  We present a numerical procedure allowing one to extract Feshbach resonance
parameters from numerical calculations without relying on approximate fitting
procedures. Our approach is based on a simple decomposition of the reactance
matrix in terms of poles and residual background contribution, and can be
applied to the general situation of inelastic overlapping resonances. A simple
lineshape for overlapping inelastic resonances, equivalent to known results in
the particular cases of isolated and overlapping elastic features, is also
rigorously derived.
