1:  package de.luschny.math.factorial;

   2:   

   3:  import de.luschny.math.arithmetic.Xint;

   4:   

   5:  public class FactorialAdditiveMoessner implements IFactorialFunction

   6:  {

   7:   

   8:      public FactorialAdditiveMoessner()

   9:      {

  10:      }

  11:   

  12:      public String getName()

  13:      {

  14:          return "AdditiveMoessner    ";

  15:      }

  16:   

  17:      public Xint factorial(int n)

  18:      {

  19:          if (n < 0)

  20:          {

  21:              throw new ArithmeticException("Factorial: n has to be >= 0, but was " + n);

  22:          }

  23:   

  24:          Xint[] s = new Xint[n + 1];

  25:          s[0] = Xint.ONE;

  26:   

  27:          for (int m = 1; m <= n; m++)

  28:          {

  29:              s[m] = Xint.ZERO;

  30:              for (int k = m; k >= 1; k--)

  31:              {

  32:                  for (int i = 1; i <= k; i++)

  33:                  {

  34:                      s[i] = s[i].add(s[i - 1]);

  35:                  }

  36:              }

  37:          }

  38:          return s[n];

  39:      }

  40:  } // endOfFactorialMoessner