# SCREENING

References: Guidon2008, Guidon2009

Sets up screening parameters if requested [Edit on GitHub]

## Keywords

- EPS_SCHWARZ

- EPS_SCHWARZ_FORCES

- P_SCREEN_CORRECTION_FACTOR

- SCREEN_ON_INITIAL_P

- SCREEN_P_FORCES

## Keyword descriptions

EPS_SCHWARZ: real = 1.00000000E-010

  Usage: EPS_SCHWARZ 1.0E-6

  Screens the near field part of the electronic repulsion integrals using the Schwarz inequality for the given threshold. [Edit on GitHub]

EPS_SCHWARZ_FORCES: real = 1.00000000E-006

  Usage: EPS_SCHWARZ_FORCES 1.0E-5

  Screens the near field part of the electronic repulsion integrals using the Schwarz inequality for the given threshold. This will be approximately the accuracy of the forces, and should normally be similar to EPS_SCF. Default value is 100*EPS_SCHWARZ. [Edit on GitHub]

P_SCREEN_CORRECTION_FACTOR: real = 0.00000000E+000

  Usage: P_SCREEN_CORRECTION_FACTOR 0.0_dp

  Recalculates integrals on the fly if the actual density matrix is larger by a given factor than the initial one. If the factor is set to 0.0_dp, this feature is disabled. [Edit on GitHub]

SCREEN_ON_INITIAL_P: logical = F

  Usage: SCREEN_ON_INITIAL_P TRUE

  Screen on an initial density matrix. For the first MD step this matrix must be provided by a Restart File. [Edit on GitHub]

SCREEN_P_FORCES: logical = T

  Usage: SCREEN_P_FORCES TRUE

  Screens the electronic repulsion integrals for the forces using the density matrix. Will be disabled for the response part of forces in MP2/RPA/TDDFT. This results in a significant speedup for large systems, but might require a somewhat tigher EPS_SCHWARZ_FORCES. [Edit on GitHub]