o2scl::astep_gsl< vec_y_t, vec_dydx_t, vec_yerr_t, func_t > Class Template Reference

Adaptive ODE stepper (GSL) More...

#include <astep_gsl.h>

Inheritance diagram for o2scl::astep_gsl< vec_y_t, vec_dydx_t, vec_yerr_t, func_t >:

Detailed Description

template<class vec_y_t = boost::numeric::ublas::vector<double>, class vec_dydx_t = vec_y_t, class vec_yerr_t = vec_y_t, class func_t = ode_funct>
class o2scl::astep_gsl< vec_y_t, vec_dydx_t, vec_yerr_t, func_t >

This class performs an adaptive step of a system of ODEs. To modify the ODE stepper which is used, use the function astep_base::set_step().

Note, this has been updated to correspond to the ode-initval2 functions in GSL.

There is an example for the usage of this class in examples/ex_ode.cpp documented in the Ordinary differential equations example section.

Todo:

Document what happens when the stepper function returns a non-zero value, as it's different now with the ode-initval2 function.

Document count, failed_steps, etc.

Idea for Future:

Compare more directly to GSL

Default template arguments

• func_t - ode_funct
• vec_t - boost::numeric::ublas::vector < double >

Definition at line 268 of file astep_gsl.h.

Public Types
typedef boost::numeric::ublas::vector< double >	ubvector

Public Member Functions
virtual int	astep (double &x, double xmax, double &h, size_t n, vec_y_t &y, vec_dydx_t &dydx_out, vec_yerr_t &yerr, func_t &derivs)
	Make an adaptive integration step of the system derivs. More...
virtual int	astep_derivs (double &x, double xmax, double &h, size_t n, vec_y_t &y, vec_dydx_t &dydx, vec_yerr_t &yerr, func_t &derivs)
	Make an adaptive integration step of the system derivs with derivatives. More...
virtual int	astep_full (double x, double xmax, double &x_out, double &h, size_t n, vec_y_t &y, vec_dydx_t &dydx, vec_y_t &yout, vec_yerr_t &yerr, vec_dydx_t &dydx_out, func_t &derivs)
	Make an adaptive integration step of the system derivs. More...
Public Member Functions inherited from o2scl::astep_base< boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, ode_funct >
virtual int	astep (double &x, double xlimit, double &h, size_t n, boost::numeric::ublas::vector< double > &y, boost::numeric::ublas::vector< double > &dydx_out, boost::numeric::ublas::vector< double > &yerr, ode_funct &derivs)=0
	Make an adaptive integration step of the system derivs. More...
virtual int	astep_derivs (double &x, double xlimit, double &h, size_t n, boost::numeric::ublas::vector< double > &y, boost::numeric::ublas::vector< double > &dydx, boost::numeric::ublas::vector< double > &yerr, ode_funct &derivs)=0
	Make an adaptive integration step of the system derivs with derivatives. More...
virtual int	astep_full (double x, double xlimit, double &x_out, double &h, size_t n, boost::numeric::ublas::vector< double > &y, boost::numeric::ublas::vector< double > &dydx, boost::numeric::ublas::vector< double > &yout, boost::numeric::ublas::vector< double > &yerr, boost::numeric::ublas::vector< double > &dydx_out, ode_funct &derivs)=0
	Make an adaptive integration step of the system derivs with derivatives. More...
int	set_step (ode_step< boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, ode_funct > &step)
	Set stepper. More...

Public Attributes
ode_control_gsl< vec_y_t, vec_dydx_t, vec_yerr_t >	con
	Control specification.
Public Attributes inherited from o2scl::astep_base< boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, ode_funct >
int	verbose
	Set output level.
ode_rkck_gsl< boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, ode_funct >	def_step
	The default stepper.

Protected Member Functions
int	evolve_apply (double t0, double t1, double &t, double &h, size_t nvar, vec_y_t &y, vec_dydx_t &dydx, vec_y_t &yout, vec_yerr_t &yerr, vec_dydx_t &dydx_out, func_t &derivs)
	Apply the evolution for the next adaptive step. More...

Protected Attributes
vec_y_t	yout_int
	Temporary storage for yout.
vec_dydx_t	dydx_int
	Internal storage for dydx.
double	last_step
	The size of the last step.
unsigned long int	count
	The number of steps.
unsigned long int	failed_steps
	The number of failed steps.
size_t	msize
	The size of the allocated vectors.
Protected Attributes inherited from o2scl::astep_base< boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, ode_funct >
ode_step< boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, boost::numeric::ublas::vector< double >, ode_funct > *	stepp
	Pointer to the stepper being used.

Member Function Documentation

astep()

template<class vec_y_t = boost::numeric::ublas::vector<double>, class vec_dydx_t = vec_y_t, class vec_yerr_t = vec_y_t, class func_t = ode_funct>

virtual int o2scl::astep_gsl< vec_y_t, vec_dydx_t, vec_yerr_t, func_t >::astep ( double &  x, double  xmax, double &  h, size_t  n, vec_y_t &  y, vec_dydx_t &  dydx_out, vec_yerr_t &  yerr, func_t &  derivs  )

inlinevirtual

This attempts to take a step of size h from the point x of an n-dimensional system derivs starting with y. On exit, x and y contain the new values at the end of the step, h contains the size of the step, dydx_out contains the derivative at the end of the step, and yerr contains the estimated error at the end of the step.

Definition at line 461 of file astep_gsl.h.

astep_derivs()

template<class vec_y_t = boost::numeric::ublas::vector<double>, class vec_dydx_t = vec_y_t, class vec_yerr_t = vec_y_t, class func_t = ode_funct>

virtual int o2scl::astep_gsl< vec_y_t, vec_dydx_t, vec_yerr_t, func_t >::astep_derivs ( double &  x, double  xmax, double &  h, size_t  n, vec_y_t &  y, vec_dydx_t &  dydx, vec_yerr_t &  yerr, func_t &  derivs  )

inlinevirtual

This attempts to take a step of size h from the point x of an n-dimensional system derivs starting with y and given the initial derivatives dydx. On exit, x, y and dydx contain the new values at the end of the step, h contains the size of the step, dydx contains the derivative at the end of the step, and yerr contains the estimated error at the end of the step.

Definition at line 506 of file astep_gsl.h.

astep_full()

template<class vec_y_t = boost::numeric::ublas::vector<double>, class vec_dydx_t = vec_y_t, class vec_yerr_t = vec_y_t, class func_t = ode_funct>

virtual int o2scl::astep_gsl< vec_y_t, vec_dydx_t, vec_yerr_t, func_t >::astep_full ( double  x, double  xmax, double &  x_out, double &  h, size_t  n, vec_y_t &  y, vec_dydx_t &  dydx, vec_y_t &  yout, vec_yerr_t &  yerr, vec_dydx_t &  dydx_out, func_t &  derivs  )

inlinevirtual

This function performs an adaptive integration step with the n-dimensional system derivs and parameter pa. It Begins at x with initial stepsize h, ensuring that the step goes no farther than xmax. At the end of the step, the size of the step taken is h and the new value of x is in x_out. Initially, the function values and derivatives should be specified in y and dydx. The function values, derivatives, and the error at the end of the step are given in yout, yerr, and dydx_out. Unlike in ode_step objects, the objects y, yout, dydx, and dydx_out must all be distinct.

This adaptive stepper function is faster than astep() or astep_derivs() because it does not require any copying of vectors.

Definition at line 557 of file astep_gsl.h.

evolve_apply()

template<class vec_y_t = boost::numeric::ublas::vector<double>, class vec_dydx_t = vec_y_t, class vec_yerr_t = vec_y_t, class func_t = ode_funct>

int o2scl::astep_gsl< vec_y_t, vec_dydx_t, vec_yerr_t, func_t >::evolve_apply ( double  t0, double  t1, double &  t, double &  h, size_t  nvar, vec_y_t &  y, vec_dydx_t &  dydx, vec_y_t &  yout, vec_yerr_t &  yerr, vec_dydx_t &  dydx_out, func_t &  derivs  )

inlineprotected

This function is based on gsl_odeiv2_evolve_apply.

Note

This function requres that y, yout, dydx and dydx_out are all distinct vectors.

Definition at line 304 of file astep_gsl.h.

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The documentation for this class was generated from the following file:

• /home/awsteiner/wcs/o2scl/src/ode/astep_gsl.h