https://www.myroms.org/wiki/index.php?action=history&feed=atom&title=Eigenproblem_Parameters Eigenproblem Parameters - Revision history 2026-04-27T16:18:06Z Revision history for this page on the wiki MediaWiki 1.42.3 https://www.myroms.org/wiki/index.php?title=Eigenproblem_Parameters&diff=2950&oldid=prev Robertson: New page: <div class="title">Eigenproblem Parameters</div> {{#lst:Variables|NEV}} {{#lst:Variables|NCV}} '''Notice:''' At present, there is no a-priori analysis to guide the selection of <span cl... 2008-04-16T20:02:36Z <p>New page: &lt;div class=&quot;title&quot;&gt;Eigenproblem Parameters&lt;/div&gt; {{#lst:Variables|NEV}} {{#lst:Variables|NCV}} &#039;&#039;&#039;Notice:&#039;&#039;&#039; At present, there is no a-priori analysis to guide the selection of &lt;span cl...</p> <p><b>New page</b></p><div>&lt;div class=&quot;title&quot;&gt;Eigenproblem Parameters&lt;/div&gt;<br /> {{#lst:Variables|NEV}}<br /> <br /> {{#lst:Variables|NCV}}<br /> <br /> <br /> &#039;&#039;&#039;Notice:&#039;&#039;&#039; At present, there is no a-priori analysis to guide the selection of &lt;span class=&quot;twilightBlue&quot;&gt;NCV&lt;/span&gt; relative to &lt;span class=&quot;twilightBlue&quot;&gt;NEV&lt;/span&gt;. The only formal requirement is that &lt;span class=&quot;twilightBlue&quot;&gt;NCV &gt; NEV&lt;/span&gt;. However in optimal perturbations, it is recommended to have &lt;span class=&quot;twilightBlue&quot;&gt;NCV &amp;ge; 2*NEV&lt;/span&gt;. In Finite Time Eigenmodes (FTE) and Adjoint Finite Time Eigenmodes (AFTE) the requirement is to have &lt;span class=&quot;twilightBlue&quot;&gt;NCV &amp;ge; 2*NEV+1&lt;/span&gt;. The efficiency of calculations depends critically on the combination of &lt;span class=&quot;twilightBlue&quot;&gt;NEV&lt;/span&gt; and &lt;span class=&quot;twilightBlue&quot;&gt;NCV&lt;/span&gt;. If &lt;span class=&quot;twilightBlue&quot;&gt;NEV&lt;/span&gt; is large (greater than 10 say), you can use &lt;span class=&quot;twilightBlue&quot;&gt;NCV=2*NEV+1&lt;/span&gt; but for &lt;span class=&quot;twilightBlue&quot;&gt;NEV&lt;/span&gt; small (less than 6) it will be inefficient to use &lt;span class=&quot;twilightBlue&quot;&gt;NCV=2*NEV+1&lt;/span&gt;. In complicated applications, you can start with &lt;span class=&quot;twilightBlue&quot;&gt;NEV=2&lt;/span&gt; and &lt;span class=&quot;twilightBlue&quot;&gt;NCV=10&lt;/span&gt;. Otherwise, it will iterate for very long time.</div> Robertson