Class Primes
- java.lang.Object
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- org.apache.commons.numbers.primes.Primes
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public final class Primes extends java.lang.Object
Methods related to prime numbers in the range ofint
.- primality test
- prime number generation
- factorization
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Field Summary
Fields Modifier and Type Field Description (package private) static java.lang.String
NUMBER_TOO_SMALL
Exception message format when an argument is too small.
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Constructor Summary
Constructors Modifier Constructor Description private
Primes()
Utility class.
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static boolean
isPrime(int n)
Primality test: tells if the argument is a (provable) prime or not.static int
nextPrime(int n)
Return the smallest prime greater than or equal to n.static java.util.List<java.lang.Integer>
primeFactors(int n)
Prime factors decomposition.
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Field Detail
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NUMBER_TOO_SMALL
static final java.lang.String NUMBER_TOO_SMALL
Exception message format when an argument is too small.- See Also:
- Constant Field Values
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Method Detail
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isPrime
public static boolean isPrime(int n)
Primality test: tells if the argument is a (provable) prime or not.It uses the Miller-Rabin probabilistic test in such a way that a result is guaranteed: it uses the firsts prime numbers as successive base (see Handbook of applied cryptography by Menezes, table 4.1).
- Parameters:
n
- Number to test.- Returns:
- true if
n
is prime. All numbers < 2 return false.
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nextPrime
public static int nextPrime(int n)
Return the smallest prime greater than or equal to n.- Parameters:
n
- Positive number.- Returns:
- the smallest prime greater than or equal to
n
. - Throws:
java.lang.IllegalArgumentException
- if n < 0.
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primeFactors
public static java.util.List<java.lang.Integer> primeFactors(int n)
Prime factors decomposition.- Parameters:
n
- Number to factorize: must be ≥ 2.- Returns:
- the list of prime factors of
n
. - Throws:
java.lang.IllegalArgumentException
- if n < 2.
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