Package org.apfloat.internal

Class FloatModMath

java.lang.Object

org.apfloat.internal.FloatElementaryModMath

org.apfloat.internal.FloatModMath

Direct Known Subclasses:

FloatFactor3NTTStepStrategy, FloatNTTConvolutionStepStrategy, FloatTableFNT, FloatWTables

public class FloatModMath
extends FloatElementaryModMath

Modulo arithmetic functions for float data.

Version:

1.0

Author:

Mikko Tommila

Constructor Summary

Constructors

Constructor	Description
FloatModMath()	Default constructor.

Method Summary

Modifier and Type	Method	Description
float[]	createWTable(float w, int n)	Create a table of powers of n:th root of unity.
float	getForwardNthRoot(float primitiveRoot, long n)	Get forward n:th root of unity.
float	getInverseNthRoot(float primitiveRoot, long n)	Get inverse n:th root of unity.
float	modDivide(float a, float b)	Modular division.
float	modInverse(float a)	Modular inverse, that is 1 / a.
float	modPow(float a, float n)	Modular power.
float	negate(float a)	Modular negation.

Methods inherited from class org.apfloat.internal.FloatElementaryModMath

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

FloatModMath

public FloatModMath()

Default constructor.

Method Detail

createWTable

public final float[] createWTable(float w,
                                  int n)

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

Parameters:

w - The n:th root of unity modulo the current modulus.

n - The table length (= transform length).

Returns:

Table of table[i]=wi mod m, i = 0, ..., n-1.

getForwardNthRoot

public float getForwardNthRoot(float primitiveRoot,
                               long n)

Get forward n:th root of unity. This is w.

Assumes that the modulus is prime.

Parameters:

primitiveRoot - Primitive root of the modulus.

n - The transform length.

Returns:

Forward n:th root of unity.

getInverseNthRoot

public float getInverseNthRoot(float primitiveRoot,
                               long n)

Get inverse n:th root of unity. This is w-1.

Assumes that the modulus is prime.

Parameters:

primitiveRoot - Primitive root of the modulus.

n - The transform length.

Returns:

Inverse n:th root of unity.

modInverse

public final float modInverse(float a)

Modular inverse, that is 1 / a. Assumes that the modulus is prime.

Parameters:

a - The operand.

Returns:

a-1 mod m.

modDivide

public final float modDivide(float a,
                             float b)

Modular division. Assumes that the modulus is prime.

Parameters:

a - The dividend.

b - The divisor.

Returns:

a*b-1 mod m.

negate

public final float negate(float a)

Modular negation.

Parameters:

a - The argument.

Returns:

-a mod m.

modPow

public final float modPow(float a,
                          float n)

Modular power. Assumes that the modulus is prime.

Parameters:

a - The base.

n - The exponent.

Returns:

an mod m.