[Octave-bug-tracker] [bug #45295] Division by Zero in 2nd derivative of NURBS surface

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?45295>

                 Summary: Division by Zero in 2nd derivative of NURBS surface
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Mi 10 Jun 2015 12:50:42 UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Sven
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: other
        Operating System: Any

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Details:

When I try to calculate the 2nd derivatives (Hessian) of my NURBS surface, I
get several divisions by Zero, that happen in bspderiv (the difference of the
subtracted knots is zero). This results in several (+-) Inf and NaN entries in
the Hessian.

I have attached my example data + the commands that lead to the error.



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File Attachments:


-------------------------------------------------------
Date: Mi 10 Jun 2015 12:50:42 UTC  Name: nrb.m  Size: 167kB   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=34194>

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