ODE.hpp

// Reaktoro is a unified framework for modeling chemically reactive systems.
//
// Copyright (C) 2014-2018 Allan Leal
//
// This library 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 2.1 of the License, or (at your option) any later version.
//
// This library 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 library. If not, see <http://www.gnu.org/licenses/>.
 
#pragma once
 
// C++ includes
#include <functional>
#include <memory>
 
// Reaktoro includes
#include <Reaktoro/Math/Matrix.hpp>
 
namespace Reaktoro {
 
using ODEFunction = std::function<int(double, VectorConstRef, VectorRef)>;
 
using ODEJacobian = std::function<int(double, VectorConstRef, MatrixRef)>;
 
enum class ODEStepMode { Adams, BDF };
 
enum class ODEIterationMode { Functional, Newton };
 
struct ODEOptions
{
    ODEStepMode step = ODEStepMode::BDF;
 
    ODEIterationMode iteration = ODEIterationMode::Newton;
 
    bool stability_limit_detection = false;
 
    double initial_step = 0.0;
 
    double stop_time = 0.0;
 
    double min_step = 0.0;
 
    double max_step = 0.0;
 
    double reltol = 1e-4;
 
    double abstol = 1.0e-6;
 
    unsigned max_order_bdf = 5;
 
    unsigned max_order_adams = 5;
 
    unsigned max_num_steps = 500;
 
    unsigned max_hnil_warnings = 10;
 
    unsigned max_num_error_test_failures = 20;
 
    unsigned max_num_nonlinear_iterations = 3;
 
    unsigned max_num_convergence_failures = 10;
 
    double nonlinear_convergence_coefficient = 0.1;
 
    Vector abstols;
};
 
class ODEProblem
{
public:
    ODEProblem();
 
    ODEProblem(const ODEProblem& other);
 
    virtual ~ODEProblem();
 
    auto operator=(ODEProblem other) -> ODEProblem&;
 
    auto setNumEquations(unsigned num) -> void;
 
    auto setFunction(const ODEFunction& f) -> void;
 
    auto setJacobian(const ODEJacobian& J) -> void;
 
    auto initialized() const -> bool;
 
    auto numEquations() const -> unsigned;
 
    auto function() const -> const ODEFunction&;
 
    auto jacobian() const -> const ODEJacobian&;
 
    auto function(double t, VectorConstRef y, VectorRef f) const -> int;
 
    auto jacobian(double t, VectorConstRef y, MatrixRef J) const -> int;
 
private:
    struct Impl;
 
    std::unique_ptr<Impl> pimpl;
};
 
class ODESolver
{
public:
    ODESolver();
 
    ODESolver(const ODESolver& other) = delete;
 
    virtual ~ODESolver();
 
    auto operator=(ODESolver other) -> ODESolver&;
 
    auto setOptions(const ODEOptions& options) -> void;
 
    auto setProblem(const ODEProblem& problem) -> void;
 
    auto initialize(double tstart, VectorConstRef y) -> void;
 
    auto integrate(double& t, VectorRef y) -> void;
 
    auto integrate(double& t, VectorRef y, double tfinal) -> void;
 
    auto solve(double& t, double dt, VectorRef y) -> void;
 
private:
    struct Impl;
 
    std::unique_ptr<Impl> pimpl;
};
 
} // namespace Reaktoro