Package org.apfloat.internal

Class Factor3NTTStrategy

java.lang.Object

org.apfloat.internal.Factor3NTTStrategy

All Implemented Interfaces:

Parallelizable, NTTStrategy

Direct Known Subclasses:

IntAparapiFactor3NTTStrategy, LongAparapiFactor3NTTStrategy

public class Factor3NTTStrategy
extends Object
implements NTTStrategy, Parallelizable

A transform that implements a 3-point transform on top of another Number Theoretic Transform that does transforms of length 2ⁿ.

Since:

1.7.0

Version:

1.8.3

Author:

Mikko Tommila

See Also:

• Factor3NTTStepStrategy

Field Summary

Fields

Modifier and Type	Field	Description
protected Factor3NTTStepStrategy	stepStrategy	The factor-3 NTT steps.

Constructor Summary

Constructors

Constructor	Description
Factor3NTTStrategy(NTTStrategy factor2Strategy)	Creates a new factor-3 transform strategy on top of an existing transform.

Method Summary

Modifier and Type	Method	Description
long	getTransformLength(long size)	Return the supported transform length for the specified data size.
void	inverseTransform(DataStorage dataStorage, int modulus, long totalTransformLength)	Perform an inverse transform on the data.
void	transform(DataStorage dataStorage, int modulus)	Perform a forward transform on the data.

Methods inherited from class java.lang.Object

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

Field Details

stepStrategy

protected Factor3NTTStepStrategy stepStrategy

The factor-3 NTT steps.

Constructor Details

Factor3NTTStrategy

public Factor3NTTStrategy(NTTStrategy factor2Strategy)

Creates a new factor-3 transform strategy on top of an existing transform. The underlying transform needs to be capable of only doing transforms of length 2ⁿ.

Parameters:

factor2Strategy - The underlying transformation strategy, that can be capable of only doing radix-2 transforms.

Method Details

transform

public void transform(DataStorage dataStorage,
 int modulus)
               throws ApfloatRuntimeException

Description copied from interface: NTTStrategy

Perform a forward transform on the data.

Multiple moduli can be used, if the convolution algorithm uses the Chinese Remainder Theorem to calculate the final result.

Specified by:

transform in interface NTTStrategy

Parameters:

dataStorage - The data to be transformed.

modulus - Number of modulus to use (in case the transform supports multiple moduli).

Throws:

ApfloatRuntimeException

inverseTransform

public void inverseTransform(DataStorage dataStorage,
 int modulus,
 long totalTransformLength)
                      throws ApfloatRuntimeException

Description copied from interface: NTTStrategy

Perform an inverse transform on the data.

Multiple moduli can be used, if the convolution algorithm uses the Chinese Remainder Theorem to calculate the final result.

Specified by:

inverseTransform in interface NTTStrategy

Parameters:

dataStorage - The data to be transformed.

modulus - Number of modulus to use (in case the transform supports multiple moduli).

totalTransformLength - Total transform length; the final result elements are divided by this value.

Throws:

ApfloatRuntimeException

getTransformLength

public long getTransformLength(long size)

Description copied from interface: NTTStrategy

Return the supported transform length for the specified data size.

Specified by:

getTransformLength in interface NTTStrategy

Parameters:

size - Length of the data to be transformed.

Returns:

Length of the transform needed by this transform.