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##### Ridft, Rdgrad, Dscf, Grad / Re: scfdamp

« Last post by**uwe**on

*December 13, 2017, 11:07:36 am*»

Hello,

the number of included Fock matrices does not change. DIIS is done in the same manner, but how much of the DIIS predicted coefficients are added to the Fock matrix, which comes out of the usual SCF procedure, is determined by this damping factor. Instead of simply adding Fock + DIIS (in a symbolic way of notation), it is Fock + 1/[damping factor] * DIIS. Well, actually the denominator is (1+damping factor) to have full DIIS with a damping factor of zero...

Regards,

Uwe

Quote

So does the high value of $scfdamp mean that DIIS won't include a lot of old Fock matrices in creating the error

the number of included Fock matrices does not change. DIIS is done in the same manner, but how much of the DIIS predicted coefficients are added to the Fock matrix, which comes out of the usual SCF procedure, is determined by this damping factor. Instead of simply adding Fock + DIIS (in a symbolic way of notation), it is Fock + 1/[damping factor] * DIIS. Well, actually the denominator is (1+damping factor) to have full DIIS with a damping factor of zero...

Regards,

Uwe