Class Lehman_CustomKOrder

java.lang.Object
de.tilman_neumann.jml.factor.FactorAlgorithm
de.tilman_neumann.jml.factor.lehman.Lehman_CustomKOrder

public class Lehman_CustomKOrder
extends FactorAlgorithm
A variant of Lehman's algorithm that allows to arrange the k's in arrays of different "performance levels". k-values that perform very well like those divisible by 315 are tested before others that do not perform that well. For large k we also use congruences of a == kN (mod 2^s) instead of Lehman's a == (k+N) (mod 2^s), which seem to be slightly more discriminative.
  • Field Summary

    Fields inherited from class de.tilman_neumann.jml.factor.FactorAlgorithm

    NUM_PRIMES_FOR_31_BIT_TDIV, tdivLimit
  • Constructor Summary

    Constructors
    Constructor Description
    Lehman_CustomKOrder​(boolean doTDivFirst)
    Full constructor.
  • Method Summary

    Modifier and Type Method Description
    long findSingleFactor​(long N)  
    java.math.BigInteger findSingleFactor​(java.math.BigInteger N)
    Find a single factor of the given N, which is composite and odd.
    java.lang.String getName()  
    static void main​(java.lang.String[] args)
    Test.

    Methods inherited from class de.tilman_neumann.jml.factor.FactorAlgorithm

    factor, factor, getDefault, searchFactors

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Constructor Details

    • Lehman_CustomKOrder

      public Lehman_CustomKOrder​(boolean doTDivFirst)
      Full constructor.
      Parameters:
      doTDivFirst - If true then trial division is done before the Lehman loop. This is recommended if arguments N are known to have factors < cbrt(N) frequently.
  • Method Details

    • getName

      public java.lang.String getName()
      Specified by:
      getName in class FactorAlgorithm
      Returns:
      The name of the algorithm, possibly including important parameters.
    • findSingleFactor

      public java.math.BigInteger findSingleFactor​(java.math.BigInteger N)
      Description copied from class: FactorAlgorithm
      Find a single factor of the given N, which is composite and odd.
      Specified by:
      findSingleFactor in class FactorAlgorithm
      Parameters:
      N - number to be factored.
      Returns:
      factor
    • findSingleFactor

      public long findSingleFactor​(long N)
    • main

      public static void main​(java.lang.String[] args)
      Test.
      Parameters:
      args - ignored