Program Listing for File gaussquad.hpp

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/*
 *      Copyright (c) 2020 Robert Shaw
 *      This file is a part of Libecpint.
 *
 *      Permission is hereby granted, free of charge, to any person obtaining
 *      a copy of this software and associated documentation files (the
 *      "Software"), to deal in the Software without restriction, including
 *      without limitation the rights to use, copy, modify, merge, publish,
 *      distribute, sublicense, and/or sell copies of the Software, and to
 *      permit persons to whom the Software is furnished to do so, subject to
 *      the following conditions:
 *
 *      The above copyright notice and this permission notice shall be
 *      included in all copies or substantial portions of the Software.
 *
 *      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *      EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *      MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *      NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *      LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *      OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *      WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef GC_QUAD_HEAD
#define GC_QUAD_HEAD

#include <functional>
#include <vector>

namespace libecpint {

    enum GCTYPE {
        ONEPOINT,
        TWOPOINT
    };

    class GCQuadrature {
    private:
        int maxN;
        int M;

        std::vector<double> x;
        std::vector<double> w;

        double I;

        GCTYPE t;

        double sumTerms(const std::function<double(double, const double*, int)> &f,
                  const double *p, int limit, int start, int end, int shift, int skip) const;

    public:

        GCQuadrature();

        GCQuadrature(const GCQuadrature &other);

        void initGrid(int points, GCTYPE t);

        std::pair<double, bool> integrate(
            std::function<double(double, const double*, int)> &f,
            const double *params, double tolerance, int start, int end) const;

        void transformZeroInf();

        void transformRMinMax(double z, double p);  // Transfromation from [-1, 1] to [rmin, rmax] from Flores06
        void untransformRMinMax(double z, double p);

        int getN() const { return maxN; }

    std::vector<double>& getX() { return x; }
    const std::vector<double>& getX() const { return x; }
    };
}

#endif