t_c_g0 Module Reference

This module computes the basic integrals for the truncated coulomb operator. More...

Functions/Subroutines
subroutine, public	t_c_g0_n (RES, use_gamma, R, T, NDERIV)
	... More...
subroutine, public	init (Nder, iunit, mepos, group)
	... More...
subroutine, public	free_c0 ()
	... More...
integer function, public	get_lmax_init ()
	Returns the value of nderiv_init so that one can check if opening the potential file is worhtwhile. More...

Detailed Description

This module computes the basic integrals for the truncated coulomb operator.

     res(1) =G_0(R,T)= ((2*erf(sqrt(t))+erf(R-sqrt(t))-erf(R+sqrt(t)))/sqrt(t))

   and up to 21 derivatives with respect to T

     res(n+1)=(-1)**n d^n/dT^n G_0(R,T)

   The function is only computed for values of R,T which fulfil

     R**2 - 11.0_dp*R + 0.0_dp < T < R**2 + 11.0_dp*R + 50.0_dp where R>=0 T>=0

   for T larger than the upper bound, 0 is returned
   (which is accurate at least up to 1.0E-16)
   while for T smaller than the lower bound, the caller is instructed
   to use the conventional gamma function instead
   (i.e. the limit of above expression for R to Infinity)

Author

Joost VandeVondele and Manuel Guidon

History

Nov 2008, 2009 Joost VandeVondele and Manuel Guidon May 2019 A. Bussy: Added a get_maxl_init function to get current status of nderiv_init and moved the file to common (made it accessible from aobasis, same place as gamma.F).

Function/Subroutine Documentation

t_c_g0_n()

subroutine, public t_c_g0::t_c_g0_n	(	real(kind=dp), dimension(*), intent(out)	RES,
		logical, intent(out)	use_gamma,
		real(kind=dp), intent(in)	R,
		real(kind=dp), intent(in)	T,
		integer, intent(in)	NDERIV
	)

...

Parameters

RES	...
use_gamma	...
R	...
T	...
NDERIV	...

Definition at line 83 of file t_c_g0.F.

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init()

subroutine, public t_c_g0::init	(	integer, intent(in)	Nder,
		integer, intent(in)	iunit,
		integer, intent(in)	mepos,
		class(mp_comm_type), intent(in)	group
	)

...

Parameters

Nder	the number of derivatives that will actually be used
iunit	contains the data file to initialize the table
mepos	...
group	...

Definition at line 1356 of file t_c_g0.F.

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free_c0()

subroutine, public t_c_g0::free_c0

...

Definition at line 1387 of file t_c_g0.F.

get_lmax_init()

integer function, public t_c_g0::get_lmax_init

Returns the value of nderiv_init so that one can check if opening the potential file is worhtwhile.

Returns

...

Author

A. Bussy, 05.2019

Definition at line 1463 of file t_c_g0.F.

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