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Re^4: Speeding up ALTTRF during XMCQDPT2 calculations

Alex Granovsky
gran@classic.chem.msu.su

Dear Thom,

On Sun Sep 16 '12 7:57pm, Thomas wrote
--------------------------------------
>Dear Alex,

>Thank you for this information. I'll try if parallel execution will improve performance.

>I have one question regarding skipping the MQCACI step. Normally, I run the MCSCF part in parallel with 

$CONTRL WIDE=.T. $END
to punch orbitals with extra accuracy, and then do the XMCQDPT2 part separately in multithreading mode with 
$MXQDPT INORB=2 $END
to read in the converged orbitals and skip the MCSCF step. Am I correct in assuming that in this scenario it is not possible to skip the MQCACI step?
>
>
>Kind regards,
>Thom

It is still possible to avoid first MQCACI this way, although the way I described before is a bit more economical.

To avoid first MQCACI procedure, add the following to the input
file for the MCSCF stage:

 $contrl wide=.t. $end
! The sd=.t. option should be used to preserve the exact symmetry
! of MCSCF orbitals during various transformations e.g. generation 
! of natural orbitals or Fock orbitals
 $mcscf iforb=.t. sd=.t. $end

Upon completion, extract all OPTIMIZED MOs and then moread all of them, including virtual ones in the input for the subsequent XMCQDPT stage.
In addition, add the following to the XMCQDPT input:

 $xmcqdpt inorb=2 iforb=0 $end

Kind regards,
Alex



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