IBSE

IBSE = 0 | 1 | 2 | 3
Default: IBSE = 2 

Description: IBSE can be used to select the algorithm for solving the Bethe-Salpeter or Casida equation.

---

The following options are available to solve the Bethe-Salpeter or Casida equation:

• IBSE = 0: Exact diagonalization with old BSE driver
• IBSE = 1: Time evolution
• IBSE = 2: Exact diagonalization
• IBSE = 3: Lanczos algorithm

IBSE = 2 and IBSE = 0 yield exactly the same results but the old driver (IBSE = 0) is typically much slower.

Mind: IBSE = 2 and IBSE = 3 only available for VASP version 6.5.0 and above.

Related tag and articles

IBSE, BSEPREC, NBANDSV, NBANDSO, CSHIFT, OMEGAMAX, BSE calculations, Time-dependent density-functional theory calculations, Bethe-Salpeter equations