List Info

Thread: Re: Re: graphviz-interest Digest, Vol 51, Issue 22
Re: Re: graphviz-interest Digest, Vol 51, Issue 22
country flaguser name
United States		 2008-06-03 10:58:12 
John Ellson wrote:
>
> But how is this going to be used?     To be useful
doesn't the 
> consumer of the output file
> also have to use inotify (or equivalent) ?      What
apps do that?
>
The original poster (Parker Jones) wanted to do:

> $ mkfifo dot_pipe
> $ dot < dot_pipe -Tpng -o changing_graph.png
Presumably he would shove a graph into the pipe and then
look into 
changing_graph.png to get the output.
I'm not sure how synchronization is guaranteed.

> If the output is not being watched, isn't it more
efficient to run dot 
> to generate the output file only on demand?
>
>
I don't know what constraints Parker has in his
application.

    Emden

_______________________________________________
graphviz-interestresearch.att.com
https://mailman.research.att.com/mailman/list
info/graphviz-interest
RE: Re: graphviz-interest Digest, Vol 51, Issue 22
country flaguser name
Belgium		 2008-06-03 17:26:43 

  


  

    
> > But how is this going to be used?     To be useful doesn't the 
> > consumer of the output file
> > also have to use inotify (or equivalent) ?      What apps do that?
> >
> The original poster (Parker Jones) wanted to do:
> 
> > $ mkfifo dot_pipe
&gt; > $ dot < dot_pipe -Tpng -o changing_graph.png
&gt; Presumably he would shove a graph into the pipe and then look into 
> changing_graph.png to get the output.
&gt; I'm not sure how synchronization is guaranteed.
> 
> > If the output is not being watched, isn't it more efficient to run dot 
> > to generate the output file only on demand?
&gt; >
> >
> I don't know what constraints Parker has in his application.

Here is my use case.
I have a graph that evolves over time as a result of intensive computation.  Starting off with an initial graph, a series of changes (add edge, remove edge) is applied.&nbsp; The time between changes ranges from a few seconds to a week or more. ;  The current graph needs to be shown.&nbsp; 

So the pipeline I have in mind looks like this (to expand on what Gordon has already said):

graph_producer -->&nbsp; dynagraph --> dot  --> image_viewer

The purpose of using dynagraph is to avoid dramatic changes in layout.

graph_producer -->&nbsp; dynagraph:  ; is via a pipe (dynagraph's incr language)
dynagraph --> dot:   is via a pipe (dot's graph language)
dot  --> image_viewer:  is via png file. ; I have been using qiv that has inotify (or something similar) built in. (Didn't know about dot's -Txlib option until John's post earlier today).

In preliminary tests I have graph_producer --> dot --> image_viewer working.&nbsp; So far dot seems to be happy receiving multiple graphs via pipe. ; The viewer complains a bit (presumably because the png is empty/incomplete at some timepoints) but redirecting to /dev/null solves that quite nicely 

So with the exception of the change to dot's -O option reported in my last post and a (hopefully) minor issue with dynagraph, I am hoping this may be a workable solution.&nbsp; However, I'm always open to suggestions.

Cheers,
Parker

MSN NZ Travel  Get inspired - dream, research, plan and book your next holiday online with 		
  

  
  
   
     
    






 [1-2]











   
 





about | contact  Other archives ( Real Estate discussion Medical topics )