segmentation fault using multiple netcf files and xdfopen

[Adam Sobel]

I have a set of netcdf files, each is 1 day.  I have a .ctl file so I can
view a bunch of them together in sequence using xdfopen.  The ctl file
is below.

If I set t to the whole time range (in this case set t 1 12) I can view
the variables u or v just fine, e.g. make animations for the whole
period, looks good.  But then if I do

define rvort=hcurl(u,v)

I get a segmentation fault.

If I set t 1, and then compute rvort as above for just the 1 day, it's fine.
If I then step through the days one at a time, it crashes at day 4.  If
however upon first opening the file I set t 4 immediately, it works
fine.  There is nothing wrong with that netcdf file.

If I change the start date in the ctl file, I get crashes at different
dates - not corresponding to the same data file, nor to the same value
of t.  It seems unpredictable when it will crash except it's always
at a fairly small value of t.

The problem isn't with hcurl, other commands that operate on
multiple times cause the same seg fault - e.g.

define uav=ave(u,t=1,t=10)

Any help much appreciated!  The version of GrADS is v1.9b4, the
operating system is HP Unix.

thanks
Adam

DSET A%y4%m2%d20000.nc
OPTIONS template yrev
TITLE netCDF file
UNDEF -999
XDEF  lon  144 LINEAR 0.00  2.5
YDEF  lat  73 LINEAR  -90.00  2.5
ZDEF  lvl  17 LEVELS  1000.00  925.00  850.00  700.00  600.00  500.00
400.00  300.00  250.00   200.00  150.00  100.00   70.00  50.00 30.00
20.00 10.00
TDEF time 12  LINEAR 0z25JUL2000  1dy
VARS   10
geop_ht=>phi   17  99 x,y,z,t
air_temp=>ts   17  99 x,y,z,t
zonal_wnd=>u   17  99 x,y,z,t
merid_wnd=>v   17  99 x,y,z,t
mix_rt0=>q   17  99 x,y,z,t
dewpt_scrn=>td   1  99 x,y,t
mslp=>ps   1  99 x,y,t
temp_scrn=>t2m   1  99 x,y,t
uwnd10m=>u10m   1  99 x,y,t
vwnd10m=>v10m   1  99 x,y,t
ENDVARS

--
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Adam H. Sobel
Department of Applied Physics and Applied Mathematics
Department of Earth and Environmental Sciences
Columbia University
500 W. 120th Street, Room 217
New York, NY 10027 USA
tel: 212-854-6587
fax: 212-854-8257
e-mail: ahs129 at columbia.edu
web: http://www.columbia.edu/~ahs129/home.html

UNTIL AUGUST 2008, ON SABBATICAL at
Bureau of Meteorology Research Centre
GPO Box 1289
Melbourne VIC 3001
Australia
tel: +61-(0)3-9669-4645
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