cspline.cpp

/***************************************************************************
        Copyright (C) 2002-2015 Kentaro Kitagawa
                           kitagawa@phys.s.u-tokyo.ac.jp
        
        This program is free software; you can redistribute it and/or
        modify it under the terms of the GNU Library General Public
        License as published by the Free Software Foundation; either
        version 2 of the License, or (at your option) any later version.
        
        You should have received a copy of the GNU Library General 
        Public License and a list of authors along with this program; 
        see the files COPYING and AUTHORS.
***************************************************************************/
#include "cspline.h"
#include <vector>

CSplineApprox::CSplineApprox(const std::map<double, double> &pts) {
    m_accel = gsl_interp_accel_alloc();
    m_spline = gsl_spline_alloc(gsl_interp_cspline, pts.size());

    std::vector<double> x, y;
    for(auto it = pts.begin(); it != pts.end(); it++) {
        x.push_back(it->first);
        y.push_back(it->second);
    }
    gsl_spline_init(m_spline, &x[0], &y[0], x.size());
}

CSplineApprox::~CSplineApprox() {
    gsl_spline_free(m_spline);
    gsl_interp_accel_free(m_accel);
}
double
CSplineApprox::approx(double x) const {
    return gsl_spline_eval(m_spline, x, m_accel);
}