[ncl-talk] gsn_csm_streamline_scalar_map segmentation fault

Thu Jul 6 16:09:43 MDT 2017

Dear Alan,

Thank you for your reply! I've also previously used this function before
and had no problem. I ran the code on our university cluster, so there is
enough RAM to store the variable.

Below attached is the outputted .nc file that goes into the function. I've
gave it a quick "ncview" check and didn't see any problem with the data.
Please let me know if you found anything wrong.  Thank you very much for
your help!

Best regards,
Meina

On Thu, Jul 6, 2017 at 11:54 AM, Alan Brammer <abrammer at albany.edu> wrote:

> Would probably help to see the data.   I’ve used this function a lot, with
> bigger domains than yours and not had issue.  However the function will
> duplicate domains, so if you’re on a laptop with very limited RAM it may
> struggle.
>
> You could save your plotting data to a small netcdf and send it to the
> list, based on the summary, the netcdf should be small than 1 MB.
>
> ncout= addfile(“ncl_talk_streamline_data.ncl”,”c”)
> ncout->Uwavghist = Uwavghist
> ncout->Vwavghist = Vwavghist
> ncout->windwavghist = windwavghist
>
>
> the ftp server is also an option if the output ends up too big.
>
>
>
> Alan
>
>
>
>
> ##############################
> Alan Brammer,
> Post-Doc Researcher
>
> Department of Atmospheric and Environmental Sciences,
> University at Albany, State University of New York, Albany, NY, 12222
> abrammer at albany.edu
> ##############################
>
> On 6 Jul 2017, at 14:05, Meina Wang <mnawang at ucdavis.edu> wrote:
>
> Dear Mary,
>
> Thank you very much for your reply, and for running the test case! The
> variable is not a very large one, and I also tried to do the vector plot
> using "vcres at vcGlyphStyle = "CurlyVector"" but also got the "Segmentation
> fault". The only option that works is the vcres at vcGlyphStyle = "WindBarb".
>  Please see below for the printVarSummary info and the resources
> setting.  Thank you very much again for your help, and please let me know
> if you spot anything suspicious.
>
> Output from printVarSummary(Uwavghist):
> Variable: Uwavghist
> Type: float
> Total Size: 76800 bytes
>             19200 values
> Number of Dimensions: 2
> Dimensions and sizes: [lat | 120] x [lon | 160]
> Coordinates:
>             lat: [30.0625..44.9375]
>             lon: [-132.9375..-113.0625]
> Number Of Attributes: 1
>
>   _FillValue : 9.96921e+36
>
> My resources setting:
>   mpres                       = True
>   mpres at gsnMaximize           = True
>   mpres at mpOutlineOn           = True
>   mpres at mpDataBaseVersion     = "MediumRes"   ; slightly better outlines
>   mpres at mpLandFillColor = "gray91"
> ;---Data is regional
>   mpres at gsnAddCyclic          = False
> ;---Change the streamline levels
>   mpres at stLevelSpacingF       = 30.
>   mpres at stLevelPalette        = "ncl_default" ; "MPL_Spectral"
>   mpres at stLineThicknessF      = 5.0         ; default is 1.0
>   mpres at stLevelSelectionMode  = "ManualLevels"
>   mpres at stMinLevelValF        = 1
>   mpres at stMaxLevelValF        = 15.
>   mpres at stLevelSpacingF       = 1.
>   mpres at mpMinLonF            =  min(lon)               ; select a
> subregion
>   mpres at mpMaxLonF            =  max(lon)
>   mpres at mpMinLatF            =   min(lat)
>   mpres at mpMaxLatF            =  max(lat)
>   mpres at pmTickMarkDisplayMode = "Always"    ; more detailed tickmarks
> printVarSummary(Uwavghist)
>
>   plot4 = gsn_csm_vector_scalar_map_ce(wks, Uwavghist,Vwavghist,
> windwavghist,mpres)
>
> Best regards,
> Meina
>
>
>
> On Thu, Jul 6, 2017 at 8:58 AM, Mary Haley <haley at ucar.edu> wrote:
>
>> Hi Meina,
>>
>> One thing that might cause gsn_csm_streamline_scalar_map to seg fault is
>> if you are trying to plot really large data arrays.
>>
>> It's always important to look at your data when NCL isn't plotting it
>> correctly, and we recommend using "printVarSummary" for this.
>>
>> How big are U and V? Please insert a "printVarSummary" command and let us
>> know what it reports:
>>
>> printVarSummary(U)
>>
>> Also, it would help to see how you are calling
>> gsn_csm_streamline_scalar_map, and what resources you're setting.
>>
>> I verified that a small test code works just fine, which I've attached
>> here, along with the data file.
>>
>> --Mary
>>
>>
>> On Wed, Jul 5, 2017 at 6:14 PM, Meina Wang <mnawang at ucdavis.edu> wrote:
>>
>>> Dear All,
>>>
>>> I wanted to use the function "gsn_csm_streamline_scalar_map" to plot
>>> wind streamline using U and V, with color-coded scaler field sqrt(U^2+V^2),
>>> but got "segmentation fault".  I then switched to function "gsn_csm
>>> _vector_scalar_map_ce" to do wind barb plot instead using the same data
>>> and it worked well.  I have previously used the streamline function and had
>>> no problem at all, so I'm wondering if any of you recently ran into the
>>> same "segmentation fault" issue as I did.  Is it the internal code of
>>> the function crashed?  Thank you.
>>>
>>> P.S. I'm using the NCL version 6.4.0. and ran on Linux machine with gcc
>>>  (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4
>>>
>>> Best,
>>> Meina
>>>
>>> --
>>> Meina Wang
>>> PhD candidate in Atmospheric Science
>>> Department of Land, Air and Water Resources
>>> University of California, Davis
>>> Davis, CA 95616
>>>
>>> _______________________________________________
>>> ncl-talk mailing list
>>> ncl-talk at ucar.edu
>>> List instructions, subscriber options, unsubscribe:
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>>>
>>>
>>
>
>
> --
> Meina Wang
> PhD candidate in Atmospheric Science
> Department of Land, Air and Water Resources
> University of California, Davis
> Davis, CA 95616
> _______________________________________________
> ncl-talk mailing list
> ncl-talk at ucar.edu
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>
>
>

-- 
Meina Wang
PhD candidate in Atmospheric Science
Department of Land, Air and Water Resources
University of California, Davis
Davis, CA 95616
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