1 | // |
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2 | // C++ Interface: CubicSplineInterpolator1D |
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3 | // |
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4 | // Description: |
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5 | // |
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6 | // |
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7 | // Author: Takeshi Nakazato <takeshi.nakazato@nao.ac.jp>, (C) 2012 |
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8 | // |
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9 | // Copyright: See COPYING file that comes with this distribution |
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10 | // |
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11 | // |
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12 | #ifndef ASAP_CUBIC_SPLINE_INTERPOLATOR_1D_H |
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13 | #define ASAP_CUBIC_SPLINE_INTERPOLATOR_1D_H |
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14 | |
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15 | #include "Interpolator1D.h" |
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16 | |
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17 | namespace asap { |
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18 | |
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19 | /** |
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20 | * Implementation of (natural) cubic spline interpolation. |
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21 | * @author TakeshiNakazato |
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22 | */ |
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23 | class CubicSplineInterpolator1D : public Interpolator1D { |
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24 | public: |
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25 | // Default constructor. |
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26 | CubicSplineInterpolator1D(); |
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27 | |
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28 | // Destructor. |
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29 | virtual ~CubicSplineInterpolator1D(); |
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30 | |
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31 | // Override Interpolator1D::setData. |
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32 | // @see Interpolator1D::setData |
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33 | void setData(double *x, float *y, unsigned int n); |
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34 | |
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35 | // Override Interpolator1D::setY. |
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36 | // @see Interpolator1D::setY() |
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37 | void setY(float *y, unsigned int n); |
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38 | |
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39 | // Perform interpolation. |
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40 | // @param[in] x horizontal location where the value is evaluated |
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41 | // by interpolation. |
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42 | // @return interpolated value at x. |
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43 | float interpolate(double x); |
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44 | private: |
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45 | // Determine second derivatives of each point based on |
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46 | // natural cubic spline condition (second derivative at each |
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47 | // end is zero). |
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48 | void evaly2(); |
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49 | |
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50 | // Do interpolation using second derivatives determined by evaly2(). |
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51 | // @param[in] x horizontal location where the value is evaluated |
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52 | // by interpolation. |
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53 | // @param[in] i location index for x. |
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54 | // @return interpolated value at x. |
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55 | float dospline(double x, unsigned int i); |
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56 | |
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57 | // Array to store second derivatives on the data points. |
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58 | float *y2_; |
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59 | |
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60 | // number of data points for second derivatives |
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61 | unsigned int ny2_; |
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62 | |
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63 | // Boolean parameter whether buffered values are effective or not. |
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64 | bool reusable_; |
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65 | }; |
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66 | |
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67 | } |
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68 | #endif |
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