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Yes, but I need to get A, x and b out, so that I can test them in pyamg for other preconditioner options. I can get A, x, and b through what I described, but I do not think x or b is the original one in the linear system. </div>
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Is there a simple way to get x and b (I just need once) of TS? Thanks.</div>
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Qi </div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Matthew Knepley <knepley@gmail.com><br>
<b>Sent:</b> Thursday, November 10, 2022 6:15 AM<br>
<b>To:</b> Tang, Qi <tangqi@msu.edu><br>
<b>Cc:</b> petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> Re: [petsc-users] Get solution and rhs in the ts monitor</font>
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<div dir="ltr">On Thu, Nov 10, 2022 at 3:18 AM Tang, Qi <<a href="mailto:tangqi@msu.edu">tangqi@msu.edu</a>> wrote:<br>
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Hi,</div>
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How could I get rhs and solution in a ksp solve of ts?</div>
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I am testing a linear problem (TS_Linear) using a bdf integrator. I tried to get the operator, rhs, and solution in the ts monitor through TSGetKSP and KSPGet***. But r = Ax-b is much larger than the ksp norm. I know the solver works fine. </div>
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<div>Ax - b is the _unpreconditioned_ norm. By default we are printing the preconditioned norm. You can see the difference by running with</div>
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<div> -ksp_monitor_true_residual</div>
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<div> Thanks,</div>
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<div> Matt</div>
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Did I misunderstand something about how TS works here? Perhaps one of the vectors is changed after the ksp solve? If so, is there a simple way to get rhs and solution that ksp of ts solved?</div>
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Thanks,</div>
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Qi</div>
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<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>
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