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/* 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 <stdlib.h>
#include <gsl/gsl_inline.h>
#include <gsl/gsl_types.h>
#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__ */
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