File r37/lisp/csl/html/r37_0605.html artifact 9642790bf2 part of check-in 9992369dd3

<A NAME=pivot>

<TITLE>pivot</TITLE></A>
<b><a href=r37_idx.html>INDEX</a></b><p><p>



<B>PIVOT</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>operator</B><P>
<P>
 
<P>
<P>
 <P> <H3> 
syntax: </H3>
<em>pivot</em>(&lt;matrix&gt;,&lt;r&gt;,&lt;c&gt;) 
<P>
<P>
<P>
&lt;matrix&gt; :- a matrix. 
<P>
<P>
&lt;r&gt;,&lt;c&gt; :- positive integers such that &lt;matrix&gt;(&lt;r&gt;, 
 &lt;c&gt;) neq 0. 
<P>
<P>
<em>pivot</em>pivots &lt;matrix&gt; about it's (&lt;r&gt;,&lt;c&gt;)'th 
entry. 
 <P>
<P>
To do this, multiples of the &lt;r&gt;'th row are added to every other 
row in the matrix. 
<P>
<P>
This means that the &lt;c&gt;'th column will be 0 except for the 
(&lt;r&gt;,&lt;c&gt;)'th entry. 
<P>
<P>
 <P> <H3> 
examples: </H3>
<P><PRE><TT>

pivot(A,2,3); 

  [      - 1    ]
  [-1  ------  0]
  [      2      ]
  [             ]
  [4     5     6]
  [             ]
  [      1      ]
  [1    ---    0]
  [      2      ]

</TT></PRE><P>Related functions: 

<A HREF=r37_0611.html>rows_pivot</A>. 
<P>
<P>