时滞微分方程

function ddex1
%DDEX1 Example 1 for DDE23.
% This is a simple example of Wille' and Baker that illustrates the
% straightforward formulation, computation, and plotting of the solution
% of a system of delay differential equations (DDEs).
%
% The differential equations
%
% y'_1(t) = y_1(t-1)
% y'_2(t) = y_1(t-1)+y_2(t-0.2)
% y'_3(t) = y_2(t)
%
% are solved on [0, 5] with history y_1(t) = 1, y_2(t) = 1, y_3(t) = 1 for
% t <= 0.
%
% The lags are specified as a vector [1, 0.2], the delay differential
% equations are coded in the subfunction DDEX1DE, and the history is
% evaluated by the function DDEX1HIST. Because the history is constant it
% could be supplied as a vector:
% sol = dde23(@ddex1de,[1, 0.2],ones(3,1),[0, 5]);
%
% See also DDE23, FUNCTION_HANDLE.
% Jacek Kierzenka, Lawrence F. Shampine and Skip Thompson
% Copyright 1984-2004 The MathWorks, Inc.
% $Revision: 1.2.4.2 $ $Date: 2005/06/21 19:24:16 $
sol = dde23(@ddex1de,[1, 0.2],@ddex1hist,[0, 5]);