cSpline.h

/*
                * Copyright (c) 2014 by James Bremner
                * All rights reserved.
                *
                * Use license: Modified from standard BSD license.
                *
                * Redistribution and use in source and binary forms are permitted
                * provided that the above copyright notice and this paragraph are
                * duplicated in all such forms and that any documentation, advertising
                * materials, Web server pages, and other materials related to such
                * distribution and use acknowledge that the software was developed
                * by James Bremner. The name "James Bremner" may not be used to
                * endorse or promote products derived from this software without
                * specific prior written permission.
                *
                * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#include <functional>
#include <vector>

namespace raven
{

class cSpline
{

public:

    cSpline(
            std::vector< double >& x,
            std::vector< double >& y );

    bool IsSane()      { return (bool) ! myError; }

    enum e_error
    {
        no_error,
        x_not_ascending,
        no_input,
        not_single_valued,
    } myError;

    e_error IsError()   { return myError; }

    void Draw( std::function<void (double x, double y)> func,
              int resolution = 100 );

    double getY( double x);

private:

    // The fitted points
    std::vector< double > myX;
    std::vector< double > myY;

    struct SplineSet
    {
        double a;   // constant
        double b;   // 1st order coefficient
        double c;   // 2nd order coefficient
        double d;   // 3rd order coefficient
        double x;   // starting x value
    };

    std::vector< SplineSet > mySplineSet;

    double myMinUniqueDelta;

    bool IsInputSane();

};
};