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

Anytime.

Thanks for being persistent. I learned something too :-)

-Julien

> Hi,
> 
> Thanks for that.
> 
> Regards,
> 
> Simon.
> 
> -----Original Message-----
> From: Unidata IDV Support [mailto:address@hidden]
> Sent: Thursday, February 17, 2011 8:56 AM
> To: Simon Metcalf
> Cc: address@hidden
> Subject: [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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> > > >
> > >
> > >
> > > 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
> 
> 


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