edu.jas.ufd

Class GCDFactory

java.lang.Object

edu.jas.ufd.GCDFactory

public class GCDFactory
extends java.lang.Object

Greatest common divisor algorithms factory. Select appropriate GCD engine based on the coefficient types.

Author:

Heinz Kredel

See Also:

Todo: Base decision also on degree vectors and number of variables of polynomials. Incorporate also number of CPUs / threads available (done with GCDProxy).

Usage

To create objects that implement the GreatestCommonDivisor interface use the GCDFactory. It will select an appropriate implementation based on the types of polynomial coefficients C. There are two methods to obtain an implementation: getProxy() and getImplementation(). getImplementation() returns an object of a class which implements the GreatestCommonDivisor interface. getProxy() returns a proxy object of a class which implements the GreatestCommonDivisorr interface. The proxy will run two implementations in parallel, return the first computed result and cancel the second running task. On systems with one CPU the computing time will be two times the time of the fastest algorithm implmentation. On systems with more than two CPUs the computing time will be the time of the fastest algorithm implmentation.

 GreatestCommonDivisor<CT> engine;
 engine = GCDFactory.<CT> getImplementation(cofac);
 or engine = GCDFactory.<CT> getProxy(cofac);
 c = engine.gcd(a, b);
 

For example, if the coefficient type is BigInteger, the usage looks like

 BigInteger cofac = new BigInteger();
 GreatestCommonDivisor<BigInteger> engine;
 engine = GCDFactory.getImplementation(cofac);
 or engine = GCDFactory.getProxy(cofac);
 c = engine.gcd(a, b);
 

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	GCDFactory() Protected factory constructor.

Method Summary

Modifier and Type	Method and Description
static GreatestCommonDivisorAbstract<BigInteger>	getImplementation(BigInteger fac) Determine suitable implementation of gcd algorithms, case BigInteger.
static GreatestCommonDivisorAbstract<BigRational>	getImplementation(BigRational fac) Determine suitable implementation of gcd algorithms, case BigRational.
static GreatestCommonDivisorAbstract<ModInteger>	getImplementation(ModIntegerRing fac) Determine suitable implementation of gcd algorithms, case ModInteger.
static GreatestCommonDivisorAbstract<ModLong>	getImplementation(ModLongRing fac) Determine suitable implementation of gcd algorithms, case ModLong.
static <C extends GcdRingElem<C>> GreatestCommonDivisorAbstract<C>	getImplementation(RingFactory<C> fac) Determine suitable implementation of gcd algorithms, other cases.
static GreatestCommonDivisorAbstract<BigInteger>	getProxy(BigInteger fac) Determine suitable procy for gcd algorithms, case BigInteger.
static GreatestCommonDivisorAbstract<BigRational>	getProxy(BigRational fac) Determine suitable proxy for gcd algorithms, case BigRational.
static GreatestCommonDivisorAbstract<ModInteger>	getProxy(ModIntegerRing fac) Determine suitable proxy for gcd algorithms, case ModInteger.
static GreatestCommonDivisorAbstract<ModLong>	getProxy(ModLongRing fac) Determine suitable proxy for gcd algorithms, case ModLong.
static <C extends GcdRingElem<C>> GreatestCommonDivisorAbstract<C>	getProxy(RingFactory<C> fac) Determine suitable proxy for gcd algorithms, other cases.

Methods inherited from class java.lang.Object

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

Constructor Detail

GCDFactory

protected GCDFactory()

Protected factory constructor.

Method Detail

getImplementation

public static GreatestCommonDivisorAbstract<ModLong> getImplementation(ModLongRing fac)

Determine suitable implementation of gcd algorithms, case ModLong.

Parameters:

fac - ModLongRing.

Returns:

gcd algorithm implementation.

getProxy

public static GreatestCommonDivisorAbstract<ModLong> getProxy(ModLongRing fac)

Determine suitable proxy for gcd algorithms, case ModLong.

Parameters:

fac - ModLongRing.

Returns:

gcd algorithm implementation.

getImplementation

public static GreatestCommonDivisorAbstract<ModInteger> getImplementation(ModIntegerRing fac)

Determine suitable implementation of gcd algorithms, case ModInteger.

Parameters:

fac - ModIntegerRing.

Returns:

gcd algorithm implementation.

getProxy

public static GreatestCommonDivisorAbstract<ModInteger> getProxy(ModIntegerRing fac)

Determine suitable proxy for gcd algorithms, case ModInteger.

Parameters:

fac - ModIntegerRing.

Returns:

gcd algorithm implementation.

getImplementation

public static GreatestCommonDivisorAbstract<BigInteger> getImplementation(BigInteger fac)

Determine suitable implementation of gcd algorithms, case BigInteger.

Parameters:

fac - BigInteger.

Returns:

gcd algorithm implementation.

getProxy

public static GreatestCommonDivisorAbstract<BigInteger> getProxy(BigInteger fac)

Determine suitable procy for gcd algorithms, case BigInteger.

Parameters:

fac - BigInteger.

Returns:

gcd algorithm implementation.

getImplementation

public static GreatestCommonDivisorAbstract<BigRational> getImplementation(BigRational fac)

Determine suitable implementation of gcd algorithms, case BigRational.

Parameters:

fac - BigRational.

Returns:

gcd algorithm implementation.

getProxy

public static GreatestCommonDivisorAbstract<BigRational> getProxy(BigRational fac)

Determine suitable proxy for gcd algorithms, case BigRational.

Parameters:

fac - BigRational.

Returns:

gcd algorithm implementation.

getImplementation

public static <C extends GcdRingElem<C>> GreatestCommonDivisorAbstract<C> getImplementation(RingFactory<C> fac)

Determine suitable implementation of gcd algorithms, other cases.

Parameters:

fac - RingFactory<C>.

Returns:

gcd algorithm implementation.

getProxy

public static <C extends GcdRingElem<C>> GreatestCommonDivisorAbstract<C> getProxy(RingFactory<C> fac)

Determine suitable proxy for gcd algorithms, other cases.

Parameters:

fac - RingFactory<C>.

Returns:

gcd algorithm implementation. Note: This method contains a hack for Google app engine to not use threads.

See Also:

ComputerThreads.NO_THREADS