ALGO: Difference between revisions

Revision as of 10:26, 26 September 2017

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.

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

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

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

ALGO=ACFDT synonymous to RPA, selects RPA total energy calculations see ACFDT/RPA calculations

GW tags have been renamed in VASP.6. as follows

VASP.5.X	scGW	scGW0	GW	GW0
VASP.6	QPGW	QPGW0	EVGW	EVGW0

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 GW0 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 GW 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 scGW0 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 scGW 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

ALGO=QPGW0R selects low scaling version of QPGW0

ALGO=EVGWR selects low scaling version of EVGW

ALGO=EVGW0R selects low scaling version of EVGW0

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 GW 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

Contents

@@ Line 23: / Line 23: @@
 <span id="GWALGOS">
 ==ALGO for response functions and [[GW calculations]] and [[ACFDT/RPA calculations]]==
+Following tags are available as of VASP.5.X.
 *{{TAG|ALGO}}=CHI calculates the response functions only.
-*{{TAG|ALGO}}=GW0 selects single-shot ''G''<sub>0</sub>''W''<sub>0</sub> calculations or partially selfconsistent ''GW'' calculations. The orbitals (wavefunctions) of the previous groundstate calculations are maintained, and [[GW recipes#g0w0|G0W0 calculations]] are performed. If {{TAG|NELM}} is set, several iterations are performed, and the QP energies are updated in the calculation of ''G'' (for details see [[GW recipes#gw0|GW0 calculations]]).
+*{{TAG|ALGO}}=TDHF selects TDHF calculations using the VASP internal Cassida code see [[BSE calculations]]
+*{{TAG|ALGO}}=BSE selects BSE calculations using the VASP internal Cassida code see [[BSE calculations]]
+*{{TAG|ALGO}}=RPA selects RPA total energy calculations see [[ACFDT/RPA calculations]]
+*{{TAG|ALGO}}=ACFDT synonymous to RPA, selects RPA total energy calculations see [[ACFDT/RPA calculations]]
+GW tags have been renamed in VASP.6. as follows
+<span id="ALGO_VASP6">
+{| class="wikitable"
+|-
+! VASP.5.X
+| scGW
+| scGW0
+| GW
+| GW0
+|-
+! VASP.6
+| QPGW
+| QPGW0
+| EVGW
+| EVGW0
+|}
+</span>
+*{{TAG|ALGO}}=EVGW0 selects single-shot ''G''<sub>0</sub>''W''<sub>0</sub> calculations or partially selfconsistent ''GW'' calculations. The orbitals (wavefunctions) of the previous groundstate calculations are maintained, and [[GW recipes#g0w0|G0W0 calculations]] are performed. If {{TAG|NELM}} is set, several iterations are performed, and the QP energies are updated in the calculation of ''G'' (for details see [[GW recipes#gw0|GW0 calculations]]).
+*{{TAG|ALGO}}=EVGW selects single-shot ''G''<sub>0</sub>''W''<sub>0</sub> calculations or partially selfconsistent ''GW'' calculations. The orbitals of the previous groundstate calculations are maintained, and [[GW recipes#g0w0|G0W0 calculations]] are performed. If {{TAG|NELM}} is set, several iterations are performed, and the QP energies are updated in the calculation of ''G'' AND ''W'' (for details see [[GW recipes#gw0|GW calculations]]).
+*{{TAG|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 [[GW recipes#scgw|scGW0 calculations]]).
+*{{TAG|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 [[GW recipes#scgw|scGW calculations]]).
-*{{TAG|ALGO}}=G0W0 selects single-shot ''G''<sub>0</sub>''W''<sub>0</sub> calculations. This flag is really   	superfluous, since the same behavior can be achieved by performing a single GW0 or GW step ({{TAG|NELM}}=1).
+Following tags are available as of VASP.6
-*{{TAG|ALGO}}=GW selects single-shot ''G''<sub>0</sub>''W''<sub>0</sub> calculations or partially selfconsistent ''GW'' calculations. The orbitals of the previous groundstate calculations are maintained, and [[GW recipes#g0w0|G0W0 calculations]] are performed. If {{TAG|NELM}} is set, several iterations are performed, and the QP energies are updated in the calculation of ''G'' AND ''W'' (for details see [[GW recipes#gw0|GW calculations]]).
+*{{TAG|ALGO}}=RPAR selects low scaling RPA total energy calculations
-*{{TAG|ALGO}}=scGW0 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 [[GW recipes#scgw|scGW0 calculations]]).
+*{{TAG|ALGO}}=ACFTDR synonym for RPAR
-*{{TAG|ALGO}}=scGW 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 [[GW recipes#scgw|scGW calculations]]).
+*{{TAG|ALGO}}=QPGWR selects low scaling version of ''QPGW''
-*{{TAG|ALGO}}=G0W0R, GW0R, GWR, scGW0R, scGWR selects low scaling GW calculations see [[Low scaling ACFDT/RPA and GW algorithms]]
+*{{TAG|ALGO}}=QPGW0R selects low scaling version of ''QPGW0''
-*{{TAG|ALGO}}=RPA selects RPA total energy calculations see [[ACFDT/RPA calculations]]
+*{{TAG|ALGO}}=EVGWR selects low scaling version of ''EVGW''
-*{{TAG|ALGO}}=ACFDT synonymous to RPA, selects RPA total energy calculations see [[ACFDT/RPA calculations]]
+*{{TAG|ALGO}}=EVGW0R selects low scaling version of ''EVGW0''
-*{{TAG|ALGO}}=RPAR, ACFDTR selects low scaling RPA total energy calculations see [[Low scaling ACFDT/RPA and GW algorithms]]
+*{{TAG|ALGO}}=scGWR selects self-consistent GW calculations. The Green's function and screened potential are updated using the corresponding Dyson equations (for detail see [[GW cacluations#scGW|here]] for more details).
-*{{TAG|ALGO}}=TDHF selects TDHF calculations using the VASP internal Cassida code see [[BSE calculations]]
+*{{TAG|ALGO}}=scGW0R selects self-consistent GW calculations. Only the Green's function is updated as solution of the corresponding Dyson equation (for detail see [[GW cacluations#scGW|here]] for more details).
-*{{TAG|ALGO}}=BSE selects BSE calculations using the VASP internal Cassida code see [[BSE calculations]]
 </span>