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# Restarts during perturbative corrections?

1 month 1 week ago #678 by Nike
Dear all,
I understand that if a job crashes during the perturbative corrections, then using rest=1 will mean MRCC goes back to the iterative step for 1 iteration, then starts the perturbative correction all the way from the beginning (spin case 1).

I have just had a job crash on "spin case 19" after about 22 days (32000 minutes) of calculations to do spin cases 1-18:
Perturbative corrections are calculated...
======================================================================
Spin case  1   Alpha:  2   Beta:  4
Number of excitations:        9674854
CPU time [min]: 18814.564                   Wall time [min]:  9849.788
======================================================================
Spin case  2   Alpha:  3   Beta:  3
Number of excitations:        53660880
CPU time [min]: 20286.653                   Wall time [min]: 10593.980
======================================================================
Spin case  3   Alpha:  4   Beta:  2
Number of excitations:        29030306
CPU time [min]: 21454.478                   Wall time [min]: 11180.785
======================================================================
Spin case  4   Alpha:  5   Beta:  1
Number of excitations:        1377072
CPU time [min]: 21644.188                   Wall time [min]: 11276.145
======================================================================
Spin case  5   Alpha:  2   Beta:  4
Number of excitations:        18634890
CPU time [min]: 22963.355                   Wall time [min]: 11946.315
======================================================================
Spin case  6   Alpha:  2   Beta:  4
Number of excitations:        41794692
CPU time [min]: 25978.119                   Wall time [min]: 13466.476
======================================================================
Spin case  7   Alpha:  3   Beta:  3
Number of excitations:        160982640
CPU time [min]: 31526.117                   Wall time [min]: 16290.082
======================================================================
Spin case  8   Alpha:  3   Beta:  3
Number of excitations:        167173416
CPU time [min]: 36412.186                   Wall time [min]: 18741.087
======================================================================
Spin case  9   Alpha:  4   Beta:  2
Number of excitations:        120744756
CPU time [min]: 41132.122                   Wall time [min]: 21124.516
======================================================================
Spin case 10   Alpha:  4   Beta:  2
Number of excitations:        58067420
CPU time [min]: 43282.776                   Wall time [min]: 22209.112
======================================================================
Spin case 11   Alpha:  5   Beta:  1
Number of excitations:        7463460
CPU time [min]: 44156.062                   Wall time [min]: 22646.983
======================================================================
Spin case 12   Alpha:  5   Beta:  1
Number of excitations:        1327932
CPU time [min]: 44337.005                   Wall time [min]: 22737.989
======================================================================
Spin case 13   Alpha:  2   Beta:  4
Number of excitations:        8318486
CPU time [min]: 44885.268                   Wall time [min]: 23013.016
======================================================================
Spin case 14   Alpha:  2   Beta:  4
Number of excitations:        80495544
CPU time [min]: 51382.765                   Wall time [min]: 26288.737
======================================================================
Spin case 15   Alpha:  2   Beta:  4
Number of excitations:        62686156
CPU time [min]: 55646.355                   Wall time [min]: 28444.712
======================================================================
Spin case 16   Alpha:  3   Beta:  3
Number of excitations:        149058000
CPU time [min]: 60427.369                   Wall time [min]: 30840.410
======================================================================
Spin case 17   Alpha:  3   Beta:  3
Number of excitations:        501528416
CPU time [min]: 77089.610                   Wall time [min]: 39213.258
======================================================================
Spin case 18   Alpha:  3   Beta:  3
Number of excitations:        160979568
CPU time [min]: 82699.806                   Wall time [min]: 42054.491
======================================================================
Spin case 19   Alpha:  4   Beta:  2
Number of excitations:        174126680

Fatal error in mrcc.
Program will stop.

************************ 2019-02-04 08:03:39 *************************
Error at the termination of mrcc.
**********************************************************************

I wonder if it's possible to make it so that we can save the results from spin cases 1-18, and then when we restart, just start with spin-case 19 immediately?

Also, I wonder if the energy contributions for each spin-case can be printed when the spin-case finishes?

The reason why is that I don't want to wait another 22 days to do spin-cases 1-18 all over again, and in the cases where there's only 19 spin-cases in total, then an estimate based on spin-cases 1-18 seems good enough. (of course ideally we'd do all 19 spin-cases, but if it means we have to restart from spin-case 1 and wait 22 days, we would rather just use the energy estimate coming from the first 18/19 spin cases).

Finally, is there an equation we can refer to in order to understand the different spin cases? I have looked at:

M. Kállay and J. Gauss (2008) Approximate treatment of higher excitations in coupled-cluster theory. II. Extension to general single-determinant reference functions and improved approaches for the canonical Hartree–Fock case. J. Chem. Phys. 129, pp. 144101, in the context of the notation in:

M. Kállay and J. Gauss (2005) Approximate treatment of higher excitations in coupled-cluster theory. J. Chem. Phys. 123, pp. 214105.

and:
Y. J. Bomble, J. F. Stanton, M. Kállay and J. Gauss (2005) Coupled cluster methods including non-iterative approximate quadruple excitation corrections. J. Chem. Phys. 123, pp. 054101.

I understand usually we only have 3 spin-cases and it becomes more spin-cases when we don't have enough RAM to do the 3 spin-cases fully, but what are the new spin-cases and how are they designed?

With best wishes!
Nike

1 month 1 week ago #679 by kallay
Dear Nike,
Unfortunately, it is not possible to restart the perturbative corrections.

Best regards,
Mihaly Kallay

3 weeks 6 days ago #681 by Nike
Dear Mihaly,
Is it at least possible to print out the energy contribution from each spin case? I have a case where 125 spin cases out of 127 completed, before the crash. The calculation took about 100 days. I started the calculation again, but if it crashes after 125 or 126 spin cases, I'd like to be able to add up the energy contributions from spin cases 1-125 as an "estimate" of what I would get with 127 spin cases.

With best wishes,
Nike