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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>Mode Tracking</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">Mode tracking is available in the sensitivity-based optimization.</span>

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</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 = "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>It is defined using three optimization parameters (<code class = "ph codeph">OPT_PARAM</code>):</p>
<pre class = "codeblock">
<code class = "ph codeph">
MODETRACKING        = &lt;on/off&gt;, &lt;<var class = "keyword varname varname">node_group</var>&gt;
MODENUMBERS         = &lt;number_modes&gt;
MODETRACK_REFERENCE = INITIAL | PREVIOUS
</code>
</pre>

<p>Mode tracking is activated using the optimization parameter <code class = "ph codeph">MODETRACKING= ON</code>.
            The second item in <code class = "ph codeph">MODETRACKING</code> defines the node group that is used for
            the mode tracking. The node group can improve performance when the node group is small.
            If no node group is defined all nodes in the model will be applied as default. This is
            reasonable for small- to medium-sized finite element models. By default the mode
            tracking applies for 5 modes. This can be changed by the item <code class = "ph codeph">MODENUMBERS =
                &lt;number_modes&gt;</code>. This number should not be set too high otherwise the
            CPU-time might have a significant increase.</p>
<p>Using the parameter <code class = "ph codeph">MODETRACK_REFERENCE</code> for the Modal Assurance Criterion (MAC)
            allows the user to define the reference modes applied when tracking the modes during the
            optimization iterations. If the parameter <code class = "ph codeph">MODETRACK_REFERENCE</code> is set to
                <code class = "ph codeph">INITIAL</code>, the reference modes are set to be the modes of the initial
            optimization iteration throughout the entire optimization history. If the parameter
                <code class = "ph codeph">MODETRACK_REFERENCE</code> is set to <code class = "ph codeph">PREVIOUS</code>, the
            reference modes are always set to be the modes of the previous optimization
            iteration.</p>
<p>Typically, setting <code class = "ph codeph">MODETRACK_REFERENCE</code> to <code class = "ph codeph">INITIAL</code> is the most
            consistent comparison in the mode tracking. However, some initial modes might change
            significantly or completely disappear during the optimization iterations and, thus, the
                <code class = "ph codeph">INITIAL</code> comparison might fail. When the <code class = "ph codeph">INITIAL</code>
            setting for <code class = "ph codeph">MODETRACK_REFERENCE</code> is failing, the only option is to apply
                <code class = "ph codeph">PREVIOUS</code> even though the comparison might not be as consistent as
                <code class = "ph codeph">INITIAL</code>.</p>
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