc

$ b - 检查工作的C编译器：/ usr / bin / gcc - works

<检测C编译器ABI信息检测C编译器ABI信息完成

- 检测C编译器ABI信息

检查工作CXX编译器：/ usr / bin / c ++

- 检查工作CXX编译器：/ usr / bin / c ++ - works

$ b - 检测CXX编译器ABI信息

- 检测CXX编译器ABI信息 - 完成

- 试试OpenMP C flag = [-fopenmp]

- 执行测试OpenMP_FLAG_DETECTED

- 执行测试OpenMP_FLAG_DETECTED - 成功

- 尝试OpenMP CXX标志= [-fopenmp]

- 执行测试OpenMP_FLAG_DETECTED

- - 执行测试OpenMP_FLAG_DETECTED - 成功

- 找到OpenMP：-fopenmp

- 配置完成

- 生成完成

解决方案

@ user2440724

我写了代码示例，如下所示：

  #include <串GT; 
 #include< iostream> 
 #include< vector> 
 #include  
使用namespace std; 
使用命名空间cv; 
 // -------------------------------------------- -------------- 
 // MAIN 
 // ----------------------- ----------------------------------- 
 int main（int argc，char * argv [] ）
 {
 #ifdef _OPENMP 
 #pragma omp parallel for 
 #endif 
 for（int i = 0; i <10; i ++）
 {
 std :: cout<< A<<的std :: ENDL; 
} 
 getchar（）; 
返回0; 
} 
  

在vs2010中，您需要启用openmp，如下所示：

好的Linux教程在这里：< a href =http://goulassoup.wordpress.com/2011/10/28/openmp-tutorial/ =nofollow noreferrer> http://goulassoup.wordpress.com/2011/10/28/openmp- tutorial /
和GNU OpenMP文档： http：/ /gcc.gnu.org/onlinedocs/libgomp/index.html#toc_Top

I want to do multi threading in one of my for loop using #pragma omp parallel. So, i am writing the following code:

#pragma omp parallel for 
for(int i=0; i<square->total; i++)
{
......
}

My project have a CMakeList.txt and Makefile. I don't understand, how do i tell the compiler and linker to use openMP?

Updates:

I have edited my CMakeList.txt with following code

find_package(OpenMP)
if (OPENMP_FOUND)
    set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
endif()

and then i did cmake .. and got the following result at terminal:

-- The C compiler identification is GNU

-- The CXX compiler identification is GNU

-- Check for working C compiler: /usr/bin/gcc

-- Check for working C compiler: /usr/bin/gcc -- works

-- Detecting C compiler ABI info

-- Detecting C compiler ABI info - done

-- Check for working CXX compiler: /usr/bin/c++

-- Check for working CXX compiler: /usr/bin/c++ -- works

-- Detecting CXX compiler ABI info

-- Detecting CXX compiler ABI info - done

-- Try OpenMP C flag = [-fopenmp]

-- Performing Test OpenMP_FLAG_DETECTED

-- Performing Test OpenMP_FLAG_DETECTED - Success

-- Try OpenMP CXX flag = [-fopenmp]

-- Performing Test OpenMP_FLAG_DETECTED

-- Performing Test OpenMP_FLAG_DETECTED - Success

-- Found OpenMP: -fopenmp

-- Configuring done

-- Generating done

解决方案

@user2440724

I wrote the code sample as you ask:

#include <string>
#include <iostream>
#include <vector>
#include <omp.h>
using namespace std;
using namespace cv;
//----------------------------------------------------------
// MAIN
//----------------------------------------------------------
int main(int argc, char* argv[])
{
#ifdef _OPENMP 
#pragma omp parallel for
#endif
    for (int i = 0; i < 10; i++)
    {
      std::cout << "A" << std::endl;    
    }
    getchar();
    return 0;
}

in vs2010 you need enable openmp as shown below:

Good tutorial for linux here: http://goulassoup.wordpress.com/2011/10/28/openmp-tutorial/ And GNU OpenMP docs: http://gcc.gnu.org/onlinedocs/libgomp/index.html#toc_Top

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