org.matheclipse.core.reflection.system

Class Equal

java.lang.Object

org.matheclipse.core.eval.interfaces.AbstractEvaluator

org.matheclipse.core.eval.interfaces.AbstractFunctionEvaluator

org.matheclipse.core.reflection.system.Equal

All Implemented Interfaces:

IFunctionEvaluator, ITernaryComparator<IExpr>, IEvaluator

Direct Known Subclasses:

Unequal

public class Equal
extends AbstractFunctionEvaluator
implements ITernaryComparator<IExpr>

== operator implementation.

Nested Class Summary

Nested classes/interfaces inherited from interface org.matheclipse.core.generic.ITernaryComparator

ITernaryComparator.COMPARE_RESULT

Field Summary

Fields

Modifier and Type	Field and Description
static Equal	CONST

Constructor Summary

Constructors

Constructor and Description
Equal()

Method Summary

Modifier and Type	Method and Description
ITernaryComparator.COMPARE_RESULT	compare(IExpr o0, IExpr o1) Return TRUE if the comparison is true Return FALSE if the comparison is false Return UNDEFINED if the comparison is undetermined (i.e. could not be evaluated)
static IExpr	equal(IAST ast)
static IExpr	equalNull(IExpr a1, IExpr a2) Compare if the first and second argument are equal.
IExpr	evaluate(IAST ast, EvalEngine engine) Symbolic evaluation of a function.
void	setUp(ISymbol symbol) Evaluate built-in rules and define Attributes for a function.
protected IExpr	simplifyCompare(IExpr a1, IExpr a2, ISymbol originalHead) Try to simplify a comparator expression.

Methods inherited from class org.matheclipse.core.eval.interfaces.AbstractFunctionEvaluator

createRuleFromMethod, getNormalizedNegativeExpression, getNormalizedNegativeExpression, getPeriodicParts, getPureImaginaryPart, getRuleAST, initSerializedRules, isNegativeExpression

Methods inherited from class org.matheclipse.core.eval.interfaces.AbstractEvaluator

numericEval

Methods inherited from class java.lang.Object

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

Field Detail

CONST

public static final Equal CONST

Constructor Detail

Equal

public Equal()

Method Detail

simplifyCompare

protected IExpr simplifyCompare(IExpr a1,
                                IExpr a2,
                                ISymbol originalHead)

Try to simplify a comparator expression. Example: 3*x > 6 wll be simplified to x> 2.

Parameters:

a1 - left-hand-side of the comparator expression

a2 - right-hand-side of the comparator expression

originalHead - symbol for which the simplification was started

Returns:

the simplified comparator expression or null if no simplification was found

evaluate

public IExpr evaluate(IAST ast,
                      EvalEngine engine)

Description copied from class: AbstractFunctionEvaluator

Symbolic evaluation of a function. ast.get(0) (or alternatively ast.head()) contains the head (i.e. the function symbol) of this abstract syntax tree (AST).
From ast.arg1() to ast.get(n) the ast contains the first to n-th argument of the function (alternatively you get the first to fifth argument with the methods arg1(), arg2(),... arg5()).
If necessary use the methods from the Validate class to check the number or types of arguments in the evaluate method.
Note: if the symbolic evaluation isn't possible or no result is found the evaluate method returns with a null value without throwing an exception!

Specified by:

evaluate in interface IFunctionEvaluator

Specified by:

evaluate in class AbstractFunctionEvaluator

Parameters:

ast - the abstract syntax tree (AST) which should be evaluated

engine - the users current evaluation engine

Returns:

the evaluated object or null, if evaluation isn't possible

See Also:

Validate, IExpr.head(), IAST.arg1(), IAST.arg2(), IAST.arg3()

equalNull

public static IExpr equalNull(IExpr a1,
                              IExpr a2)

Compare if the first and second argument are equal.

Parameters:

a1 - first argument

a2 - second argument

Returns:

F.NIL or the simplified expression, if equality couldn't be determined.

equal

public static IExpr equal(IAST ast)

compare

public ITernaryComparator.COMPARE_RESULT compare(IExpr o0,
                                                 IExpr o1)

• Return TRUE if the comparison is true
• Return FALSE if the comparison is false
• Return UNDEFINED if the comparison is undetermined (i.e. could not be evaluated)

Specified by:

compare in interface ITernaryComparator<IExpr>

Returns:

setUp

public void setUp(ISymbol symbol)

Description copied from class: AbstractFunctionEvaluator

Evaluate built-in rules and define Attributes for a function.

Specified by:

setUp in interface IEvaluator

Overrides:

setUp in class AbstractFunctionEvaluator

Parameters:

symbol - the symbol which should be set up