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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc (build 1.5.0_10) on Fri Jan 26 16:34:49 NZDT 2007 --><TITLE>MathematicalExpression</TITLE><META NAME="keywords" CONTENT="weka.core.MathematicalExpression class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="MathematicalExpression";}</SCRIPT><NOSCRIPT></NOSCRIPT></HEAD><BODY BGCOLOR="white" onload="windowTitle();"><!-- ========= START OF TOP NAVBAR ======= --><A NAME="navbar_top"><!-- --></A><A HREF="#skip-navbar_top" title="Skip navigation links"></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""><TR><TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="http://www.cs.waikato.ac.nz/ml/weka/" target="_blank"><FONT CLASS="NavBarFont1"><B>Weka's home</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../weka/core/Matchable.html" title="interface in weka.core"><B>PREV CLASS</B></A> <A HREF="../../weka/core/MathematicalExpression.Tokenizer.html" title="class in weka.core"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html?weka/core/MathematicalExpression.html" target="_top"><B>FRAMES</B></A> <A HREF="MathematicalExpression.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT> <A HREF="../../allclasses-noframe.html"><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: <A HREF="#nested_class_summary">NESTED</A> | FIELD | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><A NAME="skip-navbar_top"></A><!-- ========= END OF TOP NAVBAR ========= --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">weka.core</FONT><BR>Class MathematicalExpression</H2><PRE>java.lang.Object <IMG SRC="../../resources/inherit.gif" ALT="extended by "><B>weka.core.MathematicalExpression</B></PRE><HR><DL><DT><PRE>public class <B>MathematicalExpression</B><DT>extends java.lang.Object</DL></PRE><P>Class to build (and evaluate) the tree of the grammar:<br/> <pre> Exp -> Term '+' Exp | Term '-' Exp | Term Term -> Atom '*' Term | Atom '/' Term | Atom Atom -> <number> | '('Exp')' | function '(' Params ')' | '-' Atom | VARIABLE | Disjunction Params -> E | E,Params Disjunction -> Conjunction | Conjunction '|' Disjunction Conjunction -> NumTest | NumTest '&' Conjunction NumTest -> Exp '<' Exp | Exp '>' Exp | Exp '=' Exp | '[' Disjunction ']' | '!' '[' Disjunction ']' </pre> Code example 1: <pre> String expr = "pow(BASE,EXPONENT)*MULT"; HashMap symbols = new HashMap(); symbols.put("BASE", new Double(2)); symbols.put("EXPONENT", new Double(9)); symbols.put("MULT", new Double(0.1)); double result = MathematicalExpression.evaluate(expr, symbols); System.out.println(expr + " and " + symbols + " = " + result); </pre> Code Example 2 (utilizing a parse tree several times): <pre> String expr = "pow(BASE,EXPONENT)"; MathematicalExpression.TreeNode tree = MathematicalExpression.parse(expr); for (int i = -10; i <= 10; i++) { HashMap symbols = new HashMap(); symbols.put("BASE", new Double(2)); symbols.put("EXPONENT", new Double(i)); double result = MathematicalExpression.evaluate(tree, symbols); System.out.println(expr + " and " + symbols + " = " + result); } </pre><P><P><DL><DT><B>Version:</B></DT> <DD>$Revision: 1.2 $</DD><DT><B>Author:</B></DT> <DD>Eibe Frank (eibe@cs.waikato.ac.nz), Prados Julien (julien.prados@cui.unige.ch)</DD></DL><HR><P><!-- ======== NESTED CLASS SUMMARY ======== --><A NAME="nested_class_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"><B>Nested Class Summary</B></FONT></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static class</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/MathematicalExpression.Tokenizer.html" title="class in weka.core">MathematicalExpression.Tokenizer</A></B></CODE><BR> A tokenizer for MathematicalExpression</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static class</CODE></FONT></TD><TD><CODE><B><A HREF="../../weka/core/MathematicalExpression.TreeNode.html" title="class in weka.core">MathematicalExpression.TreeNode</A></B></CODE><BR> Tree Node of MathematicalExpression</TD></TR></TABLE> <!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../weka/core/MathematicalExpression.html#MathematicalExpression()">MathematicalExpression</A></B>()</CODE><BR> </TD></TR>⌨️ 快捷键说明
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