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#1099 evaluateJacobian seems to be wrong for Q1LocalBasis

Metadata

Property Value
Reported by Andreas Lauser (andreas.lauser@iws.uni-stuttgart.de)
Reported at May 8, 2012 12:09
Type Bug Report
Version 2.1
Operating System Unspecified / All
Last edited by Christian Engwer (christi@conan.iwr.uni-heidelberg.de)
Last edited at May 8, 2012 12:33
Closed by Christian Engwer (christi@conan.iwr.uni-heidelberg.de)
Closed at May 8, 2012 12:33
Closed in version Unknown
Resolution Not a bug
Comment multilinear is not linear

Description

I've just noticed that evaluateJacobian() for Q1 elements seem to produce jacobian vectors which depend on the position. if I'm not completely wrong (which is quite possible), this finite element is supposed to be linear in respect to all coordinates and the local gradients should be feature either -1 or 1 for all coordinates. Taking the partial derivatives on in[j] in q1localbasis.hh is also consistent with this view. I've attached a patch for dune-localfunctions (against the current dune 2.1 SVN release branch) to fix this issue. I suppose that since this issue is not present at the corners of the element, the gradients of this finite element have probably never been tested in the interior. On the other hand I might just miss something; in this case I would like to apologize for the noise.

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