Package org.apfloat.aparapi

Class ColumnSixStepFNTStrategy

java.lang.Object

org.apfloat.internal.AbstractStepFNTStrategy

org.apfloat.internal.SixStepFNTStrategy

org.apfloat.aparapi.ColumnSixStepFNTStrategy

All Implemented Interfaces:

Parallelizable, NTTStrategy

Direct Known Subclasses:

IntAparapiSixStepFNTStrategy, LongAparapiSixStepFNTStrategy

public class ColumnSixStepFNTStrategy
extends SixStepFNTStrategy

Six-step NTT implementation that processes the data in the columns of the matrix.

This transform only works together with an NTTStepStrategy implementation that processes the data in columns instead of rows and a MatrixStrategy implementation that can transpose the data.

The data size should be sufficiently large to meet the parallelization needs of the GPU. The GPU global size i.e. the number of columns in the data matrix should be at least 1024.

Since:

1.8.3

Version:

1.8.3

Field Summary

Fields inherited from class org.apfloat.internal.SixStepFNTStrategy

matrixStrategy

Fields inherited from class org.apfloat.internal.AbstractStepFNTStrategy

stepStrategy

Constructor Summary

Constructors

Constructor	Description
ColumnSixStepFNTStrategy(NTTStepStrategy stepStrategy, MatrixStrategy matrixStrategy)	Basic constructor.

Method Summary

Modifier and Type	Method	Description
protected void	multiplyElements(ArrayAccess arrayAccess, int rows, int columns, long length, long totalTransformLength, boolean isInverse, int modulus)	Multiply each matrix element by a power of the n:th root of unity.
protected void	transposeInitial(ArrayAccess arrayAccess, int n1, int n2, boolean isInverse)	The initial transpose of the forward transform, or the final transpose of the inverse transform, to transpose the columns of the matrix to be rows.
protected void	transposeMiddle(ArrayAccess arrayAccess, int n1, int n2, boolean isInverse)	The second transpose of either the forward or inverse transform.

Methods inherited from class org.apfloat.internal.SixStepFNTStrategy

inverseTransform, postTransform, preTransform, transform, transformFirst, transformSecond, transposeFinal

Methods inherited from class org.apfloat.internal.AbstractStepFNTStrategy

getTransformLength, inverseTransform, transform

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnSixStepFNTStrategy

public ColumnSixStepFNTStrategy(NTTStepStrategy stepStrategy,
                                MatrixStrategy matrixStrategy)

Basic constructor.

Parameters:

stepStrategy - A step strategy that can process data in columns.

matrixStrategy - A matrix strategy that can process the data.

Method Detail

transposeInitial

protected void transposeInitial(ArrayAccess arrayAccess,
                                int n1,
                                int n2,
                                boolean isInverse)

Description copied from class: SixStepFNTStrategy

The initial transpose of the forward transform, or the final transpose of the inverse transform, to transpose the columns of the matrix to be rows. This step is needed in the six-step algorithm but is omitted in the four-step algorithm.

Overrides:

transposeInitial in class SixStepFNTStrategy

Parameters:

arrayAccess - Accessor to the matrix data. This data will be transposed.

n1 - Number of rows in the matrix.

n2 - Number of columns in the matrix.

isInverse - true if an inverse transform is performed, false if a forward transform is performed.

transposeMiddle

protected void transposeMiddle(ArrayAccess arrayAccess,
                               int n1,
                               int n2,
                               boolean isInverse)

Description copied from class: SixStepFNTStrategy

The second transpose of either the forward or inverse transform. Normally this step is always required as the four-step algorithm only transforms columns of the matrix and the six-step algorithm transforms only rows.

Overrides:

transposeMiddle in class SixStepFNTStrategy

Parameters:

arrayAccess - Accessor to the matrix data. This data will be transposed.

n1 - Number of rows in the matrix.

n2 - Number of columns in the matrix.

isInverse - true if an inverse transform is performed, false if a forward transform is performed.

multiplyElements

protected void multiplyElements(ArrayAccess arrayAccess,
                                int rows,
                                int columns,
                                long length,
                                long totalTransformLength,
                                boolean isInverse,
                                int modulus)

Description copied from class: SixStepFNTStrategy

Multiply each matrix element by a power of the n:th root of unity.

Overrides:

multiplyElements in class SixStepFNTStrategy

Parameters:

arrayAccess - The memory array to multiply.

rows - The number of rows in the arrayAccess to multiply.

columns - The number of columns in the matrix (= n₂).

length - The length of data in the matrix being transformed.

totalTransformLength - The total transform length, for the scaling factor. Used only for the inverse case.

isInverse - If the multiplication is done for the inverse transform or not.

modulus - Index of the modulus.