[IDV #ZTF-373299]: IDV formula failing, unit problems?

esupport removed the leading spaces. Python is sensitive to spaces so add four 
spaces in the beginning of each line to the code, except the first one.

> Here is one way to do it (maybe). Add this to your Jython library
> 
> 
> def fire(rhscrn,tscrn,u10):
> rhscrn = newUnit(rhscrn,"rhscrn","K")
> tscrn = newUnit(tscrn,"tscrn","K")
> u10 = newUnit(u10,"u10","K")
> answer = 2*exp(1.524-0.0345*rhscrn+0.0338*tscrn+0.0234*u10*3.6)
> return answer
> 
> The create a formula. See section 4.2.1 of the workshop material.
> 
> See attached PNG.
> 
> -Julien
> 
> 
> 
> > Hi Julien,
> >
> > Thanks for the feedback.  It seems my assumption that it was an IDV unit 
> > panic were correct.  I don't know of a quick way to simply "change" the 
> > units as you suggest within IDV.  I could do it by modifying the headers I 
> > suppose but for extremely large data sets (the results are typically about 
> > 2 Gb) it becomes problematic and more trouble than its worth, especially 
> > when IDV's main purpose (for most I think) is a quick way to visualise 
> > data.  If you do find a workaround however please let me know.
> >
> > Eventually I'll be scripting some animations with NCL graphics and when it 
> > comes to scripting it wouldn't be a problem as you say to simply rename a 
> > unit.  I could be wrong but I'm fairly sure NCL and other NetCDF capable 
> > software would continue to process an arithmetic formula even if it didn't 
> > understand the units.  It's almost as though a simple "unit panic 
> > exception" needs to be written into IDV so that when it decides "these 
> > units are nonsensical" it thinks "OK, these are the results but I have no 
> > idea what the unit is!" instead of "Oh my I can't deal with this, I need to 
> > stop now, you're on your own!".
> >
> > Regards,
> >
> > Simon.
> >
> >
> > -----Original Message-----
> > From: Unidata IDV Support [mailto:address@hidden]
> > Sent: Wednesday, February 16, 2011 7:18 AM
> > To: Simon Metcalf
> > Cc: address@hidden
> > Subject: [IDV #ZTF-373299]: IDV formula failing, unit problems?
> >
> > Hi Simon,
> >
> > I can reproduce this problem. I understand that the unit is unitless from 
> > the physics point of view, but the IDV does not see it that way. rhscrn 
> > tscrn and u all have units associated with them which makes the IDV/ViSAD 
> > blow up. I am still looking into a solution / workaround, but that is where 
> > I am at. One way to kludge it, maybe, is to make rhscrn tscrn and u all the 
> > same unit, say temperature.
> >
> > -Julien
> >
> > > Hi Julien,
> > >
> > > I've uploaded the file along with the formula that has the parameter 
> > > names contained in the data so all you have to do is add the formula.  
> > > The formula is not a real variable but a unit-less index that defines the 
> > > relationship between some ground-level prognostics affecting fire danger. 
> > >  I assume this is why it's having unit problems but I could be wrong.  It 
> > > should be able to produce a result even if it can't identify a sensible 
> > > unit.
> > >
> > > 2*exp(1.524-0.0345*rhscrn+0.0338*tscrn+0.0234*u10*3.6)
> > >
> > > Only two time steps are included to keep the file size down.
> > >
> > > Regards,
> > >
> > > Simon.
> > >
> > > -----Original Message-----
> > > From: Unidata IDV Support [mailto:address@hidden]
> > > Sent: Tuesday, February 15, 2011 3:44 AM
> > > To: Simon Metcalf
> > > Cc: address@hidden
> > > Subject: [IDV #ZTF-373299]: IDV formula failing, unit problems?
> > >
> > > Hi Simon.
> > >
> > > In order, to better diagnose this problem, would it be possible to
> > > upload the ccam33S147E08km.nc here:
> > > http://motherlode.ucar.edu/repository/alias/idvupload
> > >
> > > Let us know when it is uploaded.
> > >
> > > Also, tell us a bit more about what you are trying to do with these data 
> > > so that we can give you a better answer.
> > >
> > > Thanks.
> > >
> > > -Julien
> > >
> > > > Full Name: Simon Metcalf
> > > > Email Address: address@hidden
> > > > Organization: NSW Rural Fire Service Package Version: 2.9u3 build
> > > > date:2011-01-14 00:05 UTC Operating
> > > > System: Windows XP
> > > > Hardware: Java: home: C:\Program Files\IDV_2.9u3\jre version:
> > > > 1.6.0_20
> > > > j3d:1.5.2 fcs (build4) Description of problem: Creating display:
> > > > Color-Shaded Plan View
> > > > visad.UnitException: visad.UnitException org.python.core.PyException
> > > >
> > > > Hi, I'm having trouble getting IDV to display the following formula:
> > > >
> > > > 2*exp(1.524-0.0345*RH+0.0338*T+0.0234*WS*3.6)
> > > >
> > > > The error above seems to indicate that it's having trouble identifying 
> > > > a correct unit for the results, which is not surprising because the 
> > > > formula is supposed to create a unit-less index value.  Can you assist 
> > > > with identifying the problem with IDV and if there is a workaround 
> > > > solution?
> > > >
> > > > Regards, Simon.
> > > >
> > > > ******************
> > > > Stack trace:
> > > > Traceback (innermost last):
> > > > File "<string>", line 1, in ?
> > > > at visad.RealType.binary(RealType.java:473)
> > > >
> > > > at visad.FunctionType.binary(FunctionType.java:270)
> > > >
> > > > at visad.FunctionType.binary(FunctionType.java:270)
> > > >
> > > > at visad.DataImpl.binary(DataImpl.java:138)
> > > >
> > > > at visad.DataImpl.add(DataImpl.java:179)
> > > >
> > > > at visad.DataImpl.__add__(DataImpl.java:1393)
> > > >
> > > > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> > > >
> > > > at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
> > > >
> > > > at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
> > > >
> > > > at java.lang.reflect.Method.invoke(Unknown Source)
> > > >
> > > >
> > > > visad.UnitException: visad.UnitException
> > > >
> > > >
> > > >
> > >
> > >
> > > Ticket Details
> > > ===================
> > > Ticket ID: ZTF-373299
> > > Department: Support IDV
> > > Priority: Normal
> > > Status: Closed
> > >
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> > > necessarily the views of the NSW Rural Fire Service.
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: ZTF-373299
> > Department: Support IDV
> > Priority: Normal
> > Status: Open
> >
> >
> 


Ticket Details
===================
Ticket ID: ZTF-373299
Department: Support IDV
Priority: Normal
Status: Closed