Scaling1d.h

Go to the documentation of this file.

// -*- LSST-C++ -*-
/*
 * Developed for the LSST Data Management System.
 * This product includes software developed by the LSST Project
 * (https://www.lsst.org).
 * See the COPYRIGHT file at the top-level directory of this distribution
 * for details of code ownership.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#ifndef LSST_AFW_MATH_POLYNOMIALS_Scaling1d_h_INCLUDED
#define LSST_AFW_MATH_POLYNOMIALS_Scaling1d_h_INCLUDED


namespace lsst { namespace geom { namespace polynomials {

class Scaling1d {
public:

    Scaling1d(double scale, double shift) noexcept:
        _scale(scale),
        _shift(shift)
    {}

    Scaling1d(Scaling1d const &) noexcept = default;

    Scaling1d(Scaling1d &&) noexcept = default;

    Scaling1d & operator=(Scaling1d const &) noexcept = default;

    Scaling1d & operator=(Scaling1d &&) noexcept = default;

    double applyForward(double x) const noexcept {
        return (x + getShift())*getScale();
    }

    double applyInverse(double y) const noexcept {
        return y/_scale - _shift;
    }

    double getScale() const noexcept { return _scale; }

    double getShift() const noexcept { return _shift; }

    Scaling1d inverted() const noexcept {
        return Scaling1d(1.0/_scale, -_shift*_scale);
    }

    Scaling1d then(Scaling1d const & second) const noexcept {
        return Scaling1d(getScale()*second.getScale(),
                                 getShift() + second.getShift()/getScale());
    }

private:
    double _scale;
    double _shift;
};

inline Scaling1d makeUnitRangeScaling1d(double min, double max) noexcept {
    return Scaling1d(2.0/(max - min), -0.5*(min + max));
}

}}} // namespace lsst::geom::polynomials

#endif // !LSST_AFW_MATH_POLYNOMIALS_Scaling1d_h_INCLUDED