 With the recognition that the polarizabilities may be tensors, the DDA can readily be applied to anisotropic materials.The extension of the DDA to treat materials with nonzero magnetic susceptibility is also straightforward, although for most applications magnetic effects are negligible.The method was improved by Draine, Flatau, and Goodman who applied Fast Fourier Transform and conjugate gradient method to calculate convolution problem arising in the DDA methodology which allowed to calculate scattering by large targets.