utils.h

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/*
 * LSST Data Management System
 * Copyright 2014-2015 AURA/LSST.
 *
 * This product includes software developed by the
 * LSST Project (http://www.lsst.org/).
 *
 * 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 LSST License Statement and
 * the GNU General Public License along with this program.  If not,
 * see <https://www.lsstcorp.org/LegalNotices/>.
 */

#ifndef LSST_SPHGEOM_UTILS_H_
#define LSST_SPHGEOM_UTILS_H_


#include "Angle.h"


namespace lsst {
namespace sphgeom {

// Forward declarations
class Vector3d;
class UnitVector3d;

double getMinSquaredChordLength(Vector3d const & v,
                                Vector3d const & a,
                                Vector3d const & b,
                                Vector3d const & n);

double getMaxSquaredChordLength(Vector3d const & v,
                                Vector3d const & a,
                                Vector3d const & b,
                                Vector3d const & n);

inline Angle getMinAngleToCircle(Angle x, Angle c) {
    return abs(x - c);
}

inline Angle getMaxAngleToCircle(Angle x, Angle c) {
    Angle a = getMinAngleToCircle(x, c);
    if (abs(x) <= abs(c)) {
        return a + Angle(PI) - 2.0 * abs(c);
    }
    if (a < abs(x)) {
        return Angle(PI) - 2.0 * abs(c) - a;
    }
    return Angle(PI) + 2.0 * abs(c) - a;
}

Vector3d getWeightedCentroid(UnitVector3d const & v0,
                             UnitVector3d const & v1,
                             UnitVector3d const & v2);

}} // namespace lsst::sphgeom

#endif // LSST_SPHGEOM_UTILS_H_