num_ops Module Reference

Numerical operations. More...

Interfaces and Types
interface	calc_zero_hh
	Finds the zero of a function using Householder iteration. More...

Functions/Subroutines
character(len=max_str_ln) function, public	calc_zero_zhang (zero, fun, x_int_in)
	Finds the zero of a function using Zhang's method, which is simpler than Brent's method.

Variables
logical, public	debug_calc_zero = .false.
	plot debug information for calc_zero

Detailed Description

Numerical operations.

Function/Subroutine Documentation

calc_zero_zhang()

character(len=max_str_ln) function, public num_ops::calc_zero_zhang	(	real(dp), intent(inout)	zero,
		external real(dp) function(real(dp), intent(in) x)	fun,
		real(dp), dimension(2), intent(in)	x_int_in )

Finds the zero of a function using Zhang's method, which is simpler than Brent's method.

Taken from from Steven Stage's correction of Zhang's paper [19].

Unlike Householder, Zhang's method needs an interval x_int_in to work in, not a guess. Also, it does not require the derivative of the function.

The routine returns an error message if no zero is found, and which is empty otherwise.

Note

The interval x_int_in needs to be so that the function values at either end are of different value.

Parameters

[in,out]	fun	fun(x) with x abscissa fun ordinate
[in,out]	zero	output
[in]	x_int_in	interval

Returns

possible error message

Definition at line 461 of file num_ops.f90.

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Variable Documentation

debug_calc_zero

logical, public num_ops::debug_calc_zero = .false.

plot debug information for calc_zero

Note

Debug version only

Definition at line 22 of file num_ops.f90.