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[IDV #PHU-486914]: question

Great news Tilly! I'm glad we were able to get things going for you. We will 
likely add this to the built-in IDV functions in a future release.

Cheers!

Sean

> Thanks, this seems to work!
> Also nice example to use for more detailed plotting :-)
> Kind regards,
> Tilly
> 
> -----Oorspronkelijk bericht-----
> Van: Unidata IDV Support [mailto:address@hidden]
> Verzonden: donderdag 6 oktober 2011 16:57
> Aan: Driesenaar, Tilly (KNMI)
> CC: address@hidden; Driesenaar, Tilly (KNMI)
> Onderwerp: [IDV #PHU-486914]: question
> 
> Ah yes, my approach was a little bit too simple. I've attached a .py file 
> that uses my code, but has been appropriately modified by Jeff McWhirter to 
> handle indexing into your variable (Thanks Jeff!). Use the contents of the 
> python file in your Jython Library and you should be good to go. 
> extractBitField(data, N) is the function you should use when you want to find 
> the bits for your data.
> 
> Let me know if this works :-)
> 
> Sean
> 
> 
> > Dear Sean,
> > I created your function in the local Jython library and then created
> > another function
> >
> > KNMIQC(QC):
> > ff=getBit(QC,17)
> > return ff
> >
> > and then I made a formula for this last one (by rightclicking the
> > function) Then I tried to display this formula with input the quality flag 
> > field in a netCDF file.
> > But then I get the error:
> > TypeError: unsupported operand type(s) for &: 'int' and 
> > 'ucar.visad.data.GeoGridFlatField'
> >
> > Probably I have to do something more to do this mask comparison for all 
> > gridpoints in the field?
> >
> > Kind regards,
> > Tilly
> >
> > -----Oorspronkelijk bericht-----
> > Van: Unidata IDV Support [mailto:address@hidden]
> > Verzonden: woensdag 5 oktober 2011 23:18
> > Aan: Driesenaar, Tilly (KNMI)
> > CC: address@hidden; Driesenaar, Tilly (KNMI)
> > Onderwerp: [IDV #PHU-486914]: question
> >
> > Sorry, replace "bitNumber" with "n" in the line before the if statement.
> >
> > Sean
> >
> > > Greetings Tilly,
> > >
> > > Add this function to your local Jython library (click "Edit" -> 
> > > "Formulas" -> "Jython Library", and select "Local Jython" -> "User's 
> > > Library"), and give it a try:
> > >
> > > def getBit(flag, n):
> > > """
> > > return the value of the nth bit of the given flag """
> > > bit_mask = 1 << (bitNumber -1)
> > > if ((bit_mask & flag) == 0):
> > > return 0
> > > else:
> > > return 1
> > >
> > > (note: if the formatting of this function does not come out right in
> > > my message, be sure to add four spaces to everything after the first
> > > line [def getBit(flag, n):], and an additional four spaces to the
> > > "return" lines)
> > >
> > > Cheers!
> > >
> > > Sean
> > >
> > >
> > > > Dear Sean
> > > > Thank you for your help!
> > > > I'm dealing with a 32 bit integer.
> > > > Cheers,
> > > > Tilly
> > > >
> > > > -----Oorspronkelijk bericht-----
> > > > Van: Unidata IDV Support [mailto:address@hidden]
> > > > Verzonden: vrijdag 23 september 2011 18:59
> > > > Aan: Driesenaar, Tilly (KNMI)
> > > > Onderwerp: [IDV #PHU-486914]: question
> > > >
> > > > Greetings Tilly!
> > > >
> > > > What kind of interger is QCF (16 bit, 32 bit?)? In Jython 2.6, the bin 
> > > > operator will be supported, so things will be much easier. However, you 
> > > > will need to create a bitmask and use the bit-wise operator & to 
> > > > extract the information you need. If I knew what kind of int you were 
> > > > dealing with, I could give you an example to extract out the 17th bit.
> > > >
> > > > Cheers!
> > > >
> > > > Sean
> > > >
> > > > > Dear IDV support desk
> > > > >
> > > > >
> > > > >
> > > > > I would like to plot the information in an integer quality flag in 
> > > > > IDV.
> > > > >
> > > > > The flag consists of several masks, e.g. the first, or second or
> > > > > 17th bit are set .
> > > > >
> > > > > In python I would use any of the following commands to extract
> > > > > information from this integer quality flag (say QCF).
> > > > >
> > > > > (As you can see I'm especially interested in the 17th bit (or
> > > > > mask value
> > > > > 2**17) )
> > > > >
> > > > >
> > > > >
> > > > > bin(int(QCF))[-18]  (look at the value of the 17th bit )
> > > > >
> > > > > or
> > > > >
> > > > > (int(QCF)/2**17)%2  (so divide by mask value and do modulo 2)
> > > > >
> > > > >
> > > > >
> > > > > How do I get this into an IDV formula?
> > > > >
> > > > > I tried (QCF/2**17)%2 , but that doesn't seem to evaluate in the
> > > > > right way.
> > > > >
> > > > >
> > > > >
> > > > > Kind regards,
> > > > >
> > > > > Tilly Driesenaar
> > > > >
> > > > > KNMI
> > > > >
> > > > > The Netherlands
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > > Ticket Details
> > > > ===================
> > > > Ticket ID: PHU-486914
> > > > Department: Support IDV
> > > > Priority: Normal
> > > > Status: Closed
> > > >
> > > >
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: PHU-486914
> > Department: Support IDV
> > Priority: Normal
> > Status: Open
> >
> >
> 
> 
> Ticket Details
> ===================
> Ticket ID: PHU-486914
> Department: Support IDV
> Priority: Normal
> Status: Open
> 


Ticket Details
===================
Ticket ID: PHU-486914
Department: Support IDV
Priority: Normal
Status: Closed