[Columbus] Columbus Digest, Vol 128, Issue 3
Thomas Mueller
th.mueller at fz-juelich.de
Thu Mar 27 06:19:38 EDT 2025
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On Wed, 26 Mar 2025, Aleksandr Zaichenko wrote:
Hi Aleksandr,
> Hi Thomas,
>
> I used the colinp script for generation of the CI inputs and didn't modify anything additionally in the ciudg inputs. It can mean
> that there is a bug in the preparations script generating inconsistent / not initialized input parameters or something is wrong in
> the cuidg memory management. I will try to use different computational parameters and let you know, if I will fix it.
>
try to change the number of frozen VOs and check.
> For the SOCI, my goal was to perform non-perturbative variational SOC initially (if I understand the given Columbus example with
> Eu1 correctly). For the test case I tried to generate (10,10,10,10) roots for the odd multiplicities and to perform this rassi
> like calculation, but unfortunately due to this memory allocation trouble I couldn't do it and tried to test just the ground state
> CI-calculation that failed too as you can see. I have taken into account that for the non-perturbative iterative SOC I have had to
> reduce problem size further, but the tests were failed, therefore I asked you about it. It is anyway important to have the CI-only
> calculation as basic non-correlated reference. Please let me know if I need to know anything about the calculations setup.
>
SO-CASCI is not rassi - it is missing some amount of electron
correlation included in rassi by expanding a model space defined
by a limited number of CASSCF wavefunctions and modifying the diagonal
elements by electron correlation energy estimated from different
calculations. This can have quite some effect on ordering and mixing
of the resulting Omega states. Perturbative SO-CI is useful for a
small or well-defined model space, but not so nicely applicable to
actinide dimers - also the rassi calculations by Roos on U2 might
be a bit shaky due to the limited model space size.
You need to do a symmetry analysis and symmetry correct MOs.
Eu+3 (f^6): in terms of LS states you have for the lowest states
^7F , ^5D, ^5L ^5G ^5H ^5I ^5F (roughly up to 5 eV, with the ground
state well separated); in total there are 119 different LS states
arising from the f^6 manyfold.
Adding SO interaction, the ground state will split up into
(L+S) .. |L-S| J= 6 ... 0 , i.e. 49 microstates in 7 energy levels.
In the worst case you will need to compute 49 roots in order to identify
the level symmetry. Converting the symmetry of the rotation-inversion
group into d2h then yields the decomposition of the 49 micro states
over the various irreps.
The complete f^6 manyfold decomposes into 295 distinct J energy levels
composed of 3003 micro states.
For the odd-electron case the number of micro states is doubled
while the number of distinct energy levels does not change.
> About this actinides ground state yes. It is a very non-trivial system, therefore we study it.
>
> PS. Is there a way to print-out/define the Omega quantum number of the SO states of the diatomic molecule?
>
No.
The symmetry analysis for a diatomic is analoguous to the atoms just with a lower
initial point group. So from the LS calculations you can already
estimate which omega states to expect and act correspondingly.
With anything having a higher symmetry than the point group actually
exploited there is a risk of missing states.
With weak bonding SO coupling, the vast number of near degenerate states
from the atoms is still not very much reduced;
Best,
Thomas
> Best,
> Aleksandr
>
> ср, 26 мар. 2025 г. в 15:42, Thomas Mueller <th.mueller at fz-juelich.de>:
> On Tue, 25 Mar 2025, Aleksandr Zaichenko wrote:
>
> AO-MO trafo is fine.
> DRT construction is fine
>
> The ci part may indicate some overflows probably because some
> variables are not initialized.
>
> I'd suspect that you created with this CASCI calculation a
> very special case which somehow crashes the memory management.
>
> What might be a good idea is to simply retain say the lowest
> two VOs and allow single and double excitations - this will
> increase your csf space by a factor of 4 - so no problem.
> This is a standard case and should work; then remove the
> doubles and check again, finally try the CASCI.
>
> SOCI with CASCI(20o,6e) is not easy.
> With actinides the ground state is not well-separated,
> so you will likely need all spin multiplicities
> (7,5,3,1). The basis set size is the same as for a
> determinant basis. 6e in 40 spin orbitals
> gives rise to 40*39*38*37*36*35/720 determinants
> (and in this case also CSFs).
> Also you will have to compute a (possibly large)
> number of roots. Symmetry would help a lot here.
>
> Thomas
>
>
>
>
> > Dear Thomas,
> >
> > Yes. It is weird in my opinion too. Initially I tried to compute the spin-orbit coupling in this active space and
> have encountered the problem, after
> > that I tried just to compute this septet ground state and met the same issue. I am not sure that the MCSCF is a good
> alternative for my case, however
> > I don't use the MR-CISD in parallel. I don't see any obvious problem in my calculation setups, moreover all beyond
> the active space is frozen and any
> > additional excitations are impossible. I can send you the logs or inputs or boths, if you want. Can I have something
> wrong with the installation or
> > something goes wrong in the program such as infinite loop arizing? I have really no idea how such memory demand can
> occur. Should I try something
> > else? This problem does not look good.
> >
> > Best,
> > Aleksandr
> >
> > вт, 25 мар. 2025 г. в 05:16, Thomas Mueller <th.mueller at fz-juelich.de>:
> > On Mon, 24 Mar 2025, Aleksandr Zaichenko via Columbus wrote:
> > Dear Aleksandr,
> >
> > this looks quite weird. There is no way to produce a 1.2 TB diagonal
> > integral file ( this would amount to a basis of
> > approx. sqrt(1.2*10**12/(8))=38*10**4 ).
> >
> > Since you have probably defined a reference space of 38760 CSFs,
> > the program should not try to use the standard dsyevx/dsyevd eigensolver
> > to extract the lowest root which would require (38760**2)*8 bytes of
> > memory plus say 20% overhead but instead use iterative reference space diagonalization.
> > The alternative is to just start from the unit vector with the smallest
> > diagonal matrix element - technically there is no difference.
> >
> > CASCI is not really the target of the MR-CISD code - although of course
> > one can use it. The only charming feature is that the iterative CASCI
> > calculation is parallel (provided it is switched on).
> >
> > BTW, for CASCI(20o,6e) without symmetry and S=0
> > the size of the CSF space should be
> > 379050 CSFs (= 21!/(3!18!) * 21!/(4!17!) * 1/21
> >
> > The alternative is to use the mcscf code, run a single macro iteration,
> > switch off orbital rotations (which ought also switch off the explicit
> > construction of the Hessian matrix components B,C and M) and set to
> > iterative solution of the CI problem. This should also force the AO-MO
> > trafo step to just compute the all-internal MOs.
> >
> > Beyond about 10**6 CSFs a CASCI calculation with MR-CISD is less
> > useful, since the formula tape construction is getting more and more
> > dominant and the matrix element construction is scalar (i.e. not fast
> > but with sufficient patience you can go to 10**9 CSFs - but imagine
> > running FCI with a general MR-CISD code is not that efficient).
> > The MCSCF code is somewhat better positioned regarding this special
> > application. Despite of all shortcomings DMRG (especially CheMPS2) does
> > a good job here.
> >
> > The documentation in $COLUMBUS/docs/fulldoc/ciudg.txt,
> > $COLUMBUS/docs/fulldoc/mcscf.txt hopefully clarifies the various
> > input options.
> >
> > Best,
> >
> > Thomas
> >
> >
> > > Dear Hans, Yes. Correct. It is the MR-CISD program. Excitations in the virtual space are 0, moreover all
> > > virtual orbitals as well as lower are frozen. The problem size from cidrtls is: total: 38760 and it seems
> > > correct. The growth of the memory
> > > Dear Hans,
> > >
> > > Yes. Correct. It is the MR-CISD program. Excitations in the virtual space are 0, moreover all virtual
> orbitals
> > > as well as lower are frozen.
> > >
> > > The problem size from cidrtls is:
> > >
> > > total: 38760
> > >
> > > and it seems correct. The growth of the memory demand occurs in the diagint file up to 1.2 Tb and
> calculation
> > > falls with SIGSEGV.
> > >
> > > It should not happen with the CI-problem of that dimension including only one root with SO, as I know. I can
> > > share listings, if you will need it.
> > >
> > > Best,
> > > Aleksandr
> > >
> > >
> > >
> > > On Mon, Mar 24, 2025 at 6:46 PM <columbus-request at lists.osc.edu> wrote:
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> > >
> > > Today's Topics:
> > >
> > > 1. CASCI extraordinary memory demand (Aleksandr Zaichenko)
> > > 2. Re: CASCI extraordinary memory demand (Hans Lischka)
> > >
> > >
> > > ----------------------------------------------------------------------
> > >
> > > Message: 1
> > > Date: Mon, 24 Mar 2025 15:36:14 -0400
> > > From: Aleksandr Zaichenko <alex.zai90 at gmail.com>
> > > To: columbus at lists.osc.edu
> > > Subject: [Columbus] CASCI extraordinary memory demand
> > > Message-ID:
> > > <CAAJgZKtK7jg7Vij3mJuNcCrShToEQrxkgJZfQ=BKkgUz6Qvc9A at mail.gmail.com>
> > > Content-Type: text/plain; charset="utf-8"
> > >
> > > Dear Columbus Team,
> > >
> > > I have a question about an ressources requirement issue with the CI module
> > > for the CASCI calculation. A calculation with active space CAS(6,20)
> > > without any external excitations (all lower orbitals are frozen, all higher
> > > orbitals are removed) contains 38760 CI-vectors (as should be) and I should
> > > get an CI-only solution for only one first root. Most QC programs do this
> > > calculation without any problem, but the Columbus CI module requires more
> > > than 1 Tb memory for that and it seems very demanding. Why is it so? Do I
> > > understand correctly, that the program tries to construct a full-CI problem
> > > for all of the 38760 roots despite 1 root being required?
> > >
> > > Best,
> > > Aleksandr
> > > -------------- next part --------------
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> > >
> > > ------------------------------
> > >
> > > Message: 2
> > > Date: Mon, 24 Mar 2025 17:45:30 -0500
> > > From: Hans Lischka <hans.lischka at univie.ac.at>
> > > To: columbus at lists.osc.edu
> > > Subject: Re: [Columbus] CASCI extraordinary memory demand
> > > Message-ID: <bc527a53-1a8d-4bea-b08a-30e2d1f800d1 at univie.ac.at>
> > > Content-Type: text/plain; charset="utf-8"; Format="flowed"
> > >
> > > Hi Aleksandr,
> > > I am not sure what kind of calculation you really did. The CI module is
> > > meant to do a MR-CISD calculation. I assume you took the CAS(6,20) as
> > > reference? How did you proceed further? The CI program will want to
> > > create all SD excitation from the 38760 configurations. Did you opt for
> > > that? This would explaining the 1TB of memory required. Look into the
> > > cidrtls file. There you will see the CI dimension. If you want the CASCI
> > > calculation you should input zero excitations (into the virtual space).
> > > Please let e know what you did.
> > > Best regards, Hans
> > >
> > > On 3/24/2025 2:36 PM, Aleksandr Zaichenko via Columbus wrote:
> > > > Dear Columbus Team, I have a question about an ressources requirement
> > > > issue with the CI module for the CASCI calculation. A calculation with
> > > > active space CAS(6,20) without any external excitations (all lower
> > > > orbitals are frozen, all higher orbitals
> > > > Dear Columbus Team,
> > > >
> > > > I have a question about an ressources requirement issue with the CI
> > > > module for the CASCI calculation. A calculation with active space
> > > > CAS(6,20) without any external excitations (all lower orbitals are
> > > > frozen, all higher orbitals are removed) contains 38760 CI-vectors (as
> > > > should be) and I should get an CI-only solution for only one first
> > > > root. Most QC programs do this calculation without any problem, but
> > > > the Columbus CI module requires more than 1 Tb memory for that and it
> > > > seems very demanding. Why is it so? Do I understand correctly, that
> > > > the program tries to construct a full-CI problem for all of the 38760
> > > > roots despite 1 root being required?
> > > >
> > > > Best,
> > > > Aleksandr
> > > >
> > > > _______________________________________________
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> > > > Columbus at lists.osc.edu
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> > > ------------------------------
> > >
> > > End of Columbus Digest, Vol 128, Issue 3
> > > ****************************************
> > >
> > >
> > >
> >
> > -----------------------------------------------------------
> > Dr. Thomas Mueller
> > Institute for Advanced Simulation (IAS)
> > Juelich Supercomputing Centre (JSC)
> >
> > Phone: +49-2461-61-3175
> > Fax: +49-2461-61-6656
> > E-mail: th.mueller at fz-juelich.de
> > WWW: https://urldefense.com/v3/__http://www.fz-juelich.de/jsc__;!!KGKeukY!yT6aPWGn6o2j3X6fY3LOrgMjljwmM9-PMmPEijedR3qACoaj1cvhuk8d6X6geCgiMedmg2JY0cyoj6qlZFon7DlueOcfvKY$
> >
> > JSC is the coordinator of the
> > John von Neumann Institute for Computing (NIC)
> > and member of the
> > Gauss Centre for Supercomputing (GCS)
> > -----------------------------------------------------------
> >
> >
> >
>
> -----------------------------------------------------------
> Dr. Thomas Mueller
> Institute for Advanced Simulation (IAS)
> Juelich Supercomputing Centre (JSC)
>
> Phone: +49-2461-61-3175
> Fax: +49-2461-61-6656
> E-mail: th.mueller at fz-juelich.de
> WWW: https://urldefense.com/v3/__http://www.fz-juelich.de/jsc__;!!KGKeukY!yT6aPWGn6o2j3X6fY3LOrgMjljwmM9-PMmPEijedR3qACoaj1cvhuk8d6X6geCgiMedmg2JY0cyoj6qlZFon7DlueOcfvKY$
>
> JSC is the coordinator of the
> John von Neumann Institute for Computing (NIC)
> and member of the
> Gauss Centre for Supercomputing (GCS)
> -----------------------------------------------------------
>
>
>
-----------------------------------------------------------
Dr. Thomas Mueller
Institute for Advanced Simulation (IAS)
Juelich Supercomputing Centre (JSC)
Phone: +49-2461-61-3175
Fax: +49-2461-61-6656
E-mail: th.mueller at fz-juelich.de
WWW: https://urldefense.com/v3/__http://www.fz-juelich.de/jsc__;!!KGKeukY!yT6aPWGn6o2j3X6fY3LOrgMjljwmM9-PMmPEijedR3qACoaj1cvhuk8d6X6geCgiMedmg2JY0cyoj6qlZFon7DlueOcfvKY$
JSC is the coordinator of the
John von Neumann Institute for Computing (NIC)
and member of the
Gauss Centre for Supercomputing (GCS)
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