% GETLOWERFREQ gets the frequency of the lowest pole in the model.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% DESCRIPTION: GETLOWERFREQ gets the frequency of the lowest pole in the
%              model.
%
% CALL:        f = getlowerFreq(pf);
%
% <a href="matlab:utils.helper.displayMethodInfo('rational', 'getlowerFreq')">Parameters Description</a>
%
% VERSION:     $Id: getlowerFreq.m,v 1.9 2011/04/08 08:56:33 hewitson Exp $
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function varargout = getlowerFreq(varargin)

  %%% Check if this is a call for parameters
  if utils.helper.isinfocall(varargin{:})
    varargout{1} = getInfo(varargin{3});
    return
  end

  pf   = varargin{1};
  poles = roots(pf.den);
  zeros = roots(pf.num);
  
  f = inf;
  for j=1:numel(poles)
    [fp,q] =  utils.math.ri2fq(poles(j));
    if fp < f
      f = fp;
    end
  end
  for j=1:numel(zeros)
    [fp,q] =  utils.math.ri2fq(zeros(j));
    if fp < f
      f = fp;
    end
  end

  % Set outputs
  varargout{1} = f;
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                               Local Functions                               %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% FUNCTION:    getInfo
%
% DESCRIPTION: Get Info Object
%
% HISTORY:     11-07-07 M Hewitson
%                Creation.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function ii = getInfo(varargin)
  if nargin == 1 && strcmpi(varargin{1}, 'None')
    sets = {};
    pl   = [];
  else
    sets = {'Default'};
    pl   = getDefaultPlist;
  end
  % Build info object
  ii = minfo(mfilename, 'rational', 'ltpda', utils.const.categories.internal, '$Id: getlowerFreq.m,v 1.9 2011/04/08 08:56:33 hewitson Exp $', sets, pl);
  ii.setModifier(false);
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% FUNCTION:    getDefaultPlist
%
% DESCRIPTION: Get Default Plist
%
% HISTORY:     11-07-07 M Hewitson
%                Creation.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function plout = getDefaultPlist()
  persistent pl;  
  if exist('pl', 'var')==0 || isempty(pl)
    pl = buildplist();
  end
  plout = pl;  
end

function pl = buildplist()
  pl = plist.EMPTY_PLIST;
end