polynomialUtils.h

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// -*- LSST-C++ -*-

/*
 * LSST Data Management System
 * Copyright 2016 LSST/AURA
 *
 * 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.
 *
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 * 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.
 *
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#ifndef LSST_MEAS_ASTROM_DETAIL_polynomialUtils_h_INCLUDED
#define LSST_MEAS_ASTROM_DETAIL_polynomialUtils_h_INCLUDED

#include "Eigen/Core"

namespace lsst { namespace meas { namespace astrom { namespace detail {

inline int computePackedOffset(int order) {
    return (order*(order + 1))/2;
}

inline int computePackedSize(int order) {
    return computePackedOffset(order + 1);
}

void computePowers(Eigen::VectorXd & r, double x);

Eigen::VectorXd computePowers(double x, int n);


class BinomialMatrix {
public:

    explicit BinomialMatrix(int const nMax) { extend(nMax); }

    double operator()(int n, int k) const {
        return getMatrix()(n, k);
    }

private:

    static void extend(int const n);

    static Eigen::MatrixXd & getMatrix();

};


}}}} // namespace lsst::meas::astrom::detail

#endif // !LSST_MEAS_ASTROM_DETAIL_polynomialUtils_h_INCLUDED