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Highlights from
Tutorial on solving DDEs with DDE23

  • exam1
  • exam1
  • exam2
  • exam2
  • exam3
  • exam3
  • exam4
  • exam4
  • exam5
  • exam5
  • exam6 This is a demonstration problem for CTMS/BD in
  • exam6 This is a demonstration problem for CTMS/BD in
  • exam7 An example from C. Marriott and C. DeLisle, Effects
  • exam7 An example from C. Marriott and C. DeLisle, Effects
  • exam8 This is the suitcase problem from Suherman, et al.,
  • exam8 This is the suitcase problem from Suherman, et al.,
  • exer1 Example 1 of K.W. Neves, Automatic integration
  • exer1 Example 1 of K.W. Neves, Automatic integration
  • exer2 Example of J.D. Farmer, Chaotic Attractors of an
  • exer2 Example of J.D. Farmer, Chaotic Attractors of an
  • exer3 Wheldon's model of chronic granuloctic leukemia
  • exer3 Wheldon's model of chronic granuloctic leukemia
  • exer5
  • exer5
  • exer6 Sample problem of ARCHI manual. The absolute error
  • exer6 Sample problem of ARCHI manual. The absolute error
  • exer7 Marchuk immunology model of E. Hairer, S.P. Norsett, and
  • exer7 Marchuk immunology model of E. Hairer, S.P. Norsett, and
  • prob1 This system of ODE's is taken from 'An Introduction to Nuermcial Methods
  • prob1 This system of ODE's is taken from 'An Introduction to Nuermcial Methods
  • prob2 This problem considers a cardiovascular model, which can be found in
  • prob2 This problem considers a cardiovascular model, which can be found in
  • prob2b This problem considers a cardiovascular model, which can be found in
  • prob2b This problem considers a cardiovascular model, which can be found in
  • prob3 This problem is epidemic model due to Cooke, more information can be
  • prob3 This problem is epidemic model due to Cooke, more information can be
  • prob4 This problem is an epidemic model due to Cooke et alia, more information
  • prob4 This problem is an epidemic model due to Cooke et alia, more information
  • prob5 This problem population growth model due to Cooke et alia, more information
  • prob5 This problem population growth model due to Cooke et alia, more information
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Tutorial on solving DDEs with DDE23

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22 Aug 2003 (Updated )

Solving delay differential equations with DDE23. Tutorial + Examples.

exer3
function sol = exer3
% Wheldon's model of chronic granuloctic leukemia 
% from N. MacDonald, Time Lags in Biological Models, 
% Springer-Verlag, Berlin, 1978.

% Copyright 2002, The MathWorks, Inc.

for tau = [7, 20]
   sol = dde23(@exer3f,tau,[100; 100],[0, 200]);
   figure
   plot(sol.x,sol.y)
   title(['Leukemia model for \tau = ',num2str(tau),'.'])
   xlabel('time t')
   ylabel('y(t)')
end

%-----------------------------------------------------------------------

function yp = exer3f(t,y,Z)
%EXER3F  The derivative function for Exercise 3 of the DDE Tutorial.

alpha = 1.1e10;
beta = 1e-12;
gamma = 1.25;
delta = 1;
lambda = 10;
mu = 4e-8;
omega = 2.43; 

ylag = Z(:,1);
yp = zeros(2,1);
yp(1) = alpha/(1 + beta*ylag(1)^gamma) - ...
        lambda*y(1)/(1 + mu*y(2)^delta);
yp(2) = lambda*y(1)/(1 + mu*y(2)^delta) - omega*y(2);

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