Tri-axial ellipsoids as models for macromolecules in solution: procedures for numerical inversion of the shape functions leading to a stable unique solution.

Two FORTRAN IV algorithms are given for determining the two axial ratios of a macromolecule (as modelled by a tri-axial ellipsoid) from its hydrodynamic parameters. The first involves a simple graphical inversion procedure of the volume independent V and R functions but can only be applied to a restricted range of macromolecules. The second algorithm is more general and involves an R-function constrained non-linear least squares fit to birefringence decay data.