[CP2K-user] [CP2K:13330] GEO_OPT a molecular is 10000 time longer then gaussian

[Linfeng Gan]

Hi Thomas,
Thanks your advice.

Best,
Linfeng

On Monday, May 18, 2020 at 4:03:44 PM UTC+8, tkuehne wrote:
>
> Dear Linfeng, 
>
> a couple of comments. Setting EPS_SCF to ridiculous low values below 1E-8 
> makes no sense - you are basically „optimizing“ noise. 
> Using OT, for a geo_opt EPS_SCF 1E-7 should be fine but you should also 
> set EPS_DEFAULT to 1E-12. Also setting all MAX_* and 
> RMS_* values to 1E-4 is a rather stringent criterion, I typically go with 
> 1/3 of the default values, i.e. 
>
> MAX_DR 1E-3
> MAX_FORCE 1.5E-4
> RMS_DR 5E-4
> RMS_FORCE 1E-4
>
> Lastly, within CP2K LBFGS is typically faster converging than BFGS, though 
> slightly less intuitive in its usage. 
>
> Cheers, 
> Thomas
>
> Am 18.05.2020 um 09:45 schrieb Linfeng Gan <li... at gmail.com 
> <javascript:>>:
>
> Here is the result.
>
>
> On Monday, May 18, 2020 at 8:41:45 AM UTC+8, Linfeng Gan wrote:
>>
>>
>>  
>>  
>>
>> Thank you for your advice, Travis.
>>
>> I had tested EPS_SCF from 1e-5 to 1e-14. I posted the 1e-5 one only 
>> because it took the shortest time to get the final structure. And I will 
>> try convergence criteria with 1e-4 as you suggest. 
>>  
>>
>> Linfeng
>>
>>
>> On Sunday, May 17, 2020 at 12:36:33 PM UTC+8, Travis wrote:
>>>
>>> Hi,
>>>
>>> I see you have EPS_SCF commented out in your input file. The default 
>>> convergence threshold is 1e-5 au which is usually not tight enough for 
>>> accurate forces (and certainly not for vibrational analysis, which is 
>>> computed numerically - hence it will take ages over Gaussian). The value 
>>> you commented out is actually better and may take less steps to converge. 
>>> Your criteria for convergence are also extremely tight, 1e-4 au is 
>>> typically enough. Also, just to be clear, CP2K when setup appropriately 
>>> will reproduce Gaussian output for the total energies for non-periodic 
>>> calculations. So you CAN use Gaussian for the gas phase reaction and CP2K 
>>> for the surface reaction.
>>>
>>> -T
>>>
>>>
>>> On Saturday, May 16, 2020 at 10:47:56 PM UTC-4, Linfeng Gan wrote:
>>>>
>>>>
>>>> Thank you very much Vladimir,
>>>>
>>>> 1) I know CP2K is not a choice for small molecules. But I am 
>>>> investigating an organic reaction which could take place in gas phase and 
>>>> on C3N4 surface. I have to compare the data between the gas phase and the 
>>>> surface. So, I can’t use gaussian or orca to that. DMol3 or CASTEP maybe is 
>>>> best choice for me, but I think we should give open source software a 
>>>> chance. So, CP2K is my choice right now. I am not very familiar with CP2K 
>>>> that it’s why I go to this forum and ask for some help. 
>>>>
>>>> 2) Agree. 
>>>>
>>>> 3) Yes, it was. 
>>>>
>>>> 4) 10000 times is an exaggeration, I apologize for that. Form the same 
>>>> initial structure, it took gaussian 41 seconds with a single Xeon 2680v2 
>>>> CPU to finish the geometry optimization, but it took CP2k 40 minutes with 
>>>> 20 CPU to do the same thing. If we include the frequencies calculation the 
>>>> time is 4 minutes vs 71 minutesX20CPU. A single SCF calculation of CP2K was 
>>>> pretty fast, but most of time was wasting in locating the minimize. 
>>>> This efficiency issue only happened in this 1-butene molecular. Another 
>>>> molecular I tested, cyclobutene, seemed much batter than 1-butene. 
>>>>
>>>> I attach all the input and the output file. So, you guy can help me to 
>>>> improve this. Thanks all.
>>>>
>>>>
>>>> Best,
>>>> LInfeng
>>>>
>>>>
>>>> On Friday, May 15, 2020 at 7:41:12 PM UTC+8, Vladimir Rybkin wrote:
>>>>>
>>>>> Dear Linfeng,
>>>>>
>>>>> a few general remarks:
>>>>> 1) CP2K is not the most efficient tool for small molecules. For 
>>>>> instance, it does a lot of integrations over cells in real and reciprocal 
>>>>> space, and for a small molecule the cell is almost everywhere empty.
>>>>> 2) CP2K does not use internal coordinates for optimisation. This has 
>>>>> to do with the fact that it's mostly meant for large periodic systems. 
>>>>> Gaussians' Berny algorithm does use internal coordinates and is very 
>>>>> efficient for small systems.
>>>>> 3) It's very likely that you 150 steps have not change the geometry 
>>>>> significantly. 
>>>>> 4) It's not completely clear where this 10000 times come from. It may 
>>>>> have to do with how you compile and run your applications.
>>>>>
>>>>> That said, there's no specific problems with optimisers and 
>>>>> efficiency. It's about applicability of tools for specific purposes. If you 
>>>>> going to work with small molecules, you'd better stick to programs made for 
>>>>> them, i.e. Gaussian. CP2K is meant for large and/or periodic systems.
>>>>>
>>>>> Yours,
>>>>>
>>>>> Vladimir
>>>>>
>>>>> пятница, 15 мая 2020 г., 2:51:51 UTC+2 пользователь Linfeng Gan 
>>>>> написал:
>>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> When I optimized 1-butene molecular at B3lYP/6-311G** level, it took 
>>>>>> much much longer than gaussian16 did.  I had test optimizer CG, BDGS 
>>>>>> and LBFGD, nothing better. It seems the optimizers have some efficiency 
>>>>>> issues. All three optimizer had taken at least 150 optimization steps to 
>>>>>> get the final structure, but the initial structure had been optimized by 
>>>>>> gaussian.   How could I improve that?
>>>>>>  
>>>>>>
>>>>>> Best
>>>>>>
>>>>>> Linfeng
>>>>>>
>>>>>
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> <opt_geo.out><opt_geo.inp>
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>
>
> ==============================
> 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 <javascript:>
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