function resp = fsvan(w,g,k);
%FSVAN Performance and robustness measures, with unity feedback.
%            [RESP] = FSVAN(W,G,K)     (K optional.)
% See FSVAN in the MFD reference manual.
%
% G is an MVFR matrix for the compensated plant, K represents a
% pre-compensator and W is the associated frequency vector for G and K.
%
% FSVAN returns a matrix, RESP, with 9 columns:
%  1: Max singular value of transmission from 'd' to the plant outputs.
%  2: Max singular value of transmission from 'n' to the plant outputs.
%  3: Max singular value for tracking error = (y-r)/r.
%  4: Max singular value of transmission from 'r' to the plant inputs.
%  5: The maximum singular value of an unstructured additive perturbation
%     for which closed loop stability can be guaranteed. (Also see 8).
%  6: The maximum singular value of an unstructured input multiplicative
%     perturbation for which closed loop stability can be guaranteed.
%  7: The maximum singular value of an unstructured output multiplicative
%     perturbation for which closed loop stability can be guaranteed.
%  8: As 5, but less conservative.
%  9: Max singular value of transmission from plant input to output.

% J-M. Boyle, 8th September 1987. Modified by J.M.Maciejowski, 9 May 1989.
% Copyright (c) 1987 by GEC Engineering Research Centre & Cambridge Control Ltd.
% MR0028.

nargs=nargin;
error(nargchk(2,3,nargs));
[m,n] = fsize(w,g);

if nargs == 2                   % K = I
  if n~=m
     error('G must be square (K = I, H = I).')
  end
  k = eyef(w,n);
else
  [mk,nk]=fsize(w,k);
  if (m~=nk) | (n~=mk)
     error('G*K and K*G must both be square (H = I).')
  end
end % 2 input arguments

h = eyef(w,m);             % Calculate an identity matrix.
                           % In FSVAN, the feedback matrix H = I.

% Call the utility function FSVUT to calculate the performance
% and robustness measures.

[dv,nv,tv,uv,av,miv,mov,av2,div] = fsvut(w,g,k,h);
resp = [dv,nv,tv,uv,av,miv,mov,av2,div];