Class LongWTables

java.lang.Object

org.apfloat.internal.LongElementaryModMath

org.apfloat.internal.LongModMath

org.apfloat.internal.LongWTables

public class LongWTables
extends LongModMath

Helper class for generating and caching tables of powers of the n:th root of unity.

Since:

1.7.0

Version:

1.9.0

Field Summary

Fields

Modifier and Type	Field	Description
private static ConcurrentMap<List<Integer>, long[]>	cache

Constructor Summary

Constructors

Modifier	Constructor	Description
private	LongWTables()

Method Summary

Modifier and Type	Method	Description
private static LongModMath	getInstance(int modulus)
static long[]	getInverseWTable(int modulus, int length)	Get a table of inverses of powers of n:th root of unity.
static long[]	getWTable(int modulus, int length)	Get a table of powers of n:th root of unity.
private static long[]	getWTable(int modulus, int length, boolean isInverse)

Methods inherited from class LongModMath

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

Methods inherited from class LongElementaryModMath

getModulus, modAdd, modMultiply, modSubtract, setModulus

Methods inherited from class Object

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

Field Details

cache

private static ConcurrentMap<List<Integer>, long[]> cache

Constructor Details

LongWTables

private LongWTables()

Method Details

getWTable

public static long[] getWTable(int modulus,
 int length)

Get a table of powers of n:th root of unity.

Parameters:

modulus - The index of the modulus to be used.

length - The length of the table to be returned, i.e. n.

Returns:

The table of powers of the n:th root of unity.

getInverseWTable

public static long[] getInverseWTable(int modulus,
 int length)

Get a table of inverses of powers of n:th root of unity.

Parameters:

modulus - The index of the modulus to be used.

length - The length of the table to be returned, i.e. n.

Returns:

The table of inverses of powers of the n:th root of unity.

getWTable

private static long[] getWTable(int modulus,
 int length,
 boolean isInverse)

getInstance

private static LongModMath getInstance(int modulus)