<div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Aug 22, 2015 at 10:39 PM, Barry Smith <span dir="ltr"><<a href="mailto:bsmith@mcs.anl.gov" target="_blank">bsmith@mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><span><br>
> On Aug 22, 2015, at 9:26 PM, Mark Adams <<a href="mailto:mfadams@lbl.gov" target="_blank">mfadams@lbl.gov</a>> wrote:<br>
></span><span><br>
> I would vote for (1).<br>
><br>
> Also, I hope cheb->random is the default.<br>
<br>
</span> Well then different machines will produce different convergence histories which is annoying for any kind of "no change" daily testing. Except for you, most of the rest of us don't like the random default, sorry :-)<br></blockquote><div><br></div><div>Well, this bit me and Garth Wells, among others I would guess.</div><div><br></div><div>The problem is that RHS are often smooth and this leads to poor convergence to the highest eigenvalue. As an example on the new ex56, elasticity, cube, traction on one side, the history of the eigen estimator looks like this (appended). Garth mentioned that he uses 50 iterations in the eigen estimator (ie, a lot), and you can see why here, It looks converged at 44 iterations at ~1.42 and then pops up to ~1.72 very quickly. This is such a big jump that it overwhelms the common 1.05 safety factor. If you add <span style="font-size:12.8px">-mg_levels_ksp_chebyshev_</span><span style="font-size:12.8px">esteig_random you see nice smooth and fast convergence (appended).</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Note, the iteration number of this jump seems to be about linear in h, so this will fail with 50 iterations on a larger problem (this one has about 6M dof).</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Now, I guess I can put </span><span style="font-size:12.8px">-mg_levels_ksp_chebyshev_</span><span style="font-size:12.8px">esteig_random in the tutorials as suggested parameters and keep them out of the tests to avoid your issue with regression tests. Right?</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Mark</span></div><div><span style="font-size:12.8px">ps, I'm sure Jed free climbed out of the pit, so you can use his rope.</span></div><div><br></div><div><br></div><div><div style="font-size:12.8px"> 39 KSP Residual norm 5.149666187461e+00 % max 1.423034674475e+00 min 5.820371669083e-04 max/min 2.444920626003e+03</div><div style="font-size:12.8px"> 40 KSP Residual norm 5.157885158697e+00 % max 1.423126042184e+00 min 5.557328840496e-04 max/min 2.560809487850e+03</div><div style="font-size:12.8px"> 41 KSP Residual norm 5.303627521687e+00 % max 1.423199352292e+00 min 5.313351872668e-04 max/min 2.678533977041e+03</div><div style="font-size:12.8px"> 42 KSP Residual norm 5.364384189061e+00 % max 1.423275534927e+00 min 5.062394822273e-04 max/min 2.811466874659e+03</div><div style="font-size:12.8px"> 43 KSP Residual norm 5.490412749639e+00 % max 1.423347554528e+00 min 4.823994222923e-04 max/min 2.950558165607e+03</div><div style="font-size:12.8px"> 44 KSP Residual norm 5.298532106786e+00 % max 1.423435653436e+00 min 4.630735554742e-04 max/min 3.073886721901e+03</div><div style="font-size:12.8px"> 45 KSP Residual norm 5.250150466693e+00 % max 1.444039693619e+00 min 4.458237353578e-04 max/min 3.239037267632e+03</div><div style="font-size:12.8px"> 46 KSP Residual norm 5.355091565702e+00 % max 1.597859894587e+00 min 4.296586330882e-04 max/min 3.718905595128e+03</div><div style="font-size:12.8px"> 47 KSP Residual norm 5.359212994059e+00 % max 1.694500733083e+00 min 4.115503583969e-04 max/min 4.117359391167e+03</div><div style="font-size:12.8px"> 48 KSP Residual norm 5.382627967217e+00 % max 1.715436978188e+00 min 3.945385500813e-04 max/min 4.347957830318e+03</div><div style="font-size:12.8px"> 49 KSP Residual norm 5.333511242816e+00 % max 1.719426018108e+00 min 3.791973408295e-04 max/min 4.534383111304e+03</div><div style="font-size:12.8px"> 50 KSP Residual norm 5.286785239032e+00 % max 1.720488275875e+00 min 3.655323031666e-04 max/min 4.706802274303e+03</div></div><div><br></div><div><span style="font-size:12.8px">with -mg_levels_ksp_chebyshev_</span><span style="font-size:12.8px">esteig_random</span><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><div><div><div> 0 KSP Residual norm 4.587476885185e+05 % max 1.000000000000e+00 min 1.000000000000e+00 max/min 1.000000000000e+00</div><div> 1 KSP Residual norm 5.000026676130e+05 % max 2.096521908651e-01 min 2.096521908651e-01 max/min 1.000000000000e+00</div><div> 2 KSP Residual norm 2.383418066969e+06 % max 9.808897648348e-01 min 5.952257317564e-03 max/min 1.647929033478e+02</div><div> 3 KSP Residual norm 2.574503036099e+06 % max 1.019204519789e+00 min 3.039124767415e-03 max/min 3.353611969855e+02</div><div> 4 KSP Residual norm 2.458678036734e+06 % max 1.244548092713e+00 min 1.992498130768e-03 max/min 6.246169436720e+02</div><div> 5 KSP Residual norm 2.344964690599e+06 % max 1.367637044108e+00 min 1.464901327469e-03 max/min 9.336035256864e+02</div><div> 6 KSP Residual norm 2.331695060244e+06 % max 1.404943514389e+00 min 1.190280622651e-03 max/min 1.180346455830e+03</div><div> 7 KSP Residual norm 2.271960219657e+06 % max 1.437957455093e+00 min 1.008722431370e-03 max/min 1.425523424853e+03</div><div> 8 KSP Residual norm 2.292028741926e+06 % max 1.502852988492e+00 min 8.809546168835e-04 max/min 1.705936900369e+03</div><div> 9 KSP Residual norm 2.233478095421e+06 % max 1.582008563628e+00 min 7.783319825046e-04 max/min 2.032562709986e+03</div><div> 10 KSP Residual norm 2.217240790630e+06 % max 1.627791394511e+00 min 7.017777386360e-04 max/min 2.319525549035e+03</div><div> 11 KSP Residual norm 2.253686552707e+06 % max 1.659357337462e+00 min 6.359067415045e-04 max/min 2.609435046303e+03</div><div> 12 KSP Residual norm 2.327352703032e+06 % max 1.682006777543e+00 min 5.780023151159e-04 max/min 2.910034672103e+03</div><div> 13 KSP Residual norm 2.258932746968e+06 % max 1.695221701128e+00 min 5.272335154902e-04 max/min 3.215314753940e+03</div><div> 14 KSP Residual norm 2.146539128962e+06 % max 1.701712426981e+00 min 4.879541184491e-04 max/min 3.487443517005e+03</div><div> 15 KSP Residual norm 2.146242364688e+06 % max 1.705375519134e+00 min 4.576872864507e-04 max/min 3.726071423917e+03</div><div> 16 KSP Residual norm 2.160438533108e+06 % max 1.708650293977e+00 min 4.278996767955e-04 max/min 3.993109568984e+03</div><div> 17 KSP Residual norm 2.184700124943e+06 % max 1.710853580610e+00 min 4.021751403604e-04 max/min 4.254001326580e+03</div><div> 18 KSP Residual norm 2.148601462370e+06 % max 1.712408913049e+00 min 3.793690742988e-04 max/min 4.513833701954e+03</div><div> 19 KSP Residual norm 2.195737087965e+06 % max 1.713723267846e+00 min 3.583883046289e-04 max/min 4.781749978199e+03</div></div></div></div></div></div></div></div>