[ncl-talk] open more than 15 workstations at one time

[Dave Allured - NOAA Affiliate]

Zhifeng,

Please include the ncl-talk address in all replies.

On Fri, Jul 3, 2015 at 3:57 PM, Zhifeng Yang <yangzf01 at gmail.com> wrote:

> Hi Dave,
> What's the meaning of running multiple NCL processes?
>

Start several copies of NCL running in the background, from your shell
command window, or from a shell script.  Or you can use the NCL "system"
command to start background processes directly from an NCL main program.

You run a process in the background by putting an ampersand "&" at the end
of the command line, at least on Linux and Unix-like systems.  See your
shell documentation.  For example:

    ncl plot.ncl var=\"precip\" time=6 &
    ncl plot.ncl var=\"temp\" time=6 &
    ncl plot.ncl var=\"uwind\" time=6 &
    ncl plot.ncl var=\"vwind\" time=6 &

In this example, the variables "var" and "time" would tell each copy of the
program which variable and which time step to plot.

Actually, the reason that I need to open more than 15 workstations is
> plotting more than 15 variables at the same time and each variable has tons
> of images. I need to distinguish the plot names based on variable names.
>

Multiple background processes will do this.  As you said, each process can
have up to 15 workstations open.  That means 15 X11 windows open, each
displaying one plot, all on the same computer desktop.

Actually, it would be simpler to open only one workstation and make one
plot from each process, and just have a lot of separate NCL processes
running at the same time.

Do you know any hint on how to investigate the internals of NCL and support
> libs?
>

NCL and most of its support libraries are open source software.  That means
you can find and download free copies of the source code, and study how
they works.  Please see the NCL info pages on downloading and installation,
for more details.

--Dave



> On Fri, Jul 3, 2015 at 5:45 PM, Dave Allured - NOAA Affiliate <
> dave.allured at noaa.gov> wrote:
>
>> Zhifeng,
>>
>> The easiest way would be to run multiple NCL processes at the same time.
>> Otherwise you are probably into investigating the internals of NCL and
>> support libraries.
>>
>> Depending on what you are trying to do, you might need to have one master
>> NCL program tell multiple slave processes what to display.  HTH.
>>
>> --Dave
>>
>>
>> On Fri, Jul 3, 2015 at 3:35 PM, Zhifeng Yang <yangzf01 at gmail.com> wrote:
>>
>>> Hi
>>> I intend to open more than 15 workstations at one time (likely 100
>>> workstations). However, when I open more than 15 workstations, I got the
>>> following error.
>>>
>>> fatal:WorkstationInitialize: Limit reached for number of simultaneous
>>> GKS Workstations
>>> fatal:Unable to initialize layer-Can't Create
>>>
>>> And I find the following statement in the description of function
>>> gsn_open_wks.
>>> "You can have up to fifteen PostScript workstations open at one time,
>>> but you can only have one NCGM or PDF workstation open at one time."
>>>
>>> Is there any way to open more than 15 workstations at one time?
>>>
>>> Thank you
>>> Zhifeng
>>>
>>
>
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