<?xml version="1.0" encoding="utf-8" ?> <!-- for emacs: -*- coding: utf-8 -*- --> <!-- Apache may like this line in the file .htaccess: AddCharset utf-8 .html --> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN" "http://www.w3.org/2002/04/xhtml-math-svg/xhtml-math-svg-flat.dtd" > <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head><title>! -- factorial</title> <link rel="stylesheet" type="text/css" href="../../../../Macaulay2/Style/doc.css"/> </head> <body> <table class="buttons"> <tr> <td><div><a href="__pl.html">next</a> | <a href="__sh_qu.html">previous</a> | <a href="__pl.html">forward</a> | <a href="__sh_qu.html">backward</a> | <a href="_operators.html">up</a> | <a href="index.html">top</a> | <a href="master.html">index</a> | <a href="toc.html">toc</a> | <a href="http://www.math.uiuc.edu/Macaulay2/">Macaulay2 web site</a></div> </td> </tr> </table> <div><a href="index.html" title="">Macaulay2Doc</a> > <a href="___The_sp__Macaulay2_splanguage.html" title="">The Macaulay2 language</a> > <a href="_operators.html" title="">operators</a> > <a href="_!.html" title="factorial">!</a></div> <hr/> <div><h1>! -- factorial</h1> <div class="single"><h2>Synopsis</h2> <ul><li><div class="list"><dl class="element"><dt class="heading">Usage: </dt><dd class="value"><div><tt>n!</tt></div> </dd></dl> </div> </li> <li><div class="single">Inputs:<ul><li><span><tt>n</tt>, <span>an <a href="___Z__Z.html">integer</a></span></span></li> </ul> </div> </li> <li><div class="single">Outputs:<ul><li><span><span>an <a href="___Z__Z.html">integer</a></span>, n factorial, 1*2*3*...*n.</span></li> </ul> </div> </li> </ul> </div> <div class="single"><h2>Description</h2> <div><table class="examples"><tr><td><pre>i1 : 30! o1 = 265252859812191058636308480000000</pre> </td></tr> <tr><td><pre>i2 : 30.! o2 = 2.65252859812191e32 o2 : RR (of precision 53)</pre> </td></tr> <tr><td><pre>i3 : 30.01! o3 = 2.74475749473282e32 o3 : RR (of precision 53)</pre> </td></tr> </table> </div> </div> <div class="waystouse"><h2>Ways to use <tt>!</tt> :</h2> <ul><li>Constant !</li> <li>QQ !</li> <li>RR !</li> <li>ZZ !</li> </ul> </div> <div class="waystouse"><h2>For the programmer</h2> <p>The object <a href="_!.html" title="factorial">!</a> is <span>a <a href="___Keyword.html">keyword</a></span>.</p> <div><div><p>This operator may be used as a postfix unary operator in an expression like <tt>x !</tt>. The user may <a href="__co_eq.html">install a method</a> for handling such expressions with code such as</p> <pre> X ! := (x) -> ...</pre> <p>where <tt>X</tt> is the class of <tt>x</tt>.</p> </div> </div> </div> </div> </body> </html>