Math Expression Plot using nfunk JEP - Java 2D Graphics

Java examples for 2D Graphics:JXGraph

  1. HOME
  2. Java
  3. 2D Graphics
  4. JXGraph

Description

Math Expression Plot using nfunk JEP

Demo Code

/*//from   w  w w .  ja  va 2 s .  c  o m
 * ExpressionPlot.java
 *
 * Created on 16 mars 2006, 15:44
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */
import org.jdesktop.swingx.JXGraph;
import org.nfunk.jep.JEP;
import org.nfunk.jep.function.Round;

class ExpressionPlot extends JXGraph.Plot {
    private final String expression;
    private final JEP parser;
    private int precision;

    public ExpressionPlot(String expression) {
        this.expression = expression;

        parser = new JEP();
        parser.addStandardConstants();
        parser.addStandardFunctions();
    }

    public double compute(double value) {
        parser.addVariable("x", value);
        parser.parseExpression(expression);

        return Round(parser.getValue(), 6);
    }

    //wa ni labot test rani
    public static void main(String args[]) {
        //test
        ExpressionPlot e = new ExpressionPlot("x^2");
        System.out.print(e.getValue());
    }

    private String getValue() {
        // TODO Auto-generated method stub
        return this.expression;
    }

    public static double Round(double d, int Rpl) {
        float p = (float) Math.pow(10, Rpl);
        d = d * p;
        float tmp = Math.round(d);
        return (double) tmp / p;
    }

}

Related Tutorials