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