<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br><div><br><blockquote type="cite"><div>On Dec 6, 2022, at 5:15 AM, 김성익 <ksi2443@gmail.com> wrote:</div><br class="Apple-interchange-newline"><div><div dir="ltr"><p class="MsoNormal" style="margin:0cm 0cm 8pt;text-align:justify;line-height:107%;font-size:10pt;font-family:"\00b9d1\00c740 \00ace0\00b515""><span lang="EN-US">Hello,</span></p><div style="margin: 0cm 0cm 8pt; text-align: justify; line-height: 107%; font-size: 10pt; font-family: "맑은 고딕";"><span lang="EN-US"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal" style="margin:0cm 0cm 8pt;text-align:justify;line-height:107%;font-size:10pt;font-family:"\00b9d1\00c740 \00ace0\00b515""><span lang="EN-US">I have some questions about pc and mumps_icntl.</span></p><p class="gmail-MsoListParagraph" style="margin:0cm 0cm 8pt 38pt;text-align:justify;line-height:107%;font-size:10pt;font-family:"\00b9d1\00c740 \00ace0\00b515""><span lang="EN-US">1.<span style="font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span><span lang="EN-US">What’s the difference between adopt
preconditioner by code (for example, PetscCall(PCSetType(pc,PCLU)) and option -pc_type
lu??<br>
And also, What’s the priority between code pcsettype and option -pc_type ??<br>
<br>
</span></p><p class="gmail-MsoListParagraph" style="margin:0cm 0cm 8pt 38pt;text-align:justify;line-height:107%;font-size:10pt;font-family:"\00b9d1\00c740 \00ace0\00b515""><span lang="EN-US">2.<span style="font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span><span lang="EN-US">When I tried to use METIS in MUMPS,
I adopted metis by option (for example, -mat_mumps_icntl_7 5). In this situation,
it is impossible to use metis without pc_type lu. However, in my case pc type lu
makes the performance poor. So I don’t want to use lu preconditioner. How can I
do this?</span></p></div></div></blockquote><div> The package MUMPS has an option to use metis in its ordering process which can be turned on as indicated while using MUMPS. Most preconditioners that PETSc can use do not use metis for any purpose hence there is no option to turn on its use. For what purpose do you wish to use metis? Partitioning, ordering, ?</div><div><br></div><div><br></div> <br><blockquote type="cite"><div><div dir="ltr"><div style="margin: 0cm 0cm 8pt; text-align: justify; line-height: 107%; font-size: 10pt; font-family: "맑은 고딕";"><span lang="EN-US"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal" style="margin:0cm 0cm 8pt;text-align:justify;line-height:107%;font-size:10pt;font-family:"\00b9d1\00c740 \00ace0\00b515""><span lang="EN-US">Thanks,</span></p><p class="MsoNormal" style="margin:0cm 0cm 8pt;text-align:justify;line-height:107%;font-size:10pt;font-family:"\00b9d1\00c740 \00ace0\00b515""><span lang="EN-US">Hyung Kim</span></p></div>
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