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<a name = "hj-top"> </a><table class = "table1" id = "table11"><tr><td><table class = "DocHeader"><tr><td class = "DocHeader1" colspan = "2"><h1>Global Stop Criterion (Number of Iterations)</h1></td></tr><tr><td class = "DocHeader4" colspan = "2"/></tr><tr><td class = "DocHeader3"><table class = "DocHeaderIntro" id = "table12"><tr><td class = "Intro1Only"><p class = "header"><p class = "abstract">
<span class = "shortdesc">The stop criteria usable in topology optimization are explained.</span>

</p>

</p></td></tr></table></td><td class = "DocHeader2"><table class = "DocTopicsSeeAlso" id = "table13"><tr><td class = "TopicsTitle">See Also</td></tr></table><table class = "DocTopicsInOtherGuides" id = "table14"><tr><td height = "8px"/></tr><tr><td class = "TopicsTitleNormal">In Other Guides</td></tr><tr><td><a title = "Definition of STOP conditions." href = "../TsoCmdMap/tso-r-cmd-stop.htm#tso-r-cmd-stop">STOP</a></td></tr><tr><td><a title = "Defines parameters to control optimization." href = "../TsoCmdMap/tso-r-cmd-optParam.htm#tso-r-cmd-optParam">OPT_PARAM</a></td></tr></table></td></tr></table>




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<p>
  The stop criterion is the maximum number of optimization iterations, which is default 50
   for sensitivity-based and 15 for controller-based optimizations. When the maximum number of
   optimization iterations is reached, the optimization algorithm always stops independent on the
   values of the two previously mentioned criteria. The allowed maximum number of optimization
  iterations can be increased or decreased by the user. This is defined by the parameter <code class = "ph codeph">ITER_MAX</code> of the <code class = "ph codeph">STOP</code>
  command.
</p>
<pre class = "codeblock">
<code class = "ph codeph">
STOP
 ID_NAME  = global_stop
 ITER_MAX = 55
END_
</code>
</pre>
<p>where <code class = "ph codeph">ITER_MAX</code> is increased to 55.</p>
<p>
<table class = "Remark" id = "table132"><tr><td class = "Remark"><span class = "run-in.important">Important:
				</span><span class = "notecontent">
<ul class = "ul" id = "tso-c-user-TopOpt-StopCond-GlobSC__ul_BDF9B0A61A7B4055982028F9F125AAFC">
<li class = "li">
The global stop criterion is defined using a
<code class = "ph codeph">STOP</code> command
whereas the convergence criteria are defined in the optimization settings
( <code class = "ph codeph">OPT_PARAM</code> command).
</li>
<li class = "li"> The global stop criterion leads to a stop of the
      optimization,  independent of a complete convergence of the result (in particular with a small
      number of iterations this cannot be achieved).</li>
<li class = "li">
For the controller-based algorithm, the number of iterations required
for full convergence is set using the <code class = "ph codeph">SPEED= ITER</code>,&lt;nr&gt;
parameter in the <code class = "ph codeph">OPT_PARAM)</code> command.</li>
<li class = "li">If there are stress design responses or nonlinear materials present in the optimization, the
      default maximum number of iterations will be automatically set to 80.</li>
</ul></span></td></tr></table>
</p>

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