并行编程代码怎么写的

时间:2025-01-23 14:56:18 游戏攻略

并行编程代码的实现方式取决于你使用的编程语言和库。以下是使用Python的`multiprocessing`库实现并行编程的示例代码:

使用`multiprocessing.Pool`

```python

import multiprocessing

import time

模拟耗时任务

def cpu_bound_task(number):

time.sleep(1)

if __name__ == '__main__':

串行执行

start_time = time.time()

for i in range(5):

cpu_bound_task(i)

end_time = time.time()

print(f"串行执行时间: {end_time - start_time}秒.")

并行执行

start_time_parallel = time.time()

with multiprocessing.Pool(5) as pool:

pool.map(cpu_bound_task, range(5))

end_time_parallel = time.time()

print(f"多进程执行时间: {end_time_parallel - start_time_parallel}秒.")

```

使用`joblib`库

```python

from joblib import Parallel, delayed

import time

模拟耗时任务

def slow_square(x):

time.sleep(1)

return x * x

普通方式

start = time.time()

result1 = [slow_square(i) for i in range(10)]

print(f"普通方式耗时: {time.time() - start}秒")

并行方式

start = time.time()

result2 = Parallel(n_jobs=4)(delayed(slow_square)(i) for i in range(10))

print(f"并行方式耗时: {time.time() - start}秒")

```

使用`concurrent.futures`库

```python

import concurrent.futures

import time

模拟耗时任务

def cpu_bound_task(number):

time.sleep(1)

return number * number

if __name__ == '__main__':

串行执行

start_time = time.time()

for i in range(5):

cpu_bound_task(i)

end_time = time.time()

print(f"串行执行时间: {end_time - start_time}秒.")

并行执行

start_time_parallel = time.time()

with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:

results = list(executor.map(cpu_bound_task, range(5)))

end_time_parallel = time.time()

print(f"多线程执行时间: {end_time_parallel - start_time_parallel}秒.")

```

使用C的`Parallel.ForEach`

```csharp

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

namespace ParallelTest

{

class ParallelTest

{

private static int TimedMessage(string argMessage, int argInterval)

{

for (int i = 0; i < argInterval; i++)

{

Console.WriteLine(argMessage);

Task.Delay(1000).Wait();

}

return 0;

}

static void Main(string[] args)

{

RetCode = TimedMessage("Five ", 4);

}

}

}

```

使用C++的OpenMP

```cpp

include

include

include

void Hello()

{

int my_rank = omp_get_thread_num();

int thread_count = omp_get_num_threads();

std::cout << "Hello World from thread " << my_rank << " of " << thread_count << std::endl;

}

int main(int argc, char* argv[])

{

int thread_count = std::strtol(argv, NULL, 10);

pragma omp parallel num_threads(thread_count)

{

Hello();

}

return 0;

}

```

总结

Python:

使用`multiprocessing`库或`joblib`库可以轻松实现并行编程。

C:

使用`Parallel.ForEach`可以并行执行任务。