eftcamb_rootfind Module Reference

This module contains the definitions of all the EFTCAMB root finding algorithms. More...

Functions/Subroutines
subroutine, public	zbrac (func, x1, x2, succes, funcZero)
	Bracketing subroutine: This subroutine does a outward search for the smallest intervall containing a root of the equation func=funcZero. More...
real(dl) function, public	zbrent (func, x1, x2, tol, funcZero, succes)
	Brent root finding algorithm: This is used to solve numerically the equation func=funcZero by means of the Brent method. Notice that the initial interval has to bracket the root of the function. More...

Detailed Description

This module contains the definitions of all the EFTCAMB root finding algorithms.

Author

Bin Hu, Marco Raveri

Function/Subroutine Documentation

subroutine, public eftcamb_rootfind::zbrac	(	external	func,
		real(dl), intent(inout)	x1,
		real(dl), intent(inout)	x2,
		logical, intent(out)	succes,
		real(dl), intent(in)	funcZero
	)

Bracketing subroutine: This subroutine does a outward search for the smallest intervall containing a root of the equation func=funcZero.

Parameters

	func	function to find the root of
[in,out]	x1	in input lower bound of the interval in which to find the root, in output lower bound of the bracketing interval
[in,out]	x2	in input upper bound of the interval in which to find the root, in output upper bound of the bracketing interval
[out]	succes	true if the algorithm succeeds false if not
[in]	funczero	the value desired func = funcZero

Definition at line 41 of file 02_root_finding.f90.

real(dl) function, public eftcamb_rootfind::zbrent	(	external	func,
		real(dl)	x1,
		real(dl)	x2,
		real(dl)	tol,
		real(dl)	funcZero,
		logical	succes
	)

Brent root finding algorithm: This is used to solve numerically the equation func=funcZero by means of the Brent method. Notice that the initial interval has to bracket the root of the function.

Parameters

func	function to find the root of
x1	in input lower bound of the interval in which to find the root. Has to be braketing.
x2	in input upper bound of the interval in which to find the root. Has to be braketing.
tol	numerical absolute tollerance. Notice that internally the algorithm mitigates this with absoute tollerance. Values below 1.d-15 are useless.
funczero	the value desired func = funcZero
succes	true if the algorithm succeeds false if not

Returns

returns the value of x at which the function satisfies func = funcZero up to numerical accuracy

Definition at line 94 of file 02_root_finding.f90.