<div dir="ltr"><div dir="ltr">On Mon, Oct 13, 2025 at 2:52 AM Miguel Salazar <<a href="mailto:miguel.salazar@corintis.com">miguel.salazar@corintis.com</a>> wrote:</div><div class="gmail_quote gmail_quote_container"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg-2607426913528195505">





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<p class="MsoNormal"><span lang="EN-US">Hi,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Is there an off-the-shelf solver or preconditioner in PETSc to handle advection-diffusion equations with large Peclet numbers (Pe > 2000)? The equations are solved with the FEM and ideally, one could just use the solver
 through the PETSc settings without having to set up any mesh hierarchy or partitioning (no geometric multigrid or domain decomposition). I read that the Approximate Ideal Restriction method is appropriate for this kind of problems, but the documentation is
 scarce. Any pointers are welcome.<br></span></p></div></div></div></blockquote><div><br></div><div>Hi Miguel,</div><div><br></div><div>We are in the process of integrating PFLARE (<a href="https://urldefense.us/v3/__https://gitlab.com/petsc/petsc/-/merge_requests/8776__;!!G_uCfscf7eWS!ZJ-UU8WRuA_VDt1Dm2hWiknuosHNCBYsXeE5bRhQvYUKO5f9hYqWqO0EPybEBT8sF5mV_wS98QMoE9AUh7nc$">https://gitlab.com/petsc/petsc/-/merge_requests/8776</a>), which is an AIR package from Steve Dargaville at Imperial. Hopefully in the next few days. You could try out the branch until then and let us know if you have problems.</div><div><br></div><div>  Thanks,</div><div><br></div><div>     Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg-2607426913528195505"><div lang="en-CH" style="overflow-wrap: break-word;"><div class="m_-2607426913528195505WordSection1"><p class="MsoNormal"><span lang="EN-US">
Thanks,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Miguel<u></u><u></u></span></p>
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</div></blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="https://urldefense.us/v3/__http://www.cse.buffalo.edu/*knepley/__;fg!!G_uCfscf7eWS!ZJ-UU8WRuA_VDt1Dm2hWiknuosHNCBYsXeE5bRhQvYUKO5f9hYqWqO0EPybEBT8sF5mV_wS98QMoE4QRYI1L$" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>