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<body class='hmmessage'><div dir='ltr'><p class="PreformattedText"><span style="color: rgb(17, 17, 17); font-family: 'Abyssinica SIL'; font-size: 12pt;"> </span><span style="color: rgb(17, 17, 17); font-family: 'Abyssinica SIL'; font-size: 12pt;">Dear all,</span></p>
<p class="PreformattedText"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size: 10.5pt; line-height: 115%; font-family: 'Arial;Liberation Sans;DejaVu Sa', serif;">I am new in PETSC. </span><span lang="EN-US" style="font-family:"Abyssinica SIL";color:#111111;mso-ansi-language:
EN-US">I am trying to test the impact of matrix ordering on the time needed for
solving linear systems. It is known that ordering matrix reduces the fill-in so
solving time decreases also. I use direct package solver 'superLU' and I tested
different orderings but I’ve always found very close execution time values. Here
is the code:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr=
KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr= KSPSetOperators(ksp,A,A,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr=
KSPSetType(ksp,KSPPREONLY);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr=
KSPGetPC(ksp,&pc);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr= PCSetType(pc,PCLU);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr=
PCFactorSetMatSolverPackage(pc,MATSOLVERSUPERLU);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr=
PCFactorSetUpMatSolverPackage(pc);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr =
MatGetOrdering(A,MATORDERINGRCM,&perm,&cperm);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr =
MatGetFactor(A,MATSOLVERSUPERLU,MAT_FACTOR_LU,&F);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr =
MatLUFactorSymbolic(F,A,perm,cperm,<a name="__DdeLink__5_2013988178">PETSC_NULL</a>);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr =
MatLUFactorNumeric(F,A,PETSC_NULL);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr =
PCFactorGetMatrix(pc,&F);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">ierr= KSPSolve(ksp,b,x);CHKERRQ(ierr);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">I execute the program with this
options : -mat_superlu_colperm NATURAL
-mat_superlu_rowperm NOROWPERM. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US">Please tell me what is the problem in my
code.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Abyssinica SIL";
color:#111111;mso-ansi-language:EN-US"> </span></p>
<p class="PreformattedText" style="margin-bottom:14.15pt;line-height:14.25pt"><span style="font-family:"Abyssinica SIL";color:#111111">Kind Regards,<o:p></o:p></span></p>
<p class="PreformattedText" style="margin-bottom:14.15pt;line-height:14.25pt"><span style="font-family:"Abyssinica SIL";color:#111111">Asma.<o:p></o:p></span></p> </div></body>
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