ALGO

ALGO = Normal | VeryFast | Fast | Conjugate | All | Damped | Subrot | Eigenval | None | Nothing | CHI | | G0W0 | GW0 | GW | scGW0 | scGW | G0W0R | GW0R | GWR | scGW0R | scGWR | ACFDT | RPA | ACFDTR | RPAR | BSE | TDHF
Default: ALGO = Normal 

Description: the ALGO tag is a convenient option to specify the electronic minimisation algorithm (as of VASP.4.5) and/or to select the type of GW calculations.

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• ALGO=Normal selects IALGO=38 (blocked Davidson iteration scheme).

• ALGO=VeryFast selects IALGO=48 (RMM-DIIS).

• ALGO=Fast selects a faily robust mixture of the Davidson and RMM-DIIS algorithms. In this case, Davidson (IALGO=38) is used for the initial phase, and then VASP switches to RMM-DIIS (IALGO=48). Subsequencly, for each ionic update, one IALGO=38 sweep is performed for each ionic step (except the first one).

• ALGO=Conjugate or ALGO=All selects an "all band simultaneous update of orbitals" (IALGO=58, in both cases the same conjugate gradient algorithm is used).

• ALGO=Damped selects a damped velocity friction algorithm (IALGO=53).

• ALGO=Subrot selects subspace rotation or diagonalization in the sub-space spanned by the orbitals (IALGO=4).

• ALGO=Eigenval allows to recalculate one electron energies, density of state and perform selected postprocessing using the current orbitals (IALGO=3) e.g. read from the WAVECAR file.

• ALGO=None or ALGO=Nothing allows to recalculate the density of states or perform selected postprocessing, using the current orbitals and one electron energies (IALGO=2) e.g. read from the WAVECAR file.

Mind: except for 'None' and 'Nothing' (which must be spelled out), the first letter determines the applied algorithm. Conjugate, Subrot, Eigenval, None and Nothing are only supported by vasp.5.2.9 and newer versions.

ALGO for response functions and GW calculations and ACFDT/RPA calculations

Following tags are available as of VASP.5.X.

• ALGO=CHI calculates the response functions only.

• ALGO=TDHF selects TDHF calculations using the VASP internal Cassida code see BSE calculations, (available as of VASP.5.2.12)

• ALGO=BSE selects BSE calculations using the VASP internal Cassida code see BSE calculations

• ALGO=ACFDT selects RPA total energy calculations see ACFDT/RPA calculations

• ALGO=RPA synonymous to ACFDT see ACFDT/RPA calculations (available as of VASP.5.3.1)

GW tags have been renamed in VASP as follows

< 5.2.12	scGW	scGW0	GW	GW0	N/A	N/A
>= 5.2.12, < 6	QPGW	QPGW0	GW	GW0	N/A	N/A
>= 6	QPGW[R]	QPGW0[R]	EVGW[R]	EVGW0[R]	scGWR	scGW0R

• ALGO=EVGW0 selects single-shot G₀W₀ calculations or partially selfconsistent GW calculations. The orbitals (wavefunctions) of the previous groundstate calculations are maintained, and G0W0 calculations are performed. If NELM is set, several iterations are performed, and the QP energies are updated in the calculation of G (for details see EVGW0 calculations).

• ALGO=EVGW selects single-shot G₀W₀ calculations or partially selfconsistent GW calculations. The orbitals of the previous groundstate calculations are maintained, and G0W0 calculations are performed. If NELM is set, several iterations are performed, and the QP energies are updated in the calculation of G AND W (for details see EVGW calculations).

• ALGO=QPGW0 selects selfconsistent GW calculations including off-diagonal components of the selfenergy. A full update of the QP energies AND one electron orbitals is performed in the calculation of G only (for details see QPGW0 calculations).

• ALGO=QPGW selects selfconsistent GW calculations including off-diagonal components of the selfenergy. A full update of the QP energies AND one electron orbitals is performed in the calculations of G AND W (for details see QPGW calculations).

Following tags are available as of VASP.6

• ALGO=RPAR selects low scaling RPA total energy calculations

• ALGO=ACFTDR synonym for RPAR

• ALGO=QPGWR selects low scaling version of QPGW (for details see QPGW calculations)

• ALGO=QPGW0R selects low scaling version of QPGW0 (for details see QPGW0 calculations)

• ALGO=EVGWR selects low scaling version of EVGW (for details see EVGW calculations)

• ALGO=EVGW0R selects low scaling version of EVGW0 (for details see EVGW0 calculations)

• ALGO=scGWR selects self-consistent GW calculations. The Green's function and screened potential are updated using the corresponding Dyson equations (for detail see here for more details).

• ALGO=scGW0R selects self-consistent GW₀ calculations. Only the Green's function is updated as solution of the corresponding Dyson equation (for detail see here for more details).

Examples that use this tag

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