ABINIT internal variables:

List and description.

This document lists several internal variables, to which the user has no direct access through a keyword, but that are derived from the input variables at the time of their processing, and used internally. Their value is fixed for a specific dataset. They are present in the dtset array, in addition to the input variables that can be directly addressed by the user.

The new user is advised to read first the new user's guide, before reading the present file. It will be easier to discover the present file with the help of the tutorial.

When the user is sufficiently familiarized with ABINIT, the reading of the ~ABINIT/Infos/tuning file might be useful. For response-function calculations using abinis, the complementary file ~ABINIT/Infos/respfn_help is needed.

Copyright (C) 1998-2004 ABINIT group (DCA, XG, RC)
This file is distributed under the terms of the GNU General Public License, see ~ABINIT/Infos/copyright or http://www.gnu.org/copyleft/gpl.txt .
For the initials of contributors, see ~ABINIT/Infos/contributors .
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Help files : New user's guide | Abinis (main) | Abinis (respfn) | Mrgddb | Anaddb | AIM (Bader) | Cut3D
Files that describe input variables:

Content of the file : alphabetical list of internals.


A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K. kptns  
L.
M. mband   mgfft   mpw  
N. ngfft   nelect  
O.
P.
Q. qptn  
R.
S.
T.
U. usepaw  
V.
W.
X.
Y.
Z.



kptns
Mnemonics: K-PoinTs re-Normalized and Shifted
Characteristic: INTERNAL
Variable type: real array kptns(3,nkpt)

If nqpt=0, or if one is doing a reponse calculation, this internal variable is derived from kpt and kptnrm: kptns(1:3,:)= kpt(1:3,:)/ kptnrm, so that it is kpt renormalized by kptnrm.
If nqpt=1 and one is not doing a ground-state calculation, this internal variable is derived from kpt,kptnrm and qptn kptns(1:3,:)= kpt(1:3,:)/ kptnrm+ qptn(1:3), so that it is kpt renormalized by kptnrm, then shifted by qptn(1:3).



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mband
Mnemonics: Maximum number of BANDs
Characteristic: INTERNAL
Variable type: integer

This internal variable deduces from nband(1:nkpt*nsppol) the maximum number of bands, over all k-points and spin-polarisation.



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mgfft
Mnemonics: Maximum of nGFFT
Characteristic: INTERNAL
Variable type: integer

This internal variable gives the maximum of ngfft(1:3).



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mpw
Mnemonics: Maximum number of Plane Waves
Characteristic: INTERNAL
Variable type: integer

This internal variable gives the maximum of the number of plane waves over all k-points. It is computed from ecut, and the description of the cell, provided by acell, rprim, and/or angdeg.



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nelect
Mnemonics: Number of ELECTrons
Characteristic: INTERNAL
Variable type: real number

This internal variable gives the number of electrons per unit cell, as computed from the sum of the valence electrons related to each atom (given by the pseudopotential), that is called "zval" and the input variable charge:
nelect=zval-charge.



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nfft
Mnemonics: Number of FFT points
Characteristic: INTERNAL
Variable type: integer

If the space parallelisation is not used, this internal variable gives the number of Fast Fourier Transform points, in the grid generated by ngfft(1:3). It is simply the product of the three components of ngfft.
If the space parallelisation is used, then it becomes the number of Fast Fourier Transform points attributed to this particular processor. It is no more the above-mentioned simple product, but a number usually close to this product divided by the number of processors on which the space is shared.



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qptn
Mnemonics: Q-PoinT re-Normalized
Characteristic: INTERNAL
Variable type: real array qptn(3)

Used if nqpt=1. This internal variable is derived from qpt and qptnrm: qptn(1:3)= qpt(1:3)/ qptnrm.



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usepaw
Mnemonics: USE Projector Augmented Waves method
Characteristic: INTERNAL
Variable type: integer parameter
Value is set by the pseudopotential files : either PAW or norm-conserving.

If the user wants to use the Projector Augmented Method, then usepaw must be 1. This variable is determined by the pseudopotentials files. Indeed, special PAW pseudo-projector files must be used (these are the equivalent of the pseudopotential files for the pseudopotential method). Such files are NOT yet available for the entire periodic table. Also, forces and stresses are not yet computed in the PAW method as implemented in ABINITv4.1. Other limitations are present as well, precluding the use of PAW for real production work. These limitations will be waived as time passes.
Related variables : pawecutdg, pawlcutd, pawmqgrdg, pawnphi, pawntheta.



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Goto : ABINIT home Page | Welcome | Suggested acknowledgments | List of input variables | Tutorial home page | Bibliography
Help files : New user's guide | Abinis (main) | Abinis (respfn) | Mrgddb | Anaddb | AIM (Bader) | Cut3D