org.cryptimeleon.math.structures.rings.cartesian

Class ProductRingElement

java.lang.Object

org.cryptimeleon.math.structures.rings.cartesian.ProductRingElement

All Implemented Interfaces:

UniqueByteRepresentable, Representable, Element, RingElement

public class ProductRingElement
extends java.lang.Object
implements RingElement

Field Summary

Fields

Modifier and Type	Field and Description
protected RingElement[]	elems

Constructor Summary

Constructors

Constructor and Description
ProductRingElement(java.util.List<? extends RingElement> elems)
ProductRingElement(Representation repr)
ProductRingElement(RingElement... elems)

Method Summary

Modifier and Type	Method and Description
ProductRingElement	add(Element e) Computes \(\text{this} + e\).
boolean	divides(RingElement e) Returns true iff there exists an \(x\) in the ring such that \(\text{this} \cdot x = e\).
RingElement[]	divideWithRemainder(RingElement e) Divides this by e with remainder, returning both quotient and remainder.
boolean	equals(java.lang.Object o)
RingElement	get(int index)
java.math.BigInteger	getRank() Implements the euclidean function of a euclidean domain.
Representation	getRepresentation() The representation of this object.
ProductRing	getStructure() Returns the Structure that this Element belongs to.
int	hashCode()
ProductRingElement	inv() Computes the multiplicative inverse of this element.
ProductRingElement	mul(java.math.BigInteger k) Computes \(\text{this} \cdot k\) (equivalent to \(\text{this} + \text{this} + \cdots\) k-times).
ProductRingElement	mul(Element e) Computes \(\text{this} \cdot e\).
ProductRingElement	neg() Computes the additive inverse of this element.
ProductRingElement	pow(java.math.BigInteger k) Calculates \(\text{this}^k\).
ByteAccumulator	updateAccumulator(ByteAccumulator accumulator) Updates the ByteAccumulator with the unique byte representation of this object.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cryptimeleon.math.structures.rings.RingElement

asInteger, div, isOne, isUnit, isZero, mul, pow, square, sub, toAdditiveGroupElement, toUnitGroupElement

Methods inherited from interface org.cryptimeleon.math.hash.UniqueByteRepresentable

getUniqueByteRepresentation

Field Detail

elems

protected RingElement[] elems

Constructor Detail

ProductRingElement

public ProductRingElement(java.util.List<? extends RingElement> elems)

ProductRingElement

public ProductRingElement(RingElement... elems)

ProductRingElement

public ProductRingElement(Representation repr)

Method Detail

getStructure

public ProductRing getStructure()

Description copied from interface: Element

Returns the Structure that this Element belongs to.

Specified by:

getStructure in interface Element

Specified by:

getStructure in interface RingElement

add

public ProductRingElement add(Element e)

Description copied from interface: RingElement

Computes \(\text{this} + e\).

Specified by:

add in interface RingElement

Parameters:

e - the addend

Returns:

the result

neg

public ProductRingElement neg()

Description copied from interface: RingElement

Computes the additive inverse of this element.

Specified by:

neg in interface RingElement

Returns:

the result

mul

public ProductRingElement mul(Element e)

Description copied from interface: RingElement

Computes \(\text{this} \cdot e\).

Specified by:

mul in interface RingElement

Parameters:

e - the factor

Returns:

the result

mul

public ProductRingElement mul(java.math.BigInteger k)

Description copied from interface: RingElement

Computes \(\text{this} \cdot k\) (equivalent to \(\text{this} + \text{this} + \cdots\) k-times).

Specified by:

mul in interface RingElement

Parameters:

k - the factor

Returns:

the result

inv

public ProductRingElement inv()

Description copied from interface: RingElement

Computes the multiplicative inverse of this element.

Specified by:

inv in interface RingElement

Returns:

the result

divides

public boolean divides(RingElement e)
                throws java.lang.UnsupportedOperationException

Description copied from interface: RingElement

Returns true iff there exists an \(x\) in the ring such that \(\text{this} \cdot x = e\).

Specified by:

divides in interface RingElement

Throws:

java.lang.UnsupportedOperationException - if this cannot be decided (efficiently)

divideWithRemainder

public RingElement[] divideWithRemainder(RingElement e)
                                  throws java.lang.UnsupportedOperationException,
                                         java.lang.IllegalArgumentException

Description copied from interface: RingElement

Divides this by e with remainder, returning both quotient and remainder.

Specifically, returns an array result such that the first entry contains the quotient and the second entry the remainder. Furthermore, result[1].getRank() < e.getRank() or result[1] = 0.

This definition implies that the remainder is zero if and only if e divides this element.

Specified by:

divideWithRemainder in interface RingElement

Throws:

java.lang.UnsupportedOperationException - if the ring is not a euclidean domain

java.lang.IllegalArgumentException - if e is zero

getRank

public java.math.BigInteger getRank()
                             throws java.lang.UnsupportedOperationException

Description copied from interface: RingElement

Implements the euclidean function of a euclidean domain.

The euclidean function is a function from \(R \setminus \{0\}\) to \(\mathbb{N}_0\) such that

• a.getRank() >= 0 for any a in the ring
• a.mul(b).getRank() >= a.getRank() for any a, b != 0
• the remainder rank after divideWithRemainder is less than the divisor's rank

For example, for a polynomial ring this corresponds to the degree of the polynomial.

The rank of the zero element is undefined (no guarantee as to what this method returns in that case).

Specified by:

getRank in interface RingElement

Throws:

java.lang.UnsupportedOperationException - if the ring is not a euclidean domain

pow

public ProductRingElement pow(java.math.BigInteger k)

Description copied from interface: RingElement

Calculates \(\text{this}^k\).

Note that \(a^0 = 1\) for any \(a\) in the ring, particularly \(0^0 = 1\).

Specified by:

pow in interface RingElement

get

public RingElement get(int index)

updateAccumulator

public ByteAccumulator updateAccumulator(ByteAccumulator accumulator)

Description copied from interface: UniqueByteRepresentable

Updates the ByteAccumulator with the unique byte representation of this object.

The input to the accumulators update function is an injective (with respect to a given domain) byte encoding of this object.

For many use-cases, the AnnotatedUbrUtil can be used to quickly implement this method.

Specified by:

updateAccumulator in interface UniqueByteRepresentable

Returns:

the same accumulator as was input

getRepresentation

public Representation getRepresentation()

Description copied from interface: Representable

The representation of this object. Used for serialization. A convenient way to implement this is using @link ReprUtil

Specified by:

getRepresentation in interface Representable

Returns:

a Representation or null if an equal object can be recreated without any information.

See Also:

Representation

equals

public boolean equals(java.lang.Object o)

Specified by:

equals in interface Element

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface Element

Overrides:

hashCode in class java.lang.Object