EDIFFG: Difference between revisions
(When EDIFFG is negeative the norm of the forces is used as a stopping criteria) |
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Description: {{TAG|EDIFFG}} defines the break condition for the ionic relaxation loop. | Description: {{TAG|EDIFFG}} defines the break condition for the ionic relaxation loop. | ||
---- | ---- | ||
When {{TAG|EDIFFG}} is positive, the relaxation is stopped when the change of the total | When {{TAG|EDIFFG}} is positive, the relaxation is stopped when the change of the total energy is smaller than {{TAG|EDIFFG}} between two ionic steps. | ||
When {{TAG|EDIFFG}} is negative, the relaxation is stopped when the norms of all the forces are smaller than |{{TAG|EDIFFG}}|. This is usually a more convenient setting. | When {{TAG|EDIFFG}} is negative, the relaxation is stopped when the norms of all the forces are smaller than |{{TAG|EDIFFG}}|. This is usually a more convenient setting. | ||
{{TAG|EDIFFG}} | If {{TAG|EDIFFG}} = 0, the ionic relaxation is stopped after {{TAG|NSW}} steps. | ||
{{NB|warning|{{TAG|EDIFFG}} does not apply to {{:Category:Molecular dynamics|molecular-dynamics}} simulations.}} | |||
== Related tags and articles == | |||
== Related | |||
{{TAG|EDIFF}} | {{TAG|EDIFF}} | ||
{{sc|EDIFFG|Examples|Examples that use this tag}} | {{sc|EDIFFG|Examples|Examples that use this tag}} | ||
---- | ---- | ||
[[Category:INCAR | [[Category:INCAR tag]][[Category:Forces]][[Category:Ionic minimization]] |
Revision as of 07:51, 7 April 2022
EDIFFG = [real]
Default: EDIFFG = EDIFF×10
Description: EDIFFG defines the break condition for the ionic relaxation loop.
When EDIFFG is positive, the relaxation is stopped when the change of the total energy is smaller than EDIFFG between two ionic steps.
When EDIFFG is negative, the relaxation is stopped when the norms of all the forces are smaller than |EDIFFG|. This is usually a more convenient setting.
If EDIFFG = 0, the ionic relaxation is stopped after NSW steps.
Warning: EDIFFG does not apply to To get an idea about what basically molecular dynamics is and what the main contents are we refer the reader to references [1] and [2]. After understanding the theory behind molecular dynamics we refer the reader to Molecular dynamics calculations, which describes how to run standard molecular dynamics simulations. Every advanced molecular dynamics method builds on the knowledge in that tutorial and should be ideally only viewed after understanding the basics.
Important filesThe input files for standard molecular dynamics runs are the same as for other calculational methods. However additionally to the structural data the POSCAR file can contain the initial velocities as a separate block. It can also contain the input on which atomic positions should be constrained or not. Constrained and bias molecular dynamics (Constrained molecular dynamics, Metadynamics and Biased molecular dynamics) also require an additional input file, the ICONST file. This file specifies the collective variables. The (ICONST) file is also required for the monitoring of geometric parameters (Monitoring geometric parameters).
Theory
How to
CompilationIMPORTANT NOTE: The simulation methods described in this section are included in VASP as of version 5.2.12, and require VASP to be compiled with the cpp flag -Dtbdyn that should be included in the corresponding line of makefile, as for instance in the following example: CPP = $(CPP_) -DHOST=\"IFC9_fftw\" \ -Dkind8 -DNGXhalf -DCACHE_SIZE=12000 -DPGF90 -Davoidalloc \ -Dtbdyn Referencessimulations. |