/// <summary>
/// Computes the product of two double double numbers.
/// </summary>
/// <param name="x">The first number.</param>
/// <param name="y">The second number.</param>
/// <returns>The product of <paramref name="x"/> and <paramref name="y"/>.</returns>
public static DoubleDouble operator *(DoubleDouble x, DoubleDouble y)
{
ExtendedMath.TwoProduct(x.hi, y.hi, out double p0, out double p1);
if (p0 == 0.0 || ExtendedMath.IsNotFinite(p0))
{
return((DoubleDouble)p0);
}
ExtendedMath.TwoProduct(x.hi, y.lo, out double p2, out double p4);
ExtendedMath.TwoProduct(x.lo, y.hi, out double p3, out double p5);
double p6 = x.lo * y.lo;
ExtendedMath.ThreeSum(p1, p2, p3, out double t1, out double t2);
t2 += p4 + p5 + p6;
ExtendedMath.ThreeSum(p0, t1, t2, out double pHi, out double pLo);
return(new DoubleDouble(pHi, pLo));
/*
* double zHi, zLo;
* ExtendedMath.TwoProduct(a.hi, b.hi, out zHi, out zLo);
* zLo = (zLo + a.hi * b.lo) + a.lo * b.hi;
* //zLo = (a.hi * b.lo + a.lo * b.hi) + zLo;
*
* return new DoubleDouble(zHi, zLo);
*/
}
/// <summary>
/// Computes the product of two double double numbers.
/// </summary>
/// <param name="a">The first number.</param>
/// <param name="b">The second number.</param>
/// <returns>The product of <paramref name="a"/> and <paramref name="b"/>.</returns>
public static DoubleDouble operator *(DoubleDouble a, DoubleDouble b)
{
double p0, p1;
ExtendedMath.TwoProduct(a.hi, b.hi, out p0, out p1);
double p2, p4;
ExtendedMath.TwoProduct(a.hi, b.lo, out p2, out p4);
double p3, p5;
ExtendedMath.TwoProduct(a.lo, b.hi, out p3, out p5);
double p6 = a.lo * b.lo;
double t1, t2;
ExtendedMath.ThreeSum(p1, p2, p3, out t1, out t2);
t2 += p4 + p5 + p6;
double pHi, pLo;
ExtendedMath.ThreeSum(p0, t1, t2, out pHi, out pLo);
return(new DoubleDouble(pHi, pLo));
/*
* double zHi, zLo;
* ExtendedMath.TwoProduct(a.hi, b.hi, out zHi, out zLo);
* zLo = (zLo + a.hi * b.lo) + a.lo * b.hi;
* //zLo = (a.hi * b.lo + a.lo * b.hi) + zLo;
*
* return new DoubleDouble(zHi, zLo);
*/
}
