Package org.tweetyproject.math.term

Class Term

java.lang.Object

org.tweetyproject.math.term.Term

Direct Known Subclasses:

AssociativeOperation, Constant, Difference, Fraction, FunctionalTerm, Variable

public abstract class Term
extends Object

This class models a mathematical term.

Author:

Matthias Thimm

Constructor Summary

Constructors

Constructor	Description
Term()

Method Summary

Modifier and Type	Method	Description
Sum	add(Term t)	Returns the sum of this and the given term.
abstract void	collapseAssociativeOperations()	This method collapses all associative operations appearing in this term, e.g.
abstract Term	derive(Variable v)	Differentiates the term with respect to the given variable.
double	doubleValue()	Computes the actual value of this term if it contains no variables.
static double[][]	evaluateMatrix(List<List<Term>> functions, double[] values, List<Variable> variables)	Evaluates each function in the given matrix with the given values for variables.
static double[]	evaluateVector(List<Term> functions, double[] values, List<Variable> variables)	Evaluates each function in the given list with the given values for variables.
static List<Double>	evaluateVector(List<Term> functions, Map<Variable,? extends Term> mapping)	Evaluates each function in the given list with the given values for variables.
abstract void	expandAssociativeOperations()	This method expands all associative operations appearing in this term, e.g.
abstract Set<AbsoluteValue>	getAbsoluteValues()	Returns all absolute values of this term.
abstract Set<Maximum>	getMaximums()	Returns all maximums of this term.
abstract Set<Minimum>	getMinimums()	Returns all minimums of this term.
abstract Set<Product>	getProducts()	Returns all products of this term.
abstract Set<Sum>	getSums()	Returns all sums of this term.
abstract List<Term>	getTerms()	Getter Terms
abstract Set<Variable>	getVariables()	Returns all variables in this term.
boolean	isContinuous()	Checks whether this term is continuous in all appearing variables.
abstract boolean	isContinuous(Variable v)	Checks whether this term is continuous in v.
abstract boolean	isInteger()	Checks whether this term represents an integer value.
boolean	isLinear()	Checks whether this term is linear.
boolean	isQuadratic()	Checks whether this term is quadratic.
Term	min(Term t)	Returns the minimum of this and the given term.
Difference	minus(Term t)	Returns the sum of this and (-1) * the given term.
Product	mult(Term t)	Returns the product of this and the given term.
Term	replaceAllTerms(double[] values, List<Variable> variables)	Replaces terms according to the given map.
Term	replaceAllTerms(Map<? extends Term,? extends Term> substitutes)	Replaces terms according to the given map.
abstract Term	replaceTerm(Term toSubstitute, Term substitution)	Replaces each occurrence of "toSubstitute" by "substitution" and return the new term.
abstract Term	simplify()	Simplifies this term in an equivalent way: - Replaces products that contain a zero by the constant zero - Removes a term one from products - Removes a term zero from sums - Aggregates constants in sums, products, and minimums - Evaluates functional terms on constants - Simplifies fractions where possible.
abstract Sum	toLinearForm()	Converts this term into a linear normal form, i.e.
abstract Sum	toQuadraticForm()	Return a quadratic form
abstract String	toString()
abstract Constant	value()	Computes the actual value of this term if it contains no variables.

Methods inherited from class java.lang.Object

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

Constructor Details

Term

public Term()

Method Details

add

public Sum add(Term t)

Returns the sum of this and the given term.

Parameters:

t - a term

Returns:

the sum of this and the given term.

minus

public Difference minus(Term t)

Returns the sum of this and (-1) * the given term.

Parameters:

t - a term

Returns:

the sum of this and (-1) * the given term.

mult

public Product mult(Term t)

Returns the product of this and the given term.

Parameters:

t - a term.

Returns:

the product of this and the given term.

min

public Term min(Term t)

Returns the minimum of this and the given term.

Parameters:

t - a term.

Returns:

the minimum of this and the given term.

value

public abstract Constant value()
                        throws IllegalArgumentException

Computes the actual value of this term if it contains no variables.

Returns:

the value of this term, either a float or an integer.

Throws:

IllegalArgumentException - if this term contains at least on variable.

doubleValue

public double doubleValue()
                   throws IllegalArgumentException

Computes the actual value of this term if it contains no variables.

Returns:

the double value of this term.

Throws:

IllegalArgumentException - if this term contains at least on variable.

isContinuous

public abstract boolean isContinuous(Variable v)

Checks whether this term is continuous in v.

Parameters:

v - a variable

Returns:

"true" iff this term is continuous in v.

isContinuous

public boolean isContinuous()

Checks whether this term is continuous in all appearing variables.

Returns:

"true" iff this term is continuous in all appearing variables

getVariables

public abstract Set<Variable> getVariables()

Returns all variables in this term.

Returns:

all variables in this term.

getProducts

public abstract Set<Product> getProducts()

Returns all products of this term.

Returns:

all products of this term.

getSums

public abstract Set<Sum> getSums()

Returns all sums of this term.

Returns:

all sums of this term.

getMinimums

public abstract Set<Minimum> getMinimums()

Returns all minimums of this term.

Returns:

all minimums of this term.

getMaximums

public abstract Set<Maximum> getMaximums()

Returns all maximums of this term.

Returns:

all maximums of this term.

getAbsoluteValues

public abstract Set<AbsoluteValue> getAbsoluteValues()

Returns all absolute values of this term.

Returns:

all absolute values of this term.

isInteger

public abstract boolean isInteger()

Checks whether this term represents an integer value.

Returns:

"true" iff this term represents an integer value.

toLinearForm

public abstract Sum toLinearForm()
                          throws IllegalArgumentException

Converts this term into a linear normal form, i.e. into a sum of products of a constant and a variable.

Returns:

a term in linear normal form.

Throws:

IllegalArgumentException - if this term cannot be converted into a linear normal form.

toQuadraticForm

public abstract Sum toQuadraticForm()
                             throws IllegalArgumentException

Return a quadratic form

Returns:

a quadratic form

Throws:

IllegalArgumentException - error

replaceTerm

public abstract Term replaceTerm(Term toSubstitute,
 Term substitution)

Replaces each occurrence of "toSubstitute" by "substitution" and return the new term.

Parameters:

toSubstitute - the term to be substituted

substitution - the new term

Returns:

this term where "toSubstitute" is replaced by "substitution"

evaluateVector

public static List<Double> evaluateVector(List<Term> functions,
 Map<Variable,? extends Term> mapping)

Evaluates each function in the given list with the given values for variables.

Parameters:

functions - a list of functions

mapping - a map mapping variables to terms

Returns:

the values

evaluateVector

public static double[] evaluateVector(List<Term> functions,
 double[] values,
 List<Variable> variables)

Evaluates each function in the given list with the given values for variables.

Parameters:

functions - a list of functions

values - the values of the variables

variables - the (ordered) list of variables

Returns:

the values

evaluateMatrix

public static double[][] evaluateMatrix(List<List<Term>> functions,
 double[] values,
 List<Variable> variables)

Evaluates each function in the given matrix with the given values for variables.

Parameters:

functions - a list of functions

values - the values of the variables

variables - the (ordered) list of variables

Returns:

the values

replaceAllTerms

public Term replaceAllTerms(double[] values,
 List<Variable> variables)

Replaces terms according to the given map.

Parameters:

values - an array of values.

variables - A list of variables that shall be substituted by the given values

Returns:

a term.

replaceAllTerms

public Term replaceAllTerms(Map<? extends Term,? extends Term> substitutes)

Replaces terms according to the given map.

Parameters:

substitutes - a map.

Returns:

a term.

isLinear

public boolean isLinear()

Checks whether this term is linear.

Returns:

"true" if this term is linear.

isQuadratic

public boolean isQuadratic()

Checks whether this term is quadratic.

Returns:

"true" if this term is quadratic.

simplify

public abstract Term simplify()

Simplifies this term in an equivalent way:
- Replaces products that contain a zero by the constant zero
- Removes a term one from products
- Removes a term zero from sums
- Aggregates constants in sums, products, and minimums
- Evaluates functional terms on constants
- Simplifies fractions where possible.

Returns:

the simplified term.

getTerms

public abstract List<Term> getTerms()

Getter Terms

Returns:

List of Terms

derive

public abstract Term derive(Variable v)
                     throws NonDifferentiableException

Differentiates the term with respect to the given variable.

Parameters:

v - a variable.

Returns:

the derivation of this term wrt. the given variable.

Throws:

NonDifferentiableException - if the term cannot be differentiated.

collapseAssociativeOperations

public abstract void collapseAssociativeOperations()

This method collapses all associative operations appearing in this term, e.g. every min{min{a,b},c} becomes min{a,b,c}.

expandAssociativeOperations

public abstract void expandAssociativeOperations()

This method expands all associative operations appearing in this term, e.g. every min{a,b,c} becomes min{min{a,b},c}.

toString

public abstract String toString()

Overrides:

toString in class Object