Raqamli texnologiyalar vazirligi muhammad al-xorazmiy nomidagi toshkent axborot texnologiyalari universiteti qarshi filiali “kompyuter injiniringi” fakulteti

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Bog'liq
1-amaliy ish

C++Nusxalash

// parallel-fibonacci.cpp
// compile with: /EHsc
#include
#include

#include
#include
#include
#include
#include
#include

using namespace concurrency;
using namespace std;

// Calls the provided work function and returns the number of milliseconds
// that it takes to call that function.
template
__int64 time_call(Function&& f)
{
__int64 begin = GetTickCount();
f();
return GetTickCount() - begin;
}

// Computes the nth Fibonacci number.
int fibonacci(int n)
{
if(n < 2)
return n;
return fibonacci(n-1) + fibonacci(n-2);
}

int wmain()
{
__int64 elapsed;

// An array of Fibonacci numbers to compute.
array a = { 24, 26, 41, 42 };

// The results of the serial computation.
vector> results1;

// The results of the parallel computation.
concurrent_vector> results2;

// Use the for_each algorithm to compute the results serially.
elapsed = time_call([&]
{
for_each (begin(a), end(a), [&](int n) {
results1.push_back(make_tuple(n, fibonacci(n)));
});
});
wcout << L"serial time: " << elapsed << L" ms" << endl;

// Use the parallel_for_each algorithm to perform the same task.
elapsed = time_call([&]
{
parallel_for_each (begin(a), end(a), [&](int n) {
results2.push_back(make_tuple(n, fibonacci(n)));
});

// Because parallel_for_each acts concurrently, the results do not
// have a pre-determined order. Sort the concurrent_vector object
// so that the results match the serial version.
sort(begin(results2), end(results2));
});
wcout << L"parallel time: " << elapsed << L" ms" << endl << endl;

// Print the results.
for_each (begin(results2), end(results2), [](tuple& pair) {
wcout << L"fib(" << get<0>(pair) << L"): " << get<1>(pair) << endl;
});
}

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