smoothing_spline.h

/* header file for smoothing_spline.c  */
/*----------------------------------------------------------------------------
 * Copyright (c) 2024 Peter Miller
 *
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 * 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
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 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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 *--------------------------------------------------------------------------*/

#ifndef _zSMOOTHING_SPLINE_H_
 #define _zSMOOTHING_SPLINE_H_
 #define s_spline_float float /* could be float or double */
//#define s_spline_type_double /* only define for double type - can then be checked with a #ifdef */ 
 #ifdef __cplusplus
extern "C" 
 {
 #endif
void SmoothingSpline( s_spline_float *x, s_spline_float *y, s_spline_float *yo, size_t _n, double lambda); // x,y are input data, x,y0 are positions of optimal knots - all arrays of size "n" (0..n-1) . lambda is smoothing 0 (max smoothing)=>1 no smoothing
																					  // values of lambda may need to be (very) small, but values <= DBL_EPSILON = 2.22 e-16 are treated as zero
																					 // if yo is NULL put updated y values back into array y
 #ifdef __cplusplus
 }
 #endif
#endif