/*! \file pimathsolver.h
 * \brief PIMathSolver
 */
/*
    PIP - Platform Independent Primitives
    PIMathSolver
    Ivan Pelipenko peri4ko@yandex.ru

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef PIMATHSOLVER_H
#define PIMATHSOLVER_H

#include "pimathmatrix.h"

/// Differential evaluations

struct PIP_EXPORT TransferFunction {
	PIVector<double> vector_Bm, vector_An;
};

class PIP_EXPORT PIMathSolver {
public:
	enum Method {
		Global                    = -1,
		Eyler_1                   = 01,
		Eyler_2                   = 02,
		EylerKoshi                = 03,
		RungeKutta_4              = 14,
		AdamsBashfortMoulton_2    = 22,
		AdamsBashfortMoulton_3    = 23,
		AdamsBashfortMoulton_4    = 24,
		PolynomialApproximation_2 = 32,
		PolynomialApproximation_3 = 33,
		PolynomialApproximation_4 = 34,
		PolynomialApproximation_5 = 35
	};

	PIMathSolver();

	void solve(double u, double h);
	void fromTF(const TransferFunction & TF);
	void setMethod(Method m) { method = m; }
	void setTime(double time);

	void solveEyler1(double u, double h);
	void solveEyler2(double u, double h);
	void solveRK4(double u, double h);
	void solveABM2(double u, double h);
	void solveABM3(double u, double h);
	void solveABM4(double u, double h);
	void solvePA(double u, double h, uint deg);
	void solvePA2(double u, double h);
	void solvePA3(double u, double h);
	void solvePA4(double u, double h);
	void solvePA5(double u, double h);

	PIMathVectord X;
	static Method method_global;
	static const char methods_desc[];

private:
	void moveF();

	PIMathMatrixd A, M;
	PIMathVectord d, a1, b1;
	PIMathVectord k1, k2, k3, k4, xx;
	PIMathVectord XX, Y, pY;
	PIVector<PIMathVectord> F;
	PIVector<double> times;
	uint size = 0, step = 0;
	Method method = Global;
	double sum = 0., td = 0., ct = 0., lp = 0., dh = 0., t = 0., x1 = 0., x0 = 0.;
	bool ok = false;
};

#endif // PIMATHSOLVER_H