/usr/include/gsl/gsl_chebyshev.h is in libgsl-dev 2.1+dfsg-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 | /* cheb/gsl_chebyshev.h
*
* Copyright (C) 1996, 1997, 1998, 1999, 2000 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.
*/
#ifndef __GSL_CHEBYSHEV_H__
#define __GSL_CHEBYSHEV_H__
#include <gsl/gsl_math.h>
#include <gsl/gsl_mode.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
/* data for a Chebyshev series over a given interval */
struct gsl_cheb_series_struct {
double * c; /* coefficients */
size_t order; /* order of expansion */
double a; /* lower interval point */
double b; /* upper interval point */
/* The following exists (mostly) for the benefit
* of the implementation. It is an effective single
* precision order, for use in single precision
* evaluation. Users can use it if they like, but
* only they know how to calculate it, since it is
* specific to the approximated function. By default,
* order_sp = order.
* It is used explicitly only by the gsl_cheb_eval_mode
* functions, which are not meant for casual use.
*/
size_t order_sp;
/* Additional elements not used by specfunc */
double * f; /* function evaluated at chebyschev points */
};
typedef struct gsl_cheb_series_struct gsl_cheb_series;
/* Calculate a Chebyshev series of specified order over
* a specified interval, for a given function.
* Return 0 on failure.
*/
gsl_cheb_series * gsl_cheb_alloc(const size_t order);
/* Free a Chebyshev series previously calculated with gsl_cheb_alloc().
*/
void gsl_cheb_free(gsl_cheb_series * cs);
/* Calculate a Chebyshev series using the storage provided.
* Uses the interval (a,b) and the order with which it
* was initially created.
*
*/
int gsl_cheb_init(gsl_cheb_series * cs, const gsl_function * func,
const double a, const double b);
/* Return the order, size of coefficient array and coefficient array ptr */
size_t gsl_cheb_order (const gsl_cheb_series * cs);
size_t gsl_cheb_size (const gsl_cheb_series * cs);
double *gsl_cheb_coeffs (const gsl_cheb_series * cs);
/* Evaluate a Chebyshev series at a given point.
* No errors can occur for a struct obtained from gsl_cheb_new().
*/
double gsl_cheb_eval(const gsl_cheb_series * cs, const double x);
int gsl_cheb_eval_err(const gsl_cheb_series * cs, const double x,
double * result, double * abserr);
/* Evaluate a Chebyshev series at a given point, to (at most) the given order.
* No errors can occur for a struct obtained from gsl_cheb_new().
*/
double gsl_cheb_eval_n(const gsl_cheb_series * cs, const size_t order,
const double x);
int gsl_cheb_eval_n_err(const gsl_cheb_series * cs, const size_t order,
const double x, double * result, double * abserr);
/* Evaluate a Chebyshev series at a given point, using the default
* order for double precision mode(s) and the single precision
* order for other modes.
* No errors can occur for a struct obtained from gsl_cheb_new().
*/
double gsl_cheb_eval_mode(const gsl_cheb_series * cs, const double x, gsl_mode_t mode);
int gsl_cheb_eval_mode_e(const gsl_cheb_series * cs, const double x, gsl_mode_t mode, double * result, double * abserr);
/* Compute the derivative of a Chebyshev series.
*/
int gsl_cheb_calc_deriv(gsl_cheb_series * deriv, const gsl_cheb_series * cs);
/* Compute the integral of a Chebyshev series. The
* integral is fixed by the condition that it equals zero at
* the left end-point, ie it is precisely
* Integrate[cs(t; a,b), {t, a, x}]
*/
int gsl_cheb_calc_integ(gsl_cheb_series * integ, const gsl_cheb_series * cs);
__END_DECLS
#endif /* __GSL_CHEBYSHEV_H__ */
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