[Pw_forum] what negative omiga means ?

[degironc]

when omega^2 is negative the code prints - sqrt(abs(omega^2))
stefano

陳 少華 wrote:

>Dear members,
>I have a little question bothering me.After I
>calculated the phonon dispersion. I got some negative
>omiga values.
>As I know ,image omiga means unstable.But what
>negative omiga means ? I suppose it should be positive
>value,if it is stable system.
>
>Best Regards
>max
>
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