CGAL users discussion list

[Belén <>]

I think that's the problem.
Thank you very much!!
Belén.

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Date: Fri, 6 Dec 2013 11:21:36 +0200
From:
To:
Subject: Re: [cgal-discuss] Join polygons after using intersection and difference.

You need to use the exact-predicate-exact-kernel not only for the definition of the Boolean Set Operation (BSO) data structures and free functions, but also for related operations, especially for computing the intersections, if you want to use the results again as input for BSO. You should use the number type defined by the kernel and probably not convert numbers from that type back and forth to inexact types (e.g., floating point).

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On Thu, Dec 5, 2013 at 6:41 PM, Belén <> wrote:

Thanks a lot!!
This is a great idea! I think this might be the problem. I convert to smaller types between operations.
I'll try your solution!!
Regards and thanks again.

Belén.

> Date: Thu, 5 Dec 2013 08:14:30 -0800
> From:

> To:
> Subject: Re: [cgal-discuss] Join polygons after using intersection and difference.
>

> Hi,
>
> Have you checked all conversions between inexact values (like double) and
> exact values (like CGAL::gmpq)?
>
> In particular, you should check that when you're importing inexact geometric
> data from files, you must convert them into exact representation and then
> only use this exact representation. Convert them back in inexact
> representation *only* for display / export purposes.
>
> I've already done this kind of mistake:
>
> My_inexact_structure a = import_from_file("...")
> CGAL::Exact_structure b = convert_to_exact(a)
> CGAL::Exact_structure c = CGAL::apply_some_algorithm(b)
> My_inexact_structure d = convert_to_inexact(c)
> display(d)
> CGAL::Exact_structure e = convert_to_exact(d) // Gives cgal assertion
> violation or some indesirable stuff
>
> I hope this advice to be helpful for solving your problem.
> Regards,
>
> Hugo Loi
> PhD student at Inria - Maverick team
>
>
>
> --
> View this message in context: http://cgal-discuss.949826.n4.nabble.com/Join-polygons-after-using-intersection-and-difference-tp4658509p4658522.html
> Sent from the cgal-discuss mailing list archive at Nabble.com.
>
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