Package com.singularsys.extensions.djep

Class DJep

  • All Implemented Interfaces:
    java.io.Serializable
    Direct Known Subclasses:
    MDJep
    public class DJep
extends XJep
    Adds differentiation facilities to Jep. For example 
     DJep j = new DJep();
 j.addStandardDiffRules();
 ....
 Node node = j.parse("x^3");
 Node diff = j.differentiate(node,"x");
 Node simp = j.simplify(diff);
 j.println(simp);
 Node node2 = j.parse("diff(x^4,x)");
 Node proc = j.preprocess(node2);
 Node simp2 = j.simplify(proc);
 j.println(simp2);
    Author:
    Rich Morris Created on 16-Nov-2003
    See Also:
    Serialized Form

    • Constructor Detail

      • DJep

        public DJep()
        Standard constructor. Use this instead of Jep or Jep if differentiation facilities are required.

    • Method Detail

      • getDifferentationVisitor

        public DifferentiationVisitor getDifferentationVisitor()
        Returns the visitor used for differentiation. Allows more advanced functions.

      • addStandardDiffRules

        public boolean addStandardDiffRules()
        Adds the standard set of differentiation rules. Corresponds to all standard functions in the Jep plus a few more. 
         sin,cos,tan,asin,acos,atan,sinh,cosh,tanh,asinh,acosh,atanh
 sqrt,log,ln,abs,angle
 sum,im,re are handled separately.
 rand and mod currently un-handled
 
 Also adds rules for functions not in Jep function list:
        sec,cosec,cot,exp,pow,sgn
        Returns:
        false on error

      • addDiffRule

        public void addDiffRule​(DiffRulesI rule)
        Adds a rule with instruction on how to differentiate a function.
        Parameters:
        rule -

      • differentiate

        public Node differentiate​(Node node,
                          java.lang.String name)
                   throws ParseException
        Differentiate an equation with respect to a variable.
        Parameters:
        node - top node of the expression tree to differentiate.
        name - differentiate with respect to this variable.
        Returns:
        the top node of a new parse tree representing the derivative.
        Throws:
        ParseException
        java.lang.IllegalArgumentException

      • replacePartialDerivativeByExpressions

        public Node replacePartialDerivativeByExpressions​(Node node)
                                           throws JepException
        Replace any partial derivatives found in the expression by their expressions.
        Parameters:
        node - expression to process, may be modified
        Returns:
        the expression after replacement
        Throws:
        JepException

      • differentiate

        public DVariable differentiate​(DVariable var,
                               java.lang.String... names)
                        throws ParseException
        Finds the derivative of a differentiable variable. Will look up existing derivative if it exists or calculate the derivative if needed.
        Parameters:
        var - variable to differentiate
        names - names of the partial derivatives to find, either a single name "x" or an array of names to find higher derivatives
        Returns:
        a variable representing the partial derivative
        Throws:
        ParseException