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<A NAME=hessian>

<TITLE>hessian</TITLE></A>
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<B>HESSIAN</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>operator</B><P>
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syntax: </H3>
<em>hessian</em>(&lt;expr&gt;,&lt;variable\_list&gt;) 
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&lt;expr&gt; :- a scalar expression. 
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&lt;variable\_list&gt; :- either a single variable or a list of 
 variables. 
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<em>hessian</em>computes the hessian matrix of &lt;expr&gt; w.r.t. the 
variables in &lt;variable\_list&gt;. 
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This is an n by n matrix where n is the number of variables and the 
(i,j)'th entry is 
<A HREF=r37_0148.html>df</A>(&lt;expr&gt;,&lt;variable\_list&gt;(i), 
&lt;variable\_list&gt;(j)). 
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examples: </H3>
<P><PRE><TT>

hessian(x*y*z+x^2,{w,x,y,z}); 

  [0  0  0  0]
  [          ]
  [0  2  z  y]
  [          ]
  [0  z  0  x]
  [          ]
  [0  y  x  0]

</TT></PRE><P>Related functions: 
<A HREF=r37_0148.html>df</A>. 
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