Akifumi Takahashi / CubicSpline

This lib is considered to be used as a sensor's calibration program. Calibration with Spline Interpolation might be useful in the case that you want some model expressing relationship such like between a value of physical quantity and your sensor's voltage, but you cannot estimate a model such as liner, square, cubic polynomial, or sine curve. This makes (Parametric) Cubic Spline Polynomial Model (Coefficients of the polynomial) from some sample plots(e.g. sets of (value, voltage)). The inverse function (x,y)->(y,x) has been implemented so as to get analog data (not stepping or leveled data).

Fork of TRP105F_Spline by Akifumi Takahashi

CubicSpline.h

Committer:
aktk
Date:
2016-05-26
Revision:
8:e7d451bb4fd4
Parent:
7:e032ddec6ed5
Child:
9:1903c6f8d5a9

File content as of revision 8:e7d451bb4fd4:

/**
 *  Spline_Cubic.h,.cpp
 *
 *  Author: aktk, aktk.j.uec@gmail.com
 *  Tokyo, Japan.
 *
 *  LOG:
 *  ver.0   2016/02.12 - 2016/02/16
 *      TRP105F_Spline.h,.cpp(Ver.2.1)
 *  ver.1   2016/05.12
 */
#ifndef Cubic_Spline_H
#define Cubic_Spline_H

#include "mbed.h"
#include <cmath>
#include <complex>


//  Vector Element Type
typedef struct {
    double x; //
    double y; //
    double t; //    use as pramameter of x,y.
} Vxyt;

enum UseType {
    AsDEBUG,
    AsMODULE
};

class CubicSpline2d
{
public:
    //  Constraction
    CubicSpline2d();
    CubicSpline2d(unsigned int);
    CubicSpline2d(unsigned int, UseType);
    //  Destraction
    ~CubicSpline2d();
    //  Functions
    double  getX(double arg_y);
    double  getY(double arg_x);
    void    calibrateSensor();
    void    saveSetting();
    void    saveSetting(const char *filename);
    void    loadSetting();
    void    loadSetting(const char *filename);
    void    printOutData();

private:
    //
    //  Variables
    //
    UseType      _useType;
    unsigned int _Sample_Num;   //  the number of samples for derive spline
    Vxyt*        _Sample_Set;
    double*      _C_x[4];    //x = Spline-f(t) = _C_x[0]  + _C_x[1]t  + _C_x[2]t^2  + _C_x[3]t^3
    double*      _C_y[4];    //y = Spline-f(t) = _C_y[0]  + _C_y[1]t  + _C_y[2]t^2  + _C_y[3]t^3
    Vxyt        _Last_Point;
    //
    //
    //
    //
    //  For calibration
    //
    //  sampling data for calibration
    void    _sampleData();
    //  generate a vector of _u_params which is used for Cubic spline model
    void    _makeModel(
        const double* arg_sampled_t,
        const double* arg_sampled_ft,
        /*-*/ double* arg_C[4],
        const unsigned int arg_num = _Sample_Num
    );
    //
    //  For calculation
    //
    //  Fuction to return the value of Cubic polynomial f(t)
    double  _cubic_f(
        const double  arg_t,
        const double  arg_C[4]
    );
    //  Function to solve a cubic polinomial
    //  by using Gardano-Tartaglia formula
    void _solve_cubic_f(
        std::complex<double>* arg_t,
        const double  arg_C[4],
        const double  arg_ft
    );
    //
    //  For debug
    //
    void    _printOutData(unsigned short    *arg, int num, char* name);
    void    _printOutData(Vxyt              *arg, int num, char* name);
    void    _printOutData(double            *arg, int num, char* name);
};
#endif