src/parsec/disk-image/parsec/parsec-benchmark/pkgs/libs/gsl/src/ode-initval/gear2.c - public/gem5-resources - Git at Google

 /* ode-initval/gear2.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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */

 /* Gear 2 */

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


 /* gear2 state object */
 typedef struct
 {
   int primed;                   /* flag indicating that yim1 is ready */
   double t_primed;              /* system was primed for this value of t */
   double last_h;                /* last step size */
   gsl_odeiv_step *primer;       /* stepper to use for priming */
   double *yim1;                 /* y_{i-1}    */
   double *k;                    /* work space */
   double *y0;                   /* work space */
   double *y0_orig;
   double *y_onestep;
   int stutter;
 }
 gear2_state_t;

 static void *
 gear2_alloc (size_t dim)
 {
   gear2_state_t *state = (gear2_state_t *) malloc (sizeof (gear2_state_t));

   if (state == 0)
     {
       GSL_ERROR_NULL ("failed to allocate space for gear2_state", GSL_ENOMEM);
     }

   state->yim1 = (double *) malloc (dim * sizeof (double));

   if (state->yim1 == 0)
     {
       free (state);
       GSL_ERROR_NULL ("failed to allocate space for yim1", GSL_ENOMEM);
     }

   state->k = (double *) malloc (dim * sizeof (double));

   if (state->k == 0)
     {
       free (state->yim1);
       free (state);
       GSL_ERROR_NULL ("failed to allocate space for k", GSL_ENOMEM);
     }

   state->y0 = (double *) malloc (dim * sizeof (double));

   if (state->y0 == 0)
     {
       free (state->k);
       free (state->yim1);
       free (state);
       GSL_ERROR_NULL ("failed to allocate space for y0", GSL_ENOMEM);
     }

   state->y0_orig = (double *) malloc (dim * sizeof (double));

   if (state->y0_orig == 0)
     {
       free (state->y0);
       free (state->k);
       free (state->yim1);
       free (state);
       GSL_ERROR_NULL ("failed to allocate space for y0_orig", GSL_ENOMEM);
     }

   state->y_onestep = (double *) malloc (dim * sizeof (double));

   if (state->y_onestep == 0)
     {
       free (state->y0_orig);
       free (state->y0);
       free (state->k);
       free (state->yim1);
       free (state);
       GSL_ERROR_NULL ("failed to allocate space for y0_orig", GSL_ENOMEM);
     }

   state->primed = 0;
   state->primer = gsl_odeiv_step_alloc (gsl_odeiv_step_rk4imp, dim);

   if (state->primer == 0)
     {
       free (state->y_onestep);
       free (state->y0_orig);
       free (state->y0);
       free (state->k);
       free (state->yim1);
       free (state);
       GSL_ERROR_NULL ("failed to allocate space for primer", GSL_ENOMEM);
     }

   state->last_h = 0.0;

   return state;
 }

 static int
 gear2_step (double *y, gear2_state_t * state,
             const double h, const double t,
             const size_t dim, const gsl_odeiv_system * sys)
 {
   /* Makes a Gear2 advance with step size h.
      y0 is the initial values of variables y.
      The implicit matrix equations to solve are:
      k = y0 + h * f(t + h, k)
      y = y0 + h * f(t + h, k)
    */

   const int iter_steps = 3;
   int nu;
   size_t i;
   double *y0 = state->y0;
   double *yim1 = state->yim1;
   double *k = state->k;

   /* Iterative solution of k = y0 + h * f(t + h, k)
      Note: This method does not check for convergence of the
      iterative solution!
    */

   for (nu = 0; nu < iter_steps; nu++)
     {
       int s = GSL_ODEIV_FN_EVAL (sys, t + h, y, k);

       if (s != GSL_SUCCESS)
         {
           return s;
         }

       for (i = 0; i < dim; i++)
         {
           y[i] = ((4.0 * y0[i] - yim1[i]) + 2.0 * h * k[i]) / 3.0;
         }
     }

   return GSL_SUCCESS;
 }

 static int
 gear2_apply (void *vstate,
              size_t dim,
              double t,
              double h,
              double y[],
              double yerr[],
              const double dydt_in[],
              double dydt_out[], const gsl_odeiv_system * sys)
 {
   gear2_state_t *state = (gear2_state_t *) vstate;

   state->stutter = 0;

   if (state->primed == 0 || t == state->t_primed || h != state->last_h)
     {
       /* Execute a single-step method to prime the process.  Note that
        * we do this if the step size changes, so frequent step size
        * changes will cause the method to stutter.
        *
        * Note that we reuse this method if the time has not changed,
        * which can occur when the adaptive driver is attempting to find
        * an appropriate step-size on its first iteration */

       int status;
       DBL_MEMCPY (state->yim1, y, dim);

       status =
         gsl_odeiv_step_apply (state->primer, t, h, y, yerr, dydt_in, dydt_out,
                               sys);

       /* Make note of step size and indicate readiness for a Gear step. */

       state->primed = 1;
       state->t_primed = t;
       state->last_h = h;
       state->stutter = 1;

       return status;
     }
   else
     {
       /* We have a previous y value in the buffer, and the step
        * sizes match, so we go ahead with the Gear step.
        */

       double *const k = state->k;
       double *const y0 = state->y0;
       double *const y0_orig = state->y0_orig;
       double *const yim1 = state->yim1;
       double *y_onestep = state->y_onestep;

       int s;
       size_t i;

       DBL_MEMCPY (y0, y, dim);

       /* iterative solution */

       if (dydt_out != NULL)
         {
           DBL_MEMCPY (k, dydt_out, dim);
         }

       /* First traverse h with one step (save to y_onestep) */

       DBL_MEMCPY (y_onestep, y, dim);

       s = gear2_step (y_onestep, state, h, t, dim, sys);

       if (s != GSL_SUCCESS)
         {
           return s;
         }

       /* Then with two steps with half step length (save to y) */

       s = gear2_step (y, state, h / 2.0, t, dim, sys);

       if (s != GSL_SUCCESS)
         {
           /* Restore original y vector */
           DBL_MEMCPY (y, y0_orig, dim);
           return s;
         }

       DBL_MEMCPY (y0, y, dim);

       s = gear2_step (y, state, h / 2.0, t + h / 2.0, dim, sys);

       if (s != GSL_SUCCESS)
         {
           /* Restore original y vector */
           DBL_MEMCPY (y, y0_orig, dim);
           return s;
         }

       /* Cleanup update */

       if (dydt_out != NULL)
         {
           s = GSL_ODEIV_FN_EVAL (sys, t + h, y, dydt_out);

           if (s != GSL_SUCCESS)
             {
               /* Restore original y vector */
               DBL_MEMCPY (y, y0_orig, dim);
               return s;
             }
         }

       /* Estimate error and update the state buffer. */

       for (i = 0; i < dim; i++)
         {
           yerr[i] = 4.0 * (y[i] - y_onestep[i]);
           yim1[i] = y0[i];
         }

       /* Make note of step size. */
       state->last_h = h;

       return 0;
     }
 }

 static int
 gear2_reset (void *vstate, size_t dim)
 {
   gear2_state_t *state = (gear2_state_t *) vstate;

   DBL_ZERO_MEMSET (state->yim1, dim);
   DBL_ZERO_MEMSET (state->k, dim);
   DBL_ZERO_MEMSET (state->y0, dim);

   state->primed = 0;
   state->last_h = 0.0;
   return GSL_SUCCESS;
 }

 static unsigned int
 gear2_order (void *vstate)
 {
   gear2_state_t *state = (gear2_state_t *) vstate;
   state = 0;                    /* prevent warnings about unused parameters */
   return 3;
 }

 static void
 gear2_free (void *vstate)
 {
   gear2_state_t *state = (gear2_state_t *) vstate;

   free (state->yim1);
   free (state->k);
   free (state->y0);
   free (state->y0_orig);
   free (state->y_onestep);
   gsl_odeiv_step_free (state->primer);

   free (state);
 }

 static const gsl_odeiv_step_type gear2_type = { "gear2",        /* name */
   1,                            /* can use dydt_in */
   0,                            /* gives exact dydt_out */
   &gear2_alloc,
   &gear2_apply,
   &gear2_reset,
   &gear2_order,
   &gear2_free
 };

 const gsl_odeiv_step_type *gsl_odeiv_step_gear2 = &gear2_type;
	/* ode-initval/gear2.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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	*/

	/* Gear 2 */

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


	/* gear2 state object */
	typedef struct
	{
	int primed; /* flag indicating that yim1 is ready */
	double t_primed; /* system was primed for this value of t */
	double last_h; /* last step size */
	gsl_odeiv_step primer; / stepper to use for priming */
	double yim1; / y_{i-1} */
	double k; / work space */
	double y0; / work space */
	double *y0_orig;
	double *y_onestep;
	int stutter;
	}
	gear2_state_t;

	static void *
	gear2_alloc (size_t dim)
	{
	gear2_state_t state = (gear2_state_t ) malloc (sizeof (gear2_state_t));

	if (state == 0)
	{
	GSL_ERROR_NULL ("failed to allocate space for gear2_state", GSL_ENOMEM);
	}

	state->yim1 = (double ) malloc (dim sizeof (double));

	if (state->yim1 == 0)
	{
	free (state);
	GSL_ERROR_NULL ("failed to allocate space for yim1", GSL_ENOMEM);
	}

	state->k = (double ) malloc (dim sizeof (double));

	if (state->k == 0)
	{
	free (state->yim1);
	free (state);
	GSL_ERROR_NULL ("failed to allocate space for k", GSL_ENOMEM);
	}

	state->y0 = (double ) malloc (dim sizeof (double));

	if (state->y0 == 0)
	{
	free (state->k);
	free (state->yim1);
	free (state);
	GSL_ERROR_NULL ("failed to allocate space for y0", GSL_ENOMEM);
	}

	state->y0_orig = (double ) malloc (dim sizeof (double));

	if (state->y0_orig == 0)
	{
	free (state->y0);
	free (state->k);
	free (state->yim1);
	free (state);
	GSL_ERROR_NULL ("failed to allocate space for y0_orig", GSL_ENOMEM);
	}

	state->y_onestep = (double ) malloc (dim sizeof (double));

	if (state->y_onestep == 0)
	{
	free (state->y0_orig);
	free (state->y0);
	free (state->k);
	free (state->yim1);
	free (state);
	GSL_ERROR_NULL ("failed to allocate space for y0_orig", GSL_ENOMEM);
	}

	state->primed = 0;
	state->primer = gsl_odeiv_step_alloc (gsl_odeiv_step_rk4imp, dim);

	if (state->primer == 0)
	{
	free (state->y_onestep);
	free (state->y0_orig);
	free (state->y0);
	free (state->k);
	free (state->yim1);
	free (state);
	GSL_ERROR_NULL ("failed to allocate space for primer", GSL_ENOMEM);
	}

	state->last_h = 0.0;

	return state;
	}

	static int
	gear2_step (double y, gear2_state_t state,
	const double h, const double t,
	const size_t dim, const gsl_odeiv_system * sys)
	{
	/* Makes a Gear2 advance with step size h.
	y0 is the initial values of variables y.
	The implicit matrix equations to solve are:
	k = y0 + h * f(t + h, k)
	y = y0 + h * f(t + h, k)
	*/

	const int iter_steps = 3;
	int nu;
	size_t i;
	double *y0 = state->y0;
	double *yim1 = state->yim1;
	double *k = state->k;

	/* Iterative solution of k = y0 + h * f(t + h, k)
	Note: This method does not check for convergence of the
	iterative solution!
	*/

	for (nu = 0; nu < iter_steps; nu++)
	{
	int s = GSL_ODEIV_FN_EVAL (sys, t + h, y, k);

	if (s != GSL_SUCCESS)
	{
	return s;
	}

	for (i = 0; i < dim; i++)
	{
	y[i] = ((4.0 * y0[i] - yim1[i]) + 2.0 * h * k[i]) / 3.0;
	}
	}

	return GSL_SUCCESS;
	}

	static int
	gear2_apply (void *vstate,
	size_t dim,
	double t,
	double h,
	double y[],
	double yerr[],
	const double dydt_in[],
	double dydt_out[], const gsl_odeiv_system * sys)
	{
	gear2_state_t state = (gear2_state_t ) vstate;

	state->stutter = 0;

	if (state->primed == 0 \|\| t == state->t_primed \|\| h != state->last_h)
	{
	/* Execute a single-step method to prime the process. Note that
	* we do this if the step size changes, so frequent step size
	* changes will cause the method to stutter.
	*
	* Note that we reuse this method if the time has not changed,
	* which can occur when the adaptive driver is attempting to find
	* an appropriate step-size on its first iteration */

	int status;
	DBL_MEMCPY (state->yim1, y, dim);

	status =
	gsl_odeiv_step_apply (state->primer, t, h, y, yerr, dydt_in, dydt_out,
	sys);

	/* Make note of step size and indicate readiness for a Gear step. */

	state->primed = 1;
	state->t_primed = t;
	state->last_h = h;
	state->stutter = 1;

	return status;
	}
	else
	{
	/* We have a previous y value in the buffer, and the step
	* sizes match, so we go ahead with the Gear step.
	*/

	double *const k = state->k;
	double *const y0 = state->y0;
	double *const y0_orig = state->y0_orig;
	double *const yim1 = state->yim1;
	double *y_onestep = state->y_onestep;

	int s;
	size_t i;

	DBL_MEMCPY (y0, y, dim);

	/* iterative solution */

	if (dydt_out != NULL)
	{
	DBL_MEMCPY (k, dydt_out, dim);
	}

	/* First traverse h with one step (save to y_onestep) */

	DBL_MEMCPY (y_onestep, y, dim);

	s = gear2_step (y_onestep, state, h, t, dim, sys);

	if (s != GSL_SUCCESS)
	{
	return s;
	}

	/* Then with two steps with half step length (save to y) */

	s = gear2_step (y, state, h / 2.0, t, dim, sys);

	if (s != GSL_SUCCESS)
	{
	/* Restore original y vector */
	DBL_MEMCPY (y, y0_orig, dim);
	return s;
	}

	DBL_MEMCPY (y0, y, dim);

	s = gear2_step (y, state, h / 2.0, t + h / 2.0, dim, sys);

	if (s != GSL_SUCCESS)
	{
	/* Restore original y vector */
	DBL_MEMCPY (y, y0_orig, dim);
	return s;
	}

	/* Cleanup update */

	if (dydt_out != NULL)
	{
	s = GSL_ODEIV_FN_EVAL (sys, t + h, y, dydt_out);

	if (s != GSL_SUCCESS)
	{
	/* Restore original y vector */
	DBL_MEMCPY (y, y0_orig, dim);
	return s;
	}
	}

	/* Estimate error and update the state buffer. */

	for (i = 0; i < dim; i++)
	{
	yerr[i] = 4.0 * (y[i] - y_onestep[i]);
	yim1[i] = y0[i];
	}

	/* Make note of step size. */
	state->last_h = h;

	return 0;
	}
	}

	static int
	gear2_reset (void *vstate, size_t dim)
	{
	gear2_state_t state = (gear2_state_t ) vstate;

	DBL_ZERO_MEMSET (state->yim1, dim);
	DBL_ZERO_MEMSET (state->k, dim);
	DBL_ZERO_MEMSET (state->y0, dim);

	state->primed = 0;
	state->last_h = 0.0;
	return GSL_SUCCESS;
	}

	static unsigned int
	gear2_order (void *vstate)
	{
	gear2_state_t state = (gear2_state_t ) vstate;
	state = 0; /* prevent warnings about unused parameters */
	return 3;
	}

	static void
	gear2_free (void *vstate)
	{
	gear2_state_t state = (gear2_state_t ) vstate;

	free (state->yim1);
	free (state->k);
	free (state->y0);
	free (state->y0_orig);
	free (state->y_onestep);
	gsl_odeiv_step_free (state->primer);

	free (state);
	}

	static const gsl_odeiv_step_type gear2_type = { "gear2", /* name */
	1, /* can use dydt_in */
	0, /* gives exact dydt_out */
	&gear2_alloc,
	&gear2_apply,
	&gear2_reset,
	&gear2_order,
	&gear2_free
	};

	const gsl_odeiv_step_type *gsl_odeiv_step_gear2 = &gear2_type;