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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>Stop Conditions (<span class = "ph">STOP</span>)</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 optimization is stopped when certain criteria are fulfilled.
These criteria are defined with the <code class = "ph codeph">STOP</code> command.</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></table></td></tr></table>




<div class = "body conbody">
<p>A  stop condition is defined by assigning a logical variable (<code class = "ph codeph">LOGICAL</code>)
to an optimization task (<code class = "ph codeph">OPTIMIZE</code>). The stop condition
can be specifically addressed with its user-defined name (<code class = "ph codeph">ID_NAME</code>).</p>
<pre class = "codeblock">
<code class = "ph codeph">
STOP
 ID_NAME  = stop_name
 LOGICAL  = logical_name
 OPTIMIZE = opt_grp_name
END_
</code>
</pre>
<p>The stop condition ends the optimization for the selected optimization
group when the value for the assigned logical variable is <code class = "ph codeph">TRUE</code>.
If several <code class = "ph codeph">STOP</code> conditions have been defined for an
optimization group, the optimization for this group is ended when one
of the stop conditions is fulfilled (corresponds to a logical <code class = "ph codeph">OR</code>
condition).</p>
<p>The logical variable can vary significantly. Before using the <code class = "ph codeph">STOP</code>
command, numerical and logical variables must be defined with the <code class = "ph codeph">VARIABLE</code>
and <code class = "ph codeph">LOGICAL</code> commands. </p>
<p>The flexibility is achieved by using various logical variables as
the stop criteria. Logical operations <code class = "ph codeph">AND</code> or <code class = "ph codeph">OR</code>
can also be included in the <code class = "ph codeph">STOP</code> command by defining
the logical variables.</p>
<p>For shape optimization, typical stop conditions can be defined more
directly by an enhanced stop command: </p>
<pre class = "codeblock">
<code class = "ph codeph">
STOP
 ID_NAME  = stop_command
 MOD_NDGR = all_nodes
 MOD_TYPE = MAX, CTRL_INP_SHAPE
 MOD_OPER = LE
 MOD_REF  = 0.01, MULT, FIRST
 OPTIMIZE = run
END_
</code>
</pre>
<p> In this case, the optimization task "run" should stop when the maximum
equivalent stress (<code class = "ph codeph">CTRL_INP_SHAPE</code>) of the node group
all_nodes is smaller than 1% of the maximum equivalent stress of the
first iteration.</p>
<p>Using this enhanced stop command, the extraction of variables and
their logical comparison is performed internally by <span class = "ph">Tosca Structure</span>
and need no longer be specified manually by the user. For a detailed
description of the several items, refer to the commands manual.</p>
<p>If desired, the global upper limit for the maximum number of iterations
can be set with a separate, brief command. In this case, a definition
of logical variables is not required.</p>
<pre class = "codeblock">
<code class = "ph codeph">
STOP
 ID_NAME  = STOP_CONDITION
 ITER_MAX = &lt;value&gt;
END_
</code>
</pre>
<p>A global stop condition is integrated in the system to limit the maximum
number of iterations for safety reasons. This stop condition is always
active. The default value for the maximum number of iterations is set
to 40. As an example, the command</p>
<pre class = "codeblock">
<code class = "ph codeph">
STOP
 ID_NAME  = STOP_CONDITION
 ITER_MAX = 55
END_
</code>
</pre>
<p>increases the maximum number of iterations. </p>
<table class = "Remark" id = "table132"><tr><td class = "Remark"><span class = "run-in.important">Important:
				</span><span class = "notecontent"><p>When the optimization is halted due to a stop condition, it is possible
that the desired results are not achieved. This is especially true for
topological optimization when stipulating the global tensile stiffness.</p></span></td></tr></table>

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