com.singularsys.jep.functions
Class Ele

java.lang.Object
  com.singularsys.jep.functions.PostfixMathCommand
      com.singularsys.jep.functions.NaryFunction
          com.singularsys.jep.functions.Ele

All Implemented Interfaces:

LValueI, PostfixMathCommandI, java.io.Serializable

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] b=[[1,2,3],[4,5,6]]; b[2][3]; // returns 6 b[2][3]=7; // sets 3rd element of 2nd row to 7 (only works with the configurable parser)

Author:

Richard Morris

See Also:

Serialized Form

Field Summary

protected int

indexShift

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, name, NaN, numberOfParameters

Constructor Summary

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.

Method Summary

boolean	checkNumberOfParameters(int n) Checks the number of parameters of the function.
java.lang.Object	ele(java.lang.Object[] args) Find the element of an array.
java.lang.Object	ele(java.lang.Object vec, java.lang.Object indexObject) Find the element of a vector
java.lang.Object	ele(java.lang.Object mat, java.lang.Object[] args) Find element of a multi-dimensional array
java.lang.Object	ele(java.lang.Object mat, java.lang.Object row, java.lang.Object col) Find the element of a matrix
java.lang.Object	eval(java.lang.Object[] args) Evaluate the function
void	set(Evaluator pv, Node node, java.lang.Object value) Performs appropriate action to set an LValue.

Methods inherited from class com.singularsys.jep.functions.NaryFunction

run

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, checkStack, getName, getNumberOfParameters, setCurNumberOfParameters, setName, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

indexShift

protected 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

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

ele

public java.lang.Object ele(java.lang.Object[] args)
                     throws EvaluationException

Find the element of an array. Calls ele(Object, Object), ele(Object, Object, Object) or ele(Object, Object[]) depending on number of arguments.

Parameters:

args - First element is the vector or matrix, subsequent elements are indices

Returns:

the element referred to by the indices

Throws:

EvaluationException

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

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

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

Since:

3.4.0