Hi Matt,<br>Thanks a lot for the suggestion.<br><br>Yan<br><br><div class="gmail_quote">On Tue, Jan 26, 2010 at 5:46 AM, Matthew Knepley <span dir="ltr"><<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">You might try the pseudo-transient continuation code.<br><br> Matt<div><div></div><div class="h5">
<br><br><div class="gmail_quote">On Mon, Jan 25, 2010 at 9:03 PM, Ryan Yan <span dir="ltr"><<a href="mailto:vyan2000@gmail.com" target="_blank">vyan2000@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div>Hi All,</div>
<div>Hopefully, this is not considered as an off-topic thread. Since I got snes converged reason -6.</div>
<div> </div>
<div>Can anyone please share some hints on how to find a good inital guess?<br><br>I am solving a nonlinear BVP(steady-states) extracted from a time-dependent problem by setting d/dt=0. The equation is conservational law for mass, momentum, internal energy, with an algebraic heating source. After all, v(velocity), P(pressure), U(fluid internal energy), can be solved from this coupled system. I am using Newton's method for this nonlinear system. Frankly, I do not have a good initial guess for the solver. The only information that I have is the inital condition for the time-dependent problem, where the BVP comes from. I have tried my solver with different inital guess for many times, but with no luck of a satisfying residual reduction.<br>
<br>So, do I have to solve the time-dependent problem after a long time stepping to get a steady solution? Or is there any better way of finding a good initial guess?<br><br>Any suggestion is highly appreciated. <br><font color="#888888"><br>
Yan </font></div>
</blockquote></div><br><br clear="all"><br></div></div><font color="#888888">-- <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>
</font></blockquote></div><br>