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<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>Equation - p2.js</title> <link rel="stylesheet" href="http://yui.yahooapis.com/3.9.1/build/cssgrids/cssgrids-min.css"> <link rel="stylesheet" href="../assets/vendor/prettify/prettify-min.css"> <link rel="stylesheet" href="../assets/css/main.css" id="site_styles"> <link rel="icon" href="../assets/favicon.ico"> <script src="http://yui.yahooapis.com/combo?3.9.1/build/yui/yui-min.js"></script> </head> <body class="yui3-skin-sam"> <div id="doc"> <div id="hd" class="yui3-g header"> <div class="yui3-u-3-4"> <h1><img src="../assets/css/logo.png" title="p2.js" width="117" height="52"></h1> </div> <div class="yui3-u-1-4 version"> <em>API Docs for: 0.7.1</em> </div> </div> <div id="bd" class="yui3-g"> <div class="yui3-u-1-4"> <div id="docs-sidebar" class="sidebar apidocs"> <div id="api-list"> <h2 class="off-left">APIs</h2> <div id="api-tabview" class="tabview"> <ul class="tabs"> <li><a href="#api-classes">Classes</a></li> 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</label> </div> <div class="apidocs"> <div id="docs-main"> <div class="content"> <h1>Equation Class</h1> <div class="box meta"> <div class="foundat"> Defined in: <a href="../files/src_equations_Equation.js.html#l7"><code>src/equations/Equation.js:7</code></a> </div> </div> <div class="box intro"> <p>Base class for constraint equations.</p> </div> <div class="constructor"> <h2>Constructor</h2> <div id="method_Equation" class="method item"> <h3 class="name"><code>Equation</code></h3> <div class="args"> <span class="paren">(</span><ul class="args-list inline commas"> <li class="arg"> <code>bodyA</code> </li> <li class="arg"> <code>bodyB</code> </li> <li class="arg"> <code>minForce</code> </li> <li class="arg"> <code>maxForce</code> </li> </ul><span class="paren">)</span> </div> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l7"><code>src/equations/Equation.js:7</code></a> </p> </div> <div class="description"> </div> <div class="params"> <h4>Parameters:</h4> <ul class="params-list"> <li class="param"> <code class="param-name">bodyA</code> <span class="type"><a href="../classes/Body.html" class="crosslink">Body</a></span> <div class="param-description"> <p>First body participating in the equation</p> </div> </li> <li class="param"> <code class="param-name">bodyB</code> <span class="type"><a href="../classes/Body.html" class="crosslink">Body</a></span> <div class="param-description"> <p>Second body participating in the equation</p> </div> </li> <li class="param"> <code class="param-name">minForce</code> <span class="type">Number</span> <div class="param-description"> <p>Minimum force to apply. Default: -Number.MAX_VALUE</p> </div> </li> <li class="param"> <code class="param-name">maxForce</code> <span class="type">Number</span> <div class="param-description"> <p>Maximum force to apply. Default: Number.MAX_VALUE</p> </div> </li> </ul> </div> </div> </div> <div id="classdocs" class="tabview"> <ul class="api-class-tabs"> <li class="api-class-tab index"><a href="#index">Index</a></li> <li class="api-class-tab methods"><a href="#methods">Methods</a></li> <li class="api-class-tab properties"><a href="#properties">Properties</a></li> </ul> <div> <div id="index" class="api-class-tabpanel index"> <h2 class="off-left">Item Index</h2> <div class="index-section methods"> <h3>Methods</h3> <ul class="index-list methods"> <li class="index-item method"> <a href="#method_addToWlambda">addToWlambda</a> </li> <li class="index-item method"> <a href="#method_computeB">computeB</a> </li> <li class="index-item method"> <a href="#method_computeGiMf">computeGiMf</a> </li> <li class="index-item method"> <a href="#method_computeGiMGt">computeGiMGt</a> </li> <li class="index-item method"> <a href="#method_computeGq">computeGq</a> </li> <li class="index-item method"> <a href="#method_computeGW">computeGW</a> </li> <li class="index-item method"> <a href="#method_computeGWlambda">computeGWlambda</a> </li> <li class="index-item method"> <a href="#method_computeInvC">computeInvC</a> </li> <li class="index-item method"> <a href="#method_gmult">gmult</a> </li> <li class="index-item method"> <a href="#method_update">update</a> </li> </ul> </div> <div class="index-section properties"> <h3>Properties</h3> <ul class="index-list properties"> <li class="index-item property"> <a href="#property_bodyA">bodyA</a> </li> <li class="index-item property"> <a href="#property_bodyB">bodyB</a> </li> <li class="index-item property"> <a href="#property_DEFAULT_RELAXATION">DEFAULT_RELAXATION</a> <span class="flag static">static</span> </li> <li class="index-item property"> <a href="#property_DEFAULT_STIFFNESS">DEFAULT_STIFFNESS</a> <span class="flag static">static</span> </li> <li class="index-item property"> <a href="#property_enabled">enabled</a> </li> <li class="index-item property"> <a href="#property_G">G</a> </li> <li class="index-item property"> <a href="#property_maxForce">maxForce</a> </li> <li class="index-item property"> <a href="#property_minForce">minForce</a> </li> <li class="index-item property"> <a href="#property_multiplier">multiplier</a> </li> <li class="index-item property"> <a href="#property_needsUpdate">needsUpdate</a> </li> <li class="index-item property"> <a href="#property_relativeVelocity">relativeVelocity</a> </li> <li class="index-item property"> <a href="#property_relaxation">relaxation</a> </li> <li class="index-item property"> <a href="#property_stiffness">stiffness</a> </li> </ul> </div> </div> <div id="methods" class="api-class-tabpanel"> <h2 class="off-left">Methods</h2> <div id="method_addToWlambda" class="method item"> <h3 class="name"><code>addToWlambda</code></h3> <div class="args"> <span class="paren">(</span><ul class="args-list inline commas"> <li class="arg"> <code>deltalambda</code> </li> </ul><span class="paren">)</span> </div> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l270"><code>src/equations/Equation.js:270</code></a> </p> </div> <div class="description"> <p>Add constraint velocity to the bodies.</p> </div> <div class="params"> <h4>Parameters:</h4> <ul class="params-list"> <li class="param"> <code class="param-name">deltalambda</code> <span class="type">Number</span> <div class="param-description"> </div> </li> </ul> </div> </div> <div id="method_computeB" class="method item"> <h3 class="name"><code>computeB</code></h3> <span class="paren">()</span> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l150"><code>src/equations/Equation.js:150</code></a> </p> </div> <div class="description"> <p>Computes the RHS of the SPOOK equation</p> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_computeGiMf" class="method item"> <h3 class="name"><code>computeGiMf</code></h3> <span class="paren">()</span> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l213"><code>src/equations/Equation.js:213</code></a> </p> </div> <div class="description"> <p>Computes G*inv(M)*f, where M is the mass matrix with diagonal blocks for each body, and f are the forces on the bodies.</p> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_computeGiMGt" class="method item"> <h3 class="name"><code>computeGiMGt</code></h3> <span class="paren">()</span> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l241"><code>src/equations/Equation.js:241</code></a> </p> </div> <div class="description"> <p>Computes G*inv(M)*G'</p> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_computeGq" class="method item"> <h3 class="name"><code>computeGq</code></h3> <span class="paren">()</span> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l162"><code>src/equations/Equation.js:162</code></a> </p> </div> <div class="description"> <p>Computes G*q, where q are the generalized body coordinates</p> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_computeGW" class="method item"> <h3 class="name"><code>computeGW</code></h3> <span class="paren">()</span> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l181"><code>src/equations/Equation.js:181</code></a> </p> </div> <div class="description"> <p>Computes G*W, where W are the body velocities</p> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_computeGWlambda" class="method item"> <h3 class="name"><code>computeGWlambda</code></h3> <span class="paren">()</span> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l197"><code>src/equations/Equation.js:197</code></a> </p> </div> <div class="description"> <p>Computes G*Wlambda, where W are the body velocities</p> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_computeInvC" class="method item"> <h3 class="name"><code>computeInvC</code></h3> <div class="args"> <span class="paren">(</span><ul class="args-list inline commas"> <li class="arg"> <code>eps</code> </li> </ul><span class="paren">)</span> </div> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l313"><code>src/equations/Equation.js:313</code></a> </p> </div> <div class="description"> <p>Compute the denominator part of the SPOOK equation: C = G*inv(M)*G' + eps</p> </div> <div class="params"> <h4>Parameters:</h4> <ul class="params-list"> <li class="param"> <code class="param-name">eps</code> <span class="type">Number</span> <div class="param-description"> </div> </li> </ul> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_gmult" class="method item"> <h3 class="name"><code>gmult</code></h3> <span class="paren">()</span> <span class="returns-inline"> <span class="type">Number</span> </span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l136"><code>src/equations/Equation.js:136</code></a> </p> </div> <div class="description"> <p>Multiply a jacobian entry with corresponding positions or velocities</p> </div> <div class="returns"> <h4>Returns:</h4> <div class="returns-description"> <span class="type">Number</span>: </div> </div> </div> <div id="method_update" class="method item"> <h3 class="name"><code>update</code></h3> <span class="paren">()</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l120"><code>src/equations/Equation.js:120</code></a> </p> </div> <div class="description"> <p>Compute SPOOK parameters .a, .b and .epsilon according to the current parameters. See equations 9, 10 and 11 in the <a href="http://www8.cs.umu.se/kurser/5DV058/VT09/lectures/spooknotes.pdf">SPOOK notes</a>.</p> </div> </div> </div> <div id="properties" class="api-class-tabpanel"> <h2 class="off-left">Properties</h2> <div id="property_bodyA" class="property item"> <h3 class="name"><code>bodyA</code></h3> <span class="type"><a href="../classes/Body.html" class="crosslink">Body</a></span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l32"><code>src/equations/Equation.js:32</code></a> </p> </div> <div class="description"> <p>First body participating in the constraint</p> </div> </div> <div id="property_bodyB" class="property item"> <h3 class="name"><code>bodyB</code></h3> <span class="type"><a href="../classes/Body.html" class="crosslink">Body</a></span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l39"><code>src/equations/Equation.js:39</code></a> </p> </div> <div class="description"> <p>Second body participating in the constraint</p> </div> </div> <div id="property_DEFAULT_RELAXATION" class="property item"> <h3 class="name"><code>DEFAULT_RELAXATION</code></h3> <span class="type">Number</span> <span class="flag static">static</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l112"><code>src/equations/Equation.js:112</code></a> </p> </div> <div class="description"> <p>The default relaxation when creating a new Equation.</p> </div> <p><strong>Default:</strong> 4</p> </div> <div id="property_DEFAULT_STIFFNESS" class="property item"> <h3 class="name"><code>DEFAULT_STIFFNESS</code></h3> <span class="type">Number</span> <span class="flag static">static</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l104"><code>src/equations/Equation.js:104</code></a> </p> </div> <div class="description"> <p>The default stiffness when creating a new Equation.</p> </div> <p><strong>Default:</strong> 1e6</p> </div> <div id="property_enabled" class="property item"> <h3 class="name"><code>enabled</code></h3> <span class="type">Boolean</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l96"><code>src/equations/Equation.js:96</code></a> </p> </div> <div class="description"> <p>Whether this equation is enabled or not. If true, it will be added to the solver.</p> </div> </div> <div id="property_G" class="property item"> <h3 class="name"><code>G</code></h3> <span class="type">Array</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l60"><code>src/equations/Equation.js:60</code></a> </p> </div> <div class="description"> <p>The Jacobian entry of this equation. 6 numbers, 3 per body (x,y,angle).</p> </div> </div> <div id="property_maxForce" class="property item"> <h3 class="name"><code>maxForce</code></h3> <span class="type">Number</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l25"><code>src/equations/Equation.js:25</code></a> </p> </div> <div class="description"> <p>Max force to apply when solving.</p> </div> </div> <div id="property_minForce" class="property item"> <h3 class="name"><code>minForce</code></h3> <span class="type">Number</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l18"><code>src/equations/Equation.js:18</code></a> </p> </div> <div class="description"> <p>Minimum force to apply when solving.</p> </div> </div> <div id="property_multiplier" class="property item"> <h3 class="name"><code>multiplier</code></h3> <span class="type">Number</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l83"><code>src/equations/Equation.js:83</code></a> </p> </div> <div class="description"> <p>The resulting constraint multiplier from the last solve. This is mostly equivalent to the force produced by the constraint.</p> </div> </div> <div id="property_needsUpdate" class="property item"> <h3 class="name"><code>needsUpdate</code></h3> <span class="type">Boolean</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l77"><code>src/equations/Equation.js:77</code></a> </p> </div> <div class="description"> <p>Indicates if stiffness or relaxation was changed.</p> </div> </div> <div id="property_relativeVelocity" class="property item"> <h3 class="name"><code>relativeVelocity</code></h3> <span class="type">Number</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l90"><code>src/equations/Equation.js:90</code></a> </p> </div> <div class="description"> <p>Relative velocity.</p> </div> </div> <div id="property_relaxation" class="property item"> <h3 class="name"><code>relaxation</code></h3> <span class="type">Number</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l53"><code>src/equations/Equation.js:53</code></a> </p> </div> <div class="description"> <p>The number of time steps needed to stabilize the constraint equation. Typically between 3 and 5 time steps.</p> </div> </div> <div id="property_stiffness" class="property item"> <h3 class="name"><code>stiffness</code></h3> <span class="type">Number</span> <div class="meta"> <p> Defined in <a href="../files/src_equations_Equation.js.html#l46"><code>src/equations/Equation.js:46</code></a> </p> </div> <div class="description"> <p>The stiffness of this equation. Typically chosen to a large number (~1e7), but can be chosen somewhat freely to get a stable simulation.</p> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> <script src="../assets/vendor/prettify/prettify-min.js"></script> <script>prettyPrint();</script> <script src="../assets/js/yui-prettify.js"></script> <script src="../assets/../api.js"></script> <script src="../assets/js/api-filter.js"></script> <script src="../assets/js/api-list.js"></script> <script src="../assets/js/api-search.js"></script> <script src="../assets/js/apidocs.js"></script> </body> </html>