<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Birendra,<div><br></div><div>I forgot to mention in my last e-mail that I was responding to your final question. You can see why this is true by looking at equations 5.35 and 5.36 in the manual.</div><div><br></div><div>Cheers,</div><div>Charles</div><div><br></div><div><br><div><div>On 3/09/2012, at 5:24 AM, Birendra jha wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Dear developers<br><br>I am trying to run my Pylith simulation faster. Right now it takes about 3 min for Linear solve (using default KSP solver, about 960 iterations) and 3 min for integrating residual. I have about 190000 hex cells (mesh is very refined in the center and becomes coarse outward). No faults. Elastic materials. I used non-uniform user specified timesteps.<br><br>I thought of following options:<br><br>(1) Try different solver. I am thinking of using field split preconditioner with multigrid, as in tet4/step02.cfg. <br>(2) Switch from vtk to hdf5 output<br>(3) Run in parallel. I am looking into running it using sge. Or just running it on one multicore machine.<br>(4) Increase linear solve tolerance from 1E-12 to 1E-11.<br>(5) Fix timestep.<br><br>Are these good options to consider?<br><br>I have a question on (5). Manual says<br>Warning: Changing the time step requires recomputing the Jacobian of the system, which can greatly increase the runtime if the time-step size changes frequently.<br><br>Where does this happen in the program, i.e a change in dt setting needNewJacobian=true? I ask this because I could not find message on the stdout about reforming Jacobian when I am using non-uniform dt (it is possible that I missed it, the timesteps remains constant for a while then changes then becomes constant again).<br><br>Thanks and regards<br>Birendra<br>_______________________________________________<br>CIG-SHORT mailing list<br><a href="mailto:CIG-SHORT@geodynamics.org">CIG-SHORT@geodynamics.org</a><br>http://geodynamics.org/cgi-bin/mailman/listinfo/cig-short<br></div></blockquote></div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Charles A. Williams</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Scientist<br>GNS Science<br>1 Fairway Drive, Avalon<br>PO Box 30368<br>Lower Hutt 5040<br>New Zealand<br>ph (office): 0064-4570-4566<br>fax (office): 0064-4570-4600</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a href="mailto:C.Williams@gns.cri.nz">C.Williams@gns.cri.nz</a></div></div></div></span></span>
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