No subject

To unsubscribe, send an email containing the message "SIGNOFF GRADSUSR"
to listserv at list.cineca.it.

And that's all you need to do. However, note that the mail should go to
LISTSERV not GRADSUSR.

Happy unsubscribing,

Nina

PEDRO JOSE MULERO wrote:
> Please get me out of this list.
>
> If this is not the way to do it, may I ask how to?
>
>
>
> ----- Original Message -----
> From: Arindam Chakraborty <arindam at MET.FSU.EDU>
> Date: Tuesday, June 19, 2007 2:30 pm
> Subject: Re: "define" values are different.  why?
> To: GRADSUSR at LIST.CINECA.IT
>
>
>>
>> Dear Users,
>>
>>     just an add up here, although last few mails including MJ's one
>> completely explains why the values are different. I noted that:
>>
>> (after all previous define commands as MJ):
>>
>>
>>
>> ga-> d a(x=30)
>>
>> Result value = 1010.57
>>
>> ga-> d a(x=31)
>>
>> Result value = 1010.45
>>
>> ga-> d b(x=29)
>>
>> Result value = 1010.57
>>
>> ga-> d c(x=29)
>>
>> Result value = 1010.57
>>
>>
>>
>> ga-> d a(x=1)
>>
>> Result value = 1011.56
>>
>> ga-> d a(x=145)
>>
>> Result value = 1011.56
>>
>> ga-> d a(x=2)
>>
>> Result value = 1011.69
>>
>> ga-> d a(x=146)
>>
>> Result value = 1011.69
>>
>>
>>
>> So, reiterating the previous explanations, x is defined for 146 grid
>> points (-1.25 to 361.25). Given that somebody does this (although
>> setting x from 1 to 144 and defining the variable is probably the best
>> way), aren't the results what to be expected? From my personal point of
>> view I would like to see that in a bracketed dimension expression
>> [e.g., a(x=30)], the value of the variable at the 30th grid point of
>> that variable is extracted instead of the 30th grid point of the
>> default file. And that's exactly what grads is doing. For that reason,
>>
>> a(x=31) is same as b(x=30) and so on.
>>
>>
>>
>>
>>
>> regards,
>>
>>
>>
>> arindam
>>
>>
>>
>> Mary Jo Nath wrote:
>>
>>
>>   Hi,
>>
>>
>>
>> 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.
>>
>>
>>
>> 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.
>>
>>
>>
>> (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.)
>>
>>
>>
>>  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
>>
>> "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 ).
>>
>>
>>
>> When I ran a similar script using NCEP data which starts at Lon = 0.,
>> I
>> didn't have this problem.
>>
>>
>>
>> Thanks,
>>
>> Mary Jo
>>
>>
>>
>> SCRIPT:
>>
>>
>>
>> sdfopen model.slp.nc
>>
>> set lat 0
>>
>> q dims
>>
>> define a=slp
>>
>> set x 1 144
>>
>> q dims
>>
>> define b=slp
>>
>> set lon 1.25 358.75
>>
>> q dims
>>
>> define c=slp
>>
>> set x 30
>>
>> d a
>>
>> d b
>>
>> d c
>>
>> d a(x=30)
>>
>> d b(x=30)
>>
>> d c(x=30)
>>
>> d a-b
>>
>> d a(x=30)-b(x=30)
>>
>> d a-c
>>
>> d a(x=30)-c(x=30)
>>
>> d b-c
>>
>> d b(x=30)-c(x=30)
>>
>>
>>
>>
>>
>> RESULTS:
>>
>>
>>
>>   sdfopen /net2/mjn/model.slp.nc
>>
>> Scanning self-describing file:  /net2/mjn/model.slp.nc
>>
>> SDF file /net2/mjn/model.slp.nc is open as file 1
>>
>> LON set to 0 360
>>
>> LAT set to -89.4944 89.4944
>>
>> LEV set to 0 0
>>
>> Time values set: 1870:1:16:12 1870:1:16:12
>>
>>   set lat 0
>>
>> LAT set to 1.01124 1.01124
>>
>>   q dims
>>
>> Default file number is: 1
>>
>> X is varying   Lon = 0 to 360   X = 0.5 to 144.5
>>
>> Y is fixed     Lat = 1.01124  Y = 46
>>
>> Z is fixed     Lev = 0  Z = 1
>>
>> T is fixed     Time = 12Z16JAN1870  T = 1
>>
>>   define a=slp
>>
>> Define memory allocation size = 584 bytes
>>
>>   set x 1 144
>>
>> LON set to 1.25 358.75
>>
>>   q dims
>>
>> Default file number is: 1
>>
>> X is varying   Lon = 1.25 to 358.75   X = 1 to 144
>>
>> Y is fixed     Lat = 1.01124  Y = 46
>>
>> Z is fixed     Lev = 0  Z = 1
>>
>> T is fixed     Time = 12Z16JAN1870  T = 1
>>
>>   define b=slp
>>
>> Define memory allocation size = 576 bytes
>>
>>   set lon 1.25 358.75
>>
>> LON set to 1.25 358.75
>>
>>   q dims
>>
>> Default file number is: 1
>>
>> X is varying   Lon = 1.25 to 358.75   X = 1 to 144
>>
>> Y is fixed     Lat = 1.01124  Y = 46
>>
>> Z is fixed     Lev = 0  Z = 1
>>
>> T is fixed     Time = 12Z16JAN1870  T = 1
>>
>>   define c=slp
>>
>> Define memory allocation size = 576 bytes
>>
>>   set x 30
>>
>> LON set to 73.75 73.75
>>
>>   d a
>>
>> Result value = 1010.45
>>
>>   d b
>>
>> Result value = 1010.45
>>
>>   d c
>>
>> Result value = 1010.45
>>
>>   d a(x=30)
>>
>> Result value = 1010.57   <==== ????
>>
>>   d b(x=30)
>>
>> Result value = 1010.45
>>
>>   d c(x=30)
>>
>> Result value = 1010.45
>>
>>   d a-b
>>
>> Result value = 0
>>
>>   d a(x=30)-b(x=30)
>>
>> Result value = 0.122498  <==== a != b
>>
>>   d a-c
>>
>>   Result value = 0
>>
>> d a(x=30)-c(x=30)
>>
>> Result value = 0.122498  <=== a != c
>>
>>   d b-c
>>
>> Result value = 0
>>
>>   d b(x=30)-c(x=30)
>>
>> Result value = 0
>>
>> EOF EXECuting test_script
>>
>>
>>
>>
>>
>> --
>> ----------------------------
>>  ARINDAM CHAKRABORTY
>>  Department of Meteorology
>>  Florida State University
>>  Tallahassee, FL-32306, USA
>>  Tel: +001-850-6443524 (Off)
>>       +001-850-5758550 (Res)
>>  Fax: +001-850-6449642
>> ____________________________
>>
>>
>>

--

Guðrún Nína Petersen
School of Environmental Sciences
University of East Anglia
Norwich
UK

email: g.n.petersen at uea.ac.uk
http://www.petersen.is/gudrun