first steps using dde23

I want to solve the function

function Change = logisticGrowth( t,Population )
  Limit=100;
  MaxGrowthRate=0.2;
  LossRate=0.02;
  Density = Population / Limit;
  Loss = Population * LossRate;
  Change=Population*MaxGrowthRate*(1-Density)-Loss;
end

with a delay of 5 years using

   delay=5;
   before=2;
   timespan=[0 100];
   dde23(@logisticGrowth,delay,before,timespan)

and Matlab tells: "Error using logisticGrowth. Too many input arguments."

I appreciate your hints.

Answer 1

[Heinz_M]

There is a possible solution.

function solution
  delay=5;
  before=2; % history
  timespan=[0, 100];
  Limit=100; 
  MaxGrowthRate=0.2;
  LossRate=0.02;
  dde_options = ddeset('RelTol',1e-07);
  sol=dde23(@logistic,delay,before,timespan,dde_options,Limit,MaxGrowthRate,LossRate);

    plot(sol.x,sol.y)
    grid on
    title('Logistic Growth with delayed impact of density')
    xlabel('t')
    ylabel('y')
  end

function Change = logistic( t,Population,Z,Limit,MaxGrowthRate,LossRate )
  Loss = Population * LossRate;
  Change=Population*MaxGrowthRate*(1-Z/Limit)-Loss;
end