[Pw_forum] Error in routine cdiaghg (337): S matrix not positive definite in position optimization of BaMgF4

Lorenzo Paulatto lorenzo.paulatto at impmc.upmc.fr
Mon Aug 21 15:34:38 CEST 2017

On 21/08/17 14:46, Yogesh Kumar wrote:
> Dear Sir,
>        I am trying to do position optimization for BaMgF4 on 24 cores. I 
> have performed scf calculation successfully using quantum espresso v 
> 5.1.1. I am getting the following error after I run the code. Input file 
> is given in the last. Please help me running this correctly.

Dear Yogesh,
some of your atoms are very close to each other (less than 0.3 bohr, 
0.16 A), this may violate the PAW assumption that the core regions of 
different ions do not touch each other. This could cause the error you 
are seeing.

Quite clearly the input positions you have given are not correct. You 
can use the small utility dist.x to get a list of the atom-atom 
distances (printed to a file called dist.out).

kind regards

Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 442 79822 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/423 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05

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