function [rsig,theta]=rsigma(A,b,omega)

% function [rsig,theta]=rsigma(A,b,omega) : ||(I+e^{j\theta}A)^{-1}b|| vs. theta
%
% Computes sigma for complex data
% omega = theta (redundant/remnant from previous versions)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

theta=omega(:);
exptheta=exp(j*theta);
I=eye(size(A));
rsig=[];
for i=1:length(theta),
rsig=[rsig; norm( inv( I-conj(exptheta(i))*A ) *b ) ];
end