On Sat, Nov 12, 2011 at 5:50 PM, behzad baghapour <span dir="ltr"><<a href="mailto:behzad.baghapour@gmail.com">behzad.baghapour@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
So, I am solving the Euler equations (inviscid compressible flow) using discontinuous Galerkin method:<br><br>M (dQ/dt) = R,<br><br>R = nonlinear residual,<br>M = mass matrix,<br><br>Implicit procedure:<br>F = M*(Q^(n+1)-Q^n)/DT - R,<br>
dF/dQ=J=M/DT-dR/dQ,<br>Newton => Q^(n+1) = Q^n - (dF/dQ)^(-1) F ( with proper preconditioning )<br><br>The nonlinear residual and Jacobian matrix are evaluated with a face-based method. Two integrals are involved (the effect of element internal connections and face flux connections). All of my calculations of flow states are solved and stored in arrays of objects called elements.So my residual and Derivative of residual routines are developed based on the element (and face) objects. Then it is better for me to keep them when using petsc as a nonlinear solver.<br>
</blockquote><div><br></div><div>Pass your mesh data structure in using the ctx argument for your residual and Jacobian evaluation routines.</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hope these make any help.<br>Thanks, <br><font color="#888888">Behzad<br>
</font></blockquote></div><br><br clear="all"><div><br></div>-- <br>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>
-- Norbert Wiener<br>