Package org.apfloat.internal
Class DoubleModMath
- java.lang.Object
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- org.apfloat.internal.DoubleElementaryModMath
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- org.apfloat.internal.DoubleModMath
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- Direct Known Subclasses:
DoubleFactor3NTTStepStrategy
,DoubleNTTConvolutionStepStrategy
,DoubleTableFNT
,DoubleWTables
public class DoubleModMath extends DoubleElementaryModMath
Modulo arithmetic functions fordouble
data.- Version:
- 1.0
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Constructor Summary
Constructors Constructor Description DoubleModMath()
Default constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description double[]
createWTable(double w, int n)
Create a table of powers of n:th root of unity.double
getForwardNthRoot(double primitiveRoot, long n)
Get forward n:th root of unity.double
getInverseNthRoot(double primitiveRoot, long n)
Get inverse n:th root of unity.double
modDivide(double a, double b)
Modular division.double
modInverse(double a)
Modular inverse, that is1 / a
.double
modPow(double a, double n)
Modular power.double
negate(double a)
Modular negation.-
Methods inherited from class org.apfloat.internal.DoubleElementaryModMath
getModulus, modAdd, modMultiply, modSubtract, setModulus
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Method Detail
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createWTable
public final double[] createWTable(double 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.
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getForwardNthRoot
public double getForwardNthRoot(double primitiveRoot, long n)
Get forward n:th root of unity. This isw
.Assumes that the modulus is prime.
- Parameters:
primitiveRoot
- Primitive root of the modulus.n
- The transform length.- Returns:
- Forward n:th root of unity.
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getInverseNthRoot
public double getInverseNthRoot(double primitiveRoot, long n)
Get inverse n:th root of unity. This isw-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.
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modInverse
public final double modInverse(double a)
Modular inverse, that is1 / a
. Assumes that the modulus is prime.- Parameters:
a
- The operand.- Returns:
a-1 mod m
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modDivide
public final double modDivide(double a, double b)
Modular division. Assumes that the modulus is prime.- Parameters:
a
- The dividend.b
- The divisor.- Returns:
a*b-1 mod m
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negate
public final double negate(double a)
Modular negation.- Parameters:
a
- The argument.- Returns:
-a mod m
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modPow
public final double modPow(double a, double n)
Modular power. Assumes that the modulus is prime.- Parameters:
a
- The base.n
- The exponent.- Returns:
an mod m
.
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