[ncl-talk] Segmentation fault on a GFS file fragment

[Dennis Shea]

On my MAC with 6.3 0 and on our 'big machine'


 Copyright (C) 1995-2015 - All Rights Reserved
 University Corporation for Atmospheric Research
 NCAR Command Language Version 6.3.0
 The use of this software is governed by a License Agreement.
 See http://www.ncl.ucar.edu/ for more details.
ncl 0>  f = addfile("gfs.t18z.sfluxgrbf03.grib2","r")
ncl 1> print(f)
ncl 2> x = f->PRES_P8_L233_GGA0_avg
ncl 3> print(x)

Variable: x
Type: float
Total Size: 18874368 bytes
            4718592 values
Number of Dimensions: 2
Dimensions and sizes:   [lat_0 | 1536] x [lon_0 | 3072]
Coordinates:
            lat_0: [89.91032..-89.91032]
            lon_0: [ 0..359.883]
Number Of Attributes: 15
  center :      US National Weather Service - NCEP (WMC)
  production_status :   Operational products
  long_name :   Pressure
  units :       Pa
  _FillValue :  1e+20
  grid_type :   Gaussian latitude/longitude
  parameter_discipline_and_category :   Meteorological products, Mass
  parameter_template_discipline_category_number :       ( 8, 0, 3, 0 )
  level_type :  High cloud top level
  level :        0
  type_of_statistical_processing :      Average
  statistical_process_duration :        initial time to forecast time
  forecast_time :       3
  forecast_time_units : hours
  initial_time :        09/29/2015 (18:00)
(0,0)   38670
(0,1)   38660

[snip]

--------
However, on another machine


/project/cas/shea/GRIB> ncl
 Copyright (C) 1995-2015 - All Rights Reserved
 University Corporation for Atmospheric Research
 NCAR Command Language Version 6.3.0
 The use of this software is governed by a License Agreement.
 See http://www.ncl.ucar.edu/ for more details.
ncl 0> f = addfile("gfs.t18z.sfluxgrbf03.grib2","r")
ncl 1> x = f->PRES_P8_L233_GGA0_avg

Segmentation fault (core dumped)

-------

I think the versions where it worked are actually internal.

Somebody with more knowledge will likely answer tomorrow.
Perhaps, a version of NCL that reads the file can be made available.



Cheers

On Tue, Sep 29, 2015 at 5:40 PM, Peter Novak <P.Novak at tudelft.nl> wrote:
> Dear NCL users and developers,
> I encountered a segmentation fault of NCL on a GRIB2 file extracted from
> NOAA GFS forecast datasets. The file is located here
> http://www.aronde.net/dump/gfs.t18z.sfluxgrbf03.grib2PRES_TOP_high.grib2.
>
> The file is extracted with curl from GFS dataset
> http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.2015092918/gfs.t18z.sfluxgrbf03.grib2,
> variable "PRES:high cloud top level" (as referred to in the index file
> at http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.2015092918/gfs.t18z.sfluxgrbf03.grib2.idx).
> The extraction command with ranges was:
> $ curl -f -s -r 24660742-27538435 <url above> -o <outfile>
>
> I am getting segfault upon the following:
> $ ncl_filedump gfs.t18z.sfluxgrbf03.grib2PRES_TOP_high.grib2 -v PRES_P8_L233_GGA0_avg
>
> The same when I try to read the file with an ncl script:
>         indat=addfile(<file>, "r")
>         vars=getfilevarnames(indat)
>         printVarSummary(indat->$vars(0)$)
>
> At the same time PanoplyJ reads the file without a hickup. Other files I
> extracted using curl from the same GFS datasets work fine, the only
> difference I spotted is that this one contains missing values (NaNf in
> PanoplyJ), perhaps that could be the cause of the problem?
>
> I would appreciate any advice regarding how to read and process this
> file with NCL, or what is exactly wrong with it.
>
> As for the NCL setup I have:
> $ ncl
> Copyright (C) 1995-2015 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 6.3.0
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
>
> $ uname -a
> Linux ... 3.16.0-38-generic #52~14.04.1-Ubuntu SMP Fri May 8 09:43:57 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
>
> Thanks for your help.
>
> Best,
>
> Peter.
>
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