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You should not include surfaces in a volume domain, that causes the
problem with the jacobian.<br>
So, the problem is solved when definining your domain as:<br>
Vol= #{Vbox};<br>
Now, for imposing your potential, you have to include the surfaces in
the support of the basis function, i.e.:<br>
FunctionSpace {<br>
{ Name fs_vglob ; Type Form0 ; // so we have scalars<br>
BasisFunction {<br>
{ Name sn ; NameOfCoef vn ; Function BF_Node ;<br>
Support Region[{Vol, Sbc}] ; Entity NodesOf[ All] ; }<br>
}<br>
Constraint {<br>
{ NameOfCoef vn ;<br>
EntityType NodesOf ; NameOfConstraint
GlobalElectricPotential ; }<br>
}<br>
}<br>
<br>
That solves the problem.<br>
Ruth<br>
<br>
<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:tptrsn@ksu.edu">tptrsn@ksu.edu</a> wrote:
<blockquote cite="mid:1202856044.47b2206c592db@webmail.ksu.edu"
type="cite">
<pre wrap="">Hello,
while working with GetDP, my major professor found this bug in GetDP. I
am wondering if anyone has explanation of this.
Attached are .geo and .pro filed of the two cases. In each they are the
same cube geometry with a simple electrostatics case of a fixed voltage
on one surface and a Neumann boundary condition specifying grad V on
the opposing surface.
In the file appropriately named -works, the side of the cube
corresponding to the +z face is set to a voltage and the -z face is set
to grad v = -5.
This solution runs and provides the expected results of a linear
gradient of voltage throughout the cube.
The file named -fails is the exact same problem as the previous example,
but the surfaces for the boundary conditions have been shifted to the
opposing faces named the Sright and Sleft. In this case the program
returns the following error:
GetDP : Error : Null determinant in 'Get_InverseMatrix'
By symmetry this is the same problem, we have just turned the cube on
one side, yet the solution fails and returns the same error message.
the combination of the other sides also returns the error message.
Sincerely,
Todd Petersen
Kansas State University
</pre>
<pre wrap="">
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</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Dr. Ir. Ruth V. Sabariego
University of Liege, Institut Montefiore,
Dept. of Electrical Engineering & Computer Science,
Applied & Computational Electromagnetics (ACE),
Sart Tilman Campus, Grande Traverse, 10 (B28), B-4000 LIEGE, Belgium
phone: +32-4-3663737 -- fax: +32-4-3662910 -- <a class="moz-txt-link-freetext" href="http://elap.montefiore.ulg.ac.be/">http://elap.montefiore.ulg.ac.be/</a></pre>
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