// ---------------------------------------------------------------------
private static void MultiplyKaratsuba(int BASE, IList <int> result, IList <int> one, IList <int> two, int dim)
{
int half = dim / 2;
// Отбрасываем при некотором значении
if (dim <= karatsubaCutoffDimension)
{
LongIntegerMethods.MultiplySimple(BASE, result, one, two);
return;
}
ListSegment <int> a = new ListSegment <int>(one, 0, half);
ListSegment <int> b = new ListSegment <int>(one, half, one.Count - half);
ListSegment <int> c = new ListSegment <int>(two, 0, half);
ListSegment <int> d = new ListSegment <int>(two, half, two.Count - half);
int[] ac = new int[dim];
int[] bd = new int[b.Count + d.Count];
int[] abcd = new int[b.Count + d.Count + 2];
MultiplyKaratsuba(BASE, ac, a, c, half);
MultiplyKaratsuba(BASE, bd, b, d, half);
int[] apb = new int[b.Count + 1];
int[] cpd = new int[d.Count + 1];
int[] acpbd = new int[b.Count + d.Count + 2];
LongIntegerMethods.Sum(BASE, apb, a, b);
LongIntegerMethods.Sum(BASE, cpd, c, d);
MultiplyKaratsuba(BASE, abcd, apb, cpd, half);
LongIntegerMethods.Sum(BASE, acpbd, ac, bd);
int[] difference = new int[b.Count + d.Count + 2];
if (LongIntegerMethods.Dif(BASE, difference, abcd, acpbd))
{
Console.WriteLine("Lower-level difference error.");
}
SumPrivate(BASE, result, ac, 0, difference, half);
SumPrivate(BASE, result, result, 0, bd, dim);
return;
}
//---------------------------------------------------------------
//---------------------NUMBER MULTIPLICATION---------------------
//---------------------------------------------------------------
/// <summary>
/// Performs a simple, square-complex multiplication of two LongInt numbers.
/// </summary>
/// <param name="one"></param>
/// <param name="two"></param>
/// <returns></returns>
public static LongInt <B> MultiplySimple(LongInt <B> one, LongInt <B> two)
{
// the resulting number can have double length.
LongInt <B> res = new LongInt <B>(one.Length + two.Length);
res.Digits.AddRange(new int[one.Length + two.Length]);
res.Negative = one.Negative ^ two.Negative;
// The big one
LongIntegerMethods.MultiplySimple(LongInt <B> .BASE, res.Digits, one.Digits, two.Digits);
// Cut the leading zeroes
res.DealWithZeroes();
return(res);
}
