Package org.apfloat.internal

Class DoubleNTTStepStrategy

java.lang.Object

org.apfloat.internal.DoubleElementaryModMath

org.apfloat.internal.DoubleModMath

org.apfloat.internal.DoubleTableFNT

org.apfloat.internal.DoubleNTTStepStrategy

All Implemented Interfaces:

Parallelizable, NTTStepStrategy

public class DoubleNTTStepStrategy
extends DoubleTableFNT
implements NTTStepStrategy, Parallelizable

Common methods to calculate Fast Number Theoretic Transforms in parallel using multiple threads.

All access to this class must be externally synchronized.

Since:

1.7.0

Version:

1.9.0

Author:

Mikko Tommila

Constructor Summary

Constructors

Constructor	Description
DoubleNTTStepStrategy()	Default constructor.

Method Summary

Modifier and Type	Method	Description
protected ParallelRunnable	createMultiplyElementsParallelRunnable(ArrayAccess arrayAccess, int startRow, int startColumn, int rows, int columns, long length, long totalTransformLength, boolean isInverse, int modulus)	Create a ParallelRunnable object for multiplying the elements of the matrix.
protected ParallelRunnable	createTransformRowsParallelRunnable(ArrayAccess arrayAccess, int length, int count, boolean isInverse, boolean permute, int modulus)	Create a ParallelRunnable object for transforming the rows of the matrix.
long	getMaxTransformLength()	Get the maximum transform length.
void	multiplyElements(ArrayAccess arrayAccess, int startRow, int startColumn, int rows, int columns, long length, long totalTransformLength, boolean isInverse, int modulus)	Multiply each matrix element (i, j) by wi * j / totalTransformLength.
void	transformRows(ArrayAccess arrayAccess, int length, int count, boolean isInverse, boolean permute, int modulus)	Transform the rows of the data matrix.

Methods inherited from class org.apfloat.internal.DoubleTableFNT

inverseTableFNT, tableFNT

Methods inherited from class org.apfloat.internal.DoubleModMath

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

Methods inherited from class org.apfloat.internal.DoubleElementaryModMath

getModulus, modAdd, modMultiply, modSubtract, setModulus

Methods inherited from class java.lang.Object

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

Constructor Details

DoubleNTTStepStrategy

public DoubleNTTStepStrategy()

Default constructor.

Method Details

multiplyElements

public void multiplyElements(ArrayAccess arrayAccess,
 int startRow,
 int startColumn,
 int rows,
 int columns,
 long length,
 long totalTransformLength,
 boolean isInverse,
 int modulus)
                      throws ApfloatRuntimeException

Description copied from interface: NTTStepStrategy

Multiply each matrix element (i, j) by wi * j / totalTransformLength. The matrix size is n₁ x n₂.

Specified by:

multiplyElements in interface NTTStepStrategy

Parameters:

arrayAccess - The memory array to multiply.

startRow - Which row in the whole matrix the starting row in the arrayAccess is.

startColumn - Which column in the whole matrix the starting column in the arrayAccess is.

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.

Throws:

ApfloatRuntimeException

transformRows

public void transformRows(ArrayAccess arrayAccess,
 int length,
 int count,
 boolean isInverse,
 boolean permute,
 int modulus)
                   throws ApfloatRuntimeException

Description copied from interface: NTTStepStrategy

Transform the rows of the data matrix. If only one processor is available, it runs all transforms in the current thread. If more than one processor are available, it dispatches the calculations to multiple threads to parallelize the calculation. The number of processors is determined using ApfloatContext.getNumberOfProcessors().

Specified by:

transformRows in interface NTTStepStrategy

Parameters:

arrayAccess - The memory array to split to rows and to transform.

length - Length of one transform (one row).

count - Number of rows.

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

permute - If permutation should be done.

modulus - Index of the modulus.

Throws:

ApfloatRuntimeException

getMaxTransformLength

public long getMaxTransformLength()

Description copied from interface: NTTStepStrategy

Get the maximum transform length.

Specified by:

getMaxTransformLength in interface NTTStepStrategy

Returns:

The maximum transform length.

createMultiplyElementsParallelRunnable

protected ParallelRunnable createMultiplyElementsParallelRunnable(ArrayAccess arrayAccess,
 int startRow,
 int startColumn,
 int rows,
 int columns,
 long length,
 long totalTransformLength,
 boolean isInverse,
 int modulus)
                                                           throws ApfloatRuntimeException

Create a ParallelRunnable object for multiplying the elements of the matrix.

Parameters:

arrayAccess - The memory array to multiply.

startRow - Which row in the whole matrix the starting row in the arrayAccess is.

startColumn - Which column in the whole matrix the starting column in the arrayAccess is.

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.

Returns:

An object suitable for multiplying the elements of the matrix in parallel.

Throws:

ApfloatRuntimeException

createTransformRowsParallelRunnable

protected ParallelRunnable createTransformRowsParallelRunnable(ArrayAccess arrayAccess,
 int length,
 int count,
 boolean isInverse,
 boolean permute,
 int modulus)
                                                        throws ApfloatRuntimeException

Create a ParallelRunnable object for transforming the rows of the matrix.

Parameters:

arrayAccess - The memory array to split to rows and to transform.

length - Length of one transform (one row).

count - Number of rows.

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

permute - If permutation should be done.

modulus - Index of the modulus.

Returns:

An object suitable for transforming the rows of the matrix in parallel.

Throws:

ApfloatRuntimeException