onstraint</div>  </div>
</div><!--header-->
<div class="contents">
<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p>A constraint is the main modeling object. </p>
<p>It provides two methods: - Post() is responsible for creating the demons and attaching them to immediate demons(). - InitialPropagate() is called once just after Post and performs the initial propagation. The subsequent propagations will be performed by the demons Posted during the <