Package org.tweetyproject.math.term

Class Sum

java.lang.Object

org.tweetyproject.math.term.Term

org.tweetyproject.math.term.AssociativeOperation

org.tweetyproject.math.term.Sum

public class Sum
extends AssociativeOperation

This class models a sum of two terms.

Author:

Matthias Thimm

Constructor Summary

Constructors

Constructor	Description
Sum()	Creates a new (empty) sum.
Sum(Collection<? extends Term> terms)	Creates a new sum with the given list of terms.
Sum(Term first, Term second)	Creates a new sum with the given terms.

Method Summary

Modifier and Type	Method	Description
Term	derive(Variable v)	Differentiates the term with respect to the given variable.
void	expandAssociativeOperations()	This method expands all associative operations appearing in this term, e.g.
Set<Sum>	getSums()	Returns all sums of this term.
boolean	isContinuous(Variable v)	Checks whether this term is continuous in v.
Term	replaceTerm(Term toSubstitute, Term substitution)	Replaces each occurrence of "toSubstitute" by "substitution" and return the new term.
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.
Sum	toLinearForm()	Converts this term into a linear normal form, i.e.
Sum	toQuadraticForm()	Return a quadratic form
String	toString()
Constant	value()	Computes the actual value of this term if it contains no variables.

Methods inherited from class org.tweetyproject.math.term.AssociativeOperation

addAllTerm, addTerm, collapseAssociativeOperations, getAbsoluteValues, getMaximums, getMinimums, getProducts, getTerms, getVariables, isInteger, removeTerm, size

Methods inherited from class org.tweetyproject.math.term.Term

add, doubleValue, evaluateMatrix, evaluateVector, evaluateVector, isContinuous, isLinear, isQuadratic, min, minus, mult, replaceAllTerms, replaceAllTerms

Methods inherited from class java.lang.Object

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

Constructor Details

Sum

public Sum()

Creates a new (empty) sum.

Sum

public Sum(Term first,
 Term second)

Creates a new sum with the given terms.

Parameters:

first - a term.

second - a term.

Sum

public Sum(Collection<? extends Term> terms)

Creates a new sum with the given list of terms.

Parameters:

terms - a list of terms.

Method Details

value

public Constant value()

Description copied from class: Term

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

Specified by:

value in class Term

Returns:

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

replaceTerm

public Term replaceTerm(Term toSubstitute,
 Term substitution)

Description copied from class: Term

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

Specified by:

replaceTerm in class Term

Parameters:

toSubstitute - the term to be substituted

substitution - the new term

Returns:

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

expandAssociativeOperations

public void expandAssociativeOperations()

Description copied from class: Term

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

Specified by:

expandAssociativeOperations in class Term

toLinearForm

public Sum toLinearForm()
                 throws IllegalArgumentException

Description copied from class: Term

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

Specified by:

toLinearForm in class Term

Returns:

a term in linear normal form.

Throws:

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

toQuadraticForm

public Sum toQuadraticForm()
                    throws IllegalArgumentException

Description copied from class: Term

Return a quadratic form

Specified by:

toQuadraticForm in class Term

Returns:

a quadratic form

Throws:

IllegalArgumentException - error

derive

public Term derive(Variable v)
            throws NonDifferentiableException

Description copied from class: Term

Differentiates the term with respect to the given variable.

Specified by:

derive in class Term

Parameters:

v - a variable.

Returns:

the derivation of this term wrt. the given variable.

Throws:

NonDifferentiableException - if the term cannot be differentiated.

isContinuous

public boolean isContinuous(Variable v)

Description copied from class: Term

Checks whether this term is continuous in v.

Specified by:

isContinuous in class Term

Parameters:

v - a variable

Returns:

"true" iff this term is continuous in v.

simplify

public Term simplify()

Description copied from class: Term

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.

Specified by:

simplify in class Term

Returns:

the simplified term.

getSums

public Set<Sum> getSums()

Description copied from class: Term

Returns all sums of this term.

Overrides:

getSums in class AssociativeOperation

Returns:

all sums of this term.

toString

public String toString()

Specified by:

toString in class Term