[Pw_forum] error on phonon calculation (root not converged)

[Liping YU]

Dear Paolo,

>--- Paolo Giannozzi <giannozz at nest.sns.it> wrote:
>  
>
>>this may actually work, but the problem that shows
>>up in  Liping's output is rather strange and nasty. 
>>    
>>
>
>  
>
>>The self-consistent  procedure seems to converge 
>>quite nicely: |ddv_scf|^2 goes  down towards the
>>threshold, then it starts to go up to crazy
>>values. 
>>    
>>
>Yes, I paid attention to this behaviour. Actually,
>recently I had very close situation: for some modes
>everything was OK, and next mode also started well,
>and then turned out to be crazy. At least in my case,
>using small mixing parameter fixed the problem.
>
>I suggest, Liping should keep us informed about the
>problem.
>  
>
Thanks for your suggestion. I am trying it with smaller alpha_mix.
I'll let you know when the results come out. Actually the first such
message occured in electric field calcualtion (see below).

Thanks!
liping
============================================

Electric Fields Calculation

iter # 1 total cpu time : 625.1 secs av.it.: 7.6
thresh= 0.100E-01 alpha_mix = 0.700 |ddv_scf|^2 = 0.708E-08

iter # 2 total cpu time : 748.8 secs av.it.: 15.3
thresh= 0.841E-05 alpha_mix = 0.700 |ddv_scf|^2 = 0.517E-09

iter # 3 total cpu time : 869.8 secs av.it.: 15.0
thresh= 0.227E-05 alpha_mix = 0.700 |ddv_scf|^2 = 0.128E-10

iter # 4 total cpu time : 995.4 secs av.it.: 15.6
thresh= 0.358E-06 alpha_mix = 0.700 |ddv_scf|^2 = 0.890E-12

iter # 5 total cpu time : 1122.9 secs av.it.: 16.0
thresh= 0.943E-07 alpha_mix = 0.700 |ddv_scf|^2 = 0.830E-13

iter # 6 total cpu time : 1252.7 secs av.it.: 16.7
thresh= 0.288E-07 alpha_mix = 0.700 |ddv_scf|^2 = 0.874E-13

iter # 7 total cpu time : 1362.9 secs av.it.: 13.9
thresh= 0.296E-07 alpha_mix = 0.700 |ddv_scf|^2 = 0.608E-14

iter # 8 total cpu time : 1484.7 secs av.it.: 15.6
thresh= 0.780E-08 alpha_mix = 0.700 |ddv_scf|^2 = 0.204E-13

iter # 9 total cpu time : 1594.0 secs av.it.: 13.9
thresh= 0.143E-07 alpha_mix = 0.700 |ddv_scf|^2 = 0.105E-15
 =-O kpoint 3 ibnd 81 solve_e: root not converged 0.807E-08 =-O 
iter # 10 total cpu time : 1722.1 secs av.it.: 16.5
thresh= 0.102E-08 alpha_mix = 0.700 |ddv_scf|^2 = 0.108E-17

iter # 11 total cpu time : 1854.0 secs av.it.: 17.1
thresh= 0.104E-09 alpha_mix = 0.700 |ddv_scf|^2 = 0.770E-19

End of electric fields calculation

......

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