<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><br class=""></div> So the really old version fails but a slightly newer but still really old version succeeds? I'm sorry but a lot has changed since that time and we really have no way of remembering what could have changed around that time that might cause this. <div class=""><br class=""></div><div class=""><div style="text-align: justify;" class=""> Why can't you use the <span style="color: rgb(51, 51, 51); text-align: justify; background-color: rgb(247, 248, 250); font-family: "Times New Roman";" class="">3.6.3</span><span style="color: rgb(51, 51, 51); text-align: justify; background-color: rgb(247, 248, 250); font-family: "Times New Roman";" class=""> version? Whatever code you are using you could upgrade to use the 3.6.3 </span><span style="text-align: justify; background-color: rgb(247, 248, 250); caret-color: rgb(51, 51, 51);" class=""><font color="#333333" face="Times New Roman" class="">instead</font></span><span style="text-align: justify; background-color: rgb(247, 248, 250);" class=""><font color="#333333" face="Times New Roman" class=""> of the 3.4.5 I actually urge you to upgrade to 3.14 our last release, if it is C code it should relatively <span style="caret-color: rgb(51, 51, 51);" class="">straightforward; if Fortran code then yes it will be a bit more painful but shouldn't take more than a day. And once that painful day is over all the pain of working with a really old version of PETSc will be gone for good.</span></font></span></div><div style="text-align: justify;" class=""><span style="text-align: justify; background-color: rgb(247, 248, 250);" class=""><font color="#333333" face="Times New Roman" class=""><span style="caret-color: rgb(51, 51, 51);" class=""><br class=""></span></font></span></div><div style="text-align: justify;" class=""><span style="text-align: justify; background-color: rgb(247, 248, 250);" class=""><font color="#333333" face="Times New Roman" class=""><span style="caret-color: rgb(51, 51, 51);" class=""> Barry</span></font></span></div><div style="text-align: justify;" class=""><span style="text-align: justify; background-color: rgb(247, 248, 250);" class=""><font color="#333333" face="Times New Roman" class=""><span style="caret-color: rgb(51, 51, 51);" class=""><br class=""></span></font></span></div><div><br class=""><blockquote type="cite" class=""><div class="">On Dec 29, 2020, at 8:41 PM, 朱昭霓 <<a href="mailto:zhuzhaoni2017@hnu.edu.cn" class="">zhuzhaoni2017@hnu.edu.cn</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class=""><br class=""></div><div class=""><font face="Times New Roman" class="">Dear Smith,</font></div><div class=""><font face="Times New Roman" class=""><br class=""></font></div><div class=""><font face="Times New Roman" class=""> Thank you so much for your prompt reply! <span style="font-variant-numeric: normal; font-variant-east-asian: normal; color: rgb(51, 51, 51); line-height: 26px; text-align: justify; background-color: rgb(247, 248, 250);" class="">I have confirmed that the </span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class="">parameters of the</span><span style="font-variant-numeric: normal; font-variant-east-asian: normal; color: rgb(51, 51, 51); line-height: 26px; text-align: justify; background-color: rgb(247, 248, 250);" class=""> linear resolver in these two</span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class=""> versions are the same and I also run the code with</span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class=""> </span>-pc_type lu<span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class="">. It disconverges</span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class=""> after the first</span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class=""> two time steps</span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class="">, </span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class="">showing "line search fails" (I have printed the running results using 3.6.3 and 3.4.5 versions in the following</span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class=""> attachment</span><span style="background-color: rgb(247, 248, 250); color: rgb(51, 51, 51); text-align: justify;" class="">). I wonder if there are some inner functions or parameters which changes with different versions leading to the disconvergence in 3.4.5 version ? </span></font></div><div class=""><br class=""></div><div class="">Best regards,</div><div class="">Zhaoni Zhu</div><div class=""><br class=""></div><div class=""><includetail class=""><div class=""> </div><div class=""> </div><div style="" class=""><div style="FONT-SIZE: 12px;FONT-FAMILY: Arial Narrow;padding:2px 0 2px 0;" class="">------------------ Original ------------------</div><div style="FONT-SIZE: 12px;background:#efefef;padding:8px;" class=""><div id="menu_sender" class=""><b class="">From: </b> "Barry Smith"<<a href="mailto:bsmith@petsc.dev" class="">bsmith@petsc.dev</a>>;</div><div class=""><b class="">Date: </b> Wed, Dec 30, 2020 03:12 AM</div><div class=""><b class="">To: </b> "朱昭霓"<<a href="mailto:zhuzhaoni2017@hnu.edu.cn" class="">zhuzhaoni2017@hnu.edu.cn</a>>; <wbr class=""></div><div class=""><b class="">Cc: </b> "petsc-users"<<a href="mailto:petsc-users@mcs.anl.gov" class="">petsc-users@mcs.anl.gov</a>>; <wbr class=""></div><div class=""><b class="">Subject: </b> Re: [petsc-users] Error occurred when version change</div></div><div class=""> </div><div style="position:relative;" class=""><div id="tmpcontent_res" class=""></div><div class=""><br class=""></div> It looks like both converged in your image, just at different rates? Note the two sides used different number of linear iterations, my guess is some default behavior of the linear solvers changed between those two ancient releases. First make sure both are using identical linear solvers. Then run both with -pc_type lu do they now have the same SNES convergence?<div class=""><br class=""></div><div class=""> Barry</div><div class=""><br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">On Dec 29, 2020, at 2:51 AM, 朱昭霓 <<a href="mailto:zhuzhaoni2017@hnu.edu.cn" class="">zhuzhaoni2017@hnu.edu.cn</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class=""><font class=""><p class="MsoNormal"><span class="src"><span lang="EN-US" class="">Dear Sir or Madam:</span></span> </p><p class="MsoNormal"><span class="src"><span lang="EN-US" class="">Hello, I am a new PETSc
learner. There are some confusions when I using different versions of PETSc. For
some reasons, I have to change my codes from the version 3.6.3 to 3.4.5. Newton
methods in 3.6.3 version converged successfully with the time step size dt=100.
While with the same dt=100 and almost the same codes, Newton methods in version
3.4.5 failed to converge. The debug test indicated that there may be something
wrong during the line search process. I have tried to search the changes in
different versions but failed. Could you please give me some suggestions? Thank
you so much.</span></span> </p><p class="MsoNormal">Best regards,</p><p class="MsoNormal">Zhaoni Zhu</p></font></div><div class=""></div><span id="cid:79511EBA-74DD-4F6D-B4FA-18843E6D98B2" class=""><Error_report.jpg></span></div></blockquote></div><br class=""></div>
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