Андрей Чусов: Новая страница: «{{class|Архитектурная акустика/Реализация/IteratorAdapterConditional}} {{example_begin}} #include "collection_…»

2018-01-08T14:37:22Z

Новая страница: «{{class|Архитектурная акустика/Реализация/IteratorAdapterConditional}} {{example_begin}} <source lang="cpp"> #include "collection_…»

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{{class|Архитектурная акустика/Реализация/IteratorAdapterConditional}}

{{example_begin}}
<source lang="cpp">
#include "collection_base.h"
#include <array>
#include <iostream>

using namespace Chusov::Math;

template <class Container>
std::array<int, 20 * 10> extract_even_range_for(const Container& cont)
{
std::vector<std::thread> vecThreads;
std::array<int, 20 * 10> EvenValues;
for (unsigned i = 0; i < std::thread::hardware_concurrency(); ++i)
vecThreads.emplace_back([&vecThreads, i, &cont, &EvenValues]()
{
for (auto&& v :
adapt_iterator_range<IteratorAdapterConditional>(
adapt_iterator_range<IteratorAdapterForStep>(
Chusov::Memory::make_iterator_range(make_iterator_adapter<IteratorAdapter2D>(cont.crbegin()) + i, cont.crend()),
std::thread::hardware_concurrency(),
adapt_iterator_range<IteratorAdapter2D>(cont.crbegin(), cont.crend())
),
[](int x) -> bool {return (x & 1) == 0; },
//or: [](IteratorAdapterForStep<IteratorAdapter2D<Matrix<int>::const_reverse_iterator>> _it) -> bool {return (*_it & 1) == 0;},
//or: [](IteratorAdapter2D<Matrix<int>::const_reverse_iterator> _it) -> bool {return (*_it & 1) == 0;},
[&cont](auto _it) -> bool {return _it.adaptation_base() != cont.crend(); }
//or: [&cont](IteratorAdapterForStep<IteratorAdapter2D<Matrix<int>::const_reverse_iterator>> it) -> bool {return it != cont.crend();}
)
)
EvenValues[20 * 10 - v / 2] = v;
});
for (auto&& thr : vecThreads)
thr.join();
return EvenValues;
}

template <class Container>
std::array<int, 20 * 10> extract_even_direct_for(const Container& cont)
{
std::vector<std::thread> vecThreads;
std::array<int, 20 * 10> EvenValues;
for (unsigned i = 0; i < std::thread::hardware_concurrency(); ++i)
vecThreads.emplace_back([&vecThreads, i, &cont, &EvenValues]()
{
for (auto it = make_iterator_adapter<IteratorAdapterConditional>(
make_iterator_adapter<IteratorAdapterForStep>(
i,
std::thread::hardware_concurrency(),
adapt_iterator_range<IteratorAdapter2D>(cont.crbegin(), cont.crend())
),
//generic lambda causes ambiguity: should it pass an iterator or a value here
[](IteratorAdapterForStep<IteratorAdapter2D<Matrix<int>::const_reverse_iterator>> _it) -> bool {return (*_it & 1) == 0; },
[&cont](auto _it) -> bool {return _it.adaptation_base() != cont.crend(); }
); it.adaptation_base() != make_iterator_adapter<IteratorAdapter2D>(cont.crend()); ++it)
EvenValues[20 * 10 - *it / 2] = *it;
});
for (auto&& thr : vecThreads)
thr.join();
return EvenValues;
}

int main(int argc, char** argv)
{
auto m2 = Matrix<int>(0, 20, 20);
auto x = 1;
for (auto&& v : adapt_iterator_range<IteratorAdapter2D>(m2.begin(), m2.end()))
v = x++;
auto rng_based = extract_even_range_for(m2);
std::cout << "\nElements of an array with even elements of a matrix put in parallel in reverse order (range-for based).\n";
for (auto val:rng_based)
std::cout << val << "\t";
std::cout << "\n";
auto direct_based = extract_even_direct_for(m2);
for (auto val : direct_based)
std::cout << val << "\t";
std::cout << "\n";
return 0;
}
</source>
{{example_end}}

Архитектурная акустика/Реализация/IteratorAdapterConditional - История изменений

Андрей Чусов: Новая страница: «{{class|Архитектурная акустика/Реализация/IteratorAdapterConditional}} {{example_begin}} #include "collection_…»