function g = frga(w,f)
%FRGA   Relative gain array of square system.
%
%       g = frga(w,f)
%       
%       g is an MVFR matrix, each component matrix being
%       the relative gain array of the MVFR matrix f at
%       one frequency. w is the associated frequency vector.
%
%       If w = 0 then Bristol's original RGA is obtained.

%       Dr J.M. Maciejowski  20 November 1987.
% Copyright (c) 1987 by GEC Engineering Research Centre & Cambridge Control Ltd
% MRN0009

[m,n]=fsize(w,f);
if m~=n
  error('Not a square system. (FRGA)');  
end

for k=1:length(w)
  fk=fgetf(w,f,k);
  fki=inv(fk);
  g = [g ; fk.*fki.'];  
end