57 lines
1.8 KiB
C++
57 lines
1.8 KiB
C++
/***************************************************************************
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* Copyright (c) 2023 Ondsel, Inc. *
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* *
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* This file is part of OndselSolver. *
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* *
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* See LICENSE file for details about copyright. *
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***************************************************************************/
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#include "LinearMultiStepMethod.h"
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#include "FullColumn.h"
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using namespace MbD;
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FColDsptr MbD::LinearMultiStepMethod::derivativeatpresentpast(int n, double t, FColDsptr y, std::shared_ptr<std::vector<FColDsptr>> ypast)
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{
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//"Interpolate or extrapolate."
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//"dfdt(t) = df0dt + d2f0dt2*(t - t0) + d3f0dt3*(t - t0)^2 / 2! + ..."
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auto answer = this->derivativepresentpast(n, y, ypast);
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if (t != time) {
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auto dt = t - time;
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auto dtpower = 1.0;
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for (int i = n + 1; i <= order; i++)
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{
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auto diydti = this->derivativepresentpast(i, y, ypast);
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dtpower = dtpower * dt;
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answer->equalSelfPlusFullColumntimes(diydti, dtpower * (OneOverFactorials->at((size_t)i - n)));
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}
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}
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return answer;
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}
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FColDsptr MbD::LinearMultiStepMethod::derivativepresentpast(int order, FColDsptr y, std::shared_ptr<std::vector<FColDsptr>> ypast)
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{
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assert(false);
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return FColDsptr();
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}
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double MbD::LinearMultiStepMethod::pvdotpv()
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{
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assert(false);
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return 0.0;
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}
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double MbD::LinearMultiStepMethod::firstPastTimeNode()
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{
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return timeNodes->at(0);
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}
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FColDsptr MbD::LinearMultiStepMethod::derivativepresentpastpresentDerivativepastDerivative(int n,
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FColDsptr y, std::shared_ptr<std::vector<FColDsptr>> ypast,
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FColDsptr ydot, std::shared_ptr<std::vector<FColDsptr>> ydotpast)
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{
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assert(false);
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return FColDsptr();
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}
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