TABLE OF CONTENTS
::pwtk::pseudo::ecutwfcFromPPFile
PURPOSE
Get the suggested minimum ecutwfc from the PP file.
NOTES
- if "Suggested minimum cutoff" record does not exist or "Suggested minimum cutoff" <= 0.5*$::pwtk::pseudo::opts(min_ecutwfc), an empty string is returned
get pseudo_dir from the current input ppf file must exist: if it does not, calculations will fail