I agree that using scf_must_converge=.false. is not the best solution if
you start with it without testing! But the question was why the
calculation stopped after 80 iterations. The default for
electron_maxstep is 100 and who knows maybe it was stopped too soon and
it would have converged at 92. In any case it stopped because it was
told to stop at 80 iterations. Why it didn't reach convergence is
another matter.
Using scf_must_converge=.false. is not that bad if you test the system
beforehand. There are systems that will not converge in the first step
and then the algorithm moves the atoms a bit and then convergence is
achieved as it should.
All the best,
Lucian
On 20/07/2022 22:26, Tiana, Davide wrote:
That (using scf_must_converge=.false. is a very vary bad advice. If
the system is not converging after 80 iterations most likely there's
something wrong. This could be the pseudo, the geometry, or any thing.
You should check the convergence rate between each step and see if it
fluctuate and of how much. Then, maybe it is almost converged so you
simply need to extend the number of cycles from 80 to 100 or 150.
Last but not least, you can know if it's not converging because your
threshold is too tight, or it's not converging at all. If the latter
you need to find why. By using scf_must_converge=.false. you'll simply
risk to end in a wrong state.
All the best
Davide
------------------------------
Message: 3
Date: Wed, 20 Jul 2022 10:40:09 +0300
From: "Lucian D. Filip" <[email protected]>
To: [email protected]
Subject: Re: [QE-users] relax : convergence NOT achieved after 80
iterations: stopping
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
here is the problem! you told QE to only do 80 iterations in a scf step.
After the 80 iterations there was no convergence and the calculation
stopped. If you want it to continue to the next step and let QE move the
atoms even if the first scf iteration did not converge you should use
the following flag together with the electron_maxstep:
scf_must_converge = .false.
--
*Dr. Lucian Dragos Filip*
National Institute of Materials Physics
Atomistilor str. 405A, PO Box MG. 7
Magurele, 077125
Bucharest, Romania
E-mail: [email protected]
Website: https://lucianfilip.wordpress.com/
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_______________________________________________
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--
*Dr. Lucian Dragos Filip*
National Institute of Materials Physics
Atomistilor str. 405A, PO Box MG. 7
Magurele, 077125
Bucharest, Romania
E-mail: [email protected]
Website: https://lucianfilip.wordpress.com/
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
