CGAL users discussion list

[Zohar Levi <>]

Ok, I found the problem with the parameterization. For Floatter's mean coordinates or Tutte's barycenter you need to calculate the lambdas and solve a simple linear system. You solved the linear system using conjugate gradients instead of a simple LU and forward substitution. Could anyone explain this please??

Could anyone hint on the simplest and fastest direction to solve this?

---

From: Laurent Saboret <>
To:
Sent: Tuesday, August 25, 2009 10:59:55 AM
Subject: Re: [cgal-discuss] Parameterization solver

>
> Hi,
>
> I used the parameterizer to parameterize a vertex with its first ring of neighbors (using default values). We are talking about 7 vertices in average. On a larger neighborhood the parameterizer worked fine. On this small neighborhood the default solver almost always complained it couldn't solve the system. Using the Tau solver it worked almost always - there was a time when it crashed during LU factorization - but there's a bigger problem: It took it almost a second to solve the system. This renders it to be impractical.
>
> I think you should also add precompiled debug libraries of the tau solver. I understand it crashes much more than the release version, which makes it unusable, but at least I could compile my application in debug, and operate other parts of it. Adding the libraries would help me with unnecessarily clattering my code with #ifdefs.
>
> Thanks.
>

Hi (again) Zohar,

CGAL 3.4 contains precompiled debug libraries of TAUCS and a few bug fixes in the parameterization code. Please try again with CGAL 3.4 in debug mode.

If the problem is still present, please post your code and input file to this mailing list.

Best regards,
-- Laurent Saboret
INRIA Sophia-Antipolis
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