Package org.apfloat.internal

Class LongTableFNTStrategy

java.lang.Object

org.apfloat.internal.LongElementaryModMath

org.apfloat.internal.LongModMath

org.apfloat.internal.LongTableFNT

org.apfloat.internal.LongTableFNTStrategy

All Implemented Interfaces:

NTTStrategy

public class LongTableFNTStrategy
extends LongTableFNT
implements NTTStrategy

Fast Number Theoretic Transform strategy that uses lookup tables for powers of n:th root of unity and permutation indexes.

All access to this class must be externally synchronized.

Version:

1.9.0

Author:

Mikko Tommila

Constructor Summary

Constructors

Constructor	Description
LongTableFNTStrategy()	Default constructor.

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 org.apfloat.internal.LongTableFNT

inverseTableFNT, tableFNT

Methods inherited from class org.apfloat.internal.LongModMath

createWTable, getForwardNthRoot, getInverseNthRoot, modDivide, modInverse, modPow, negate

Methods inherited from class org.apfloat.internal.LongElementaryModMath

getModulus, modAdd, modMultiply, modSubtract, setModulus

Methods inherited from class java.lang.Object

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

Constructor Detail

LongTableFNTStrategy

public LongTableFNTStrategy()

Default constructor.

Method Detail

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.