public void Drot(DoubleMatrix1D x, DoubleMatrix1D y, double c, double s)
{
x.CheckSize(y);
DoubleMatrix1D tmp = x.Copy();
x.Assign(F1.Mult(c));
x.Assign(y, F2.PlusMult(s));
y.Assign(F1.Mult(c));
y.Assign(tmp, F2.MinusMult(s));
}