Graph not updating on startup

[Ben Lewis]

Hi Trevor,

Your update rate should not necessary be the same as your sampling rate. For slow sampling rates 
(e.g. less than 1 Hz) this may be okay but no so for faster sampling rates.

I guess it depends on whether your data file is local or remote (accessed over a network). My data 
files are typically remote. I regularly sample multiple channels at 10 kHz and use a Kst update 
interval of 1 sec. This means that Kst reads 10k new samples every update. If I set the Kst interval 
to 100 microseconds Kst would not have time to read each sample before the next sample was produced.

I would suggest starting with an update interval of around one second and then reducing this in 
steps if there are no update problems. In your case this means Kst will read 20 new samples on each 
update.

Regards, Ben


On 24/03/2017 10:36 AM, Trevor Young wrote:
> The file is ascii.  I have the update type set to change detection.  Perhaps time interval would 
> be better. It is a 20hz data feed so I'll try setting the update interval to 50ms.
>
> Your test loop seems to work fine.
>
> On Thu, Mar 23, 2017 at 12:53 PM, Barth Netterfield <netterfield at astro.utoronto.ca 
> <mailto:netterfield at astro.utoronto.ca>> wrote:
>
>     I just tried the following test:
>     in one terminal:
>
>     while 1;
>     do date +%s >> tmp.dat && sleep 1
>     done
>
>     In another terminal
>
>     kst2 tmp.dat -y 1
>
>     The resulting plot updates every second, as expected.  Can you try this test?
>
>
>     On Thu, Mar 23, 2017 at 6:46 PM, Barth Netterfield <netterfield at astro.utoronto.ca
>     <mailto:netterfield at astro.utoronto.ca>> wrote:
>
>         Hmmm... these are ascii files?
>
>         It sounds like the update type isn't getting set right.
>
>         If you open one of the vectors in the vector edit dialog, what does it say the update type is?
>
>
>
>         On Thu, Mar 23, 2017 at 6:35 PM, Trevor Young <tnyoung at hawaii.edu
>         <mailto:tnyoung at hawaii.edu>> wrote:
>
>             Actually I must have originally gotten the package from the opensuse binaries page.  I
>             installed a package from the ubuntu vivid ppa but still have the same problem. Perhaps
>             it is debian related.  Nobody else has ever experienced this?
>
>             On Thu, Mar 23, 2017 at 10:54 AM, Trevor Young <tnyoung at hawaii.edu
>             <mailto:tnyoung at hawaii.edu>> wrote:
>
>                 You're right, I thought I had grabbed 2.0.8 from the ubuntu ppa but I had only
>                 gotten 2.0.3 from the debian repo. I have several debian systems where I am happy
>                 to pull from the ubuntu ppa but I have another system where a kst binary isn't
>                 available at all so I'd like to learn to compile and it uses qt5 instead of qt4. 
>                 How do I effect the cmake switch mentioned on the kst source page?
>
>                 Thanks
>
>                 Trevor
>
>                 On Thu, Mar 23, 2017 at 3:06 AM, C Barth Netterfield
>                 <netterfield at astro.utoronto.ca <mailto:netterfield at astro.utoronto.ca>> wrote:
>
>                     Hi, Trevor,
>
>                     Unfortunately, the version of kst in debian is extremely old, and full of
>                     known bugs, and there is no maintainer for that debian package :-(
>
>                     We do have an ubuntu ppa we keep up to date (but you would have to switch to a
>                     recent ubuntu)
>
>                     Or you can build from source.  Let me know if you would like some help with
>                     that.
>
>                     cbn
>
>                     On Wednesday, March 22, 2017 8:38:04 PM EDT Trevor Young wrote:
>                     > I have a script logging data to file and use kde to graph it but I often
>                     > encounter an issue with the graph not updating itself on startup.  Kst will
>                     > load an initial set of data, and then a second or so later, do a single
>                     > second update.  The graph won't start live updating until I go into the
>                     > data manager and double click on any of the entries there, then it starts
>                     > to auto update. I don't need to make any changes, just have to double click
>                     > on something and bring up the dialog box. Has anyone else encountered this
>                     > or have an idea why this may be happening?
>                     >
>                     > I'm running an up to date copy of debian stable.
>                     >
>                     > Thanks.
>
>
>
>
>
>                 -- 
>                 Trevor Young
>                 Senior Marine Technician
>                 Ocean Technology Group
>                 University of Hawaii Marine Center
>
>
>
>
>             -- 
>             Trevor Young
>             Senior Marine Technician
>             Ocean Technology Group
>             University of Hawaii Marine Center
>
>
>
>
>         -- 
>         C. Barth Netterfield
>         University of Toronto
>         416-845-0946 <tel:%28416%29%20845-0946>
>
>
>
>
>     -- 
>     C. Barth Netterfield
>     University of Toronto
>     416-845-0946 <tel:%28416%29%20845-0946>
>
>
>
>
> -- 
> Trevor Young
> Senior Marine Technician
> Ocean Technology Group
> University of Hawaii Marine Center
>

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