org.lsmp.djep.matrixJep.function

Class MAssign

java.lang.Object

org.nfunk.jep.function.PostfixMathCommand

org.nfunk.jep.function.Assign

org.lsmp.djep.matrixJep.function.MAssign

All Implemented Interfaces:

MatrixSpecialEvaluationI, SpecialPreProcessorI, CallbackEvaluationI, PostfixMathCommandI

public class MAssign
extends Assign
implements MatrixSpecialEvaluationI, SpecialPreProcessorI

A matrix enabled assignment function. The lhs of an assignment must be a variable.

Author:

Rich Morris Created on 23-Feb-2004

Field Summary

Fields inherited from class org.nfunk.jep.function.PostfixMathCommand

curNumberOfParameters, numberOfParameters

Constructor Summary

Constructors

Constructor and Description
MAssign()

Method Summary

Modifier and Type	Method and Description
MatrixValueI	evaluate(MatrixNodeI node, MatrixEvaluator visitor, MatrixJep j) A special methods for evaluating an assignment.
MatrixNodeI	preprocess(ASTFunNode node, MatrixPreprocessor visitor, MatrixJep mjep, MatrixNodeFactory nf) Subverts the preprocessing stage.
void	run(Stack s) The run method should not be called.

Methods inherited from class org.nfunk.jep.function.Assign

evaluate

Methods inherited from class org.nfunk.jep.function.PostfixMathCommand

checkNumberOfParameters, checkStack, getNumberOfParameters, setCurNumberOfParameters

Methods inherited from class java.lang.Object

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

Constructor Detail

MAssign

public MAssign()

Method Detail

run

public void run(Stack s)
         throws ParseException

The run method should not be called. Use evaluate(org.lsmp.djep.matrixJep.nodeTypes.MatrixNodeI, org.lsmp.djep.matrixJep.MatrixEvaluator, org.lsmp.djep.matrixJep.MatrixJep) instead.

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class PostfixMathCommand

Throws:

ParseException

evaluate

public MatrixValueI evaluate(MatrixNodeI node,
                             MatrixEvaluator visitor,
                             MatrixJep j)
                      throws ParseException

A special methods for evaluating an assignment. When an assignment is encountered, first evaluate the rhs. Then set the value of the lhs to the result.

Specified by:

evaluate in interface MatrixSpecialEvaluationI

Parameters:

node - The top node.

visitor - The parser visitor

j - The current MatrixJep instance.

Returns:

Value after evaluation.

Throws:

ParseException

preprocess

public MatrixNodeI preprocess(ASTFunNode node,
                              MatrixPreprocessor visitor,
                              MatrixJep mjep,
                              MatrixNodeFactory nf)
                       throws ParseException

Description copied from interface: SpecialPreProcessorI

Subverts the preprocessing stage. Preprocessing performs a number of operations:

1. Converts each node into one of the subtypes of MatrixNodeI
2. Calculate the dimensions for the results
3. Performs any special symbolic operations such as differentation

In general the first step in preprocessing is to run the preprocessor on the children of the node. This can be done using

 MatrixNodeI children[] = visitor.visitChildrenAsArray(node,null);
 

The final step is to construct a node of the correct type. The MatrixNodeFactory argument has a number of methods to do this. For example

 return (ASTMFunNode) nf.buildOperatorNode(node.getOperator(),children,rhsDim);
 

Note how the dimension is specified.

Specified by:

preprocess in interface SpecialPreProcessorI

Parameters:

node - the top node of the tree representing the function and its arguments.

visitor - A reference to the preprocessing visitor.

mjep - A reference of the MatrixJep instance.

nf - A reference to the node factory object.

Returns:

A new MatrixNodeI representing the converted function.

Throws:

ParseException - if some error occurs.