FERWE - Revision history

Schlipf at 07:46, 25 February 2025

2025-02-25T07:46:17Z

← Older revision		Revision as of 07:46, 25 February 2025
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	The band index runs fastest.		The band index runs fastest.
	The occupancies must be between 0 and 1.		The occupancies must be between 0 and 1.
	In the case of spin-polarized calculations ({{~~TAG~~\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel.		In the case of spin-polarized calculations ({{TAGO\|ISPIN\|2}}), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel.
	Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.		Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.

Schlipf at 07:45, 25 February 2025

2025-02-25T07:45:58Z

← Older revision		Revision as of 07:45, 25 February 2025
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	Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital.		Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital.
	By default, VASP will order the eigenenergies so that enforcing {{TAG\|FERWE}} will move the electrons to the originally unoccupied 65th orbital because it has now the lower energy.		By default, VASP will order the eigenenergies so that enforcing {{TAG\|FERWE}} will move the electrons to the originally unoccupied 65th orbital because it has now the lower energy.
	This problem can be often circumvented by specifying {{~~TAG~~\|LDIAG~~}}=~~.FALSE. in the {{FILE\|INCAR}} file.		This problem can be often circumvented by specifying {{TAGO\|LDIAG\|.FALSE.}} in the {{FILE\|INCAR}} file.

Schlipf at 10:23, 24 February 2025

2025-02-24T10:23:28Z

← Older revision		Revision as of 10:23, 24 February 2025
Line 8:		Line 8:
	The band index runs fastest.		The band index runs fastest.
	The occupancies must be between 0 and 1.		The occupancies must be between 0 and 1.

	In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel.		In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel.
	Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.		Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.

			Note that the partial occupancies are also written to the {{FILE\|OUTCAR}} file
			k-point 8 : 0.3750 0.0000 0.0000
			band No. band energies occupation
			1 -2.0636 2.00000
			2 0.1506 2.00000
			3 6.0155 1.99808
			4 6.0188 1.99432
			5 7.3309 1.71014
			6 7.3311 1.54777
			7 8.0841 0.28501
			8 8.0894 0.18039
			9 9.5834 0.00086
			10 9.5880 0.00071
			11 13.0368 0.00000
			12 14.3253 0.00000
			Keep in mind that for systems without spin-polarization the occupations are twice as large in the {{FILE\|OUTCAR}} file than what you should provide for {{TAG\|FERWE}} because of spin degeneracy.
	{{NB\|mind\|VASP changes the number of bands {{TAG\|NBANDS}} to accommodate your parallel setup. If {{TAG\|NBANDS}} is inconsistent with the number of elements you provide with {{TAG\|FERWE}} VASP will exit with an error message. The used {{TAG\|NBANDS}} is indicated in the error message. Adjust the occupancies provided to {{TAG\|FERWE}} to this new value. Alternatively, you can choose an {{TAG\|NBANDS}} as the common factor of all your parallel setups to avoid changes in the number of bands (see [[NBANDS#Parallelization\|here]]).}}		{{NB\|mind\|VASP changes the number of bands {{TAG\|NBANDS}} to accommodate your parallel setup. If {{TAG\|NBANDS}} is inconsistent with the number of elements you provide with {{TAG\|FERWE}} VASP will exit with an error message. The used {{TAG\|NBANDS}} is indicated in the error message. Adjust the occupancies provided to {{TAG\|FERWE}} to this new value. Alternatively, you can choose an {{TAG\|NBANDS}} as the common factor of all your parallel setups to avoid changes in the number of bands (see [[NBANDS#Parallelization\|here]]).}}

	~~The~~ occupancies ~~are even kept~~ fixed during ionic relaxations or molecular dynamics simulations. However, keeping the orbital occupancies fixed, requires that the orbital order does not change during the self-consistency cycle or during the optimization of the orbitals. Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital. ~~Then the subspace diagonalization step~~ will ~~swap both orbitals, but~~ the ~~occupancies~~ will ~~remain as read from~~ the ~~INCAR file (this means that~~ the originally unoccupied 65th orbital ~~will move to~~ the ~~64th place and it will hence become occupied)~~. This problem can be often circumvented by specifying {{TAG\|LDIAG}}=.FALSE. in ~~the INCAR file.~~		You can use {{TAG\|FERWE}} to keep occupancies fixed during ionic relaxations or molecular dynamics simulations.
			However, keeping the orbital occupancies fixed, requires that the orbital order does not change during the self-consistency cycle or during the optimization of the orbitals.
	~~Note that the partial occupancies are also written to~~ the {{FILE\|~~OUTCAR~~}} file~~, but in this case they are multiplied by 2, i.e. they are between 0 and 2~~.		Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital.
			By default, VASP will order the eigenenergies so that enforcing {{TAG\|FERWE}} will move the electrons to the originally unoccupied 65th orbital because it has now the lower energy.
			This problem can be often circumvented by specifying {{TAG\|LDIAG}}=.FALSE. in the {{FILE\|INCAR}} file.


	== Related tags and articles ==		== Related tags and articles ==
	{{TAG\|FERDO}},		{{TAG\|FERDO}},
	{{TAG\|ISMEAR}}		{{TAG\|ISMEAR}},
			{{TAG\|NBANDS}},
			{{TAG\|LDIAG}}

	{{sc\|FERWE\|Examples\|Examples that use this tag}}		{{sc\|FERWE\|Examples\|Examples that use this tag}}

	[[Category:INCAR tag]][[Category:Electronic occupancy]][[Category:Density of states]]		[[Category:INCAR tag]][[Category:Electronic occupancy]][[Category:Density of states]]

Schlipf at 10:13, 24 February 2025

2025-02-24T10:13:44Z

← Older revision		Revision as of 10:13, 24 February 2025
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	To set the occupancies, specify		To set the occupancies, specify
	{{TAG\|FERWE}} = f(1) f(2) f(3) ... f({{TAG\|NBANDS}}×N<sub>'''k'''</sub>)		{{TAG\|FERWE}} = f(1) f(2) f(3) ... f({{TAG\|NBANDS}}×N<sub>'''k'''</sub>)
	The occupancies must be specified for all bands and k points. The band index runs fastest. The occupancies must be between 0 and 1.		The occupancies must be specified for all bands and k points.
			The band index runs fastest.
			The occupancies must be between 0 and 1.

			In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel.
			Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.
			{{NB\|mind\|VASP changes the number of bands {{TAG\|NBANDS}} to accommodate your parallel setup. If {{TAG\|NBANDS}} is inconsistent with the number of elements you provide with {{TAG\|FERWE}} VASP will exit with an error message. The used {{TAG\|NBANDS}} is indicated in the error message. Adjust the occupancies provided to {{TAG\|FERWE}} to this new value. Alternatively, you can choose an {{TAG\|NBANDS}} as the common factor of all your parallel setups to avoid changes in the number of bands (see [[NBANDS#Parallelization\|here]]).}}

	The occupancies are even kept fixed during ionic relaxations or molecular dynamics simulations. However, keeping the orbital occupancies fixed, requires that the orbital order does not change during the self-consistency cycle or during the optimization of the orbitals. Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital. Then the subspace diagonalization step will swap both orbitals, but the occupancies will remain as read from the INCAR file (this means that the originally unoccupied 65th orbital will move to the 64th place and it will hence become occupied). This problem can be often circumvented by specifying {{TAG\|LDIAG}}=.FALSE. in the INCAR file.		The occupancies are even kept fixed during ionic relaxations or molecular dynamics simulations. However, keeping the orbital occupancies fixed, requires that the orbital order does not change during the self-consistency cycle or during the optimization of the orbitals. Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital. Then the subspace diagonalization step will swap both orbitals, but the occupancies will remain as read from the INCAR file (this means that the originally unoccupied 65th orbital will move to the 64th place and it will hence become occupied). This problem can be often circumvented by specifying {{TAG\|LDIAG}}=.FALSE. in the INCAR file.
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	Note that the partial occupancies are also written to the {{FILE\|OUTCAR}} file, but in this case they are multiplied by 2, i.e. they are between 0 and 2.		Note that the partial occupancies are also written to the {{FILE\|OUTCAR}} file, but in this case they are multiplied by 2, i.e. they are between 0 and 2.

	In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.
	{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in the corresponding warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}}.}}

	== Related tags and articles ==		== Related tags and articles ==

Schlipf at 10:00, 24 February 2025

2025-02-24T10:00:11Z

← Older revision		Revision as of 10:00, 24 February 2025
Line 6:		Line 6:
	{{TAG\|FERWE}} = f(1) f(2) f(3) ... f({{TAG\|NBANDS}}×N<sub>'''k'''</sub>)		{{TAG\|FERWE}} = f(1) f(2) f(3) ... f({{TAG\|NBANDS}}×N<sub>'''k'''</sub>)
	The occupancies must be specified for all bands and k points. The band index runs fastest. The occupancies must be between 0 and 1.		The occupancies must be specified for all bands and k points. The band index runs fastest. The occupancies must be between 0 and 1.

			The occupancies are even kept fixed during ionic relaxations or molecular dynamics simulations. However, keeping the orbital occupancies fixed, requires that the orbital order does not change during the self-consistency cycle or during the optimization of the orbitals. Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital. Then the subspace diagonalization step will swap both orbitals, but the occupancies will remain as read from the INCAR file (this means that the originally unoccupied 65th orbital will move to the 64th place and it will hence become occupied). This problem can be often circumvented by specifying {{TAG\|LDIAG}}=.FALSE. in the INCAR file.

			Note that the partial occupancies are also written to the {{FILE\|OUTCAR}} file, but in this case they are multiplied by 2, i.e. they are between 0 and 2.

	In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.		In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.

Huebsch: /* Related tags and articles */

2024-10-17T10:10:34Z

Huebsch at 10:10, 17 October 2024

2024-10-17T10:10:23Z

← Older revision		Revision as of 10:10, 17 October 2024
Line 8:		Line 8:

	In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.		In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.

	{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in the corresponding warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}}.}}		{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in the corresponding warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}}.}}

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	----		----

	[[Category:INCAR tag]][[Category:Electronic ~~minimization~~]][[Category:Density of states]]		[[Category:INCAR tag]][[Category:Electronic occupancy]][[Category:Density of states]]

Ftran at 13:17, 6 June 2023

2023-06-06T13:17:30Z

← Older revision		Revision as of 13:17, 6 June 2023
Line 9:		Line 9:
	In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.		In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.

	{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in a warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}}.}}		{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in the corresponding warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}}.}}

	== Related tags and articles ==		== Related tags and articles ==

Ftran at 13:16, 6 June 2023

2023-06-06T13:16:44Z

← Older revision		Revision as of 13:16, 6 June 2023
Line 9:		Line 9:
	In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.		In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.

	{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in a warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}} ~~indicated in the~~.}}		{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in a warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}}.}}

	== Related tags and articles ==		== Related tags and articles ==

Ftran at 13:14, 6 June 2023

2023-06-06T13:14:12Z

← Older revision		Revision as of 13:14, 6 June 2023
Line 9:		Line 9:
	In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.		In the case of spin-polarized calculations ({{TAG\|ISPIN}}=2), {{TAG\|FERWE}} sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the {{TAG\|FERDO}} tag.

	{{NB\|mind\|If the calculation stops when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation.}}		{{NB\|mind\|If the calculation stops with an error message when reading {{TAG\|FERWE}}, then this may be due to an automatic increase of the number of bands {{TAG\|NBANDS}} in parallel calculation (the new value of {{TAG\|NBANDS}} is indicated in a warning message). If this is the case, then the number of occupancies provided to {{TAG\|FERWE}} should be increased according to the new {{TAG\|NBANDS}} indicated in the.}}

	== Related tags and articles ==		== Related tags and articles ==

← Older revision		Revision as of 10:10, 17 October 2024
Line 15:		Line 15:

	{{sc\|FERWE\|Examples\|Examples that use this tag}}		{{sc\|FERWE\|Examples\|Examples that use this tag}}
	~~----~~

	[[Category:INCAR tag]][[Category:Electronic occupancy]][[Category:Density of states]]		[[Category:INCAR tag]][[Category:Electronic occupancy]][[Category:Density of states]]