Data file has the following structure:
First 3 numbers are: refractive index and density of ice, and number of
components to be taken from the list to follow. Each line in this list has
6 elements: real and imaginary parts of the refractive index, mean radius
(in mkm), and its geometrical standard deviation (GSD), mass concentration
(in ng/g), and density of the component. It is assumed that particle radii
are distributed log-normally with the mean radius and GSD defined above.

All densities must be expressed in the same units, e.g. [g/cm^3].
Wavelength of the incident light must be expressed in nm via option -L,
by default it is equal to 550 nm.

On the output absorption (a) and scattering (b) coefficients are expressed
in 1/m, and asymmetry parameter (g=<cos theta>) is dimensionless.

If option -n is specified, additional section in the data file is needed.
For each component a line, containing 5 elements c0, c1, c2, d0, b will be
read in. First line is for the ice, so only 3 components are needed, since
refractive index of the ice is assumed to be purely real.
In such a case information about the refractive indices, contained in
the previous section of the file, will be disregarded, and the following
formula will be used instead: N = c0 + c1 ln L + c2 ln^2 L + i d0 (L/337)^b

Option -ice shows a_all = 7.87e+39 exp-0.48175L + 8100 exp-6700/L + a(L)
and b_e = b(L) [1-g(L)]. First two terms in the expression for a_all
describe contribution of the pure ice to the absorption.