<div dir="ltr">Hi,<div> When I try to increase the number of processors to solve the same matrix(to acquire the smallest eigenvalue) , I find all the results differ from each other within the 1e-5 scope (Though the ||Ax-kx||/||kx|| are all achieve 1e-8) . And the solve time are first decreasing then increasing.</div><div>my question is </div><div>(1) Is there anyway to make the result more constant </div><div>(2) Does the time decreasing because the matrix dimension are too small for so many processors? Is there any way to reduce the solve time when increasing the number of processors?</div><div><br></div><div>Thank you!</div><div>Runfeng</div><div><br></div><div><br></div><div>matrix type MATSBAIJ</div><div>matrix dimension 2078802</div><div>solver krylovschur</div><div>blocksize 1<br><span style="color:rgb(77,81,86);font-family:arial,sans-serif;font-size:14px">dimension of the subspace </span>PETSC_DEFAULT</div><div>number of eigenvalues 6<br></div><div>the maximum dimension allowed for the projected problem PETSC_DEFAULT<br></div><div>-eps_non_hermitian <br></div><div><br><table border="0" cellpadding="0" cellspacing="0" width="757" height="271" style="border-collapse:collapse;width:324.45pt">
<colgroup><col width="146" style="width:62.95pt">
<col width="164" style="width:70.3pt">
<col width="220" style="width:94.7pt">
<col width="225" style="width:96.8pt">
</colgroup><tbody><tr height="33" style="height:14.55pt">
<td class="et1" height="33" width="146" style="height:14.55pt;width:62.95pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">number of processors</td>
<td width="164" style="width:70.3pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et1" width="220" style="width:94.7pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">result</td>
<td class="et1" width="225" style="width:96.8pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"> solve time</td>
</tr>
<tr height="33" style="height:14.55pt">
<td class="et1" height="33" align="right" style="height:14.55pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">16</td>
<td style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et2" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">-302.06881196 </td>
<td class="et1" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">526</td>
</tr>
<tr height="33" style="height:14.55pt">
<td class="et1" height="33" align="right" style="height:14.55pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">32</td>
<td style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et2" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">-302.06881892 </td>
<td class="et1" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">224</td>
</tr>
<tr height="33" style="height:14.55pt">
<td class="et1" height="33" align="right" style="height:14.55pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">64</td>
<td style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et2" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">-302.06881989 </td>
<td class="et1" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">139</td>
</tr>
<tr height="33" style="height:14.55pt">
<td class="et1" height="33" align="right" style="height:14.55pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">128</td>
<td style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et2" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">-302.06881236 </td>
<td class="et1" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">122</td>
</tr>
<tr height="33" style="height:14.55pt">
<td class="et1" height="33" align="right" style="height:14.55pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">256</td>
<td style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et2" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">-302.06881938 </td>
<td class="et1" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">285</td>
</tr>
<tr height="33" style="height:14.55pt">
<td class="et1" height="33" align="right" style="height:14.55pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">512</td>
<td style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et2" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">-302.06881029 </td>
<td class="et3" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"><font color="#000000">510</font></td>
</tr>
<tr height="33" style="height:14.55pt">
<td class="et1" height="33" align="right" style="height:14.55pt;padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">640</td>
<td style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap"></td>
<td class="et2" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">-302.06882377 </td>
<td class="et1" align="right" style="padding-top:1px;padding-left:1px;padding-right:1px;color:rgb(0,0,0);font-size:12pt;font-family:宋体;border:none;vertical-align:middle;white-space:nowrap">291</td>
</tr>
</tbody></table></div></div>