kopia lustrzana https://github.com/vsamy/DiFipp
32 wiersze
798 B
C++
32 wiersze
798 B
C++
#pragma once
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#include "type_checks.h"
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#include <complex>
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#include <vector>
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namespace fratio {
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template <typename T, typename = std::enable_if_t<std::is_arithmetic<T>::value || is_complex_t<T>::value>>
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struct VietaAlgo;
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template <typename T>
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struct VietaAlgo<T> {
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// Vieta's computation: https://en.wikipedia.org/wiki/Vieta%27s_formulas
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static std::vector<T> polyCoeffFromRoot(const std::vector<T>& poles);
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};
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template <typename T>
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std::vector<T> VietaAlgo<T>::polyCoeffFromRoot(const std::vector<T>& poles)
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{
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std::vector<T> coeff(poles.size() + 1, 0);
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coeff[0] = 1;
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for (size_t i = 0; i < poles.size(); ++i) {
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for (size_t k = i + 1; k > 0; --k) {
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coeff[k] = coeff[k] - poles[i] * coeff[k - 1];
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}
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}
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return coeff;
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}
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} // namespace fratio
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