Re: Summing formula

• To: "Scott. Stephens" <Scott.Stephens@xxxxxxxx>
• Subject: Re: Summing formula
• From: "Tom Whittaker" <tomw@xxxxxxxxxxxxx>
• Date: Wed, 7 Mar 2007 08:41:01 -0600

And, finally (?), in reponse to the question:  "how can I sum up the
grids I selected using the IDV's time selector?", the answer is:

1. change the formula to remove the second parameter
2. change the 'addEmUp()' method to something like this:

from visad.python.JPythonMethods import *
#
#This is the default  editable users jython library

import visad
from visad.python.JPythonMethods import *

def addEmUp(g):
 a = 0
 num = getDomainSizes(g)
 for k in range(num[0]):
   a = g[k] + a
 return

tom

On 3/6/07, Tom Whittaker <whittaker@xxxxxxxx> wrote:

I realized after I hit "Send" that in this case the "getNthTimeGrid()"
is not really needed.  You can simply say:  "  a = g[k] + a ".
Perhaps the former is more illustrative as to what's going on,
however.

tom


On 3/6/07, Tom Whittaker <tomw@xxxxxxxxxxxxx> wrote:
> Hi Scott....
>
> The IDV formulas are ideal for this.  If you're not familiar, let me
> suggest this.
>
> 1. Create a small Jython script in the "User Library"
> (Edit->Formulas->Jython LIbrary).  If you're
>     no familiar with Python syntax, just note that the number of
> spaces (indents) on a line
>     are important since they determine the blocks in the code.  Here's
> my suggestion:
>
> def addEmUp(g, n):
>   a = 0
>   for k in range(int(n)):
>     a = getNthTimeGrid(g, k) + a
>   return a
>
>      Don't forget to "File->Save" the library.
>
> 2. Then create a formula to call this.  For example:
>          Name = Add times
>          Formula =  addEmUp(grid, user_NumbTimes)
>
>      In the "Advanced" section, I would recommend enabling only the
> Displays relevant to your data (for example, Controur Plan View).
>
> Then use the Chooser to get pointed to your grids, and in the Field
> Selector, pick your formula.  A small window will appear asking you
> for the value of "NumbTimes".  Enter a number.  Then you'll be asked
> to select from the usual list of grids -- pick the one your interested
> in.
>
> By the way, the "getNthTimeGrid()" is a method defined in the "System
> Jython library" -- lots of other goodies in there as well!
>
> Hope this gets you going!!
>
> tom
>
>
> On 3/6/07, Scott.Stephens <Scott.Stephens@xxxxxxxx> wrote:
> >
> >  Hi,
> >
> >  Has a sum function been built for IDV? I would like to generate precip
> > totals for varying time intervals, (e.g. total model QPF for a model's run
> > time, etc), but can't figure out the best way to generate the desired output
> > using multiple forecast hours.
> >
> >  Thanks for your time,
> >  Scott
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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>
>
> --
> Tom Whittaker
> University of Wisconsin-Madison
> Space Science & Engineering Center (SSEC)
> Cooperative Institute for Meteorological Satellite Studies (CIMSS)
> 1225 W. Dayton Street
> Madison, WI  53706  USA
> ph: +1 608 262 2759
>


--
Tom Whittaker
University of Wisconsin-Madison
Space Science & Engineering Center (SSEC)
Cooperative Institute for Meteorological Satellite Studies (CIMSS)
1225 W. Dayton Street
Madison, WI  53706  USA
ph: +1 608 262 2759

--
Tom Whittaker
University of Wisconsin-Madison
Space Science & Engineering Center (SSEC)
Cooperative Institute for Meteorological Satellite Studies (CIMSS)
1225 W. Dayton Street
Madison, WI  53706  USA
ph: +1 608 262 2759

• References:
  • Summing formula
    • From: Scott.Stephens
  • Re: Summing formula
    • From: Tom Whittaker
  • Re: Summing formula
    • From: Tom Whittaker