[Wien] question about mixing scf calculations with different NUME in param.inc at compilation

[Tomas Kana]

Dear professor Blaha, 
Thank you very much for your answer. 
For sure I first use clean_lapw before starting 
new iterations. I am using the sequential version (really many 
calculations for many different structures). 
Fortunately, I have faced no crash of clusters on the 
governmental supercomputing center up to now. (They allow 
even running disruptive tasks).
With best regards 
Tomas Kana 

For sure you should not run calculations with these 2 warning.
You cannot expect to get the same results with RKmax = 7 or 6, the mixer gets confused by that if you do not delete old broyden files.
Also the NUME warning is important, although from your 6720 e, it should be sufficient and can probably be neglected.

On the other hand, I do not quite understand why the NMATMAX reduction 
occurs at all. NMATMAX is used primarily for sequential runs to avoid 
paging.
I suppose you are using the mpi-parallel version ? While this needs 
twice as much memory, it divides it to all your cores, so the effective 
NMATMAX is increased by sqrt(n-cores). So with 64 cores, the effective 
NMATMAX=400000, and I doubt that your matrices are larger than that.

PS: Compilation with NMATMAX=500000 is potentially VERY dangerous, as it may "crash" you computer when it runs out of memory.

Am 10.12.2024 um 14:21 schrieb Tomas Kana:
> Dear Wien2k community,
> 
> 
> I am calculating  a Mg23Al30 structure as in input for Phonopy code.
> I have build a supercell with 636 atoms in the unit cell.
> case.scf gives a total number of  6720 electrons.
> For the 14 scf iterations I used proper version
> wien2k/21.1.matmax500k (the name
> given by our system admins) that was compiled using
> NMATMAX=   500000
> NUME=   50000
> in param.inc.
> After running out of computer time, I continued the scf calculation
> but I did not pay attention and used the version wien2k/21.1  with
> NMATMAX=   50000
> NUME=   6000
> in param.inc
> I know from previous posts that
> NUME > "number of electrons"/2 + 20-30%
> When analyzing the file case.scf
> it has two warnings:
> :WARN :      WARNING: RKmax reduced due to NMATMAX
> :WARN :      WARNING: NE limited by NUME in param.inc
> I do not mind the first warning, it only reduced RMT times Kmax
> from 7.0 to 5.94.
> I tried to analyze the second warning and found that
> after 14 "right" cycles the interstitial (grep :NPC  case.scf)
> charge decreased from  742 to 711 (I give only integers, not the
> numbers after decimal points).
> I now plan tostop the calculations and use the density
> calculated using wien2k/21.1  as starting density for calculation
> using wien2k/21.1.matmax500k.
> Is this correct?
> Thank you for your answer.
> 
> 
> 
> 
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-- 
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Peter Blaha,  Inst. f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-158801165300
Email: peter.blaha at tuwien.ac.at
WWW:   http://www.imc.tuwien.ac.at      WIEN2k: http://www.wien2k.at
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