[ferret_users] erratic IF masking behaviour

[Lev Tarasov <lev@xxxxxx>]

Why does the IF condition not work in the
masking below and how do I fix this:
(ie CONDITION should be false, but hdf doesn't take on
the ELSE value of hd)

let hdf= IF ifhf eq 1 then hdhf else hd

yes? list ifhf
             VARIABLE : IF HFB GT HDG THEN 1 ELSE 0
             FILENAME : idHhpt.nn9927
             LONGITUDE: 69W (interpolated)
             LATITUDE : 41.5N (interpolated)
             T        : -20
          0.5000

yes? list hd
...
             LONGITUDE: 69W (interpolated)
             LATITUDE : 41.5N (interpolated)
          36.75
yes? list hdf
...
             LONGITUDE: 69W (interpolated)
             LATITUDE : 41.5N (interpolated)
          35.50

note using
 	NOAA/PMEL TMAP
 	FERRET v6.401
 	Linux(g77) 2.6.9-89.ELsmp - 12/09/09
 	11-Dec-13 00:05


Cheers,

lev

Lev Tarasov -   Dept of Physics and Physical Oceanography,
		Memorial University of Newfoundland.
                email: lev@xxxxxx
                http://www.physics.mun.ca/~lev/
         	Currently at Antarctic Research Centre,
                Victoria University of Wellington