[QE-users] Why does the output data of plot_num=7 have negative values?

[toshi1higu at docomo.ne.jp]

Dear QE Users,
This is a question about pp.x plot_num. I calculated plot_num=7 for a
hydrogen atom and a carbon nanotube. For the hydrogen atom, I used normcons
for pseudopotential. For the carbon nanotube, I used ultrasoft for
pseudopotential. When I looked at the results, positive and negative values
were output. I think that |psi|^2 would be output in plot_num=7 analysis. I
think |psi|^2 only had positive values. I don't understand why negative
values are coming out.

Best regards,
Toshiharu Higuchi