org.matheclipse.core.reflection.system

Class Eliminate

java.lang.Object

org.matheclipse.core.eval.interfaces.AbstractFunctionEvaluator

org.matheclipse.core.reflection.system.Eliminate

All Implemented Interfaces:

IFunctionEvaluator, IEvaluator

public class Eliminate
extends AbstractFunctionEvaluator

Try to eliminate a variable in a set of equations (i.e. Equal[...] expressions). See Wikipedia - System of linear equations - Elimination of variables.

Constructor Summary

Constructors

Constructor and Description
Eliminate()

Method Summary

Modifier and Type	Method and Description
IAST	eliminateOneVariable(java.util.ArrayList<org.matheclipse.core.reflection.system.Eliminate.VariableCounterVisitor> analyzerList, ISymbol variable) Analyze the Equal() terms, if we find an expression which equals the given variabe
IExpr	evaluate(IAST ast) Symbolic evaluation of a function.
static IExpr	extractVariable(IExpr exprWithVariable, IExpr exprWithoutVariable, Predicate<IExpr> predicate, ISymbol variable) Extract a value for the given variabe.

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

createRuleFromMethod, getPeriodicParts, getPureImaginaryPart, getRuleAST, isNegativeExpression, numericEval, setUp

Methods inherited from class java.lang.Object

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

Constructor Detail

Eliminate

public Eliminate()

Method Detail

extractVariable

public static IExpr extractVariable(IExpr exprWithVariable,
                                    IExpr exprWithoutVariable,
                                    Predicate<IExpr> predicate,
                                    ISymbol variable)

Extract a value for the given variabe.

Parameters:

exprWithVariable - expression which contains the given variabe.

exprWithoutVariable - expression which doesn't contain the given variabe.

variable - the variable which should be eliminated.

Returns:

null if we can't find an equation for the given variable.

eliminateOneVariable

public IAST eliminateOneVariable(java.util.ArrayList<org.matheclipse.core.reflection.system.Eliminate.VariableCounterVisitor> analyzerList,
                                 ISymbol variable)

Analyze the Equal() terms, if we find an expression which equals the given variabe

Parameters:

termsEqualZeroList - list of Equal() terms

variable - the variable which should be eliminated.

Returns:

null if we can't eliminate an equation from the list for the given variabe

evaluate

public IExpr evaluate(IAST ast)

Symbolic evaluation of a function. ast.get(0) contains the head (i.e. the function symbol) of this abstract syntax tree (AST). ast.get(1) to ast.get(n) contains the first to n-th argument of the function.
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

Returns:

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

See Also:

Validate