org.apfloat.internal

Class ThreeNTTConvolutionStrategy

java.lang.Object

org.apfloat.internal.ThreeNTTConvolutionStrategy

All Implemented Interfaces:

ConvolutionStrategy

Direct Known Subclasses:

ParallelThreeNTTConvolutionStrategy

public class ThreeNTTConvolutionStrategy
extends Object
implements ConvolutionStrategy

Convolution using three Number Theoretic Transforms and the Chinese Remainder Theorem to get the final result.

Multiplication can be done in linear time in the transform domain, where the multiplication is simply an element-by-element multiplication.

All access to this class must be externally synchronized.

Since:

1.7.0

Version:

1.7.0

Author:

Mikko Tommila

Field Summary

Fields

Modifier and Type	Field and Description
protected CarryCRTStrategy	carryCRTStrategy The carry-CRT to use.
protected NTTStrategy	nttStrategy The transform to use.
protected NTTConvolutionStepStrategy	stepStrategy The convolution steps to use.

Constructor Summary

Constructors

Constructor and Description
ThreeNTTConvolutionStrategy(int radix, NTTStrategy nttStrategy) Creates a new convoluter that uses the specified transform for transforming the data.

Method Summary

Modifier and Type	Method and Description
protected DataStorage	autoConvolute(DataStorage x, long resultSize) Convolutes a data set with itself.
protected DataStorage	autoConvoluteOne(DataStorage x, long length, int modulus, boolean cached) Performs an autoconvolution modulo one modulus, of the specified transform length.
DataStorage	convolute(DataStorage x, DataStorage y, long resultSize) Convolutes the two sets of data.
protected DataStorage	convoluteOne(DataStorage x, DataStorage y, long length, int modulus, boolean cached) Performs a convolution modulo one modulus, of the specified transform length.
protected DataStorage	createCachedDataStorage(long size) Create a cached (if possible) data storage for the specified number of elements.
protected DataStorage	createDataStorage(DataStorage dataStorage) Create a cached data storage from the (possibly) cached data storage.
protected void	lock(long length) Lock the execution against a synchronization lock.
protected void	unlock() Remove the synchronization lock.

Methods inherited from class java.lang.Object

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

Field Detail

nttStrategy

protected NTTStrategy nttStrategy

The transform to use.

carryCRTStrategy

protected CarryCRTStrategy carryCRTStrategy

The carry-CRT to use.

stepStrategy

protected NTTConvolutionStepStrategy stepStrategy

The convolution steps to use.

Constructor Detail

ThreeNTTConvolutionStrategy

public ThreeNTTConvolutionStrategy(int radix,
                                   NTTStrategy nttStrategy)

Creates a new convoluter that uses the specified transform for transforming the data.

Parameters:

radix - The radix to be used.

nttStrategy - The transform to be used.

Method Detail

convolute

public DataStorage convolute(DataStorage x,
                             DataStorage y,
                             long resultSize)
                      throws ApfloatRuntimeException

Description copied from interface: ConvolutionStrategy

Convolutes the two sets of data.

Specified by:

convolute in interface ConvolutionStrategy

Parameters:

x - First data set.

y - Second data set.

resultSize - Number of elements needed in the result data.

Returns:

The convolved data.

Throws:

ApfloatRuntimeException

convoluteOne

protected DataStorage convoluteOne(DataStorage x,
                                   DataStorage y,
                                   long length,
                                   int modulus,
                                   boolean cached)
                            throws ApfloatRuntimeException

Performs a convolution modulo one modulus, of the specified transform length.

Parameters:

x - First data set.

y - Second data set.

length - Length of the transformation.

modulus - Which modulus to use.

cached - If the result data should be kept cached in memory when possible.

Returns:

The result of the convolution for one modulus.

Throws:

ApfloatRuntimeException

autoConvolute

protected DataStorage autoConvolute(DataStorage x,
                                    long resultSize)
                             throws ApfloatRuntimeException

Convolutes a data set with itself.

Parameters:

x - The data set.

resultSize - Number of elements needed in the result data.

Returns:

The convolved data.

Throws:

ApfloatRuntimeException

autoConvoluteOne

protected DataStorage autoConvoluteOne(DataStorage x,
                                       long length,
                                       int modulus,
                                       boolean cached)
                                throws ApfloatRuntimeException

Performs an autoconvolution modulo one modulus, of the specified transform length.

Parameters:

x - The data set.

length - Length of the transformation.

modulus - Which modulus to use.

cached - If the result data should be kept cached in memory when possible.

Returns:

The result of the convolution for one modulus.

Throws:

ApfloatRuntimeException

lock

protected void lock(long length)

Lock the execution against a synchronization lock.

Parameters:

length - The length of the data being processed for determining the type of lock to use.

unlock

protected void unlock()

Remove the synchronization lock.

createCachedDataStorage

protected DataStorage createCachedDataStorage(long size)
                                       throws ApfloatRuntimeException

Create a cached (if possible) data storage for the specified number of elements.

Parameters:

size - The number of elements.

Returns:

The data storage.

Throws:

ApfloatRuntimeException

createDataStorage

protected DataStorage createDataStorage(DataStorage dataStorage)
                                 throws ApfloatRuntimeException

Create a cached data storage from the (possibly) cached data storage.

Parameters:

dataStorage - The data storage, which may be cached.

Returns:

The data storage, which isn't cached.

Throws:

ApfloatRuntimeException