fpCurve.hpp

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/***************************************************************************************************
!                                ____________________  ___   ________ __
!                               / ____/  _/_  __/ __ \/   | / ____/ //_/
!                              / /_   / /  / / / /_/ / /| |/ /   / ,<
!                             / __/ _/ /  / / / ____/ ___ / /___/ /| |
!                            /_/   /___/ /_/ /_/   /_/  |_\____/_/ |_|
!
!                                     A Curve Fitting Package
!
!   fpCurve.hpp (class fpCurve)
!> @brief Standalone C++ wrapper for fitpack_curve (no fortran-arrays dependency)
!
!   @author Federico Perini
!   @date   2026-08-27
!
!   References :
!     - C. De Boor, "On calculating with b-splines", J Approx Theory 6 (1972) 50-62
!     - M. G. Cox, "The numerical evaluation of b-splines", J Inst Maths Applics 10 (1972) 134-149
!     - P. Dierckx, "Curve and surface fitting with splines", Monographs on numerical analysis,
!                    Oxford university press, 1993.
!
! **************************************************************************************************/
 
#ifndef FPCURVE_HPP_INCLUDED
#define FPCURVE_HPP_INCLUDED
 
#include "fitpack_config.h"
 
#if HAVE_FXARRAY
#include "fxArrays.hpp"
#endif
 
#include "fitpack_curve_c.h"
#include "fpFitter.hpp"
#include <string>
#include <vector>
#include <cstdint>
#include <memory>
#include <stdexcept>
#include <variant>
#include <optional>
#include <array>
#include "fpPoint.hpp"
 
static_assert(sizeof(fitpack_curve_c) == sizeof(fitpack_fitter_c),
    "C descriptor layout mismatch: fitpack_curve_c vs fitpack_fitter_c");

class fpCurve : public fpFitter {
public:
    // ===========================================================================================
    // Constructors and Destructor
    // ===========================================================================================

    fpCurve() : fpFitter(NoAlloc{}) {
        fitpack_curve_c_allocate(as<fitpack_curve_c>(), nullptr);
    }

    ~fpCurve() override {
        fitpack_curve_c_destroy(as<fitpack_curve_c>(), nullptr);
    }

    fpCurve(const fpCurve& other) : fpFitter(NoAlloc{}) {
        *as<fitpack_curve_c>() = fitpack_curve_c_null;
        fitpack_curve_c_copy(as<fitpack_curve_c>(), other.as<fitpack_curve_c>(), false, nullptr);
    }

    fpCurve& operator=(const fpCurve& other) {
        if (this != &other) {
            fitpack_curve_c_destroy(as<fitpack_curve_c>(), nullptr);
            fitpack_curve_c_copy(as<fitpack_curve_c>(), other.as<fitpack_curve_c>(), false, nullptr);
        }
        return *this;
    }

    fpCurve(fpCurve&& other) noexcept : fpFitter(NoAlloc{}) {
        *as<fitpack_curve_c>() = fitpack_curve_c_null;
        fitpack_curve_c_move_alloc(as<fitpack_curve_c>(), other.as<fitpack_curve_c>(), nullptr);
    }

    fpCurve& operator=(fpCurve&& other) noexcept {
        if (this != &other) {
            fitpack_curve_c_destroy(as<fitpack_curve_c>(), nullptr);
            fitpack_curve_c_move_alloc(as<fitpack_curve_c>(), other.as<fitpack_curve_c>(), nullptr);
        }
        return *this;
    }

    explicit fpCurve(fitpack_curve_c& c_wrapper, bool move = false) : fpFitter(NoAlloc{}) {
        if (move) {
            fitpack_curve_c_move_alloc(as<fitpack_curve_c>(), &c_wrapper, nullptr);
        } else {
            *as<fitpack_curve_c>() = fitpack_curve_c_null;
            fitpack_curve_c_copy(as<fitpack_curve_c>(), &c_wrapper, false, nullptr);
        }
    }

    explicit fpCurve(fitpack_curve_c& c_wrapper, ViewTag) : fpFitter(NoAlloc{}) {
        *as<fitpack_curve_c>() = c_wrapper;
        as<fitpack_curve_c>()->is_pointer = true;
    }
 
    // ===========================================================================================
    // Utility Methods
    // ===========================================================================================

    bool is_allocated() const override {
        return as<fitpack_curve_c>()->cptr != nullptr;
    }

    bool is_pointer() const override {
        return as<fitpack_curve_c>()->is_pointer;
    }

    const char* c_type_name() const override {
        return fitpack_curve_c_c_type_name(*as<fitpack_curve_c>());
    }

    const char* cpp_type_name() const override {
        return "fpCurve";
    }

    fitpack_curve_c& c_handle() {
        return *as<fitpack_curve_c>();
    }

    const fitpack_curve_c& c_handle() const {
        return *as<fitpack_curve_c>();
    }

    static fpCurve make_view() {
        return fpCurve(NoAlloc{});
    }

    fpFitter& as_parent() {
        return static_cast<fpFitter&>(*this);
    }
    const fpFitter& as_parent() const {
        return static_cast<const fpFitter&>(*this);
    }
 
    // ===========================================================================================
    // Method Wrappers (standalone — no fxArray dependency)
    // ===========================================================================================

    virtual void new_points(std::vector<double>& x, std::vector<double>& y, double* w = nullptr) {
        int32_t n = static_cast<int32_t>(x.size());
        fitpack_curve_c_new_points(as<fitpack_curve_c>(), n, x.data(), y.data(), w);
    }
 

    virtual int32_t new_fit(std::vector<double>& x, std::vector<double>& y, double* w = nullptr, double* smoothing = nullptr, int32_t* order = nullptr) {
        int32_t n = static_cast<int32_t>(x.size());
        return fitpack_curve_c_new_fit(as<fitpack_curve_c>(), n, x.data(), y.data(), w, smoothing, order);
    }
 
 
    virtual int32_t fit(double* smoothing = nullptr, int32_t* order = nullptr, bool* keep_knots = nullptr) {
        return fitpack_curve_c_fit(as<fitpack_curve_c>(), smoothing, order, keep_knots);
    }
 
    virtual int32_t interpolate(int32_t* order = nullptr, bool* reset_knots = nullptr) {
        return fitpack_curve_c_interpolate(as<fitpack_curve_c>(), order, reset_knots);
    }
 
    virtual int32_t least_squares(double* smoothing = nullptr, bool* reset_knots = nullptr) {
        return fitpack_curve_c_least_squares(as<fitpack_curve_c>(), smoothing, reset_knots);
    }
 
    virtual double eval(double x, int32_t& ierr) {
        return fitpack_curve_c_curve_eval_one(as<fitpack_curve_c>(), x, &ierr);
    }
 
    virtual double eval(double x) const {
        return fitpack_curve_c_curve_eval_one_noerr(as<fitpack_curve_c>(), x);
    }

    virtual std::vector<double> eval(std::vector<double>& x, int32_t& ierr) {
        int32_t n = static_cast<int32_t>(x.size());
        std::vector<double> result(n);
        int32_t n_result = 0;
        fitpack_curve_c_curve_eval_many(as<fitpack_curve_c>(), n, x.data(), &ierr, result.data(), &n_result, n);
        result.resize(n_result);
        return result;
    }
 

    virtual std::vector<double> eval(std::vector<double>& x) {
        int32_t n = static_cast<int32_t>(x.size());
        std::vector<double> result(n);
        int32_t n_result = 0;
        fitpack_curve_c_curve_eval_many_pure(as<fitpack_curve_c>(), n, x.data(), result.data(), &n_result, n);
        result.resize(n_result);
        return result;
    }
 
 
    virtual double integral(double from, double to) {
        return fitpack_curve_c_integral(as<fitpack_curve_c>(), from, to);
    }

    virtual void fourier_coefficients(std::vector<double>& alpha, std::vector<double>& a, std::vector<double>& b, int32_t* ierr = nullptr) {
        int32_t n = static_cast<int32_t>(alpha.size());
        fitpack_curve_c_fourier_coefficients(as<fitpack_curve_c>(), n, alpha.data(), a.data(), b.data(), ierr);
    }
 

    virtual std::vector<double> zeros(int32_t max_size, int32_t* ierr = nullptr) {
        std::vector<double> result(max_size);
        int32_t n_result = 0;
        fitpack_curve_c_zeros(as<fitpack_curve_c>(), ierr, result.data(), &n_result, max_size);
        result.resize(n_result);
        return result;
    }
 
 
    virtual double dfdx(double x, int32_t order, int32_t* ierr = nullptr) {
        return fitpack_curve_c_curve_derivative(as<fitpack_curve_c>(), x, order, ierr);
    }

    virtual std::vector<double> dfdx(std::vector<double>& x, int32_t order, int32_t* ierr = nullptr) {
        int32_t n = static_cast<int32_t>(x.size());
        std::vector<double> result(n);
        int32_t n_result = 0;
        fitpack_curve_c_curve_derivatives(as<fitpack_curve_c>(), n, x.data(), order, ierr, result.data(), &n_result, n);
        result.resize(n_result);
        return result;
    }
 

    virtual std::vector<double> dfdx_all(double x, int32_t& ierr, int32_t n_result) {
        std::vector<double> result(n_result);
        fitpack_curve_c_curve_all_derivatives(as<fitpack_curve_c>(), x, &ierr, result.data(), n_result);
        return result;
    }
 

    virtual std::vector<double> dfdx_all(double x, int32_t n_result) {
        std::vector<double> result(n_result);
        fitpack_curve_c_curve_all_derivatives_pure(as<fitpack_curve_c>(), x, result.data(), n_result);
        return result;
    }
 
 
    virtual void insert_knot(double x, int32_t* ierr = nullptr) {
        fitpack_curve_c_curve_insert_knot_one(as<fitpack_curve_c>(), x, ierr);
    }

    virtual void insert_knot(std::vector<double>& x, int32_t* ierr = nullptr) {
        int32_t n = static_cast<int32_t>(x.size());
        fitpack_curve_c_curve_insert_knot_many(as<fitpack_curve_c>(), n, x.data(), ierr);
    }
 
 
    int32_t comm_size() const override {
        return fitpack_curve_c_comm_size(as<fitpack_curve_c>());
    }

    void comm_pack(std::vector<double>& buffer) const override {
        int32_t n = static_cast<int32_t>(buffer.size());
        fitpack_curve_c_comm_pack(as<fitpack_curve_c>(), n, buffer.data());
    }
 

    void comm_expand(std::vector<double>& buffer) override {
        int32_t n = static_cast<int32_t>(buffer.size());
        fitpack_curve_c_comm_expand(as<fitpack_curve_c>(), n, buffer.data());
    }
 
 
    double mse() const override {
        return fitpack_curve_c_mse(as<fitpack_curve_c>());
    }
 
    int32_t core_comm_size() const override {
        return fitpack_curve_c_core_comm_size(as<fitpack_curve_c>());
    }

    void core_comm_pack(std::vector<double>& buffer) const override {
        int32_t n = static_cast<int32_t>(buffer.size());
        fitpack_curve_c_core_comm_pack(as<fitpack_curve_c>(), n, buffer.data());
    }
 

    void core_comm_expand(std::vector<double>& buffer) override {
        int32_t n = static_cast<int32_t>(buffer.size());
        fitpack_curve_c_core_comm_expand(as<fitpack_curve_c>(), n, buffer.data());
    }
 
 
    void destroy_base() override {
        fitpack_curve_c_destroy_base(as<fitpack_curve_c>());
    }
 
    // ===========================================================================================
    // Component Array Accessors
    // ===========================================================================================

    std::vector<double> x_vector() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_x(as<fitpack_curve_c>(), &raw, extents);
        const int64_t total = extents[0];
        if (raw == nullptr || total <= 0) return {};
        const double* first = reinterpret_cast<const double*>(raw);
        return std::vector<double>(first, first + total);
    }
 
#if HAVE_FXARRAY
    fxArray<double> x() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_x(as<fitpack_curve_c>(), &raw, extents);
        FX_SIZE bounds[2];   // (lower, upper) per dimension, Fortran lbound 1
        for (int k = 0; k < 1; ++k) {
            bounds[2 * k] = 1;
            bounds[2 * k + 1] = static_cast<FX_SIZE>(extents[k]);
        }
        array_c descr = array_c_null;
        array_c_from_ptr(&descr, "x", static_cast<void*>(raw),
                         getCFITypeFlag<double>(),
                         static_cast<FX_SIZE>(sizeof(double)),
                         static_cast<FX_RANK>(1), bounds);
        return fxArray<double>(descr);
    }
#endif // HAVE_FXARRAY

    std::vector<double> y_vector() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_y(as<fitpack_curve_c>(), &raw, extents);
        const int64_t total = extents[0];
        if (raw == nullptr || total <= 0) return {};
        const double* first = reinterpret_cast<const double*>(raw);
        return std::vector<double>(first, first + total);
    }
 
#if HAVE_FXARRAY
    fxArray<double> y() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_y(as<fitpack_curve_c>(), &raw, extents);
        FX_SIZE bounds[2];   // (lower, upper) per dimension, Fortran lbound 1
        for (int k = 0; k < 1; ++k) {
            bounds[2 * k] = 1;
            bounds[2 * k + 1] = static_cast<FX_SIZE>(extents[k]);
        }
        array_c descr = array_c_null;
        array_c_from_ptr(&descr, "y", static_cast<void*>(raw),
                         getCFITypeFlag<double>(),
                         static_cast<FX_SIZE>(sizeof(double)),
                         static_cast<FX_RANK>(1), bounds);
        return fxArray<double>(descr);
    }
#endif // HAVE_FXARRAY

    std::vector<double> sp_vector() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_sp(as<fitpack_curve_c>(), &raw, extents);
        const int64_t total = extents[0];
        if (raw == nullptr || total <= 0) return {};
        const double* first = reinterpret_cast<const double*>(raw);
        return std::vector<double>(first, first + total);
    }
 
#if HAVE_FXARRAY
    fxArray<double> sp() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_sp(as<fitpack_curve_c>(), &raw, extents);
        FX_SIZE bounds[2];   // (lower, upper) per dimension, Fortran lbound 1
        for (int k = 0; k < 1; ++k) {
            bounds[2 * k] = 1;
            bounds[2 * k + 1] = static_cast<FX_SIZE>(extents[k]);
        }
        array_c descr = array_c_null;
        array_c_from_ptr(&descr, "sp", static_cast<void*>(raw),
                         getCFITypeFlag<double>(),
                         static_cast<FX_SIZE>(sizeof(double)),
                         static_cast<FX_RANK>(1), bounds);
        return fxArray<double>(descr);
    }
#endif // HAVE_FXARRAY

    std::vector<double> w_vector() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_w(as<fitpack_curve_c>(), &raw, extents);
        const int64_t total = extents[0];
        if (raw == nullptr || total <= 0) return {};
        const double* first = reinterpret_cast<const double*>(raw);
        return std::vector<double>(first, first + total);
    }
 
#if HAVE_FXARRAY
    fxArray<double> w() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_w(as<fitpack_curve_c>(), &raw, extents);
        FX_SIZE bounds[2];   // (lower, upper) per dimension, Fortran lbound 1
        for (int k = 0; k < 1; ++k) {
            bounds[2 * k] = 1;
            bounds[2 * k + 1] = static_cast<FX_SIZE>(extents[k]);
        }
        array_c descr = array_c_null;
        array_c_from_ptr(&descr, "w", static_cast<void*>(raw),
                         getCFITypeFlag<double>(),
                         static_cast<FX_SIZE>(sizeof(double)),
                         static_cast<FX_RANK>(1), bounds);
        return fxArray<double>(descr);
    }
#endif // HAVE_FXARRAY

    std::vector<double> wrk_fou_vector() const {
        double* raw = nullptr;
        int64_t extents[2] = {0, 0};
        fitpack_curve_c_getcomp_wrk_fou(as<fitpack_curve_c>(), &raw, extents);
        const int64_t total = extents[0] * extents[1];
        if (raw == nullptr || total <= 0) return {};
        const double* first = reinterpret_cast<const double*>(raw);
        return std::vector<double>(first, first + total);
    }

    std::array<int64_t, 2> wrk_fou_shape() const {
        double* raw = nullptr;
        int64_t extents[2] = {0, 0};
        fitpack_curve_c_getcomp_wrk_fou(as<fitpack_curve_c>(), &raw, extents);
        return { extents[0], extents[1] };
    }
 
#if HAVE_FXARRAY
    fxArray<double> wrk_fou() const {
        double* raw = nullptr;
        int64_t extents[2] = {0, 0};
        fitpack_curve_c_getcomp_wrk_fou(as<fitpack_curve_c>(), &raw, extents);
        FX_SIZE bounds[4];   // (lower, upper) per dimension, Fortran lbound 1
        for (int k = 0; k < 2; ++k) {
            bounds[2 * k] = 1;
            bounds[2 * k + 1] = static_cast<FX_SIZE>(extents[k]);
        }
        array_c descr = array_c_null;
        array_c_from_ptr(&descr, "wrk_fou", static_cast<void*>(raw),
                         getCFITypeFlag<double>(),
                         static_cast<FX_SIZE>(sizeof(double)),
                         static_cast<FX_RANK>(2), bounds);
        return fxArray<double>(descr);
    }
#endif // HAVE_FXARRAY

    std::vector<double> t_vector() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_t(as<fitpack_curve_c>(), &raw, extents);
        const int64_t total = extents[0];
        if (raw == nullptr || total <= 0) return {};
        const double* first = reinterpret_cast<const double*>(raw);
        return std::vector<double>(first, first + total);
    }
 
#if HAVE_FXARRAY
    fxArray<double> t() const {
        double* raw = nullptr;
        int64_t extents[1] = {0};
        fitpack_curve_c_getcomp_t(as<fitpack_curve_c>(), &raw, extents);
        FX_SIZE bounds[2];   // (lower, upper) per dimension, Fortran lbound 1
        for (int k = 0; k < 1; ++k) {
            bounds[2 * k] = 1;
            bounds[2 * k + 1] = static_cast<FX_SIZE>(extents[k]);
        }
        array_c descr = array_c_null;
        array_c_from_ptr(&descr, "t", static_cast<void*>(raw),
                         getCFITypeFlag<double>(),
                         static_cast<FX_SIZE>(sizeof(double)),
                         static_cast<FX_RANK>(1), bounds);
        return fxArray<double>(descr);
    }
#endif // HAVE_FXARRAY
 
    // ===========================================================================================
    // Scalar Property Accessors
    // ===========================================================================================
 
    int32_t& m() {
        return *fitpack_curve_c_ref_m(as<fitpack_curve_c>());
    }
    const int32_t& m() const {
        return *fitpack_curve_c_ref_m(as<fitpack_curve_c>());
    }
 
    int32_t& order() {
        return *fitpack_curve_c_ref_order(as<fitpack_curve_c>());
    }
    const int32_t& order() const {
        return *fitpack_curve_c_ref_order(as<fitpack_curve_c>());
    }
 
    double& xleft() {
        return *fitpack_curve_c_ref_xleft(as<fitpack_curve_c>());
    }
    const double& xleft() const {
        return *fitpack_curve_c_ref_xleft(as<fitpack_curve_c>());
    }
 
    double& xright() {
        return *fitpack_curve_c_ref_xright(as<fitpack_curve_c>());
    }
    const double& xright() const {
        return *fitpack_curve_c_ref_xright(as<fitpack_curve_c>());
    }
 
    int32_t& nest() {
        return *fitpack_curve_c_ref_nest(as<fitpack_curve_c>());
    }
    const int32_t& nest() const {
        return *fitpack_curve_c_ref_nest(as<fitpack_curve_c>());
    }
 
    int32_t& bc() {
        return *fitpack_curve_c_ref_bc(as<fitpack_curve_c>());
    }
    const int32_t& bc() const {
        return *fitpack_curve_c_ref_bc(as<fitpack_curve_c>());
    }
 
    int32_t& knots() {
        return *fitpack_curve_c_ref_knots(as<fitpack_curve_c>());
    }
    const int32_t& knots() const {
        return *fitpack_curve_c_ref_knots(as<fitpack_curve_c>());
    }
 
    // ===========================================================================================
    // Ergonomic overloads — extra_methods/fpCurveErgonomics.hpp (hand-maintained)
    //
    // The call shapes of the pre-0.3.0 hand-written wrapper, on top of the generated raw entry
    // points. Every one forwards to a virtual raw method, so fpPeriodicCurve inherits them and
    // still reaches its own Fortran routines through dispatch.
    // ===========================================================================================

    FP_SIZE degree() const { return order(); }

    FP_FLAG new_fit(const std::vector<FP_REAL>& x, const std::vector<FP_REAL>& y,
                    FP_REAL smoothing = 1000.0)
    {
        std::vector<FP_REAL> xw(x), yw(y);
        return new_fit(xw, yw, nullptr, &smoothing, nullptr);
    }

    FP_FLAG new_fit(const std::vector<FP_REAL>& x, const std::vector<FP_REAL>& y,
                    const std::vector<FP_REAL>& w, FP_REAL smoothing = 1000.0)
    {
        std::vector<FP_REAL> xw(x), yw(y), ww(w);
        return new_fit(xw, yw, ww.data(), &smoothing, nullptr);
    }

    FP_FLAG fit(FP_SIZE order)                    { return fit(nullptr, &order, nullptr); }
    FP_FLAG fit(FP_REAL smoothing)                { return fit(&smoothing, nullptr, nullptr); }
    FP_FLAG fit(FP_REAL smoothing, FP_SIZE order) { return fit(&smoothing, &order, nullptr); }

    FP_FLAG interpolate(FP_SIZE order) { return interpolate(&order, nullptr); }

    FP_REAL eval(FP_REAL x, FP_FLAG* ierr)
    {
        FP_FLAG ierr0 = FITPACK_OK;
        const FP_REAL y = eval(x, ierr0);
        if (ierr) *ierr = ierr0;
        return y;
    }

    std::vector<FP_REAL> eval(const std::vector<FP_REAL>& x, FP_FLAG* ierr)
    {
        std::vector<FP_REAL> xw(x);
        FP_FLAG ierr0 = FITPACK_OK;
        std::vector<FP_REAL> y = eval(xw, ierr0);
        if (ierr) *ierr = ierr0;
        return y;
    }

    std::vector<fpPoint<2>> eval(FP_REAL xmin, FP_REAL xmax, FP_SIZE npts, FP_FLAG* ierr = nullptr)
    {
        std::vector<FP_REAL> x(static_cast<std::size_t>(npts > 0 ? npts : 0));
        if (npts > 1)
        {
            const FP_REAL dx = (xmax - xmin) / (npts - 1);
            for (FP_SIZE i = 0; i < npts; ++i) x[static_cast<std::size_t>(i)] = xmin + i * dx;
        }
        else if (npts == 1) x[0] = xmin;
 
        FP_FLAG ierr0 = FITPACK_OK;
        std::vector<FP_REAL> y = eval(x, ierr0);
        if (ierr) *ierr = ierr0;
 
        std::vector<fpPoint<2>> xy(x.size());
        for (std::size_t i = 0; i < x.size() && i < y.size(); ++i) xy[i] = {x[i], y[i]};
        return xy;
    }

    FP_REAL ddx(FP_REAL x, FP_SIZE order, FP_FLAG* ierr = nullptr) { return dfdx(x, order, ierr); }

    std::vector<FP_REAL> ddx(FP_REAL x, FP_FLAG* ierr = nullptr)
    {
        FP_FLAG ierr0 = FITPACK_OK;
        std::vector<FP_REAL> d = dfdx_all(x, ierr0, degree() + 1);
        if (ierr) *ierr = ierr0;
        return d;
    }

    void    set_bc(FP_FLAG value) { bc() = value; }
    FP_FLAG get_bc() const        { return bc(); }

    FP_FLAG fourier(const std::vector<FP_REAL>& alpha, std::vector<FP_REAL>& A, std::vector<FP_REAL>& B)
    {
        std::vector<FP_REAL> aw(alpha);
        A.resize(alpha.size());
        B.resize(alpha.size());
        FP_FLAG ierr = FITPACK_OK;
        fourier_coefficients(aw, A, B, &ierr);
        return ierr;
    }
 
protected:
    explicit fpCurve(NoAlloc tag) : fpFitter(tag) {}
 
};
 
#endif /* FPCURVE_HPP_INCLUDED */