Package com.singularsys.jep.functions

Class Ele

  • All Implemented Interfaces:
    LValueI, PostfixMathCommandI, java.io.Serializable
    Direct Known Subclasses:
    MatrixEle, ThreadSafeEle
    public class Ele
extends NaryFunction
implements LValueI
    Function which allows array access using the a[3] notation on left and right hand side. The first element is indexed with 1. a=[4,3,2,1]; a[2]; // Returns 2 a[2]=5; // Sets the 2nd element of a to 5. So a is now [4,5,2,1] // Two dimensional matrices only work with the configurable parser b=[[1,2,3],[4,5,6]]; b[2][3]; // returns 6 b[2][3]=7; // sets 3rd element of 2nd row to 7
    Author:
    Richard Morris
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      Ele()
      Element access with mathematical convention, first element has index 1
      Ele​(boolean javaIndex)
      Element access, either java convention (first element has index 0) or mathematical convention (first element has index 1) can be specified.

    • Field Detail

      • indexShift

        protected final int indexShift

    • Constructor Detail

      • Ele

        public Ele()
        Element access with mathematical convention, first element has index 1

      • Ele

        public Ele​(boolean javaIndex)
        Element access, either java convention (first element has index 0) or mathematical convention (first element has index 1) can be specified.
        Parameters:
        javaIndex - whether to use the java convention, if true index start at 0.

    • Method Detail

      • checkNumberOfParameters

        public boolean checkNumberOfParameters​(int n)
        Description copied from class: PostfixMathCommand
        Checks the number of parameters of the function. Functions which set numberOfParameter=-1 should overload this method
        Specified by:
        checkNumberOfParameters in interface PostfixMathCommandI
        Overrides:
        checkNumberOfParameters in class PostfixMathCommand
        Parameters:
        n - number of parameters function will be called with.
        Returns:
        false if an illegal number of parameters is supplied, true otherwise.

      • set

        public void set​(Evaluator pv,
                Node node,
                java.lang.Object value)
         throws EvaluationException
        Description copied from interface: LValueI
        Performs appropriate action to set an LValue.
        Specified by:
        set in interface LValueI
        Parameters:
        pv - a pointer to the evaluator. The pv.eval() method can be used to evaluate the children of the node.
        node - The top node for the LValue
        value - the value obtained by evaluating the right hand side.
        Throws:
        EvaluationException - if the calculation cannot be performed

      • eval

        public java.lang.Object eval​(java.lang.Object[] args)
                      throws EvaluationException
        Description copied from class: NaryFunction
        Evaluate the function
        Specified by:
        eval in class NaryFunction
        Parameters:
        args - arguments to the function
        Returns:
        value returned by the function
        Throws:
        EvaluationException - if the calculation cannot be performed

      • ele

        public java.lang.Object ele​(java.lang.Object vec,
                            java.lang.Object indexObject)
                     throws EvaluationException
        Find the element of a vector
        Parameters:
        vec - the vector
        indexObject - the index either as a vector with a single value or as a single value.
        Returns:
        element of vec referred to by the index.
        Throws:
        EvaluationException - if the calculation cannot be performed
        Since:
        3.4.0

      • ele

        public java.lang.Object ele​(java.lang.Object mat,
                            java.lang.Object row,
                            java.lang.Object col)
                     throws EvaluationException
        Find the element of a matrix
        Parameters:
        mat - the matrix represented a a Vector<Vector<Object>>
        row - the index
        col - the index
        Returns:
        element of matrix referred to by row/col
        Throws:
        EvaluationException - if the calculation cannot be performed
        Since:
        3.4.0

      • ele

        public java.lang.Object ele​(java.lang.Object mat,
                            java.lang.Object[] args)
                     throws EvaluationException
        Find element of a multi-dimensional array
        Parameters:
        mat - the array
        args - array of indices
        Returns:
        element in mat referred to by indices
        Throws:
        EvaluationException - if the calculation cannot be performed
        Since:
        3.4.0

      • getVariable

        protected Variable getVariable​(Evaluator pv,
                               ASTVarNode node)
        Find the variable associated with a node. Overwitten by subclasses which require thread-safety.
        Parameters:
        pv - the evaluator
        node - the node
        Returns:
        the variable
        Since:
        3.5