Le 19 septembre 2018 à 15:28:54, Alan Braslau (braslau.list@comcast.net(mailto:braslau.list@comcast.net)) a écrit:

> On Tue, 18 Sep 2018 19:21:31 -0700
> Fabrice L wrote:
>
> > The problem is that the process take hours of compilations, and
> > tests are not easy to do. Anyway, I will enrich my « minimal » code to my
> > « full » code in order to find the difference… and the problem. I will
> > update the thread as soon as can.
>
> My over 700k object graphics example, processed several times (repeatedly, over several pages with modifications) took less than one minute to process. In fact, each graphic took almost as long to render from the pdf as it did for metapost/lua to process.
> 
> Alan 

I do not know what your example is (but I’m curious: can I see this somewhere ?).

In my case, the long time needed is to check if a new object does not intersect with any other object: so when I try to find the maximum size of the 1000th object at a given position, I have to check with the 999 others… I do this with « intersectiontimes ». And so on for the 10001th… I have a course try to find solutions to gain time, like using the coordinate of a new object: when the coordinate of a new object is chosen, I do not need to check potential intersections with objects far away… but surprisingly (to me) this take more time than to blindly check with every object.

This is an algorithmic problem more than a ConTeXt/Metapost one… but I you have suggestions, I’m sure I can learn !

Below is minimal code. (Just to be clear, this code work, even for 20K objects.)
Thanks.

\starttext
  \startMPpage
  path Obj[] , ObjTemp ;
  pair ObjPos , Inter ;
  numeric NObj ; 
  % Change herte "NObj" to a big numer (says 20K) 
  NObj := 100;
  numeric Danger, MaxSize ;

  % Draw an initial object of random shape and random size ;
  Obj[1]:= fullsquare randomized .001in 
  scaled (uniformdeviate(.5)*1in)
  shifted (uniformdeviate(5)*1in,uniformdeviate(5)*1in) ;
  Obj[1] := curved ( Obj[1] );
  fill Obj[1] withcolor cyan randomized (.2,1.5);
  draw Obj[1] withcolor black randomized (.2,1.5);

  for i=2 upto NObj :
  Danger := 0;
% Choose a position for the object :
  ObjPos := (uniformdeviate(5)*1in,uniformdeviate(5)*1in) ;
  % Choose a form :
  Obj[i] := fullsquare randomized .01in ;
  Obj[i] := curved ( Obj[i] );
  % Choose a scale so the object does not interact with any other object:
    for j=1 upto 50:
       MaxSize := (j*.01in) ;
    ObjTemp := Obj[i] scaled MaxSize shifted ObjPos ;
       %draw ObjTemp withcolor magenta ;
       % Check if this temporary object intersect with any other object :
       for k=1 upto (i-1):
        string trace ;
         Inter := Obj[k] intersectiontimes ObjTemp ;
         if (xpart Inter) <> -1 : Danger := 1; fi ;
         if Danger=1: MaxSize := ((j-1)*.01in) ; fi;
         exitif Danger = 1; 
       endfor;
       exitif Danger = 1; 
  endfor ;
  Obj[i] := Obj[i] scaled MaxSize shifted ObjPos ;

  fill Obj[i] withcolor cyan randomized (.2,1.5);
  draw Obj[i] withcolor black randomized (.2,1.5);
  endfor;
  \stopMPpage
\stoptext