BSEPREC

BSEPREC = Low | Medium | High | Accurate
Default: BSEPREC = Medium

Description: BSEPREC determines the precision for the time-evolution calculation in BSE and TDDFT, i.e., the step size and the number of steps.

The timestep in the time-evolution calculation is inversely proportional to the maximum transition energy OMEGAMAX and the number of steps is inversely proportional to the broadening CSHIFT. To make the algorithm sufficiently stable these parameters are scaled depending on the precision tag BSEPREC.

BSEPREC	OMEGAMAX	CSHIFT
Accurate (a)	×4	×10
High (h)	×3	×7.5
Medium (m)	×2.5	×6.25
Low (l)	×2	×5

For example, the number of steps for BSEPREC = Low is <math>N_{\rm steps}=\frac{OMEGAMAXx2}{CSHIFTx5}

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