I will be very thankful for any thoughts on this issue. Also if you know QE experts please kindly redirect the message.
> On Nov 26, 2018, at 6:05 PM, Aleksandra Oranskaia > <aleksandra.oransk...@kaust.edu.sa> wrote: > > Hello dear users and developers of QE, > > I am trying to calculate phonons using very good structure (tightly > optimized, matching the experimental one, etc), but whatever I do the result > is: > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > Error in routine cdiaghg (448): > S matrix not positive definite > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > > I varied: > - number of processors (with too large # of processors similar issues are > reported) > - ecutrho increasing it up to ecutwfc*15 > - different smearings schemes (the system is a narrow band gap semiconductor) > - different diagonalization procedures (from my personal experience: david > fail sometimes where cg saves the day) > - used nosym=.true. > > I would highly appreciate any thoughts on the nature of this mistake > happening in the very beginning of phonon calculation. > > > Best, > Alex. > ___ > Aleksandra Oranskaia (M.Sc.) > ChemS PhD student, KAUST > Phone: +966 50 1335254 > > > > > > -- This message and its contents, including attachments are intended solely for the original recipient. If you are not the intended recipient or have received this message in error, please notify me immediately and delete this message from your computer system. Any unauthorized use or distribution is prohibited. Please consider the environment before printing this email.
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