File indexing completed on 2024-05-12 15:27:10

 /***************************************************************************
     File                 : nsl_smooth.h
     Project              : LabPlot
     Description          : NSL smooth functions
     --------------------------------------------------------------------
     Copyright            : (C) 2016 by Stefan Gerlach (stefan.gerlach@uni.kn)
 
  ***************************************************************************/
 
 /***************************************************************************
  *                                                                         *
  *  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 2 of the License, or      *
  *  (at your option) any later version.                                    *
  *                                                                         *
  *  This program is distributed in the hope that it will be useful,        *
  *  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.                           *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
  *   along with this program; if not, write to the Free Software           *
  *   Foundation, Inc., 51 Franklin Street, Fifth Floor,                    *
  *   Boston, MA  02110-1301  USA                                           *
  *                                                                         *
  ***************************************************************************/
 
 #ifndef NSL_SMOOTH_H
 #define NSL_SMOOTH_H
 
 #include <gsl/gsl_matrix.h>
 
 #define NSL_SMOOTH_TYPE_COUNT 4
 typedef enum {nsl_smooth_type_moving_average, nsl_smooth_type_moving_average_lagged, nsl_smooth_type_percentile,
     nsl_smooth_type_savitzky_golay} nsl_smooth_type;
 extern const char* nsl_smooth_type_name[];
 /* TODO: LOWESS/etc., Bezier, B-Spline, (FFT Filter) */
 
 /* mode of extension for padding signal 
  *  none: reduce points at edges
  *  interp: polynomial interpolation
  *  mirror:   3 2 | 1 2 3 4 5 | 4 3 (reflect)
  *  nearest:  1 1 | 1 2 3 4 5 | 5 5 (repeat)
  *  constant: L L | 1 2 3 4 5 | R R
  *  periodic: 4 5 | 1 2 3 4 5 | 1 2 (wrap)
 */
 #define NSL_SMOOTH_PAD_MODE_COUNT 6
 typedef enum {nsl_smooth_pad_none, nsl_smooth_pad_interp, nsl_smooth_pad_mirror, nsl_smooth_pad_nearest,
     nsl_smooth_pad_constant, nsl_smooth_pad_periodic} nsl_smooth_pad_mode;
 extern const char* nsl_smooth_pad_mode_name[];
 
 #define NSL_SMOOTH_WEIGHT_TYPE_COUNT 8
 typedef enum {nsl_smooth_weight_uniform, nsl_smooth_weight_triangular, nsl_smooth_weight_binomial, 
     nsl_smooth_weight_parabolic, nsl_smooth_weight_quartic, nsl_smooth_weight_triweight, 
     nsl_smooth_weight_tricube, nsl_smooth_weight_cosine } nsl_smooth_weight_type;
 extern const char* nsl_smooth_weight_type_name[];
 /*TODO: IIR: exponential, Gaussian, see nsl_sf_kernel */
 
 /* values used for constant padding */
 extern double nsl_smooth_pad_constant_lvalue, nsl_smooth_pad_constant_rvalue;
 
 /********* Smoothing algorithms **********/
 
 /* Moving average */
 int nsl_smooth_moving_average(double *data, size_t n, size_t points, nsl_smooth_weight_type weight, nsl_smooth_pad_mode mode);
 
 /* Lagged moving average */
 int nsl_smooth_moving_average_lagged(double *data, size_t n, size_t points, nsl_smooth_weight_type weight, nsl_smooth_pad_mode mode);
 
 /* Percentile filter */
 int nsl_smooth_percentile(double *data, size_t n, size_t points, double percentile, nsl_smooth_pad_mode mode);
 
 /* Savitzky-Golay coefficients */
 /**
  * \brief Compute Savitzky-Golay coefficients and store them into #h.
  *
  * This function follows GSL conventions in that it writes its result into a matrix allocated by
  * the caller and returns a non-zero result on error.
  *
  * The coefficient matrix is defined as the matrix H mapping a set of input values to the values
  * of the polynomial of order #polynom_order which minimizes squared deviations from the input
  * values. It is computed using the formula \$H=V(V^TV)^(-1)V^T\$, where \$V\$ is the Vandermonde
  * matrix of the point indices.
  *
  * For a short description of the mathematical background, see
  * http://www.statistics4u.info/fundstat_eng/cc_filter_savgol_math.html
  */
 int nsl_smooth_savgol_coeff(size_t points, int order, gsl_matrix *h);
 
 /* set values for constant padding */
 void nsl_smooth_pad_constant_set(double lvalue, double rvalue);
 
 /* Savitzky-Golay smoothing */
 /**
  * \brief Savitzky-Golay smoothing of (uniformly distributed) data.
  *
  * When the data is not uniformly distributed, Savitzky-Golay looses its interesting conservation
  * properties. On the other hand, a central point of the algorithm is that for uniform data, the
  * operation can be implemented as a convolution. This is considerably more efficient than a more
  * generic method able to handle non-uniform input data.
  */
 int nsl_smooth_savgol(double *data, size_t n, size_t points, int order, nsl_smooth_pad_mode mode);
 
 /* Savitzky-Golay default smoothing (interp) */
 int nsl_smooth_savgol_default(double *data, size_t n, size_t points, int order);
 
 /* TODO SmoothFilter::smoothModifiedSavGol(double *x_in, double *y_inout)
     see SmoothFilter.cpp of libscidavis
 */
 
 #endif /* NSL_SMOOTH_H */