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<P><FONT SIZE=2 FACE="Arial">I apologise in advance for sending such a newbie question to the list. In Payment if someone could</FONT>
<BR><FONT SIZE=2 FACE="Arial">set me on my way I will add my simple example(s) to the main example list.</FONT>
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<P><FONT SIZE=2 FACE="Arial">In an effort to walk (more of a crawl) before I run I am trying to simply</FONT>
<BR><FONT SIZE=2 FACE="Arial">calculate the voltage and current density distribution in a flat bar of copper (no temperature effects assumed)</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Fragments for this exist in the mail archives as well as documentation. However,</FONT>
<BR><FONT SIZE=2 FACE="Arial">I must be doing something wrong as my results are always zero when using Dirichlet BC at both ends</FONT>
<BR><FONT SIZE=2 FACE="Arial">and constant (but non-zero) when I use dirichlet at one end and Neumann BC at the other.</FONT>
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<P><FONT SIZE=2 FACE="Arial">I assume that the null Neumann BC along the long sides is implicit.</FONT>
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<P><FONT SIZE=2 FACE="Arial">I have attached my .geo, .pro and solver.par files for the Dirichlet BC (1V at one end 0v at the other)</FONT>
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<P><FONT SIZE=2 FACE="Arial">THe Formulation was :</FONT>
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<P><FONT SIZE=2 FACE="Arial">Formulation {</FONT>
<BR><FONT SIZE=2 FACE="Arial"> { Name Voltage_Steady ; Type FemEquation ;</FONT>
<BR><FONT SIZE=2 FACE="Arial"> Quantity { </FONT>
<BR><FONT SIZE=2 FACE="Arial"> { Name Volt ; Type Local ; NameOfSpace Vgrad ; }</FONT>
<BR><FONT SIZE=2 FACE="Arial"> }</FONT>
<BR><FONT SIZE=2 FACE="Arial"> Equation {</FONT>
<BR><FONT SIZE=2 FACE="Arial"> Galerkin { [ invrho[] * Dof {d Volt} , {d Volt} ] ; </FONT>
<BR><FONT SIZE=2 FACE="Arial"> In Bar ; Jacobian JVol ; Integration GradGrad ; }</FONT>
<BR><FONT SIZE=2 FACE="Arial"> }</FONT>
<BR><FONT SIZE=2 FACE="Arial"> }</FONT>
<BR><FONT SIZE=2 FACE="Arial">}</FONT>
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<P><FONT SIZE=2 FACE="Arial">When I run the Dirichlet at both ends I receive a Warning: Null right Hand Side in Linear Equation</FONT>
<BR><FONT SIZE=2 FACE="Arial">which I assume is correct given the problem formulations. I also get an indication that NaN is</FONT>
<BR><FONT SIZE=2 FACE="Arial">being generated in the SOlver (GMRES).</FONT>
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<P><FONT SIZE=2 FACE="Arial">Not surprisingly the Warning goes away when I use the Neumann BC. THe Solver does not report any</FONT>
<BR><FONT SIZE=2 FACE="Arial">NaN problems.<FONT FACE="Arial" SIZE=2 COLOR="#000000"> <<simpleBar.geo>> </FONT><FONT FACE="Arial" SIZE=2 COLOR="#000000"> <<simpleBar.pre>> </FONT><FONT FACE="Arial" SIZE=2 COLOR="#000000"> <<solver.par>> </FONT></FONT>
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<P><FONT SIZE=2 FACE="Arial">Thanks, the mail archives have been a big help</FONT>
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<P><FONT SIZE=2 FACE="Arial">Laird Bolt</FONT>
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