[gpaw-users] Convergence issue with mBEEF

Jens Jørgen Mortensen jensj at fysik.dtu.dk
Thu Nov 27 11:44:58 CET 2014


On 11/26/2014 04:53 PM, Jess Wellendorff wrote:
>
> On 11/26/2014 03:53 PM, Jens Jørgen Mortensen wrote:
>> On 11/25/2014 10:44 PM, Jess Wellendorff wrote:
>>> Marcin: The mBEEf functional was fitted on PBEsol electron densities 
>>> obtained using rather tight SCF criteria. I think something else 
>>> must be the root cause of this issue. Perhaps GPAW does not supply 
>>> LibXC with sufficiently accurate kinetic energy densities?
>>>
>>> Monish: Honestly, I believe the only solution to your problem is to 
>>> lower the SCF convergence criteria, perhaps even completely 
>>> eliminate them for the eigenstates and rely only on density and 
>>> energy criteria. I have successfully used this approach. It is not 
>>> pretty, but it works :)
>>>
>>> If you take a look at the mBEEF test script (gpaw/test/mbeef.py), 
>>> the SCF criteria for very quick molecular calculatios are set to 
>>> {'eigenstates':1.e+2, 'density':1.e-2, 'energy':1.e-4}. These are 
>>> bullet-proof settings for a simple test. In general, the density and 
>>> energy criteria can probably be tightened more. Also, I would expect 
>>> the eigenstate issue to be much less pronounced in bulk calculations.
>>
>> What is it that makes mBEEF so special?  I'm struggling with a test 
>> calculation for a nitrogen atom (not mBEEF, but mBEEF-vdW) and I can 
>> also not converge the eigenstates.  Strange thing is that TPSS works 
>> fine.
> JJ: I don't get it, you're saying that this is not an issue with TPSS? 
> I think it certainly am, it's an issue for all the metaGGAs. Here is 
> my GPAW output for TPSS and the N2 molecule:

Yes, but try with eigensolver='rmm-diis' - then TPSS-N2 converges 
nicely, but mBEEF-vdW does not?

Jens Jørgen

> ******************************
> Number of Valence Electrons: 10
>                      log10-error:    Total        Iterations:
>            Time      WFS    Density  Energy       Fermi  Poisson
> iter:   1  08:50:39  -0.44          -20.362686    0      17
> iter:   2  08:50:39  -1.11          -20.364991    0
> iter:   3  08:50:39  -1.11          -20.363382    0
> iter:   4  08:50:41  -1.26  -2.29   -20.362235    0      5
> iter:   5  08:50:44  -1.12  -2.41   -20.361605    0      6
> iter:   6  08:50:46  -0.89  -3.32   -20.359967    0      3
> iter:   7  08:50:49  -0.94  -3.49   -20.360150    0      3
> iter:   8  08:50:51  -0.92  -3.73   -20.360137    0      3
> iter:   9  08:50:53  -0.92  -4.37   -20.360187    0      2
> iter:  10  08:50:55  -0.92  -4.55   -20.360091    0      1
> iter:  11  08:50:58  -0.92  -4.73   -20.360269    0      1
> iter:  12  08:51:00  -0.92  -4.80   -20.360286    0      1
> iter:  13  08:51:03  -0.92  -4.94   -20.360311    0      1
> iter:  14  08:51:06  -0.92  -5.10   -20.360363    0      1
> iter:  15  08:51:08  -0.92  -5.96   -20.360300    0      1
> iter:  16  08:51:10  -0.92  -6.44   -20.360284    0      1
> iter:  17  08:51:13  -0.92  -6.60   -20.360280    0      1
> iter:  18  08:51:15  -0.92  -6.73   -20.360281    0      1
> iter:  19  08:51:17  -0.92  -6.83   -20.360281    0      1
> iter:  20  08:51:20  -0.92  -6.92   -20.360281    0      1
> iter:  21  08:51:22  -0.92  -7.11   -20.360281    0      1
> iter:  22  08:51:24  -0.92  -7.27   -20.360280    0      1
> iter:  23  08:51:26  -0.92  -7.59   -20.360280    0      1
> iter:  24  08:51:29  -0.92  -7.88   -20.360281    0      1
> iter:  25  08:51:31  -0.92  -7.99   -20.360281    0      1
> iter:  26  08:51:33  -0.92  -8.08   -20.360281    0      1
> iter:  27  08:51:35  -0.92  -8.59   -20.360281    0      1
> iter:  28  08:51:38  -0.92  -8.83   -20.360281    0      1
> iter:  29  08:51:40  -0.92  -8.99   -20.360281    0      1
> iter:  30  08:51:42  -0.92  -9.40   -20.360281    0      1
> iter:  31  08:51:44  -0.92  -9.60   -20.360281    0      1
> iter:  32  08:51:47  -0.92  -9.80   -20.360281    0      1
> iter:  33  08:51:49  -0.92 -10.03   -20.360281    0      1
> iter:  34  08:51:51  -0.92 -10.18   -20.360281    0      1
> iter:  35  08:51:53  -0.92 -10.44   -20.360281    0      1
> iter:  36  08:51:56  -0.92 -10.62   -20.360281    0      1
> iter:  37  08:51:58  -0.92 -10.79   -20.360281    0      1
> iter:  38  08:52:00  -0.92 -10.96   -20.360281    0      1
> iter:  39  08:52:03  -0.92 -11.70   -20.360281    0      1
> iter:  40  08:52:06  -0.92 -11.86   -20.360281    0      1
> iter:  41  08:52:08  -0.92 -12.03   -20.360281    0      1
> iter:  42  08:52:11  -0.92 -12.33   -20.360281    0      1
> iter:  43  08:52:13  -0.92 -12.55   -20.360281    0      1
> iter:  44  08:52:15  -0.92 -13.25   -20.360281    0      1
> ******************************
>
> Best,
> Jess
>
>>
>> It helped a bit to use eigensolver='rmm-diis'.
>>
>> Jens Jørgen
>>
>>>
>>> Hope this helps.
>>> Best,
>>> Jess
>>>
>>> On 11/25/2014 06:53 PM, Marcin Dulak wrote:
>>>> On 11/25/2014 04:37 PM, Wellendorff, Jess wrote:
>>>>> Hi Monish, in my experience, the eigenstates can be hard to 
>>>>> converge with metagga. Is this your problem?
>>>> i remember even with the older BEEF-vdW molecules are hard to 
>>>> converge.
>>>> Maybe this is due to loose SCF thresholds used when fitting the 
>>>> functional (was it the case also for mBEEF?),
>>>> so the resulting functional by design is not reaching a tight 
>>>> convergence.
>>>>
>>>> Best regards,
>>>>
>>>> Marcin
>>>>>
>>>>> Best,
>>>>> Jess
>>>>>
>>>>>
>>>>>> On Nov 25, 2014, at 14:48, mohnish pandey 
>>>>>> <mohnish.iitk at gmail.com> wrote:
>>>>>>
>>>>>> Dear all,
>>>>>>
>>>>>> I am trying to do some test calculations with mBEEF functional 
>>>>>> for some solids like ZnO. But I am facing difficulty in 
>>>>>> converging the calculations. I tried tweaking mixing, Fermi 
>>>>>> temperature etc, but it didn't help. Would really appreciate if 
>>>>>> somebody helps me out with the issue. Thanks a lot in advance.
>>>>>>
>>>>>> -- 
>>>>>> Regards,
>>>>>> Mohnish,
>>>>>> -----------------------------------------------------------------
>>>>>> Mohnish Pandey,
>>>>>> PhD Student,
>>>>>> Center for Atomic-scale Materials Design,
>>>>>> Department of Physics,
>>>>>> Technical University of Denmark
>>>>>> -----------------------------------------------------------------
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>>>>
>>>
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