Re: Segmentation Fault

Hi Carl,
I am looking into this. So far all I can tell is that the seg fault happens within a call to the NetCDF library. i am trying to probe it further to see where the fault really lies.
 -dave

On Feb 1, 2012, at 6:47 AM, Carl Schreck wrote:

> Hey guys,
>
> I'm also trying to help Mike with this problem. The results are pretty similar using 6.0.0:
>
> ----
> $ ncl
> Copyright (C) 1995-2011 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 6.0.0
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
> ncl 0> f=addfile("vp.850.nc","r")
> ncl 1> x=f->vp
> ncl 2> printVarSummary(x)
>
> Variable: x
> Type: float
> Total Size: 3873819840 bytes
> 968454960 values
> Number of Dimensions: 3
> Dimensions and sizes: [time | 33349] x [lat | 121] x [lon | 240]
> Coordinates:
> time: [1656744..1856832]
> lat: [-90..90]
> lon: [-180..178.5]
> Number Of Attributes: 6
> _FillValue : -999.9
> mapping : cylindrical_equidistant_projection_grid
> grid_resolution : 1.5_degrees
> pressure_level : 850
> units : m^2s^-1
> long_name : velocity_potential
> ncl 3> y=f->vp(:,0,:)
> Segmentation fault
>
> ----
>
> So on line 1, it successfully reads the entire variable at once. But in line 3, it seg faults when we try to read a single latitude (or even a range like 0:9). This is using ncl_ncarg-6.0.0.Linux_RedHat_x86_64_gcc412.tar.gz
>
> I'm sure Mike can put the data somewhere that you can access it in case it's a problem with the actual file.
>
> Carl
>
>
> On Tue, Jan 31, 2012 at 3:58 PM, Ventrice, Michael J <mventrice@albany.edu> wrote:
> Dennis and Rick,
>
> Yes, ok do I understand that. But why am I still seg-faulting in 6.0.0 when I read in the first latitude and not all latidudes?
>
> Thanks,
> Mike
>
>
> --
> Michael J. Ventrice
> Department of Atmospheric and Environmental Sciences
> University at Albany, New York, ES 218
> MVentrice@albany.edu
> Mike.Ventrice@gmail.com
> http://mikeventrice.weebly.com/index.html
>
> ________________________________________
> From: Dennis Shea [shea@ucar.edu]
> Sent: Tuesday, January 31, 2012 3:49 PM
> To: Ventrice, Michael J
> Cc: Rick Brownrigg; ncl-talk@ucar.edu
> Subject: Re: Segmentation Fault
>
> NCL v5.2.1 does not support variables > 2GB
>
> The variable is 33349*121*240 * 4 > 2GB
>
> The 4 is because each float is 4 bytes
>
>
> On 1/31/12 1:09 PM, Rick Brownrigg wrote:
>
> Variable: x
> Type: float
> Total Size: -421147456 bytes
> 968454960 values
> Number of Dimensions: 3
> Dimensions and sizes: [time | 33349] x [lat | 121] x [lon | 240]
>
> You must upgrade to v6.0.0 for variables > 2GB
>
>
> > Hi Mike,
> >
> > The output you show is from ncl5.2.1, and it certainly makes sense
> > (e.g., the Total size field reporting "-421147456 bytes"
> > Can you post the results of the same commands entered into V6.0.0 ?'
> > What do you mean by "read the data in as a whole"?
> >
> > Thanks,
> > Rick
> >
> > On Jan 31, 2012, at 12:27 PM, Ventrice, Michael J wrote:
> >
> >> Hello,
> >>
> >> I am working the 1.5 deg ECMWF interim data where I have came across a
> >> problem I am unable to fix. I have built large-files consisting of Jan
> >> 1989 - September 2011 data, and am able to read the data in as a
> >> whole, but when I try to read the first latitude point in, I recieve a
> >> segmentation fault. I recieve segmantation faults for both v5.2.1 and
> >> v.6.0 of NCL. Would you be able to attempt to help me understand what
> >> is going wrong?
> >>
> >> Thank you,
> >> Mike Ventrice
> >>
> >> ncl
> >> Copyright (C) 1995-2010 - All Rights Reserved
> >> University Corporation for Atmospheric Research
> >> NCAR Command Language Version 5.2.1
> >> The use of this software is governed by a License Agreement.
> >> Seehttp://www.ncl.ucar.edu/for more details.
> >> ncl 0> f=addfile("vp.850.nc <http://vp.850.nc>","r")
> >> ncl 1> x=f->vp
> >> ncl 2> printVarSummary(x)
> >>
> >>
> >> Variable: x
> >> Type: float
> >> Total Size: -421147456 bytes
> >> 968454960 values
> >> Number of Dimensions: 3
> >> Dimensions and sizes: [time | 33349] x [lat | 121] x [lon | 240]
> >> Coordinates:
> >> time: [1656744..1856832]
> >> lat: [-90..90]
> >> lon: [-180..178.5]
> >> Number Of Attributes: 6
> >> _FillValue : -999.9
> >> mapping : cylindrical_equidistant_projection_grid
> >> grid_resolution : 1.5_degrees
> >> pressure_level : 850
> >> units : m^2s^-1
> >> long_name : velocity_potential
> >> ncl 3> delete(x)
> >> ncl 4> y=f->vp(:,0,:)
> >> Segmentation fault
> >>
> >> --
> >> Michael J. Ventrice
> >> Department of Atmospheric and Environmental Sciences
> >> University at Albany, New York, ES 218
> >> MVentrice@albany.edu <mailto:MVentrice@albany.edu>
> >> Mike.Ventrice@gmail.com <mailto:Mike.Ventrice@gmail.com>
> >> http://mikeventrice.weebly.com/index.html
> >> _______________________________________________
> >> ncl-talk mailing list
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> >
> >
> >
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>
>
> --
> Carl J. Schreck III, PhD
> Postdoctoral Research Associate
> Cooperative Institute for Climate and Satellites (CICS-NC)
> North Carolina State University and NOAA's National Climatic Data Center
> 151 Patton Avenue
> Asheville, NC 28801
> Tel: 828-257-3140
> carl@cicsnc.org
> http://monitor.cicsnc.org/mjo/
> http://www.atmos.albany.edu/student/carl/
>
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Received on Thu Feb 2 01:48:15 2012