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Re^3: Speeding up ALTTRF during XMCQDPT2 calculations

Thomas
thomaspijper@hotmail.com

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


On Sun Sep 16 '12 4:49pm, Alex Granovsky wrote
----------------------------------------------
>Dear Thom,

>>Finally, with Firefly v. 8.0.0 it is possible to get rid of the
>>first MQCACI and integral transformation procedures for some types
>>of XMCQDPT2 jobs. These types are, however, the most typically
>>used ones. I'll document this in my next post to this thread.

>Assume the averaging is exactly the same in both SA-CASSCF and
>XMCQDPT2 procedures i.e. the weights defined by the WSTATE arrays
>are the exactly the same and refer to the same states. Provided
>this is indeed the case, one can avoid the first integral transformation
>and CASCI procedure (performed by the routine MQCACI) by overlapping
>part of calculations with those performed at the MCSCF stage and
>reusing them at XMCQDPT2 stage.

>To use this feature, one needs to direct MCSCF code to form
>semi-canonical Fock orbitals and to save core and active Fock
>operators. This can be done as follows:

>

 $mcscf iforb=.t. $end

>One also needs to instruct QDPT code to reuse this information:

>

 $xmcqdpt iforb(1)=-1,1,1 $end

>This will do the trick.  

>Kind regards,
>Alex

>

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