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Re: [cgal-discuss] 2D Arrangement - Precondition error


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  • From: Efi Fogel <>
  • To:
  • Subject: Re: [cgal-discuss] 2D Arrangement - Precondition error
  • Date: Tue, 10 May 2016 09:38:01 +0300
  • Authentication-results: mail2-smtp-roc.national.inria.fr; spf=None ; spf=Pass ; spf=None
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Are you sure your segments are disjoint in their interiors?
Even if they were before they were saved in a file, if they were saved using (inexact) floating point, they might have turned into non disjoint.
I suggest you replace insert_non_intersecting_curves() with insert() and observe.

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On Tue, May 10, 2016 at 12:54 AM, Everton Constantino <> wrote:
Hi,
I'm new to CGAL, so forgive me if my question is answered somewhere
else and I failed to find the answer.

I'm reading a very big file with a set of straight segments, after
reading each segment I use the insert_non_intersecting_curves to add
them. I have the same exact setup from here
http://doc.cgal.org/latest/Visibility_2/index.html

I can read all the file in small chunks but when I try to read the whole
thing I get the following error during the execution of the
insert_non_intersecting_curves:
terminate called after throwing an instance of
'CGAL::Precondition_exception'
  what():  CGAL ERROR: precondition violation!
  Expr: comp_f(object, nodeP->object) != LARGER
  File: /usr/include/CGAL/Multiset.h
  Line: 2141

I'm using CGAL from Archlinux repo, latest stuff.

Tried reading the docs to find what this precondition means but no luck.
The segments are actually roads. I tried changing to the non_caching
version since data is sparsely connected but no luck either, same error.

If I read half the file, for example, the thing runs perfectly. If I try
to read around the segment that gave the error it also works fine.

Am I doing something obviously stupid?

Regards,
--
Everton R. Constantino <>
"Success is overrated"




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