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We don't consider drop tolerance preconditioners as reliable or robust so I don't see anyone implementing it. On Feb 27, 2024, at 10: 11 AM, Константин Мурусидзе <konstantin. murusidze@ math. msu. ru> wrote: Thank you! Should we expect it
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<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;"><div><br></div> We don't consider drop tolerance preconditioners as reliable or robust so I don't see anyone implementing it.<div><br></div><div><br id="lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Feb 27, 2024, at 10:11 AM, Константин Мурусидзе <konstantin.murusidze@math.msu.ru> wrote:</div><br class="Apple-interchange-newline"><div><div>Thank you! Should we expect it to appear in the near future?</div><div><br></div><div><br></div><div>27.02.2024, 18:07, "Barry Smith" <bsmith@petsc.dev>:</div><blockquote><div><br></div> I'm sorry for the confusion. PETSc does not have a drop tolerance ILU so this function does nothing as you've noted.<div><br></div><div> Barry</div><div><br id="1197d38eabd6a1f130a6b8653e70493blineBreakAtBeginningOfMessage"><div><br><blockquote><div>On Feb 27, 2024, at 7:27 AM, Константин Мурусидзе <<a href="mailto:konstantin.murusidze@math.msu.ru">konstantin.murusidze@math.msu.ru</a>> wrote:</div><br class="34bd394265c9c48ce7af3175baf9655dApple-interchange-newline"><div><div id="d18b04406b72166485ba660d39850c07pfptBannera03q3qf" dir="ltr" style="background-color:rgb( 208 , 216 , 220 ) !important;border-radius:4px !important;border-top-color:rgb( 144 , 164 , 174 ) !important;border-top-style:solid !important;border-top-width:4px !important;display:block !important;font-family:'revert' !important;margin-bottom:16px !important;margin-left:0px !important;margin-right:0px !important;margin-top:16px !important;min-width:200px !important;padding-bottom:8px !important;padding-left:16px !important;padding-right:16px !important;padding-top:8px !important;text-align:left !important"><div id="d18b04406b72166485ba660d39850c07pfptBannera03q3qf" style="display:block !important;float:left !important;font-family:'unset' !important;margin-bottom:1px !important;margin-left:0px !important;margin-right:0px !important;margin-top:0px !important;max-width:600px !important"><div id="d18b04406b72166485ba660d39850c07pfptBannera03q3qf" style="background-color:rgb( 208 , 216 , 220 ) !important;display:block !important;font-family:'arial' , sans-serif !important;font-size:14px !important;font-weight:bold !important;line-height:18px !important;visibility:visible !important">This Message Is From an External Sender</div><div id="d18b04406b72166485ba660d39850c07pfptBannera03q3qf" style="background-color:rgb( 208 , 216 , 220 ) !important;display:block !important;font-family:'arial' , sans-serif !important;font-size:12px !important;line-height:18px !important;margin-top:2px !important;visibility:visible !important">This message came from outside your organization.</div></div><div style="clear:both !important;display:block !important;font-size:0.01px !important;height:0px;line-height:0 !important;visibility:hidden !important"></div></div><div style="font-family:'helvetica';font-size:18px;font-style:normal;font-weight:400;text-align:start;text-decoration:none;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">Hello! I have such problem, while solving linear system and using PCFactorSetDropTolerance. As I understand this function could significantly reduce number of iterations of system of solution, but there is no iterations decreasing.<span style="background-color:transparent">I had try a lot of options for this function, but there is no result</span><div>Could you suggest me if I have some mistake, while I setting up the preconditioner?</div><div> </div><div> PetscCall(KSPSetType(ksp, KSPCG));</div></div><div style="font-family:'helvetica';font-size:18px;font-style:normal;font-weight:400;text-align:start;text-decoration:none;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><div><div> PetscCall(KSPSetInitialGuessNonzero(ksp,PETSC_TRUE));</div><div> PetscCall(KSPSetNormType(ksp, KSP_NORM_DEFAULT));</div><div> PetscCall(KSPCGSetType(ksp, KSP_CG_SYMMETRIC));</div></div><div> </div><div><div> PetscCall(KSPGetPC(ksp, &pc));</div><div> PetscCall(PCSetType(pc, PCILU));</div><div> PetscCall(PCFactorSetShiftType(pc, MAT_SHIFT_POSITIVE_DEFINITE));</div><div> </div><div> PetscCall(PCFactorSetLevels(pc, 2));</div><div> PetscCall(PCFactorSetReuseOrdering(pc,PETSC_TRUE));</div><div> PetscCall(PCFactorSetDropTolerance(pc, 1.e-5, 1.e-3, 10000));</div><div> PetscCall(PCFactorSetZeroPivot(pc, 1.e-3));</div><div> PetscCall(KSPSetTolerances(ksp, 1.e-8, 1.e-8, PETSC_DEFAULT, PETSC_DEFAULT));</div></div><div> </div><div><div> PetscCall(KSPSetFromOptions(ksp));</div></div><div> </div><div><div> PetscCall(KSPSolve(ksp, b, x));</div><div> PetscCall(KSPGetIterationNumber(ksp, &its));</div></div></div></div></blockquote></div><br></div></blockquote></div></blockquote></div><br></div></body></html>