private BaseDyadCoordinate <Complex> setNonDiagonalElements(
DispersionParameter dispersion,
CartesianCoordinate displacement)
{
double rmod = displacement.Norm;
double rmod2 = rmod * rmod;
double rmod3 = rmod2 * rmod;
double kmod = dispersion.WaveVector.Norm;
double kr = kmod * rmod;
BaseDyadCoordinate <Complex> dyadProduct = displacement.DyadProduct(displacement);
var initDyad = new DiagonalDyadCoordinate <Complex>(rmod2);
BaseDyadCoordinate <Complex> firstMember = (kmod * kmod) * (dyadProduct - initDyad);
BaseDyadCoordinate <Complex> secondMember = (1 / rmod2) * (Complex.ImaginaryOne * kr - 1) *
(3 * dyadProduct - initDyad);
Complex multiplier = Complex.FromPolarCoordinates(1 / rmod3, kr);
return(multiplier * (firstMember + secondMember));
}
