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Alex Granovsky
gran@classic.chem.msu.su

I've attached the complete input and output file for a very similar
job running using 16 physical cores of Intel(R) Xeon(R) E5-2630 v3-
based workstation. Please take a look at CPU/Wall clock times for
different stages.

Note, the MQCACI step is the only expensive stage that presently
runs using only a single core, and hence it can be rather slow.
This will be changed in future Firefly releases.

Conventional calculations with bigcas=1 would create huge disk files
and use several passes duplicating part of the work. Most likely they
would be more expensive than generator-direct ones. In addition, they require special I/O tuning options.


Hope this helps.

Best wishes,
Alex






On Wed Oct 18 '17 10:49pm, Dawid wrote
--------------------------------------
>Dear Alex,

>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
>----------------------------------------------
>>Dear Dawid,

>>very recently we have published a paper on fluorinated stilbenes

>>http://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
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>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

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