linear interpolation functions in grads-2.0.a5.oga.5

Henrique Barbosa hmjbarbosa at GMAIL.COM
Tue Mar 23 20:30:52 EDT 2010


Dear James,

I am getting the same problem as you when using Mike's linreg().
grads-bundle 2.0.a7-oga.3 just exits with no error message.

Have you solved the problem?

[]'s
Henrique

On Wed, Jul 15, 2009 at 8:38 PM, James T. Potemra <jimp at hawaii.edu> wrote:
> Hi Mike:
>
> Thanks for the reply.  For some reason this causes my grads to exit.
> I open the file, pick a point (lat,lon), then run trend=linreg(y) and
> grads just quits (no error or seg fault):
>
>             Welcome to the OpenGrADS Bundle Distribution
>             --------------------------------------------
>
> For additional information enter "opengrads --help".
>
> Starting
> "/usr/local/grads-2.0.a5.oga.5/Contents/Linux/Versions/2.0.a5.oga.5/x86_64/grads
> -HC 1  -l -g 1000x800 " ...
>
>
> Grid Analysis and Display System (GrADS) Version 2.0.a5.oga.5
> Copyright (c) 1988-2008 by Brian Doty and the
> Institute for Global Environment and Society (IGES)
> GrADS comes with ABSOLUTELY NO WARRANTY
> See file COPYRIGHT for more information
>
> Config: v2.0.a5.oga.5 little-endian readline printim grib2 netcdf
> hdf4-sds opendap-grids,stn athena geotiff
> Issue 'q config' command for more information.
> Loading User Defined Extensions table
> </usr/local/grads-2.0.a5.oga.5/Contents/Linux/Versions/2.0.a5.oga.5/x86_64/gex/udxt>
> ... ok.
> GX Package Initialization: Size = 11 8.5
> Command line history in /export/lii/jimp/.grads.log
> ga-> open c20c_tas
> Scanning description file:  c20c_tas
> Data file c20c_tas.nc is open as file 1
> LON set to 0 360
> LAT set to -89.4944 89.4944
> LEV set to 1 1
> Time values set: 1861:7:1:0 1861:7:1:0
> E set to 1 1
> ga-> set lat 0
> LAT set to 1.01124 1.01124
> ga-> set lon 180
> LON set to 181.25 181.25
> ga-> set t 1 140
> Time values set: 1861:7:1:0 2000:7:1:0
> ga-> d tas
> ga-> trend=linreg(tas)
>
>
> Michael Fiorino wrote:
>>
>> jim,
>>
>> my linreg extension does work...  e.g., trend=linreg(y)
>>
>> in a script the m and b are printed to the 'result' variable.
>>
>> /r mike
>>
>> James T. Potemra wrote:
>>
>>> I'm running grads-2.0.a5.oga.5 on a 64-bit linux machine and want to do
>>> a linear
>>> fit to a time-series.  There appears to be a UDF called "linreg" that is
>>> included
>>> in Mike Fiorino's UDF library, but the man page at
>>> http://opengrads.org/doc/udxt/libmf/
>>> does not list this function.
>>>
>>> Conversely, there is a man page for "tregr2" at
>>> http://opengrads.org/doc/udxt/libbjt/
>>> as part of Ben-Jei Tsuang's UDF library, but that does not appear in the
>>> UDC list
>>> (see list below).
>>>
>>> I would like to plot a linear fit through a time-series of a particular
>>> variable.  It looks
>>> like either of these would do this, but in my case the independent
>>> variable is time, and
>>> I'm not sure if I need to somehow define that in the Y = m * X + b
>>> syntax for either
>>> tregr2 or linreg.
>>>
>>> I'd appreciate any suggestions.  Thanks,
>>>
>>> Jim
>>>
>>>
>>> ------------------------------------------------------------------------------------------------------
>>>
>>>
>>> ga-> q udf
>>>
>>>  User
>>>  Defined
>>>  FUNCTION          Short Description                Function at Library
>>> ---------- -----------------------------------
>>> --------------------------
>>> lt         Less than operator                   f_bjt@^libbjt.gex
>>> jd         Julian day                           f_bjt@^libbjt.gex
>>> cosz       Cosine solar zenith angle            f_bjt@^libbjt.gex
>>> dayratio   Daylight ratio                       f_bjt@^libbjt.gex
>>> if         Conditional function                 f_bjt@^libbjt.gex
>>> maxv       Maximum value                        f_bjt@^libbjt.gex
>>> minv       Minimum value                        f_bjt@^libbjt.gex
>>> which      Label gridpoints                     f_bjt@^libbjt.gex
>>> ftest      F-test                               f_bjt@^libbjt.gex
>>> ttest      T-test                               f_bjt@^libbjt.gex
>>> tfit       Point  linear regression             f_bjt@^libbjt.gex
>>> fit        Global linear regression             f_bjt@^libbjt.gex
>>> tcorr2     Time correlation                     f_bjt@^libbjt.gex
>>> tregr2     Point linear regression              f_bjt@^libbjt.gex
>>> tmave2     Time averaging w/masking             f_bjt@^libbjt.gex
>>> madvu      Calculates -d(u*EXPR)/dx             f_bjt@^libbjt.gex
>>> madvv      Calculates -d(V*EXPR)/dy             f_bjt@^libbjt.gex
>>> madvw      Calculates -d(W*EXPR)/dp             f_bjt@^libbjt.gex
>>> muadv      Zonal advection                      f_bjt@^libbjt.gex
>>> mvadv      Meridional advection                 f_bjt@^libbjt.gex
>>> mwadv      Vertical advection                   f_bjt@^libbjt.gex
>>> satvap     Saturated vapor pressure             f_bjt@^libbjt.gex
>>> dew        Dew point temperature                f_bjt@^libbjt.gex
>>> lw         Thermal infrared fluxes              f_bjt@^libbjt.gex
>>> lw2        Thermal infrared fluxes v2           f_bjt@^libbjt.gex
>>> pinterp    Pressure interpolation               f_bjt@^libbjt.gex
>>> zinterp    Height interpolation                 f_bjt@^libbjt.gex
>>> line       Draws a line                         f_bjt@^libbjt.gex
>>> vint2      Mass-weighted vertical integral      f_bjt@^libbjt.gex
>>> fish       Poisson solver                       f_fish@^fish.gex
>>> fish_psi   Compute streamfunction               f_psichi@^fish.gex
>>> fish_chi   Compute velocity potential           f_psichi@^fish.gex
>>> fish_vor   Compute vorticity                    f_psichi@^fish.gex
>>> fish_div   Compute divergence                   f_psichi@^fish.gex
>>> dewpt      Dew-point temperature                f_gsudf@^gsudf.gex
>>> ept        Equivalent potential temperature     f_gsudf@^gsudf.gex
>>> epi        Potential Instability                f_gsudf@^gsudf.gex
>>> plcl       Pressure at LCL                      f_gsudf@^gsudf.gex
>>> shear      Wind Shear                           f_gsudf@^gsudf.gex
>>> srh1km     Storm-relative Helicity 0-1km'       f_gsudf@^gsudf.gex
>>> srh3km     Storm-relative Helicity 0-3km'       f_gsudf@^gsudf.gex
>>> tlcl       Temperature at LCL                   f_gsudf@^gsudf.gex
>>> tsindex    Chance of T-storm Initiation         f_gsudf@^gsudf.gex
>>> ttindex    Total Totals Index                   f_gsudf@^gsudf.gex
>>> wchill     Wind Chill Index (New)               f_gsudf@^gsudf.gex
>>> hello      Hello, World! sample function        f_hello@^libhello.gex
>>> ipc_save   Save expression to stream            f_Save@^libipc.gex
>>> ipc_load   Load variable from file              f_Load@^libipc.gex
>>> smth2d     Shuman smoother/de-smoother          f_smth2d@^libmf.gex
>>> uv2trw     Find radial/tangential velocity      f_uv2trw@^libmf.gex
>>> re2        General interpolator (regrid2)       f_re2@^libmf.gex
>>> esmrf      Saturation vapor pressure (old MRF)  f_esmrf@^libmf.gex
>>> linreg     Linear regression: mx + b            f_linreg@^libmf.gex
>>> re         General interpolator                 ffre@^re.gex
>>> re_        General interpolator (verbose)       ffre_dbg@^re.gex
>>> regrid2    regrid2-like wrapper for re()        f_gsudf@^gsudf.gex
>>> reimg      Interpolation for Image Generation'  f_gsudf@^gsudf.gex
>>> sh_filt    Spherical harmonic filter            f_shfilt@^shfilt.gex
>>> sh_power   Spherical harmonic spectra           f_shpowr@^shfilt.gex
>>> ---------- -----------------------------------
>>> --------------------------
>>>
>



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