/* interpolation/gsl_interp.h * * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2004 Gerard Jungman * * 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 3 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. */ /* Author: G. Jungman */ #ifndef __GSL_INTERP_H__ #define __GSL_INTERP_H__ #include #include #include #undef __BEGIN_DECLS #undef __END_DECLS #ifdef __cplusplus # define __BEGIN_DECLS extern "C" { # define __END_DECLS } #else # define __BEGIN_DECLS /* empty */ # define __END_DECLS /* empty */ #endif __BEGIN_DECLS /* evaluation accelerator */ typedef struct { size_t cache; /* cache of index */ size_t miss_count; /* keep statistics */ size_t hit_count; } gsl_interp_accel; /* interpolation object type */ typedef struct { const char * name; unsigned int min_size; void * (*alloc) (size_t size); int (*init) (void *, const double xa[], const double ya[], size_t size); int (*eval) (const void *, const double xa[], const double ya[], size_t size, double x, gsl_interp_accel *, double * y); int (*eval_deriv) (const void *, const double xa[], const double ya[], size_t size, double x, gsl_interp_accel *, double * y_p); int (*eval_deriv2) (const void *, const double xa[], const double ya[], size_t size, double x, gsl_interp_accel *, double * y_pp); int (*eval_integ) (const void *, const double xa[], const double ya[], size_t size, gsl_interp_accel *, double a, double b, double * result); void (*free) (void *); } gsl_interp_type; /* general interpolation object */ typedef struct { const gsl_interp_type * type; double xmin; double xmax; size_t size; void * state; } gsl_interp; /* available types */ GSL_VAR const gsl_interp_type * gsl_interp_linear; GSL_VAR const gsl_interp_type * gsl_interp_polynomial; GSL_VAR const gsl_interp_type * gsl_interp_cspline; GSL_VAR const gsl_interp_type * gsl_interp_cspline_periodic; GSL_VAR const gsl_interp_type * gsl_interp_akima; GSL_VAR const gsl_interp_type * gsl_interp_akima_periodic; GSL_VAR const gsl_interp_type * gsl_interp_steffen; gsl_interp_accel * gsl_interp_accel_alloc(void); int gsl_interp_accel_reset (gsl_interp_accel * a); void gsl_interp_accel_free(gsl_interp_accel * a); gsl_interp * gsl_interp_alloc(const gsl_interp_type * T, size_t n); int gsl_interp_init(gsl_interp * obj, const double xa[], const double ya[], size_t size); const char * gsl_interp_name(const gsl_interp * interp); unsigned int gsl_interp_min_size(const gsl_interp * interp); unsigned int gsl_interp_type_min_size(const gsl_interp_type * T); int gsl_interp_eval_e(const gsl_interp * obj, const double xa[], const double ya[], double x, gsl_interp_accel * a, double * y); double gsl_interp_eval(const gsl_interp * obj, const double xa[], const double ya[], double x, gsl_interp_accel * a); int gsl_interp_eval_deriv_e(const gsl_interp * obj, const double xa[], const double ya[], double x, gsl_interp_accel * a, double * d); double gsl_interp_eval_deriv(const gsl_interp * obj, const double xa[], const double ya[], double x, gsl_interp_accel * a); int gsl_interp_eval_deriv2_e(const gsl_interp * obj, const double xa[], const double ya[], double x, gsl_interp_accel * a, double * d2); double gsl_interp_eval_deriv2(const gsl_interp * obj, const double xa[], const double ya[], double x, gsl_interp_accel * a); int gsl_interp_eval_integ_e(const gsl_interp * obj, const double xa[], const double ya[], double a, double b, gsl_interp_accel * acc, double * result); double gsl_interp_eval_integ(const gsl_interp * obj, const double xa[], const double ya[], double a, double b, gsl_interp_accel * acc); void gsl_interp_free(gsl_interp * interp); INLINE_DECL size_t gsl_interp_bsearch(const double x_array[], double x, size_t index_lo, size_t index_hi); #ifdef HAVE_INLINE /* Perform a binary search of an array of values. * * The parameters index_lo and index_hi provide an initial bracket, * and it is assumed that index_lo < index_hi. The resulting index * is guaranteed to be strictly less than index_hi and greater than * or equal to index_lo, so that the implicit bracket [index, index+1] * always corresponds to a region within the implicit value range of * the value array. * * Note that this means the relationship of 'x' to x_array[index] * and x_array[index+1] depends on the result region, i.e. the * behaviour at the boundaries may not correspond to what you * expect. We have the following complete specification of the * behaviour. * Suppose the input is x_array[] = { x0, x1, ..., xN } * if ( x == x0 ) then index == 0 * if ( x > x0 && x <= x1 ) then index == 0, and sim. for other interior pts * if ( x == xN ) then index == N-1 * if ( x > xN ) then index == N-1 * if ( x < x0 ) then index == 0 */ INLINE_FUN size_t gsl_interp_bsearch(const double x_array[], double x, size_t index_lo, size_t index_hi) { size_t ilo = index_lo; size_t ihi = index_hi; while(ihi > ilo + 1) { size_t i = (ihi + ilo)/2; if(x_array[i] > x) ihi = i; else ilo = i; } return ilo; } #endif INLINE_DECL size_t gsl_interp_accel_find(gsl_interp_accel * a, const double x_array[], size_t size, double x); #ifdef HAVE_INLINE INLINE_FUN size_t gsl_interp_accel_find(gsl_interp_accel * a, const double xa[], size_t len, double x) { size_t x_index = a->cache; if(x < xa[x_index]) { a->miss_count++; a->cache = gsl_interp_bsearch(xa, x, 0, x_index); } else if(x >= xa[x_index + 1]) { a->miss_count++; a->cache = gsl_interp_bsearch(xa, x, x_index, len-1); } else { a->hit_count++; } return a->cache; } #endif /* HAVE_INLINE */ __END_DECLS #endif /* __GSL_INTERP_H__ */