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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>DV_TOPO</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">Definition of the design elements for topology optimization.</span>

</p>
<p>This page discusses: </p><ul><li><a href = "#tso-r-cmd-dvTopo__tso-r-cmd-dvTopo-rmk" id = "toc_rg" title = "">Remarks</a></li><li><a href = "#tso-r-cmd-dvTopo__tso-r-cmd-dvTopo-expl" id = "toc_rg" title = "">Examples</a></li></ul>
</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 = "You can define the Design Area to denote the set of elements that might be removed during the topology optimization. In contrast you can define frozen areas that remain unchanged." href = "../TsoUserMap/tso-t-user-TopOpt-DesArea.htm#tso-t-user-TopOpt-DesArea">Defining the Design Area for Topology Optimization</a></td></tr></table></td></tr></table>




<div class = "body refbody">
<table class = "table" id = "tso-r-cmd-dvTopo__aa1395580"><caption/><colgroup><col/><col/><col/></colgroup><tbody class = "tbody">
<tr class = "row">
<td class = "entry"><p><span class = "ph uicontrol">ID_NAME</span></p></td>
<td class = "entry"><p>= <code class = "ph codeph">&lt;id_name_of_dv_topo&gt;</code></p></td>
<td class = "entry"><p>Name of the <code class = "ph codeph">DV_TOPO</code> definition.</p></td>
</tr>
<tr class = "row">
<td class = "entry"><p><span class = "ph uicontrol">EL_GROUP</span></p></td>
<td class = "entry"><p>= <code class = "ph codeph">&lt;name_of_element_group&gt;</code></p></td>
<td class = "entry"><p>Name of the element group.</p></td>
</tr>
<tr class = "row">
<td class = "entry"><p><span class = "ph uicontrol">INITIAL_DV_FIELD</span> </p></td>
<td class = "entry"><p>= <code class = "ph codeph">&lt;name_of_file&gt;</code> </p></td>
<td class = "entry"><p>Name of the file with the initial material distribution field to be used for the optimization.</p></td>
</tr>
</tbody></table>

<div class = "section" id = "tso-r-cmd-dvTopo__tso-r-cmd-dvTopo-rmk"><h2 class = "title sectiontitle">Remarks</h2>

<ol class = "ol">
<li class = "li">All elements in the element group might be modified during optimization.</li>
<li class = "li">Only certain types of elements (for more information, see <a class = "xref" href = "../TsoUserMap/tso-c-ov.htm" title = "This document contains a user guide for Tosca Structure, a modular system for nonparametric structural optimization.">Tosca Structure User Guide</a>) are permitted to be optimization elements. All elements not permitted
     are removed from the group.</li>
<li class = "li">The <code class = "ph codeph">INITIAL_DV_FIELD</code> option is available only for sensitivity-based
          optimization.</li>
<li class = "li">The file applied at <code class = "ph codeph">INITIAL_DV_FIELD</code> containing the initial material
          distribution must be located in the start directory of the optimization job.  The format of the file must be ONF (Optimization
          Neutral File). The initial material distribution is extracted from the data block 740 with
          the title <span class = "ph">MAT_PROP_NORMALIZED</span>. </li>
<li class = "li">When using a material distribution of a previous optimization run for the new optimization,
rename the file TP_XXX.onf (for example, to <code class = "ph codeph">INITIAL_MAT.onf</code>).
Otherwise, name conflicts with the running optimization (with newly generated
material distribution files TP_YYY.onf) might lead to confusion in the post
processing: the start file TP_XXX.onf might be considered and shown as the last
iteration (if XXX is larger as the last iteration in the actual optimization).
(For more information, see <a class = "xref" href = "../TsoUserMap/tso-t-user-TopOpt-DesArea-DesVar.htm#tso-t-user-TopOpt-DesArea-DesVar-PrevRun">Use Results from Previous Runs as Initial Material Distribution</a>). </li>
<li class = "li">The former parameter <code class = "ph codeph">RESTART_FILE</code> was renamed to <code class = "ph codeph">INITIAL_DV_FIELD</code> to avoid confusion with the restart of unintentionally stopped optimization runs
(see <a class = "xref" href = "../TsoUserMap/tso-c-usr-control-restart.htm#tso-c-usr-control-restart" title = "An optimization is an iterative process that can run several hours or days depending on the size of the model. Different problems can arise during this process that can lead to a termination of the optimization task. Tosca Structure has a built-in restart functionality that can be used to avoid starting the complete optimization task again after a stop because of external factors. Optimization starts at the iteration where the interruption occurred. Tosca Structure's resume feature allows the user to continue a converged optimization with new convergence or stop criteria.">Restart and Resume Modes</a>).</li>
<li class = "li"><code class = "ph codeph">INITIAL_DV_FIELD</code> for topology optimization means an initial material distribution for design variables.</li>
</ol>
</div>


<div class = "section" id = "tso-r-cmd-dvTopo__tso-r-cmd-dvTopo-expl"><p><map name = "FPMap1"><area href = "#hj-top" title = "Back to Top" shape = "rect" coords = "416, 0, 435, 10"/></map><span class = "itemsprite"/></p><h2 class = "title sectiontitle">Examples</h2>

<pre class = "codeblock">
<code class = "ph codeph">DV_TOPO
  ID_NAME  = dv_topo_name
  EL_GROUP = design_elem_grp
END_
</code></pre>
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