dplot.m

离散控制系统设计的MATLAB 代码

function dplot(dataX, dataY);
% It works similar to stem, but uses a triangle as the marker.
% Also uses the dotted-line option for the stem part.

%%%%%%%%%%%%%%%%%%%% dplot.m %%%%%%%%%%%%%%%%%%%%
%   Discrete-Time Control Problems using        %
%       MATLAB and the Control System Toolbox   %
%   by J.H. Chow, D.K. Frederick, & N.W. Chbat  %
%         Brooks/Cole Publishing Company        %
%                September 2002                 %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

if (nargin > 2) | (nargin == 0)
   error('The input variables are not correct');
end
if nargin == 1
   id     = 1:length(dataX);
   pos_id = find(dataX>=0);
   id(pos_id) = [];
   neg_id = id;
   if ~isempty(pos_id)
   	stem(pos_id, dataX(pos_id), 'filled');
   	ho = findobj(gca, 'marker', 'o');
   	set(ho, 'marker', '^');
      hold;
   end
   if ~isempty(neg_id)
   	stem(neg_id, dataX(neg_id), 'filled');
   	ho = findobj(gca, 'marker', 'o');
      set(ho, 'marker', 'v');   
   end   
   line([1 length(dataX)], [0 0]);
else
   id     = 1:length(dataX);
   pos_id = find(dataY>=0);
   id(pos_id) = [];
   neg_id = id;
   if ~isempty(pos_id)
  		 stem(dataX(pos_id), dataY(pos_id), ':','filled');
	    ho = findobj(gca, 'marker', 'o');
   	 set(ho, 'marker', '^');   
   	 hold;
   end
   if ~isempty(neg_id)
   	stem(dataX(neg_id), dataY(neg_id),':','filled');
   	ho = findobj(gca, 'marker', 'o');
      set(ho, 'marker', 'v');  
   end
	line([min(dataX) max(dataX)], [0 0]);
end
hold off;
%%%%%%%%%%