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- /* poly/gsl_poly.h
- *
- * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2004, 2007 Brian Gough
- *
- * 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_POLY_H__
- #define __GSL_POLY_H__
- #include <stdlib.h>
- #include "gsl_complex.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
- /* Evaluate polynomial
- *
- * c[0] + c[1] x + c[2] x^2 + ... + c[len-1] x^(len-1)
- *
- * exceptions: none
- */
- double gsl_poly_eval(const double c[], const int len, const double x);
- #ifdef HAVE_INLINE
- extern inline
- double
- gsl_poly_eval(const double c[], const int len, const double x)
- {
- int i;
- double ans = c[len-1];
- for(i=len-1; i>0; i--) ans = c[i-1] + x * ans;
- return ans;
- }
- #endif /* HAVE_INLINE */
- /* Work with divided-difference polynomials, Abramowitz & Stegun 25.2.26 */
- int
- gsl_poly_dd_init (double dd[], const double x[], const double y[],
- size_t size);
- double
- gsl_poly_dd_eval (const double dd[], const double xa[], const size_t size, const double x);
- #ifdef HAVE_INLINE
- extern inline
- double
- gsl_poly_dd_eval(const double dd[], const double xa[], const size_t size, const double x)
- {
- size_t i;
- double y = dd[size - 1];
- for (i = size - 1; i--;) y = dd[i] + (x - xa[i]) * y;
- return y;
- }
- #endif /* HAVE_INLINE */
- int
- gsl_poly_dd_taylor (double c[], double xp,
- const double dd[], const double x[], size_t size,
- double w[]);
- /* Solve for real or complex roots of the standard quadratic equation,
- * returning the number of real roots.
- *
- * Roots are returned ordered.
- */
- int gsl_poly_solve_quadratic (double a, double b, double c,
- double * x0, double * x1);
- int
- gsl_poly_complex_solve_quadratic (double a, double b, double c,
- gsl_complex * z0, gsl_complex * z1);
- /* Solve for real roots of the cubic equation
- * x^3 + a x^2 + b x + c = 0, returning the
- * number of real roots.
- *
- * Roots are returned ordered.
- */
- int gsl_poly_solve_cubic (double a, double b, double c,
- double * x0, double * x1, double * x2);
- int
- gsl_poly_complex_solve_cubic (double a, double b, double c,
- gsl_complex * z0, gsl_complex * z1,
- gsl_complex * z2);
- /* Solve for the complex roots of a general real polynomial */
- typedef struct
- {
- size_t nc ;
- double * matrix ;
- }
- gsl_poly_complex_workspace ;
- gsl_poly_complex_workspace * gsl_poly_complex_workspace_alloc (size_t n);
- void gsl_poly_complex_workspace_free (gsl_poly_complex_workspace * w);
- int
- gsl_poly_complex_solve (const double * a, size_t n,
- gsl_poly_complex_workspace * w,
- gsl_complex_packed_ptr z);
- __END_DECLS
- #endif /* __GSL_POLY_H__ */
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