[CP2K-user] [CP2K:13372] Problem with geometry optimization using LS_SCF

Thomas Kühne tku... at gmail.com
Mon May 25 19:59:44 UTC 2020
Previous message (by thread): [CP2K-user] [CP2K:13369] Problem with geometry optimization using LS_SCF
Next message (by thread): [CP2K-user] Problem with geometry optimization using LS_SCF
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Dear Torstein, 

beside the advice by Fabian to reduce the numerical noise within the forces to improve 
the convergence of the geometry optimization, set EXTRAPOLATION_ORDER to 3 for 
consistency. Since the sign-method is an alternative to diagonalization, which is at variance 
to OT that is a direct minimization method (inspite the fact that the minimization steps 
are also called SCF iterations within CP2K!), the largest difference is due to the rather 
simplistic mixing. You may try to use DIIS acceleration (LS_DIIS T together with appropriate 
values for INI_DIIS & NMIXING) or BROYDEN_MIXING inside RHO_MIXING. 

Cheers, 
Thomas

> Am 25.05.2020 um 13:45 schrieb Torstein Fjermestad <tfjer... at gmail.com>:
> 
> Dear Thomas,
> 
> Thanks for your fast reply.
> I did not restart the Hessian matrix in test 3.
> The LS_SCF section with all default made explicit, you can see here:
> The complete input file is attached.
> Thanks
> 
> Regards,
> Torstein
> 
>      &LS_SCF
>        LS_DIIS  F
>        INI_DIIS  2
>        MAX_DIIS  4
>        NMIXING  2
>        EPS_DIIS     1.0000000000000001E-01
>        MAX_SCF  20
>        EPS_SCF     9.9999999999999995E-08
>        MIXING_FRACTION     4.5000000000000001E-01
>        EPS_FILTER     9.9999999999999995E-08
>        EPS_LANCZOS     1.0000000000000000E-03
>        MAX_ITER_LANCZOS  128
>        MU    -1.0000000000000001E-01
>        FIXED_MU  F
>        EXTRAPOLATION_ORDER  4
>        S_PRECONDITIONER  ATOMIC
>        PURIFICATION_METHOD  SIGN_MATRIX
>        DYNAMIC_THRESHOLD  F
>        NON_MONOTONIC  T
>        MATRIX_CLUSTER_TYPE  ATOMIC
>        SINGLE_PRECISION_MATRICES  F
>        RESTART_WRITE  F
>        RESTART_READ  F
>        S_INVERSION  SIGN_SQRT
>        SIGN_SQRT_ORDER  3
>        REPORT_ALL_SPARSITIES  T
>        PERFORM_MU_SCAN  F
>        CHECK_S_INV  F
>      &END LS_SCF
> 
> 
> mandag 25. mai 2020 12.58.48 UTC+2 skrev tkuehne følgende:
> Dear Torstein, 
> 
> apparently you are not exploiting the WF guess in your LS_SCF run, as you have guessed. 
> Without an input I can only speculate, but by default EXTRAPOLATION_ORDER is 4 within 
> LS_SCF and 3 for all other methods. Regarding test 3, did you also restart the Hessian matrix? 
> 
> Cheers, 
> Thomas
> 
>> Am 25.05.2020 um 12:34 schrieb Torstein Fjermestad <tf... at gmail.com <>>:
>> 
>> Dear all, 
>> 
>> First some background for my question:
>> I got computing hours on a cluster with GPUs. I did some tests with single point calculations, and I found that linear scaling SCF ran about 5 times faster than "normal" SCF for my system on that cluster. The total energy between SCF and LS_SCF differed only by about 0.04 kJ mol-1; and I therefore found the results encouraging. 
>> 
>> I then went on to compare LS_SCF and "normal" SCF for geometry optimizations on a machine without GPUs. I did three tests:
>> Test 1: Single point calculation
>> Test 2: Geometry optimization starting from the geometry in Test 1
>> Test 3: Geometry optimization starting from the optimized geometry in Test 2
>> 
>> I used the following keywords in the LS_SCF section. 
>> 
>> &LS_SCF
>>   EPS_FILTER 1.0E-7
>>   EPS_SCF    1.0E-7
>> &END
>> 
>> At the beginning of the attached output files the complete input is echoed. 
>> 
>> I now describe the results of the tests.
>> 
>> Test 1: Single point calculation. The total energy differs by 0.05 kJ mol-1
>> 
>> entry
>> Total energy/ Ha
>> wall time / s
>> LS_SCF?
>> 1
>> -3499.00767
>> 309
>> yes
>> 2
>> -3499.00768
>> 380
>> no
>> 
>> 
>> Test 2: Geometry optimization starting from the geometry in Test 1. SCF_GUESS ATOMIC is used 
>> 
>> entry
>> Total energy, first geom / Ha
>> max. grad of first step
>> # geometry steps
>> Total energy, optim geom / Ha
>> wall time, s
>> wall time / geom. step, s
>> LS_SCF?
>> 1
>> -3499.00767
>> 0.03493
>> 54
>> Did not converge within the requested wall time
>> 7260 a
>> 134
>> yes
>> 2
>> -3499.00769
>> 0.03613
>> 123
>> -3499.11153
>> 4386
>> 36
>> no
>> a Requested wall time in submit script
>> 
>> In Test 2, the wall time per geometry step is much longer when LS_SCF is used than when "normal" SCF is used. This is in spite of Test 1 showing that LS_SCF is notably faster for a single point calculation. 
>> Am I doing something wrong here?
>> Is the start guess of the wavefunction at each geometry step perhaps not adequate in the case of LS_SCF?
>> How should I change the LS_SCF parameters in order to improve the calculation?
>> 
>> Test 3: Re-optimization of the optimized structure in Test 2 (entry 2). SCF_GUESS ATOMIC is used 
>>  
>> entry
>> Total energy, first geom / Ha
>> max.grad of first step
>> # geometry steps
>> Total energy, optim geom / Ha
>> wall time
>> wall time / geom step
>> LS_SCF?
>> 1
>> -3499.11150
>> 0.00016
>> 1
>> -3499.11153
>> 396
>> 396
>> no
>> 2
>> -3499.11147
>> 0.00183
>> 19
>> Did not converge within the requested wall time
>> 7260a
>> 382
>> yes
>> a Requested wall time in submit script
>> 
>> Not unexpectedly, in Test 3,  the geometry optimization with "normal" SCF converges after 1 geometry step. 
>> However, the geometry optimization with LS_SCF did not converge within two hours and took only 19 geometry steps.
>> I see that the max. gradient of the first geometry step is much higher in the case of LS_SCF than in the case of "normal" SCF. 
>> Are there some LS_SCF parameters I should adjust to check if the gradient has converged?
>> 
>> I would really appreciate help in this matter, because in the current situation, I am not able to use LS_SCF for geometry optimizations. 
>> 
>> Thanks and regards,
>> Torstein Fjermestad
>> 
>>   
>> 
>>  
>> 
>> 
>> 
>> -- 
>> You received this message because you are subscribed to the Google Groups "cp2k" group.
>> To unsubscribe from this group and stop receiving emails from it, send an email to c... at googlegroups.com <>.
>> To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/432b51c8-1d61-491e-a235-cb81b77bd3a7%40googlegroups.com <https://groups.google.com/d/msgid/cp2k/432b51c8-1d61-491e-a235-cb81b77bd3a7%40googlegroups.com?utm_medium=email&utm_source=footer>.
>> <cp2k-forum-May25-2020.zip>
> 
> 
> 
> ==============================
> Thomas D. Kühne
> Dynamics of Condensed Matter
> Chair of Theoretical Chemistry
> University of Paderborn
> Warburger Str. 100
> D-33098 Paderborn
> Germany
> td... at mail.upb.de <>
> +49/(0)5251/60-5726
> 
> 
> -- 
> You received this message because you are subscribed to the Google Groups "cp2k" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to cp... at googlegroups.com <mailto:cp... at googlegroups.com>.
> To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/b88518c9-cfe4-4e9e-a465-c97ecb552942%40googlegroups.com <https://groups.google.com/d/msgid/cp2k/b88518c9-cfe4-4e9e-a465-c97ecb552942%40googlegroups.com?utm_medium=email&utm_source=footer>.
> <input-explicit.inp>



==============================
Thomas D. Kühne
Dynamics of Condensed Matter
Chair of Theoretical Chemistry
University of Paderborn
Warburger Str. 100
D-33098 Paderborn
Germany
tdku... at mail.upb.de
+49/(0)5251/60-5726

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20200525/2c2dafa0/attachment.htm>
Previous message (by thread): [CP2K-user] [CP2K:13369] Problem with geometry optimization using LS_SCF
Next message (by thread): [CP2K-user] Problem with geometry optimization using LS_SCF
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
More information about the CP2K-user mailing list