Note

This website is presently under development. The primary website for MOPAC is still http://openmopac.net until the majority of its contents have been migrated here.

IUPD

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IUPD is used only in the EF routine. IUPD should very rarely be touched. IUPD controls how the Hessian is updated. Values for IUPD are 0: skip the update; 1: Use Powell’s method; 2: use the BFGS update. For more information, see Description of EF and TS.