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Class ia_parser.Exp

java.lang.Object
   |
   +----ia_parser.Exp

public abstract class Exp
extends Object
This class represents interval arithmetic expressions.

It has methods for binding the variables in the expression to intervals, evaluating the expression, narrowing the the variables which appear in the expression, and retrieving the bindings of the variables in the expression.

These expressions consists of variables, intervals, and constants combined with various function and predicate symbols. Each variable in an expression has an associated interval value which can be used to evaluate the expression or to narrow the expression (assuming the top level operator is a relation operator).

Expressions are constructed using the Parser class.


Constructor Index

 o Exp()

Method Index

 o bindVars(RealIntervalTable)
Bind the variables in the expression to intervals as specified by the table T.
 o eval(RealIntervalTable)
Evaluate the expression using the Table T for the values of the variables.
 o getVarBindings(RealIntervalTable)
Traverse the expression and store all the variable bindings in the tree T.
 o ival()
Return the current interval value of the expression
 o narrow()
Narrow the variables appearing in the expression.

Constructors

 o Exp
 public Exp()

Methods

 o ival
 public abstract RealInterval ival()
Return the current interval value of the expression

 o bindVars
 public abstract void bindVars(RealIntervalTable T)
Bind the variables in the expression to intervals as specified by the table T. If a variable in the expression does not appear in T, then it will be initialized to (-infinity,infinity) and will be stored in T.

If T is null then this does nothing. If T is empty, but not null, then it reinitializes all variables and stores them in T.

 o getVarBindings
 public abstract void getVarBindings(RealIntervalTable T)
Traverse the expression and store all the variable bindings in the tree T. If T is initially empty this will find all variables in the expression and store them with their bindings in T. If T is non-empty it will simply add the bindings to T. If T is null it will do nothing.

 o eval
 public abstract RealInterval eval(RealIntervalTable T) throws IAException
Evaluate the expression using the Table T for the values of the variables. If T is null, then just use the current values of the variables.

 o narrow
 public abstract boolean narrow()
Narrow the variables appearing in the expression.


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