step.c

该文件为c++的数学函数库!是一个非常有用的编程工具.它含有各种数学函数,为科学计算、工程应用等程序编写提供方便！

/* ode-initval/odeiv.c
 * 
 * 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 2 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* Author:  G. Jungman
 */
#include <config.h>
#include <stdlib.h>
#include <gsl/gsl_errno.h>
#include <gsl/gsl_odeiv.h>

gsl_odeiv_step * 
gsl_odeiv_step_alloc(const gsl_odeiv_step_type * T, size_t dim)
{
  gsl_odeiv_step *s = (gsl_odeiv_step *) malloc (sizeof (gsl_odeiv_step));

  if (s == 0)
    {
      GSL_ERROR_NULL ("failed to allocate space for ode struct", GSL_ENOMEM);
    };

  s->type = T;
  s->dimension = dim;

  s->state = s->type->alloc(dim);

  if (s->state == 0)
    {
      free (s);         /* exception in constructor, avoid memory leak */

      GSL_ERROR_NULL ("failed to allocate space for ode state", GSL_ENOMEM);
    };
    
  return s;
}

const char *
gsl_odeiv_step_name(const gsl_odeiv_step * s)
{
  return s->type->name;
}

unsigned int
gsl_odeiv_step_order(const gsl_odeiv_step * s)
{
  return s->type->order(s->state);
}

int
gsl_odeiv_step_apply(
  gsl_odeiv_step * s,
  double t,
  double h,
  double y[],
  double yerr[],
  const double dydt_in[],
  double dydt_out[],
  const gsl_odeiv_system * dydt)
{
  return s->type->apply(s->state, s->dimension, t, h, y, yerr, dydt_in, dydt_out, dydt);
}

int
gsl_odeiv_step_reset(gsl_odeiv_step * s)
{
  return s->type->reset(s->state, s->dimension);
}

void
gsl_odeiv_step_free(gsl_odeiv_step * s)
{
  s->type->free(s->state);
  free(s);
}