Re: [ferret_users] scat2gridgauss not functioning properly

[Stephen Guimond <sguimond@xxxxxxx>]

Ansley,

Thank you for your help.  A 50,000 point limit seems rather low.  I routinely work with datasets well over this limit so dynamically allocated memory seems like the way to go.  Will you make this updated scat2gridlaplace available in the next FERRET release?

Steve

----- Original Message -----
From: Ansley Manke <Ansley.B.Manke@xxxxxxxx>
Date: Tuesday, August 26, 2008 12:04 pm
Subject: Re: [ferret_users] scat2gridgauss not functioning properly
To: guimond@xxxxxxxxxxxxx
Cc: jaison@xxxxxxxxxxxxxx, oar.pmel.ferret_users@xxxxxxxx

> Hi Stephen,
> The underlying code that scat2gridlaplace calls to do the gridding 
> operation has some work space that's hardwired in size to 50,000 
> points. 
> Your data is 960*367 = 352367 points so the code eventually 
> overwrites 
> memory and causes the crash. We should at least put in a test for 
> that 
> limit being exceeded so you'd get a useful error message - but I 
> should 
> be able to set up the work space with dynamically-allocated memory 
> so 
> it'd work correctly.
> 
> Ansley
> 
> Stephen Guimond wrote:
> > Hi Jaison,
> >
> > Thank you for your response, using a 1-D axis for x and y input 
> values worked.  I suppose the "objective_analysis_demo" script 
> should be fixed because it shows 2-D axes for x and y input.
> >
> > Another thing I found was that using "scat2gridlaplace" causes a 
> crash of FERRET.  I used similar input as I did with 
> "scat2gridgauss", but with cay and nrng both equal to 5.  I am 
> using FERRET v6.1  for 32-bit Linux.  Have you found anything similar?
> >
> > Thanks,
> > Steve
> >
> >
> > ----- Original Message -----
> > From: jaison@xxxxxxxxxxxxxx
> > Date: Wednesday, August 20, 2008 9:51 pm
> > Subject: Re: [ferret_users] scat2gridgauss not functioning properly
> > To: guimond@xxxxxxxxxxxxx
> > Cc: ferret_users@xxxxxxxx
> >
> >   
> >> Hi Steve,
> >>           According to documentation (and from experience), the 
> >> first two
> >> input arguments to SCAT2GRIDGAUSS function should be defined on 
> >> either X
> >> (and ZT) or Y (and ZT) axis, but NOT on both X and Y at the same 
> time.>> (see  Ch3 Sec2.3.37.  SCAT2GRIDGAUSS_XY). In your script 
> add the 
> >> followinglines
> >>
> >>   let xx1D = XSEQUENCE(xx)
> >>   let yy1D = XSEQUENCE(yy)
> >>
> >> then use these variables in SCAT2GRIDGAUSS function as
> >>
> >>   let sgrid = scat2gridgauss_xy(xx1D, yy1D, .........)
> >>
> >> Ok. The last argument (9th one) is not used in newer versions of 
> >> Ferret.The 3 arguments before that, XSCALE, YSCALE and CUTOFF 
> need 
> >> to be chosen
> >> to match your destination grid. Read the documentation carefully 
> for>> CUTOFF. You can try few different values to choose between 
> high-
> >> data loss
> >> (smaller SCALE and CUTOFF) and high-smoothing (higher SCALE and 
> >> CUTOFF),with respect to the destination grid. For example, if 
> >> CUTOFF is 2, then
> >> XSCALE can be dx (of destination grid) and YSCALE can be dy.
> >>
> >> Also note that, it is always a good habit to add proper units while
> >> defining axis, and use proper names (xlon, ylat or xkm, ykm etc).
> >>
> >> Please let me  know if you have any questions.
> >>
> >> Thanks and Regards,
> >>
> >> Jaison
> >>
> >>     
> >>> Hello Ferreters,
> >>>
> >>> I am trying to put scattered data onto a regular grid and tried 
> >>>       
> >> with the scat2gridgauss
> >>     
> >>> function.
> >>>
> >>> Here is my code:
> >>>
> >>> ! the scattered data axes...
> >>> def axis/x=1:960:1 x;def axis/y=1:367:1 y;def grid/x=x/y=y g
> >>> file/format=stream/grid=g/var="xx,yy,zz,dbz" output.dat
> >>> ! the regular grid axes...
> >>> def axis/x=-240:240:0.5 nx;def axis/y=-240:240:0.5 ny
> >>> let sgrid = scat2gridgauss_xy(xx, yy, dbz, x[gx=nx], y[gy=ny], 
> >>>       
> >> 2.,2.,2.,0)>
> >>     
> >>> The result does not work (toying with the last few parameters 
> >>>       
> >> makes no difference),
> >>     
> >>> although it does have the grid I expect.  I'm assuming the same 
> >>>       
> >> will be true for the
> >>     
> >>> scat2gridlaplace functions as well.
> >>>
> >>> Any ideas?
> >>>
> >>> Thanks,
> >>> Steve
> >>>
> >>>
> >>> =======================================================
> >>> Stephen R. Guimond
> >>> Graduate Research Assistant
> >>> Florida State University
> >>> Center for Ocean-Atmospheric Prediction Studies (COAPS)
> >>> =======================================================
> >>>
> >>>       
> >>
> >>
> >>     
> >
> > =======================================================
> > Stephen R. Guimond
> > Graduate Research Assistant
> > Florida State University
> > Center for Ocean-Atmospheric Prediction Studies (COAPS)
> > =======================================================
> >   
> 
> 
> 

=======================================================
Stephen R. Guimond
Graduate Research Assistant
Florida State University
Center for Ocean-Atmospheric Prediction Studies (COAPS)
=======================================================