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<tt>Hi,<br>
<br>
I wasn't able to find anything on the board regarding this issue. Maybe
someone can explain why do I get different values in the script (below)
for the defined variable "a" & "b" ? ("b" and "c" are the same and
correct.) I would expect a = b = c regardless of how I access the
values of those variables. <br>
<br>
Below is the full script and the results. The data file is attached if
anyone would like to run the script on their machine . If you get
different results, please let me know. <br>
<br>
(I'm using Config: v1.9b4 32-bit little-endian on a Linux workstation.
I get the same results, though, using older versions 1.7beta9 and
1.8SL10.)<br>
<br>
I think this is occurring because of this data's grid, where X=1 is
longitude 1.25E instead of 0E. By default GrADS maps "set lon 0 360"
into "X = 0.5 to 144.5", so however "define" works, GrADS returns the
proper value for "a" if "set x 30" is done first, but doesn't return
the expected value if you do<br>
"d a(x=30)". Variables "b" and "c" work because I explicitly "set x 1
144" or "set lon 1.25 358.75" (which correspond to X=1 and X=144 ). <br>
<br>
When I ran a similar script using NCEP data which starts at Lon = 0., I
didn't have this problem.<br>
<br>
Thanks,<br>
Mary Jo<br>
<br>
SCRIPT:<br>
<br>
sdfopen model.slp.nc<br>
set lat 0<br>
q dims<br>
define a=slp<br>
set x 1 144 <br>
q dims<br>
define b=slp<br>
set lon 1.25 358.75<br>
q dims<br>
define c=slp<br>
set x 30<br>
d a<br>
d b<br>
d c<br>
d a(x=30)<br>
d b(x=30)<br>
d c(x=30)<br>
d a-b<br>
d a(x=30)-b(x=30)<br>
d a-c<br>
d a(x=30)-c(x=30)<br>
d b-c<br>
d b(x=30)-c(x=30)<br>
<br>
<br>
RESULTS:<br>
<br>
<b>sdfopen /net2/mjn/model.slp.nc</b><br>
Scanning self-describing file: /net2/mjn/model.slp.nc<br>
SDF file /net2/mjn/model.slp.nc is open as file 1<br>
LON set to 0 360 <br>
LAT set to -89.4944 89.4944 <br>
LEV set to 0 0 <br>
Time values set: 1870:1:16:12 1870:1:16:12 <br>
<b>set lat 0</b><br>
LAT set to 1.01124 1.01124 <br>
<b>q dims</b><br>
Default file number is: 1 <br>
X is varying Lon = 0 to 360 X = 0.5 to 144.5<br>
Y is fixed Lat = 1.01124 Y = 46<br>
Z is fixed Lev = 0 Z = 1<br>
T is fixed Time = 12Z16JAN1870 T = 1<br>
<b>define a=slp</b><br>
Define memory allocation size = 584 bytes<br>
<b>set x 1 144</b> <br>
LON set to 1.25 358.75 <br>
<b>q dims</b><br>
Default file number is: 1 <br>
X is varying Lon = 1.25 to 358.75 X = 1 to 144<br>
Y is fixed Lat = 1.01124 Y = 46<br>
Z is fixed Lev = 0 Z = 1<br>
T is fixed Time = 12Z16JAN1870 T = 1<br>
<b>define b=slp</b><br>
Define memory allocation size = 576 bytes<br>
<b>set lon 1.25 358.75</b><br>
LON set to 1.25 358.75 <br>
<b>q dims</b><br>
Default file number is: 1 <br>
X is varying Lon = 1.25 to 358.75 X = 1 to 144<br>
Y is fixed Lat = 1.01124 Y = 46<br>
Z is fixed Lev = 0 Z = 1<br>
T is fixed Time = 12Z16JAN1870 T = 1<br>
<b>define c=slp</b><br>
Define memory allocation size = 576 bytes<br>
<b>set x 30</b><br>
LON set to 73.75 73.75 <br>
<b>d a</b><br>
Result value = 1010.45 <br>
<b>d b</b><br>
Result value = 1010.45 <br>
<b>d c</b><br>
Result value = 1010.45 <br>
<b>d a(x=30)</b><br>
Result value = 1010.57 <i><==== ????</i><br>
<b>d b(x=30)</b><br>
Result value = 1010.45 <br>
<b>d c(x=30)</b><br>
Result value = 1010.45 <br>
<b>d a-b</b><br>
Result value = 0 <br>
<b>d a(x=30)-b(x=30)</b><br>
Result value = 0.122498 <i><==== a != b</i><br>
<b>d a-c</b><br>
<b>Result value = 0 <br>
d a(x=30)-c(x=30)</b><br>
Result value = 0.122498 <i><=== a != c</i><br>
<b>d b-c</b><br>
Result value = 0 <br>
<b>d b(x=30)-c(x=30</b>)<br>
Result value = 0 <br>
EOF EXECuting test_script<br>
</tt>
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