stochastic gompertz model and using ode15s

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George Hendry 2022-2-23

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https://ww2.mathworks.cn/matlabcentral/answers/1656905-stochastic-gompertz-model-and-using-ode15s

评论： George Hendry 2022-2-25

I have looked at previous examples of gompertz models and how to form the data and produce a graph and following similar examples I tried to reproduce that. My model is dX(t)= [a*x(t)-b(2)*log(x(t))*x(t)]*dt+(d*x(t))*dw(t). And trying to use previous examples I created

function yr = fit_GompModel(y,t) % Objective Function: Integrates ODE & Returns Vector

x0 = [20]; % Initial Value of the differential equation (dx = 20)

[y,ys]=ode15s(@GompModel,t,x0);

function dx = GompModel(t,y)

dx (1) = (p(1)*y(t)-p(2)*log(y(t))*y(1))*dt+(p(3)*y(t))*dw(y);

p(1)= 0.1;

p(2)= 0.3;

p(3)= 1;

end

yr = ys(:,1);

end

I keep getting a error in the third line was wondering what I was doing wrong?thanks

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回答（1 个）

Torsten 2022-2-23

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https://ww2.mathworks.cn/matlabcentral/answers/1656905-stochastic-gompertz-model-and-using-ode15s#answer_902990

编辑：Torsten 2022-2-23

在 MATLAB Online 中打开

function yr = fit_GompModel(tr,p) % Objective Function: Integrates ODE & Returns Vector
  x0 = 20; % Initial Value of the differential equation (dx = 20)
  [T,Y] = ode15s(@(t,y)GompModel(t,y,p),tr,x0);
  yr = Y(:,1);
end
function dx = GompModel(t,y,p)            
  dx(1) = ?;
end