RootFind1dNewton.h

// 1-D Newton Root finding class
#pragma once
 
#include <functional>
#include <tuple>
 
#include <isce3/core/Poly1d.h>
 
#include "detail/RootFind1dBase.h"
 
namespace isce3 { namespace math {

class RootFind1dNewton : public detail::RootFind1dBase {
    // aliases
protected:
    using func_t = std::function<double(double)>;
    using tuple4_t = std::tuple<double, double, bool, int>;
    using poly1d_t = isce3::core::Poly1d;
    using func2_t = std::function<std::tuple<double, double>(double)>;
 
public:
    // inherit all constructors from base class
    using detail::RootFind1dBase::RootFind1dBase;
 
    // methods
    std::tuple<double, double, bool, int> root(
            const isce3::core::Poly1d& f, double x0 = 0) const;

    std::tuple<double, double, bool, int> root(
            const std::function<double(double)>& f,
            const std::function<double(double)>& f_der, double x0 = 0) const;

    std::tuple<double, double, bool, int> root(
            const std::function<std::tuple<double, double>(double)>& f,
            double x0 = 0) const;
 
private:
    tuple4_t _newton(const func2_t& f, double x0) const;

    tuple4_t _newton_strict(const func2_t& f, double x0) const;
};
 
}} // namespace isce3::math