ALGO - Revision history

Huebsch: /* Line-search output (direct optimizers) */

2026-06-23T11:52:57Z

Line-search output (direct optimizers)

← Older revision		Revision as of 11:52, 23 June 2026
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	}}		}}
	=== Line-search output (direct optimizers) ===		=== Line-search output (direct optimizers) ===
	For ~~the direct-optimization algorithms (~~{{TAG\|ALGO\|All}}/~~{{TAG\|ALGO\|~~Conjugate}} ~~and {{TAG\|ALGO\|Damped}})~~, each step also prints the diagnostics of the conjugate-gradient line minimization, for example:		For {{TAG\|ALGO\|All/Conjugate}}, each step also prints the diagnostics of the conjugate-gradient line minimization ({{TAG\|ISEARCH}}), for example:

	CGA: 8 -0.815350365436E+01 -0.26844E+00 -0.26700E+00 896 0.102E+00 0.183E-02		CGA: 8 -0.815350365436E+01 -0.26844E+00 -0.26700E+00 896 0.102E+00 0.183E-02

Huebsch: Huebsch moved page Construction:ALGO to ALGO without leaving a redirect

2026-06-23T11:50:05Z

Huebsch moved page Construction:ALGO to ALGO without leaving a redirect

← Older revision	Revision as of 11:50, 23 June 2026
(No difference)

Huebsch: Document the conjugate-gradient line-search output of the direct optimizers

2026-06-23T10:14:23Z

Document the conjugate-gradient line-search output of the direct optimizers

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 * Plot '''rms(c)''' as a function of electronic steps '''N'''. Large values indicate the electronic density is still changing and perhaps fluctuating (charge sloshing).
 }}
 <span id="GWALGOS">

Huebsch: Wrap ALGO setting values in


2026-06-23T09:13:30Z
Wrap ALGO setting values in <code>

				
				
				
				
				
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Description: Selects the electronic-minimization algorithm and/or the many-body method: Description: Selects the electronic-minimization algorithm and/or the many-body method:
:::* [[#Electronic-minimization algorithms|Electronic minimization]] (ground state) :::* [[#Electronic-minimization algorithms|Electronic minimization]] (ground state)
:::** ''Self-consistency cycle'': Normal (default), Fast, VeryFast, Exact, Subrot :::** ''Self-consistency cycle'': <code>Normal</code> (default), <code>Fast</code>, <code>VeryFast</code>, <code>Exact</code>, <code>Subrot</code>
:::** ''Direct optimization'': All / Conjugate, Damped :::** ''Direct optimization'': <code>All</code> / <code>Conjugate</code>, <code>Damped</code>
:::** ''Postprocessing'': Eigenval, None / Nothing :::** ''Postprocessing'': <code>Eigenval</code>, <code>None</code> / <code>Nothing</code>
:::* [[#GWALGOS|Response functions, GW, BSE, and ACFDT/RPA]] :::* [[#GWALGOS|Response functions, GW, BSE, and ACFDT/RPA]]
:::** CHI, TDHF, BSE, Timeev, ACFDT / RPA, ACFDTR / RPAR, and CRPA :::** <code>CHI</code>, <code>TDHF</code>, <code>BSE</code>, <code>Timeev</code>, <code>ACFDT</code> / <code>RPA</code>, <code>ACFDTR</code> / <code>RPAR</code>, and <code>CRPA</code>
:::** ''GW variants'': EVGW0, EVGW, QPGW0, QPGW, GW0R, GWR, G0W0R, EVGW0R :::** ''GW variants'': <code>EVGW0</code>, <code>EVGW</code>, <code>QPGW0</code>, <code>QPGW</code>, <code>GW0R</code>, <code>GWR</code>, <code>G0W0R</code>, <code>EVGW0R</code>
---- ----
{{Available|4.5}} {{Available|4.5}}
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! {{TAG|ALGO}} !! Algorithm !! {{TAG|IALGO}} !! Class !! Notes ! {{TAG|ALGO}} !! Algorithm !! {{TAG|IALGO}} !! Class !! Notes
|- |-
| Normal ''(default)'' || [[Blocked-Davidson algorithm|blocked Davidson]] || 38 || self-consistency cycle || Robust default, recommended for most calculations. | <code>Normal</code> ''(default)'' || [[Blocked-Davidson algorithm|blocked Davidson]] || 38 || self-consistency cycle || Robust default, recommended for most calculations.
|- |-
| Fast || [[Blocked-Davidson algorithm|blocked Davidson]] + [[RMM-DIIS]] || 68 || self-consistency cycle || Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). This setting is faster and cheaper per electronic step, but less robust and less reliable in the sense that it may diverge or cannot find the true minimum. Use to obtain a first estimate, but mind that orbitals (and hence forces, stress, etc.) may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version. | <code>Fast</code> || [[Blocked-Davidson algorithm|blocked Davidson]] + [[RMM-DIIS]] || 68 || self-consistency cycle || Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). This setting is faster and cheaper per electronic step, but less robust and less reliable in the sense that it may diverge or cannot find the true minimum. Use to obtain a first estimate, but mind that orbitals (and hence forces, stress, etc.) may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.
|- |-
| VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order. | <code>VeryFast</code> || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select <code>Old VeryFast</code> for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order.
|- |-
| Conjugate / All || [[Blocked-Davidson algorithm|blocked Davidson]] + all-band conjugate gradient || 58 || direct optimization || Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG|ISEARCH|1}}). Appropriate choice for magnetic systems and systems where {{TAG|ALGO|Normal}} failed. | <code>Conjugate</code> / <code>All</code> || [[Blocked-Davidson algorithm|blocked Davidson]] + all-band conjugate gradient || 58 || direct optimization || Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG|ISEARCH|1}}). Appropriate choice for magnetic systems and systems where {{TAG|ALGO|Normal}} failed.
|- |-
| Damped || [[Blocked-Davidson algorithm|blocked Davidson]] + damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately. | <code>Damped</code> || [[Blocked-Davidson algorithm|blocked Davidson]] + damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately.
|- |-
| Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing. | <code>Exact</code> || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.
|- |-
| Subrot || subspace rotation || 4 || self-consistency cycle || Diagonalization within the subspace spanned by the current orbitals. Rarely used stand-alone. | <code>Subrot</code> || subspace rotation || 4 || self-consistency cycle || Diagonalization within the subspace spanned by the current orbitals. Rarely used stand-alone.
|- |-
| Eigenval || recompute eigenvalues || 3 || postprocessing || Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE|WAVECAR}} file). | <code>Eigenval</code> || recompute eigenvalues || 3 || postprocessing || Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE|WAVECAR}} file).
|- |-
| None / Nothing || no orbital update || 2 || postprocessing || Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE|WAVECAR}} file). | <code>None</code> / <code>Nothing</code> || no orbital update || 2 || postprocessing || Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE|WAVECAR}} file).
|} |}
{{NB|warning|Only the iterative [[Self-consistency cycle|self-consistency-cycle]] minimizers support potential-only functionals/methods, e.g., {{TAG|METAGGA|MBJ}} or {{TAG|LSFBXC|True}}. This is because direct optimization relies on the gradient of the energy and not just the potential.}} {{NB|warning|Only the iterative [[Self-consistency cycle|self-consistency-cycle]] minimizers support potential-only functionals/methods, e.g., {{TAG|METAGGA|MBJ}} or {{TAG|LSFBXC|True}}. This is because direct optimization relies on the gradient of the energy and not just the potential.}}
{{NB|tip|Except for 'None', 'Nothing', 'Exact', and 'Eigenval' (which must be spelled out), only the first letter determines the selected algorithm.}} {{NB|tip|Except for <code>None</code>, <code>Nothing</code>, <code>Exact</code>, and <code>Eigenval</code> (which must be spelled out), only the first letter determines the selected algorithm.}}
Conjugate, Subrot, Eigenval, None, and Nothing are supported as of vasp.5.2.9. The "Old Fast"/"Old VeryFast" variants (also "of"/"fo" and "ov"/"vo") are available in vasp.6 and select the corresponding vasp.5 algorithms. <code>Conjugate</code>, <code>Subrot</code>, <code>Eigenval</code>, <code>None</code>, and <code>Nothing</code> are supported as of vasp.5.2.9. The <code>Old Fast</code>/<code>Old VeryFast</code> variants (also <code>of</code>/<code>fo</code> and <code>ov</code>/<code>vo</code>) are available in vasp.6 and select the corresponding vasp.5 algorithms.
For more technical details, read {{TAG|IALGO}} and {{TAG|LDIAG}}. For more technical details, read {{TAG|IALGO}} and {{TAG|LDIAG}}.



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  ...   ...



The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with a delay ({{TAG|NELMDL}} non-self-consistent blocked-Davidson sweeps) at fixed density, so the first steps for {{TAG|ALGO|Fast}}, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>: The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with a delay ({{TAG|NELMDL}} non-self-consistent blocked-Davidson sweeps) at fixed density, so the first steps for <code>Fast</code>, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>:
{| class="wikitable" {| class="wikitable"
! Label !! Algorithm ! Label !! Algorithm
|- |-
| <code>DAV:</code> || [[Blocked-Davidson algorithm|blocked Davidson]] ({{TAG|IALGO}}=38; {{TAG|ALGO}}=Normal and the initial phase of Fast, VeryFast, All and Damped) | <code>DAV:</code> || [[Blocked-Davidson algorithm|blocked Davidson]] ({{TAG|IALGO}}=38; {{TAG|ALGO}}=Normal and the initial phase of <code>Fast</code>, <code>VeryFast</code>, <code>All</code> and <code>Damped</code>)
|- |-
| <code>RMM:</code> || [[RMM-DIIS]] ({{TAG|IALGO}}=48; {{TAG|ALGO}}=VeryFast and the main phase of Fast) | <code>RMM:</code> || [[RMM-DIIS]] ({{TAG|IALGO}}=48; {{TAG|ALGO}}=VeryFast and the main phase of <code>Fast</code>)
|- |-
| <code>SDA:</code> / <code>CGA:</code> || steepest-descent / conjugate-gradient all-band step ({{TAG|IALGO|58}}; {{TAG|ALGO}}=All or Conjugate) | <code>SDA:</code> / <code>CGA:</code> || steepest-descent / conjugate-gradient all-band step ({{TAG|IALGO|58}}; {{TAG|ALGO}}=All or <code>Conjugate</code>)
|- |-
| <code>DMP:</code> || damped dynamics ({{TAG|IALGO|53}}; {{TAG|ALGO|Damped}}) | <code>DMP:</code> || damped dynamics ({{TAG|IALGO|53}}; {{TAG|ALGO|Damped}})



Huebsch: Add 'blocked Davidson +' to All/Conjugate and Damped (Davidson delay phase, confirmed intrinsic to IALGO=58/53 via bare-IALGO tests)
2026-06-23T08:59:24Z
Add 'blocked Davidson +' to All/Conjugate and Damped (Davidson delay phase, confirmed intrinsic to IALGO=58/53 via bare-IALGO tests)

				
				
				
				
				
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| VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order. | VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order.
|- |-
| Conjugate / All || all-band conjugate gradient || 58 || direct optimization || Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG|ISEARCH|1}}). Appropriate choice for magnetic systems and systems where {{TAG|ALGO|Normal}} failed. | Conjugate / All || [[Blocked-Davidson algorithm|blocked Davidson]] + all-band conjugate gradient || 58 || direct optimization || Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG|ISEARCH|1}}). Appropriate choice for magnetic systems and systems where {{TAG|ALGO|Normal}} failed.
|- |-
| Damped || damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately. | Damped || [[Blocked-Davidson algorithm|blocked Davidson]] + damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately.
|- |-
| Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing. | Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.



Huebsch at 08:53, 23 June 2026
2026-06-23T08:53:04Z


				
				
				
				
				
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| Normal ''(default)'' || [[Blocked-Davidson algorithm|blocked Davidson]] || 38 || self-consistency cycle || Robust default, recommended for most calculations. | Normal ''(default)'' || [[Blocked-Davidson algorithm|blocked Davidson]] || 38 || self-consistency cycle || Robust default, recommended for most calculations.
|- |-
| Fast || [[Blocked-Davidson algorithm|blocked Davidson]] + [[RMM-DIIS]] || 68 || self-consistency cycle || Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). For easily converging systems, this setting is faster and cheaper. It is recommended for [[:Category:Molecular dynamics|molecular dynamics]] and [[Structure optimization|ionic relaxations]] to obtain a first estimate, but orbitals and hence forces may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version. | Fast || [[Blocked-Davidson algorithm|blocked Davidson]] + [[RMM-DIIS]] || 68 || self-consistency cycle || Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). This setting is faster and cheaper per electronic step, but less robust and less reliable in the sense that it may diverge or cannot find the true minimum. Use to obtain a first estimate, but mind that orbitals (and hence forces, stress, etc.) may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.
|- |-
| VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order. | VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order.
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| Damped || damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately. | Damped || damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately.
|- |-
| Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive and memory-heavy, mainly when many empty states are required or for testing. | Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.
|- |-
| Subrot || subspace rotation || 4 || self-consistency cycle || Diagonalization within the subspace spanned by the current orbitals. | Subrot || subspace rotation || 4 || self-consistency cycle || Diagonalization within the subspace spanned by the current orbitals. Rarely used stand-alone.
|- |-
| Eigenval || recompute eigenvalues || 3 || postprocessing || Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE|WAVECAR}} file). | Eigenval || recompute eigenvalues || 3 || postprocessing || Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE|WAVECAR}} file).



Huebsch at 08:43, 23 June 2026
2026-06-23T08:43:41Z


				
				
				
				
				
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=== Recommendations === === Recommendations ===
* '''Most systems''': {{TAG|ALGO|Normal}} (blocked Davidson) is the most robust choice and the default. * '''Most systems''': {{TAG|ALGO|Normal}} (blocked Davidson) is the most robust choice and the default.
* '''Large systems''': [[RMM-DIIS]] (<code>Fast</code> or <code>VeryFast</code>) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG|LREAL|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG|NELMDL}}) and is the least robust on its own. * '''Large systems and molecular dynamics''': [[RMM-DIIS]] (<code>Fast</code> or <code>VeryFast</code>) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG|LREAL|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG|NELMDL}}) and is the least robust on its own. For [[MD calculations]] and [[structure optimization]] or metals, also mind that barely occupied bands are less optimized ({{TAG|WEIMIN}}).
* '''[[Magnetic materials]], [[DFT+U]], [[:Category:Exchange-correlation_functionals#Meta_generalized_gradient_approximation_(meta-GGA)|meta-GGA]], [[:Category:Exchange-correlation_functionals#Hartree-Fock_(HF)_and_hybrid_functionals|Hartree-Fock and hybrid functionals]]''': The [[Direct optimization of the orbitals|direct optimizers]] {{TAG|ALGO|All}} (or <code>Conjugate</code>) are more robust and recommended; use the improved line search ({{TAG|ISEARCH|1}}). {{TAG|ALGO|VeryFast}} is '''not''' supported for hybrid functionals. * '''[[Magnetic materials]], [[DFT+U]], [[:Category:Exchange-correlation_functionals#Meta_generalized_gradient_approximation_(meta-GGA)|meta-GGA]], [[:Category:Exchange-correlation_functionals#Hartree-Fock_(HF)_and_hybrid_functionals|Hartree-Fock and hybrid functionals]]''': The [[Direct optimization of the orbitals|direct optimizers]] {{TAG|ALGO|All}} (or <code>Conjugate</code>) are more robust and recommended; use the improved line search ({{TAG|ISEARCH|1}}). {{TAG|ALGO|VeryFast}} is '''not''' supported for hybrid functionals.
* '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': You may try {{TAG|ALGO|Damped}} with an appropriate time step ({{TAG|TIME}}) and a somewhat larger {{TAG|NBANDS}}, if other algorithms fail. * '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': You may try {{TAG|ALGO|Damped}} with an appropriate time step ({{TAG|TIME}}) and a somewhat larger {{TAG|NBANDS}}, if other algorithms fail.



Huebsch at 08:39, 23 June 2026
2026-06-23T08:39:23Z


				
				
				
				
				
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| Damped || damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately. | Damped || damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately.
|- |-
| Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive, mainly for testing or when many empty states are required. | Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive and memory-heavy, mainly when many empty states are required or for testing.
|- |-
| Subrot || subspace rotation || 4 || self-consistency cycle || Diagonalization within the subspace spanned by the current orbitals. | Subrot || subspace rotation || 4 || self-consistency cycle || Diagonalization within the subspace spanned by the current orbitals.



Huebsch: Fast IALGO 68 (not 38/48); fix ionic-relaxation link -> Structure optimization
2026-06-23T08:31:28Z
Fast IALGO 68 (not 38/48); fix ionic-relaxation link -> Structure optimization

				
				
				
				
				
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| Normal ''(default)'' || [[Blocked-Davidson algorithm|blocked Davidson]] || 38 || self-consistency cycle || Robust default, recommended for most calculations. | Normal ''(default)'' || [[Blocked-Davidson algorithm|blocked Davidson]] || 38 || self-consistency cycle || Robust default, recommended for most calculations.
|- |-
| Fast || [[Blocked-Davidson algorithm|blocked Davidson]] + [[RMM-DIIS]] || 38 / 48 || self-consistency cycle || Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). For easily converging systems, this setting is faster and cheaper. It is recommended for [[:Category:Molecular dynamics|molecular dynamics]] and [[ionic relaxations]] to obtain a first estimate, but orbitals and hence forces may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version. | Fast || [[Blocked-Davidson algorithm|blocked Davidson]] + [[RMM-DIIS]] || 68 || self-consistency cycle || Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). For easily converging systems, this setting is faster and cheaper. It is recommended for [[:Category:Molecular dynamics|molecular dynamics]] and [[Structure optimization|ionic relaxations]] to obtain a first estimate, but orbitals and hence forces may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.
|- |-
| VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order. | VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order.



Huebsch at 08:25, 23 June 2026
2026-06-23T08:25:23Z


				
				
				
				
				
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---- ----
{{Available|4.5}} {{Available|4.5}}
The {{TAG|ALGO}} tag has two kinds of settings: For a ground-state calculation, it selects the [[#Electronic-minimization algorithms|electronic-minimization algorithm]]; that may be one of the self-consistency-cycle minimizers, the direct optimizers, or the postprocessing modes (Eigenval, None). For [[many-body perturbation theory]], it instead selects the [[#GWALGOS|algorithm for response functions, the GW variant, BSE, time evolution, and ACFDT/RPA]]. The stopping criterion is set using {{TAG|EDIFF}}, however we recommend checking the [[#Output during the electronic minimization|output during the electronic minimization]] as described below in order to judge convergence. The {{TAG|ALGO}} tag has two kinds of settings: For a ground-state calculation, it selects the '''electronic-minimization algorithm''' (see [[#Electronic-minimization algorithms|Electronic-minimization algorithms]] section below); that may be one of the self-consistency-cycle minimizers, the direct optimizers, or the postprocessing modes. For [[many-body perturbation theory]], it instead selects the [[#GWALGOS|algorithm for response functions, the GW variant, BSE, time evolution, and ACFDT/RPA]]. The stopping criterion is set using {{TAG|EDIFF}} and {{TAG|NELM}}. We recommend checking the [[#Output during the electronic minimization|output during the electronic minimization]] as described below to judge the convergence.
{{NB|tip|To recompute the density of states (DOS), obtain the projected DOS or carry out any postprocessing from existing orbitals (e.g., a {{FILE|WAVECAR}} from a previous run) ''without'' re-optimizing them, set {{TAG|ALGO|None}}.  Or to additionally recompute the one-electron energies set {{TAG|ALGO|Eigenval}}.}} {{NB|tip|To recompute the density of states (DOS), obtain the projected DOS or carry out any postprocessing from existing orbitals (e.g., a {{FILE|WAVECAR}} from a previous run) ''without'' re-optimizing them, set {{TAG|NELM|1}}, {{TAG|LDIAG|False}}, and {{TAG|ALGO|None}}.  Or to additionally recompute the one-electron energies set {{TAG|ALGO|Eigenval}}.}}
== Electronic-minimization algorithms == == Electronic-minimization algorithms ==
For a [[Setting up an electronic minimization|self-consistent ground-state calculation]], {{TAG|ALGO}} selects how the orbitals are optimized at each electronic step. Each value corresponds to a setting of the lower-level tag {{TAG|IALGO}}. The algorithms fall into two groups (see the ''Class'' column): the [[Self-consistency cycle|self-consistency-cycle]] methods iterate the charge density with a [[:Category:Density mixing|charge-density mixer]], whereas the [[Direct optimization of the orbitals|direct-optimization]] methods minimize the energy functional directly, updating the density from the orbitals without a charge mixer. For a [[Setting up an electronic minimization|self-consistent ground-state calculation]], {{TAG|ALGO}} selects how the orbitals are optimized at each electronic step. Each value corresponds to a setting of the lower-level tag {{TAG|IALGO}}. The algorithms fall into two groups (see the ''Class'' column): the [[Self-consistency cycle|self-consistency-cycle]] methods iterate the charge density with a [[:Category:Density mixing|charge-density mixer]], whereas the [[Direct optimization of the orbitals|direct-optimization]] methods minimize the energy functional directly, updating the density from the orbitals without a charge mixer.
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| VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order. | VeryFast || [[RMM-DIIS]] || 48 || self-consistency cycle || Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order.
|- |-
| Conjugate / All || all-band conjugate gradient || 58 || direct optimization || Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG|ISEARCH|1}}). Appropriate choice for magnetic systems, potential-only methods and systems where {{TAG|ALGO|Normal}} failed. | Conjugate / All || all-band conjugate gradient || 58 || direct optimization || Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG|ISEARCH|1}}). Appropriate choice for magnetic systems and systems where {{TAG|ALGO|Normal}} failed.
|- |-
| Damped || damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals; useful for difficult systems. Combine with {{TAG|LDIAG|.FALSE.}} to conserve the initial orbital order. | Damped || damped molecular dynamics || 53 || direct optimization || Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG|TIME}} appropriately.
|- |-
| Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive, mainly for testing or when many empty states are required. | Exact || exact diagonalization || 90 || self-consistency cycle || Full diagonalization; expensive, mainly for testing or when many empty states are required.
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| None / Nothing || no orbital update || 2 || postprocessing || Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE|WAVECAR}} file). | None / Nothing || no orbital update || 2 || postprocessing || Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE|WAVECAR}} file).
|} |}
{{NB|warning|Only the iterative [[Self-consistency cycle|self-consistency-cycle]] minimizers support potential-only functionals/methods, e.g., {{TAG|METAGGA|MBJ}} or {{TAG|LSFBXC|True}}. This is because direct optimization relies on the gradient of the energy and not just the potential.}}
{{NB|tip|Except for 'None', 'Nothing', 'Exact', and 'Eigenval' (which must be spelled out), only the first letter determines the selected algorithm.}} {{NB|tip|Except for 'None', 'Nothing', 'Exact', and 'Eigenval' (which must be spelled out), only the first letter determines the selected algorithm.}}
Conjugate, Subrot, Eigenval, None, and Nothing are supported as of vasp.5.2.9. The "Old Fast"/"Old VeryFast" variants (also "of"/"fo" and "ov"/"vo") are available in vasp.6 and select the corresponding vasp.5 algorithms. Conjugate, Subrot, Eigenval, None, and Nothing are supported as of vasp.5.2.9. The "Old Fast"/"Old VeryFast" variants (also "of"/"fo" and "ov"/"vo") are available in vasp.6 and select the corresponding vasp.5 algorithms.
For more technical details, read {{TAG|IALGO}} and {{TAG|LDIAG}}.



== Recommendations == === Recommendations ===
* '''Most systems''': {{TAG|ALGO|Normal}} (blocked Davidson) is the most robust choice and the default. {{TAG|ALGO}}=Fast (Davidson followed by [[RMM-DIIS]]) is a faster alternative, well suited to [[:Category:Molecular dynamics|molecular dynamics]] and [[Structure optimization|ionic relaxations]]. * '''Most systems''': {{TAG|ALGO|Normal}} (blocked Davidson) is the most robust choice and the default.
* '''Large systems''': [[RMM-DIIS]] (Fast or VeryFast) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG|LREAL|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG|NELMDL}}) and is the least robust on its own. * '''Large systems''': [[RMM-DIIS]] (<code>Fast</code> or <code>VeryFast</code>) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG|LREAL|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG|NELMDL}}) and is the least robust on its own.
* '''Insulators, and Hartree–Fock / meta-GGA / [[:Category:Hybrid functionals|hybrid functionals]]''': The [[Direct optimization of the orbitals|direct optimizers]] {{TAG|ALGO|All}} (or <code>Conjugate</code>) are robust and recommended; use the improved line search ({{TAG|ISEARCH|1}}) and set {{TAG|NBANDS}} close to half the number of electrons. {{TAG|ALGO|VeryFast}} is '''not''' supported for hybrid functionals. * '''[[Magnetic materials]], [[DFT+U]], [[:Category:Exchange-correlation_functionals#Meta_generalized_gradient_approximation_(meta-GGA)|meta-GGA]], [[:Category:Exchange-correlation_functionals#Hartree-Fock_(HF)_and_hybrid_functionals|Hartree-Fock and hybrid functionals]]''': The [[Direct optimization of the orbitals|direct optimizers]] {{TAG|ALGO|All}} (or <code>Conjugate</code>) are more robust and recommended; use the improved line search ({{TAG|ISEARCH|1}}). {{TAG|ALGO|VeryFast}} is '''not''' supported for hybrid functionals.
* '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': use {{TAG|ALGO|Damped}} with an appropriate time step ({{TAG|TIME}}) and a somewhat larger {{TAG|NBANDS}}. * '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': You may try {{TAG|ALGO|Damped}} with an appropriate time step ({{TAG|TIME}}) and a somewhat larger {{TAG|NBANDS}}, if other algorithms fail.
* '''Potential-only meta-GGAs''' (e.g., {{TAG|METAGGA|MBJ}}): use {{TAG|ALGO|All}}. Because these functionals provide only a potential and no consistent total energy, the orbital conjugate-gradient algorithm is more stable than charge-density mixing — particularly in the presence of vacuum regions. Preconverge with PBE and restart from its {{FILE|WAVECAR}}, and raise {{TAG|NELM}} (convergence is slow); see [[METAGGA]]. * '''Potential-only functionals or methods''' (e.g., {{TAG|METAGGA|MBJ}} or {{TAG|LSFBXC}}): use {{TAG|ALGO|Normal}}. Because these functionals provide only a potential and no consistent total energy, the iterative [[Self-consistency cycle|self-consistency-cycle]] minimizers work by applying the Hamiltonian repeatedly without taking the expression of the energy into account.
* '''Charge sloshing''': prefer the mixing ([[Self-consistency cycle|self-consistency-cycle]]) algorithms (Normal or Fast) and tune the [[:Category:Density mixing|mixing tags]] ({{TAG|AMIX}}, {{TAG|BMIX}}, …); see [[Troubleshooting electronic convergence]]. For fast convergence of the self-consistency cycle, {{TAG|LMAXMIX}} must be set appropriately, e.g., {{TAG|LMAXMIX|6}} for systems with ''f'' electrons. * '''Elongated geometries, systems including vacuum, slabs, surfaces''': prefer the mixing ([[Self-consistency cycle|self-consistency-cycle]]) algorithms (<code>Normal</code> or <code>Fast</code>). These systems are prone to charge sloshing, which can be reduced by fine-tuning the [[:Category:Density mixing|mixing tags]] ({{TAG|AMIX}}, {{TAG|BMIX}}, …); see [[Troubleshooting electronic convergence]]. For fast convergence of the self-consistency cycle, {{TAG|LMAXMIX}} must be set appropriately, e.g., {{TAG|LMAXMIX|6}} for systems with ''f'' electrons.  
* '''Preparing many empty states''' (e.g., for [[GW calculations|GW]] or [[ACFDT/RPA calculations|RPA]]), run {{TAG|ALGO|Exact}} after a normal [[ground-state calculations|ground-state calculation]]. * '''Preparing many empty states''' (e.g., for [[GW calculations|GW]] or [[ACFDT/RPA calculations|RPA]]), run {{TAG|ALGO|Exact}} after a normal [[ground-state calculations|ground-state calculation]].
* '''Postprocessing from a {{FILE|WAVECAR}}''': {{TAG|ALGO|Eigenval}} recomputes one-electron energies and the [[:Category:Density of states|density of states]]; {{TAG|ALGO|None}} recomputes occupancies and the [[:Category:Density of states|density of states]]. * '''Postprocessing from a {{FILE|WAVECAR}}''': {{TAG|ALGO|Eigenval}} recomputes one-electron energies and the [[:Category:Density of states|density of states]]; {{TAG|ALGO|None}} recomputes occupancies and the [[:Category:Density of states|density of states]].
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  ...   ...



The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with {{TAG|NELMDL}} non-self-consistent blocked-Davidson sweeps at fixed density, so the first steps for {{TAG|ALGO|Fast}}, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>: The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with a delay ({{TAG|NELMDL}} non-self-consistent blocked-Davidson sweeps) at fixed density, so the first steps for {{TAG|ALGO|Fast}}, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>:
{| class="wikitable" {| class="wikitable"
! Label !! Algorithm ! Label !! Algorithm

← Older revision		Revision as of 09:13, 23 June 2026
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	Description: Selects the electronic-minimization algorithm and/or the many-body method:		Description: Selects the electronic-minimization algorithm and/or the many-body method:
	:::* [[#Electronic-minimization algorithms\|Electronic minimization]] (ground state)		:::* [[#Electronic-minimization algorithms\|Electronic minimization]] (ground state)
	:::** ''Self-consistency cycle'': Normal (default), Fast, VeryFast, Exact, Subrot		:::** ''Self-consistency cycle'': <code>Normal</code> (default), <code>Fast</code>, <code>VeryFast</code>, <code>Exact</code>, <code>Subrot</code>
	:::** ''Direct optimization'': All / Conjugate, Damped		:::** ''Direct optimization'': <code>All</code> / <code>Conjugate</code>, <code>Damped</code>
	:::** ''Postprocessing'': Eigenval, None / Nothing		:::** ''Postprocessing'': <code>Eigenval</code>, <code>None</code> / <code>Nothing</code>
	:::* [[#GWALGOS\|Response functions, GW, BSE, and ACFDT/RPA]]		:::* [[#GWALGOS\|Response functions, GW, BSE, and ACFDT/RPA]]
	:::** CHI, TDHF, BSE, Timeev, ACFDT / RPA, ACFDTR / RPAR, and CRPA		:::** <code>CHI</code>, <code>TDHF</code>, <code>BSE</code>, <code>Timeev</code>, <code>ACFDT</code> / <code>RPA</code>, <code>ACFDTR</code> / <code>RPAR</code>, and <code>CRPA</code>
	:::** ''GW variants'': EVGW0, EVGW, QPGW0, QPGW, GW0R, GWR, G0W0R, EVGW0R		:::** ''GW variants'': <code>EVGW0</code>, <code>EVGW</code>, <code>QPGW0</code>, <code>QPGW</code>, <code>GW0R</code>, <code>GWR</code>, <code>G0W0R</code>, <code>EVGW0R</code>
	----		----
	{{Available\|4.5}}		{{Available\|4.5}}
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	! {{TAG\|ALGO}} !! Algorithm !! {{TAG\|IALGO}} !! Class !! Notes		! {{TAG\|ALGO}} !! Algorithm !! {{TAG\|IALGO}} !! Class !! Notes
	\|-		\|-
	\| Normal ''(default)'' \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] \|\| 38 \|\| self-consistency cycle \|\| Robust default, recommended for most calculations.		\| <code>Normal</code> ''(default)'' \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] \|\| 38 \|\| self-consistency cycle \|\| Robust default, recommended for most calculations.
	\|-		\|-
	\| Fast \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + [[RMM-DIIS]] \|\| 68 \|\| self-consistency cycle \|\| Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). This setting is faster and cheaper per electronic step, but less robust and less reliable in the sense that it may diverge or cannot find the true minimum. Use to obtain a first estimate, but mind that orbitals (and hence forces, stress, etc.) may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.		\| <code>Fast</code> \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + [[RMM-DIIS]] \|\| 68 \|\| self-consistency cycle \|\| Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). This setting is faster and cheaper per electronic step, but less robust and less reliable in the sense that it may diverge or cannot find the true minimum. Use to obtain a first estimate, but mind that orbitals (and hence forces, stress, etc.) may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.
	\|-		\|-
	\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.		\| <code>VeryFast</code> \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select <code>Old VeryFast</code> for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.
	\|-		\|-
	\| Conjugate / All \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + all-band conjugate gradient \|\| 58 \|\| direct optimization \|\| Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG\|ISEARCH\|1}}). Appropriate choice for magnetic systems and systems where {{TAG\|ALGO\|Normal}} failed.		\| <code>Conjugate</code> / <code>All</code> \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + all-band conjugate gradient \|\| 58 \|\| direct optimization \|\| Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG\|ISEARCH\|1}}). Appropriate choice for magnetic systems and systems where {{TAG\|ALGO\|Normal}} failed.
	\|-		\|-
	\| Damped \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.		\| <code>Damped</code> \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.
	\|-		\|-
	\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.		\| <code>Exact</code> \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.
	\|-		\|-
	\| Subrot \|\| subspace rotation \|\| 4 \|\| self-consistency cycle \|\| Diagonalization within the subspace spanned by the current orbitals. Rarely used stand-alone.		\| <code>Subrot</code> \|\| subspace rotation \|\| 4 \|\| self-consistency cycle \|\| Diagonalization within the subspace spanned by the current orbitals. Rarely used stand-alone.
	\|-		\|-
	\| Eigenval \|\| recompute eigenvalues \|\| 3 \|\| postprocessing \|\| Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE\|WAVECAR}} file).		\| <code>Eigenval</code> \|\| recompute eigenvalues \|\| 3 \|\| postprocessing \|\| Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE\|WAVECAR}} file).
	\|-		\|-
	\| None / Nothing \|\| no orbital update \|\| 2 \|\| postprocessing \|\| Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE\|WAVECAR}} file).		\| <code>None</code> / <code>Nothing</code> \|\| no orbital update \|\| 2 \|\| postprocessing \|\| Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE\|WAVECAR}} file).
	\|}		\|}
	{{NB\|warning\|Only the iterative [[Self-consistency cycle\|self-consistency-cycle]] minimizers support potential-only functionals/methods, e.g., {{TAG\|METAGGA\|MBJ}} or {{TAG\|LSFBXC\|True}}. This is because direct optimization relies on the gradient of the energy and not just the potential.}}		{{NB\|warning\|Only the iterative [[Self-consistency cycle\|self-consistency-cycle]] minimizers support potential-only functionals/methods, e.g., {{TAG\|METAGGA\|MBJ}} or {{TAG\|LSFBXC\|True}}. This is because direct optimization relies on the gradient of the energy and not just the potential.}}
	{{NB\|tip\|Except for 'None', 'Nothing', 'Exact', and 'Eigenval' (which must be spelled out), only the first letter determines the selected algorithm.}}		{{NB\|tip\|Except for <code>None</code>, <code>Nothing</code>, <code>Exact</code>, and <code>Eigenval</code> (which must be spelled out), only the first letter determines the selected algorithm.}}
	Conjugate, Subrot, Eigenval, None, and Nothing are supported as of vasp.5.2.9. The "Old Fast"/"Old VeryFast" variants (also "of"/"fo" and "ov"/"vo") are available in vasp.6 and select the corresponding vasp.5 algorithms.		<code>Conjugate</code>, <code>Subrot</code>, <code>Eigenval</code>, <code>None</code>, and <code>Nothing</code> are supported as of vasp.5.2.9. The <code>Old Fast</code>/<code>Old VeryFast</code> variants (also <code>of</code>/<code>fo</code> and <code>ov</code>/<code>vo</code>) are available in vasp.6 and select the corresponding vasp.5 algorithms.
	For more technical details, read {{TAG\|IALGO}} and {{TAG\|LDIAG}}.		For more technical details, read {{TAG\|IALGO}} and {{TAG\|LDIAG}}.

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	...		...

	The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with a delay ({{TAG\|NELMDL}} non-self-consistent blocked-Davidson sweeps) at fixed density, so the first steps for ~~{{TAG\|ALGO\|~~Fast}}, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>:		The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with a delay ({{TAG\|NELMDL}} non-self-consistent blocked-Davidson sweeps) at fixed density, so the first steps for <code>Fast</code>, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>:
	{\| class="wikitable"		{\| class="wikitable"
	! Label !! Algorithm		! Label !! Algorithm
	\|-		\|-
	\| <code>DAV:</code> \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] ({{TAG\|IALGO}}=38; {{TAG\|ALGO}}=Normal and the initial phase of Fast, VeryFast, All and Damped)		\| <code>DAV:</code> \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] ({{TAG\|IALGO}}=38; {{TAG\|ALGO}}=Normal and the initial phase of <code>Fast</code>, <code>VeryFast</code>, <code>All</code> and <code>Damped</code>)
	\|-		\|-
	\| <code>RMM:</code> \|\| [[RMM-DIIS]] ({{TAG\|IALGO}}=48; {{TAG\|ALGO}}=VeryFast and the main phase of Fast)		\| <code>RMM:</code> \|\| [[RMM-DIIS]] ({{TAG\|IALGO}}=48; {{TAG\|ALGO}}=VeryFast and the main phase of <code>Fast</code>)
	\|-		\|-
	\| <code>SDA:</code> / <code>CGA:</code> \|\| steepest-descent / conjugate-gradient all-band step ({{TAG\|IALGO\|58}}; {{TAG\|ALGO}}=All or Conjugate)		\| <code>SDA:</code> / <code>CGA:</code> \|\| steepest-descent / conjugate-gradient all-band step ({{TAG\|IALGO\|58}}; {{TAG\|ALGO}}=All or <code>Conjugate</code>)
	\|-		\|-
	\| <code>DMP:</code> \|\| damped dynamics ({{TAG\|IALGO\|53}}; {{TAG\|ALGO\|Damped}})		\| <code>DMP:</code> \|\| damped dynamics ({{TAG\|IALGO\|53}}; {{TAG\|ALGO\|Damped}})

← Older revision		Revision as of 08:59, 23 June 2026
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	\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.		\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.
	\|-		\|-
	\| Conjugate / All \|\| all-band conjugate gradient \|\| 58 \|\| direct optimization \|\| Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG\|ISEARCH\|1}}). Appropriate choice for magnetic systems and systems where {{TAG\|ALGO\|Normal}} failed.		\| Conjugate / All \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + all-band conjugate gradient \|\| 58 \|\| direct optimization \|\| Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG\|ISEARCH\|1}}). Appropriate choice for magnetic systems and systems where {{TAG\|ALGO\|Normal}} failed.
	\|-		\|-
	\| Damped \|\| damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.		\| Damped \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.
	\|-		\|-
	\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.		\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.

← Older revision		Revision as of 08:53, 23 June 2026
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	\| Normal ''(default)'' \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] \|\| 38 \|\| self-consistency cycle \|\| Robust default, recommended for most calculations.		\| Normal ''(default)'' \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] \|\| 38 \|\| self-consistency cycle \|\| Robust default, recommended for most calculations.
	\|-		\|-
	\| Fast \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + [[RMM-DIIS]] \|\| 68 \|\| self-consistency cycle \|\| Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). ~~For easily converging systems, this~~ setting is faster and cheaper. ~~It is recommended for [[:Category:Molecular dynamics\|molecular dynamics]] and [[Structure optimization\|ionic relaxations]]~~ to obtain a first estimate, but orbitals and hence forces may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.		\| Fast \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + [[RMM-DIIS]] \|\| 68 \|\| self-consistency cycle \|\| Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). This setting is faster and cheaper per electronic step, but less robust and less reliable in the sense that it may diverge or cannot find the true minimum. Use to obtain a first estimate, but mind that orbitals (and hence forces, stress, etc.) may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.
	\|-		\|-
	\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.		\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.
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	\| Damped \|\| damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.		\| Damped \|\| damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.
	\|-		\|-
	\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive and memory-heavy~~, mainly~~ when many empty states are required or for testing.		\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive and memory-heavy. Use when many empty states are required (restarting from preconverged orbitals) or for testing.
	\|-		\|-
	\| Subrot \|\| subspace rotation \|\| 4 \|\| self-consistency cycle \|\| Diagonalization within the subspace spanned by the current orbitals.		\| Subrot \|\| subspace rotation \|\| 4 \|\| self-consistency cycle \|\| Diagonalization within the subspace spanned by the current orbitals. Rarely used stand-alone.
	\|-		\|-
	\| Eigenval \|\| recompute eigenvalues \|\| 3 \|\| postprocessing \|\| Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE\|WAVECAR}} file).		\| Eigenval \|\| recompute eigenvalues \|\| 3 \|\| postprocessing \|\| Recompute one-electron energies, the density of states, and selected postprocessing from fixed orbitals (e.g., read from the {{FILE\|WAVECAR}} file).

← Older revision		Revision as of 08:43, 23 June 2026
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	=== Recommendations ===		=== Recommendations ===
	* '''Most systems''': {{TAG\|ALGO\|Normal}} (blocked Davidson) is the most robust choice and the default.		* '''Most systems''': {{TAG\|ALGO\|Normal}} (blocked Davidson) is the most robust choice and the default.
	* '''Large systems''': [[RMM-DIIS]] (<code>Fast</code> or <code>VeryFast</code>) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG\|LREAL\|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG\|NELMDL}}) and is the least robust on its own.		* '''Large systems and molecular dynamics''': [[RMM-DIIS]] (<code>Fast</code> or <code>VeryFast</code>) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG\|LREAL\|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG\|NELMDL}}) and is the least robust on its own. For [[MD calculations]] and [[structure optimization]] or metals, also mind that barely occupied bands are less optimized ({{TAG\|WEIMIN}}).
	* '''[[Magnetic materials]], [[DFT+U]], [[:Category:Exchange-correlation_functionals#Meta_generalized_gradient_approximation_(meta-GGA)\|meta-GGA]], [[:Category:Exchange-correlation_functionals#Hartree-Fock_(HF)_and_hybrid_functionals\|Hartree-Fock and hybrid functionals]]''': The [[Direct optimization of the orbitals\|direct optimizers]] {{TAG\|ALGO\|All}} (or <code>Conjugate</code>) are more robust and recommended; use the improved line search ({{TAG\|ISEARCH\|1}}). {{TAG\|ALGO\|VeryFast}} is '''not''' supported for hybrid functionals.		* '''[[Magnetic materials]], [[DFT+U]], [[:Category:Exchange-correlation_functionals#Meta_generalized_gradient_approximation_(meta-GGA)\|meta-GGA]], [[:Category:Exchange-correlation_functionals#Hartree-Fock_(HF)_and_hybrid_functionals\|Hartree-Fock and hybrid functionals]]''': The [[Direct optimization of the orbitals\|direct optimizers]] {{TAG\|ALGO\|All}} (or <code>Conjugate</code>) are more robust and recommended; use the improved line search ({{TAG\|ISEARCH\|1}}). {{TAG\|ALGO\|VeryFast}} is '''not''' supported for hybrid functionals.
	* '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': You may try {{TAG\|ALGO\|Damped}} with an appropriate time step ({{TAG\|TIME}}) and a somewhat larger {{TAG\|NBANDS}}, if other algorithms fail.		* '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': You may try {{TAG\|ALGO\|Damped}} with an appropriate time step ({{TAG\|TIME}}) and a somewhat larger {{TAG\|NBANDS}}, if other algorithms fail.

← Older revision		Revision as of 08:39, 23 June 2026
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	\| Damped \|\| damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.		\| Damped \|\| damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.
	\|-		\|-
	\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive, mainly ~~for testing or~~ when many empty states are required.		\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive and memory-heavy, mainly when many empty states are required or for testing.
	\|-		\|-
	\| Subrot \|\| subspace rotation \|\| 4 \|\| self-consistency cycle \|\| Diagonalization within the subspace spanned by the current orbitals.		\| Subrot \|\| subspace rotation \|\| 4 \|\| self-consistency cycle \|\| Diagonalization within the subspace spanned by the current orbitals.

← Older revision		Revision as of 08:31, 23 June 2026
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	\| Normal ''(default)'' \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] \|\| 38 \|\| self-consistency cycle \|\| Robust default, recommended for most calculations.		\| Normal ''(default)'' \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] \|\| 38 \|\| self-consistency cycle \|\| Robust default, recommended for most calculations.
	\|-		\|-
	\| Fast \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + [[RMM-DIIS]] \|\| ~~38 / 48~~ \|\| self-consistency cycle \|\| Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). For easily converging systems, this setting is faster and cheaper. It is recommended for [[:Category:Molecular dynamics\|molecular dynamics]] and [[ionic relaxations]] to obtain a first estimate, but orbitals and hence forces may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.		\| Fast \|\| [[Blocked-Davidson algorithm\|blocked Davidson]] + [[RMM-DIIS]] \|\| 68 \|\| self-consistency cycle \|\| Davidson for the initial phase, then [[RMM-DIIS]]; one Davidson sweep per ionic step (except the first). For easily converging systems, this setting is faster and cheaper. It is recommended for [[:Category:Molecular dynamics\|molecular dynamics]] and [[Structure optimization\|ionic relaxations]] to obtain a first estimate, but orbitals and hence forces may be less accurate compared to <code>Normal</code> or <code>All</code>. Updated in vasp.6.0.0; select <code>Old Fast</code> for the vasp.5 version.
	\|-		\|-
	\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.		\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.

← Older revision		Revision as of 08:25, 23 June 2026
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	----		----
	{{Available\|4.5}}		{{Available\|4.5}}
	The {{TAG\|ALGO}} tag has two kinds of settings: For a ground-state calculation, it selects the [[#Electronic-minimization algorithms\|~~electronic~~-minimization ~~algorithm~~]]; that may be one of the self-consistency-cycle minimizers, the direct optimizers, or the postprocessing modes ~~(Eigenval, None)~~. For [[many-body perturbation theory]], it instead selects the [[#GWALGOS\|algorithm for response functions, the GW variant, BSE, time evolution, and ACFDT/RPA]]. The stopping criterion is set using {{TAG\|EDIFF}}~~, however we~~ recommend checking the [[#Output during the electronic minimization\|output during the electronic minimization]] as described below ~~in order~~ to judge convergence.		The {{TAG\|ALGO}} tag has two kinds of settings: For a ground-state calculation, it selects the '''electronic-minimization algorithm''' (see [[#Electronic-minimization algorithms\|Electronic-minimization algorithms]] section below); that may be one of the self-consistency-cycle minimizers, the direct optimizers, or the postprocessing modes. For [[many-body perturbation theory]], it instead selects the [[#GWALGOS\|algorithm for response functions, the GW variant, BSE, time evolution, and ACFDT/RPA]]. The stopping criterion is set using {{TAG\|EDIFF}} and {{TAG\|NELM}}. We recommend checking the [[#Output during the electronic minimization\|output during the electronic minimization]] as described below to judge the convergence.
	{{NB\|tip\|To recompute the density of states (DOS), obtain the projected DOS or carry out any postprocessing from existing orbitals (e.g., a {{FILE\|WAVECAR}} from a previous run) ''without'' re-optimizing them, set {{TAG\|ALGO\|None}}. Or to additionally recompute the one-electron energies set {{TAG\|ALGO\|Eigenval}}.}}		{{NB\|tip\|To recompute the density of states (DOS), obtain the projected DOS or carry out any postprocessing from existing orbitals (e.g., a {{FILE\|WAVECAR}} from a previous run) ''without'' re-optimizing them, set {{TAG\|NELM\|1}}, {{TAG\|LDIAG\|False}}, and {{TAG\|ALGO\|None}}. Or to additionally recompute the one-electron energies set {{TAG\|ALGO\|Eigenval}}.}}
	== Electronic-minimization algorithms ==		== Electronic-minimization algorithms ==
	For a [[Setting up an electronic minimization\|self-consistent ground-state calculation]], {{TAG\|ALGO}} selects how the orbitals are optimized at each electronic step. Each value corresponds to a setting of the lower-level tag {{TAG\|IALGO}}. The algorithms fall into two groups (see the ''Class'' column): the [[Self-consistency cycle\|self-consistency-cycle]] methods iterate the charge density with a [[:Category:Density mixing\|charge-density mixer]], whereas the [[Direct optimization of the orbitals\|direct-optimization]] methods minimize the energy functional directly, updating the density from the orbitals without a charge mixer.		For a [[Setting up an electronic minimization\|self-consistent ground-state calculation]], {{TAG\|ALGO}} selects how the orbitals are optimized at each electronic step. Each value corresponds to a setting of the lower-level tag {{TAG\|IALGO}}. The algorithms fall into two groups (see the ''Class'' column): the [[Self-consistency cycle\|self-consistency-cycle]] methods iterate the charge density with a [[:Category:Density mixing\|charge-density mixer]], whereas the [[Direct optimization of the orbitals\|direct-optimization]] methods minimize the energy functional directly, updating the density from the orbitals without a charge mixer.
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	\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.		\| VeryFast \|\| [[RMM-DIIS]] \|\| 48 \|\| self-consistency cycle \|\| Fewest Hamiltonian evaluations but least robust. Not supported for [[:Category:Hybrid functionals\|hybrid functionals]]. Updated in vasp.6; select "Old VeryFast" for the vasp.5 version. Combine with {{TAG\|LDIAG\|.FALSE.}} to conserve the initial orbital order.
	\|-		\|-
	\| Conjugate / All \|\| all-band conjugate gradient \|\| 58 \|\| direct optimization \|\| Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG\|ISEARCH\|1}}). Appropriate choice for magnetic systems~~, potential-only methods~~ and systems where {{TAG\|ALGO\|Normal}} failed.		\| Conjugate / All \|\| all-band conjugate gradient \|\| 58 \|\| direct optimization \|\| Simultaneous update of all orbitals. The two values are synonymous. Recommended together with the improved line-search algorithm ({{TAG\|ISEARCH\|1}}). Appropriate choice for magnetic systems and systems where {{TAG\|ALGO\|Normal}} failed.
	\|-		\|-
	\| Damped \|\| damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals~~; useful for difficult systems~~. ~~Combine with~~ {{TAG\|~~LDIAG\|.FALSE.~~}} ~~to conserve the initial orbital order~~.		\| Damped \|\| damped molecular dynamics \|\| 53 \|\| direct optimization \|\| Damped velocity-friction dynamics for the orbitals. Robustness and time-to-solution strongly depend on setting {{TAG\|TIME}} appropriately.
	\|-		\|-
	\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive, mainly for testing or when many empty states are required.		\| Exact \|\| exact diagonalization \|\| 90 \|\| self-consistency cycle \|\| Full diagonalization; expensive, mainly for testing or when many empty states are required.
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	\| None / Nothing \|\| no orbital update \|\| 2 \|\| postprocessing \|\| Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE\|WAVECAR}} file).		\| None / Nothing \|\| no orbital update \|\| 2 \|\| postprocessing \|\| Recompute the density of states or postprocessing from fixed orbitals ''and'' one-electron energies (e.g., read from the {{FILE\|WAVECAR}} file).
	\|}		\|}
			{{NB\|warning\|Only the iterative [[Self-consistency cycle\|self-consistency-cycle]] minimizers support potential-only functionals/methods, e.g., {{TAG\|METAGGA\|MBJ}} or {{TAG\|LSFBXC\|True}}. This is because direct optimization relies on the gradient of the energy and not just the potential.}}
	{{NB\|tip\|Except for 'None', 'Nothing', 'Exact', and 'Eigenval' (which must be spelled out), only the first letter determines the selected algorithm.}}		{{NB\|tip\|Except for 'None', 'Nothing', 'Exact', and 'Eigenval' (which must be spelled out), only the first letter determines the selected algorithm.}}
	Conjugate, Subrot, Eigenval, None, and Nothing are supported as of vasp.5.2.9. The "Old Fast"/"Old VeryFast" variants (also "of"/"fo" and "ov"/"vo") are available in vasp.6 and select the corresponding vasp.5 algorithms.		Conjugate, Subrot, Eigenval, None, and Nothing are supported as of vasp.5.2.9. The "Old Fast"/"Old VeryFast" variants (also "of"/"fo" and "ov"/"vo") are available in vasp.6 and select the corresponding vasp.5 algorithms.
			For more technical details, read {{TAG\|IALGO}} and {{TAG\|LDIAG}}.

	== Recommendations ==		=== Recommendations ===
	* '''Most systems''': {{TAG\|ALGO\|Normal}} (blocked Davidson) is the most robust choice and the default~~. {{TAG\|ALGO}}=Fast (Davidson followed by [[RMM-DIIS]]) is a faster alternative, well suited to [[:Category:Molecular dynamics\|molecular dynamics]] and [[Structure optimization\|ionic relaxations]]~~.		* '''Most systems''': {{TAG\|ALGO\|Normal}} (blocked Davidson) is the most robust choice and the default.
	* '''Large systems''': [[RMM-DIIS]] (Fast or VeryFast) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG\|LREAL\|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG\|NELMDL}}) and is the least robust on its own.		* '''Large systems''': [[RMM-DIIS]] (<code>Fast</code> or <code>VeryFast</code>) reduces the ''O''(''N''<sup>3</sup>) orthonormalization cost and is faster for large cells; combine with {{TAG\|LREAL\|Auto}}. VeryFast needs good initial orbitals (it uses a large {{TAG\|NELMDL}}) and is the least robust on its own.
	* '''~~Insulators~~, ~~and Hartree–Fock /~~ meta-GGA / [[:Category:~~Hybrid functionals~~\|hybrid functionals]]''': The [[Direct optimization of the orbitals\|direct optimizers]] {{TAG\|ALGO\|All}} (or <code>Conjugate</code>) are robust and recommended; use the improved line search ({{TAG\|ISEARCH\|1}}) ~~and set {{TAG\|NBANDS}} close to half the number of electrons~~. {{TAG\|ALGO\|VeryFast}} is '''not''' supported for hybrid functionals.		* '''[[Magnetic materials]], [[DFT+U]], [[:Category:Exchange-correlation_functionals#Meta_generalized_gradient_approximation_(meta-GGA)\|meta-GGA]], [[:Category:Exchange-correlation_functionals#Hartree-Fock_(HF)_and_hybrid_functionals\|Hartree-Fock and hybrid functionals]]''': The [[Direct optimization of the orbitals\|direct optimizers]] {{TAG\|ALGO\|All}} (or <code>Conjugate</code>) are more robust and recommended; use the improved line search ({{TAG\|ISEARCH\|1}}). {{TAG\|ALGO\|VeryFast}} is '''not''' supported for hybrid functionals.
	* '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': ~~use~~ {{TAG\|ALGO\|Damped}} with an appropriate time step ({{TAG\|TIME}}) and a somewhat larger {{TAG\|NBANDS}}.		* '''Metals or small-gap systems with Hartree–Fock / meta-GGA''': You may try {{TAG\|ALGO\|Damped}} with an appropriate time step ({{TAG\|TIME}}) and a somewhat larger {{TAG\|NBANDS}}, if other algorithms fail.
	* '''Potential-only ~~meta-GGAs~~''' (e.g., {{TAG\|METAGGA\|MBJ}}): use {{TAG\|ALGO\|~~All~~}}. Because these functionals provide only a potential and no consistent total energy, the ~~orbital conjugate~~-~~gradient algorithm is more stable than charge~~-~~density mixing — particularly in~~ the ~~presence~~ of ~~vacuum regions. Preconverge with PBE and restart from its {{FILE\|WAVECAR}}, and raise {{TAG\|NELM}} (convergence is slow); see [[METAGGA]]~~.		* '''Potential-only functionals or methods''' (e.g., {{TAG\|METAGGA\|MBJ}} or {{TAG\|LSFBXC}}): use {{TAG\|ALGO\|Normal}}. Because these functionals provide only a potential and no consistent total energy, the iterative [[Self-consistency cycle\|self-consistency-cycle]] minimizers work by applying the Hamiltonian repeatedly without taking the expression of the energy into account.
	* '''~~Charge sloshing~~''': prefer the mixing ([[Self-consistency cycle\|self-consistency-cycle]]) algorithms (Normal or Fast) ~~and tune~~ the [[:Category:Density mixing\|mixing tags]] ({{TAG\|AMIX}}, {{TAG\|BMIX}}, …); see [[Troubleshooting electronic convergence]]. For fast convergence of the self-consistency cycle, {{TAG\|LMAXMIX}} must be set appropriately, e.g., {{TAG\|LMAXMIX\|6}} for systems with ''f'' electrons.		* '''Elongated geometries, systems including vacuum, slabs, surfaces''': prefer the mixing ([[Self-consistency cycle\|self-consistency-cycle]]) algorithms (<code>Normal</code> or <code>Fast</code>). These systems are prone to charge sloshing, which can be reduced by fine-tuning the [[:Category:Density mixing\|mixing tags]] ({{TAG\|AMIX}}, {{TAG\|BMIX}}, …); see [[Troubleshooting electronic convergence]]. For fast convergence of the self-consistency cycle, {{TAG\|LMAXMIX}} must be set appropriately, e.g., {{TAG\|LMAXMIX\|6}} for systems with ''f'' electrons.
	* '''Preparing many empty states''' (e.g., for [[GW calculations\|GW]] or [[ACFDT/RPA calculations\|RPA]]), run {{TAG\|ALGO\|Exact}} after a normal [[ground-state calculations\|ground-state calculation]].		* '''Preparing many empty states''' (e.g., for [[GW calculations\|GW]] or [[ACFDT/RPA calculations\|RPA]]), run {{TAG\|ALGO\|Exact}} after a normal [[ground-state calculations\|ground-state calculation]].
	* '''Postprocessing from a {{FILE\|WAVECAR}}''': {{TAG\|ALGO\|Eigenval}} recomputes one-electron energies and the [[:Category:Density of states\|density of states]]; {{TAG\|ALGO\|None}} recomputes occupancies and the [[:Category:Density of states\|density of states]].		* '''Postprocessing from a {{FILE\|WAVECAR}}''': {{TAG\|ALGO\|Eigenval}} recomputes one-electron energies and the [[:Category:Density of states\|density of states]]; {{TAG\|ALGO\|None}} recomputes occupancies and the [[:Category:Density of states\|density of states]].
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	...		...

	The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with {{TAG\|NELMDL}} non-self-consistent blocked-Davidson sweeps at fixed density, so the first steps for {{TAG\|ALGO\|Fast}}, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>:		The leading label marks the algorithm (and phase) used in that step. SCF runs from scratch always begin with a delay ({{TAG\|NELMDL}} non-self-consistent blocked-Davidson sweeps) at fixed density, so the first steps for {{TAG\|ALGO\|Fast}}, <code>VeryFast</code>, <code>All</code>, <code>Damped</code> (and all steps for <code>Normal</code>) are labeled <code>DAV:</code>:
	{\| class="wikitable"		{\| class="wikitable"
	! Label !! Algorithm		! Label !! Algorithm