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Dawid
dawid.grabarek@pwr.edu.pl

Thank you for your suggestion with $MCQGENS group. In fact, now I
can do my check run without errors so hopefully I will manage to
perform these calculations. Could you roughly estimate the computational
cost increase due to using the same options in $MCQGENS as in
your input compared to the default ones, please?

Best wishes,
Dawid

On Wed Oct 18 '17 7:16pm, Alex Granovsky wrote
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>Dear Dawid,

>very recently we have published a paper on fluorinated stilbenes

>http://pubs.acs.org/doi/pdf/10.1021/jacs.7b09611http://pubs.acs.org/doi/pdf/10.1021/jacs.7b09611

>where we performed lots of XMCQDPT2/CAS(14,14) computations.

>The most efficient and less memory-consuming way to perform such
>computations with current Firefly is to use generators-direct code.

>I'm attaching a part of a typical input file we used.
>
>
>As to bigcas option and MQLMB2 memory demands, MQLMB2 allocates
>memory using several sequential calls to memory management routines,
>not a single call; This explains the behavior you are observing.

>Hope this helps.

>Kind regards,
>Alex Granovsky
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>On Mon Oct 16 '17 1:03pm, Dawid wrote
>-------------------------------------
>>Dear Firefly Users,

>>I want to perform XMCQDPT2 single-point calculations with
>>CAS(14,14), i.e. very large CAS. I encounter numerous issues
>>with memory. I have used
>>$XMCQDPT2
>>bigcas=1
>>.
>>.
>>.
>>$END

>>to largely reduce memory requirements but it is still not enough.
>>Now, I noticed that if I use  either mwords=300 or mwords=320,
>>I get following errors:
>> ********** ROUTINE MQLMB2 (   1) ***************************************
>> ***** ERROR: MEMORY REQUEST EXCEEDS MAXIMUM.
>>   301512972 WORDS REQUIRED    300000000 AVAILABLE.

>> ADDRESS 0x093F7B87 HAS INITIATED PROGRAM ABORT BECAUSE OF FATAL ERROR(S)
>>
>>
>>OR
>>
>>
>> ********** ROUTINE MQLMB2 (   1) ***************************************
>> ***** ERROR: MEMORY REQUEST EXCEEDS MAXIMUM.
>>   367923267 WORDS REQUIRED    320000000 AVAILABLE.

>> ADDRESS 0x603D7B87 HAS INITIATED PROGRAM ABORT BECAUSE OF FATAL ERROR(S)
>>
>>
>>So why do I have greater requirements when I give more?
>>By the way, what can I do to decreases needed memory?
>>I provide essential parts of input (I think so):

>> $SMP
>>  np=4
>>  httnp=1
>>  smppar=.TRUE.
>> $END

>> $SYSTEM
>>  mwords=300
>>  timlim=36000
>> $END

>> $XMCQDPT
>>  bigcas=1
>>  inorb=1
>>  nstate=15
>>  wstate(1)=1,1,1,1
>>  edshft=0.02
>>  mxbase=30
>>  halloc=.TRUE.
>>  thrgen=1d-20
>>  genzro=1d-20
>>  threri=1.0d-20
>>  thrcon=1d-8
>> $END

>>Best wishes,
>>Dawid