org.apfloat.internal
Class IntFactor3NTTStrategy

java.lang.Object
  org.apfloat.internal.IntElementaryModMath
      org.apfloat.internal.IntModMath
          org.apfloat.internal.IntFactor3NTTStrategy

All Implemented Interfaces:

NTTStrategy

public class IntFactor3NTTStrategy
extends IntModMath
implements NTTStrategy

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

Version:

1.1

Author:

Mikko Tommila

Constructor Summary

IntFactor3NTTStrategy(NTTStrategy factor2Strategy)
Creates a new factor-3 transform strategy on top of an existing transform.

Method Summary

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.IntModMath

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

Methods inherited from class org.apfloat.internal.IntElementaryModMath

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

IntFactor3NTTStrategy

public IntFactor3NTTStrategy(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 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.