<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dmitry,<div><br></div><div><div><div>On Aug 12, 2012, at 3:13 AM, Dmitry Karpeev <<a href="mailto:karpeev@mcs.anl.gov">karpeev@mcs.anl.gov</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div class="gmail_quote">On Sat, Aug 11, 2012 at 6:36 PM, Subramanya Gautam Sadasiva <span dir="ltr"><<a href="mailto:ssadasiv@purdue.edu" target="_blank">ssadasiv@purdue.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
I was trying the snes solver on the obstacle problem by modifying miscellaneous ex 7 and I get only linear convergence times.Is this what is expected from the virs solver?<br></blockquote><div>Yes, in the sense that you can't expect Newton's typical quadratic convergence: you are not using Newton's method in the usual sense,</div>
<div>since the linear (and, in a sense, the nonlinear) problem you are solving changes every time the coincidence set changes.</div></div></blockquote><div><br></div><div>You see this is really bad for a case like mine where essentially I am solving a quadratic problem with box constraints (Jac and Constraints are constant during each solve). Is there anything we can do to use this structure shouldn't we be able to get a quadratic convergence ?</div><div><br></div><div>Thanks,</div><div>Ata</div><br><blockquote type="cite"><div class="gmail_quote"><div><br></div><div>Dmitry. </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
THanks,<br>
Subramanya<br>
<br>
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