Detailed Description

template<class func_t = funct>
class o2scl::root_bkt_cern< func_t >

This class attempts to find $ x_1 $ and $ x_2 $ in $ [a,b] $ such that:

$f(x_1) f(x_2) \leq 0$ ,
$|f(x_1)| \leq|f(x_2)|$ , and
$| x_1-x_2| \leq 2~\mathrm{tol\_abs}~(1+|x_0|)$ .

The function solve_bkt() requires inputs x1 and x2 such that the first condition, $f(x_1) f(x_2) \leq 0$ , already holds.

The variable root::tol_abs defaults to $10^{-8}$ and root::ntrial defaults to 200.

The function solve_bkt() will call the error handler if the root is not initially bracketed. If root::err_nonconv is true (as it is by default), then the error handler will also be called if the number function evaluations is greater than root::ntrial.

After a call to solve_bkt(), root::last_ntrial contains the total number of iterations which were used

See the One-dimensional solvers section of the User's guide for general information about O2scl solvers.

Based on the CERNLIB routines RZEROX and DZEROX, which was based on Bus75 and is documented at http://wwwasdoc.web.cern.ch/wwwasdoc/shortwrupsdir/c200/top.html

Definition at line 73 of file root_bkt_cern.h.

Public Member Functions
int	set_mode (int m)
	Set mode of solution (1 or 2) More...

virtual const char *	type ()
	Return the type, `"root_bkt_cern"`.

virtual int	solve_bkt (double &x1, double x2, func_t &func)
	Solve `func` in region returning .

Public Member Functions inherited from o2scl::root_bkt< funct >
virtual int	solve_bkt (double &x1, double x2, funct &func)=0
	Solve `func` in region returning .

virtual int	solve (double &x, funct &func)
	Solve `func` using `x` as an initial guess. More...

virtual int	solve_de (double &x, funct &func, funct &df)
	Solve `func` using `x` as an initial guess using derivatives `df`.

Public Member Functions inherited from o2scl::root< funct, funct, double >
virtual int	print_iter (double x, double y, int iter, double value=0.0, double limit=0.0, std::string comment="")
	Print out iteration information. More...

Protected Member Functions
double	sign (double a, double b)
	FORTRAN-like function for sign.

Protected Attributes
int	mode
	Internal storage for the mode. More...

Additional Inherited Members
Public Attributes inherited from o2scl::root_bkt< funct >
double	bracket_step
	The relative stepsize for automatic bracketing (default value is zero) More...

double	bracket_min
	The minimum stepsize for automatic bracketing (default zero)

size_t	bracket_iters
	The number of iterations in attempt to bracket root (default 10)

Public Attributes inherited from o2scl::root< funct, funct, double >
double	tol_rel
	The maximum value of the functions for success (default $10^{-8}$ )

double	tol_abs
	The minimum allowable stepsize (default $10^{-12}$ )

int	verbose
	Output control (default 0)

int	ntrial
	Maximum number of iterations (default 100)

bool	err_nonconv
	If true, call the error handler if the solver does not converge (default true)

int	last_ntrial
	The number of iterations used in the most recent solve.

Member Function Documentation

◆ set_mode()

template<class func_t = funct>

int o2scl::root_bkt_cern< func_t >::set_mode ( int m )

inline

1 should be used for simple functions where the cost is inexpensive in comparison to one iteration of solve_bkt(), or functions which have a pole near the root (this is the default).
2 should be used for more time-consuming functions.

If an integer other than 1 or 2 is specified, the error handler is called.

Definition at line 116 of file root_bkt_cern.h.

Member Data Documentation

◆ mode

template<class func_t = funct>

int o2scl::root_bkt_cern< func_t >::mode

protected

This internal variable is actually defined to be smaller by 1 than the "mode" as it is defined in the CERNLIB documentation in order to avoid needless subtraction in solve_bkt().

Definition at line 87 of file root_bkt_cern.h.

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

/home/awsteiner/wcs/o2scl/src/root/root_bkt_cern.h

Detailed Description

template<class func_t = funct> class o2scl::root_bkt_cern< func_t >

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Member Function Documentation

◆ set_mode()

Member Data Documentation

◆ mode

template<class func_t = funct>
class o2scl::root_bkt_cern< func_t >