Why is there an error when I call my function?

Question

random 2017-4-12

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/334937-why-is-there-an-error-when-i-call-my-function

回答： Rollin Baker 2017-4-14

if true
function dzdt = hodgefun(t,z)
Vna = 115; Vk = -12; V = 10.6; 
g_na = 120; g_K = 36; g_L = 0.3; 
Cm = 1; i = 9;
Vm=z(1);
m=z(2);
n=z(3);
h=z(3);
Er = -70;
E = [-50 -55]; 
Vm = E - Er;
A_n = (0.01.*(Vm+10))./(exp(((Vm+10)./10)-1));
B_n = 0.125.*exp(Vm./80);
A_m = (0.1.*(Vm+25))./(exp(((Vm+25)./10)-1));
B_m = 4.*exp(Vm./18);
A_h = 0.07.*exp(Vm./20);
B_h = 1./(exp(((Vm+30)./10)+1));
dVmdt= [i - ((g_K.*(n.^4)).*(Vm - Vk)) - ((g_na.*(m.^3).*h).*(Vm - Vna)) - (g_L.*(Vm - V_L))]./Cm;
dmdt= (A_m.*Vm.*(1-m)) - (B_m.*Vm.*m)
dndt= (A_n.*Vm.*(1-n)) - (B_n.*Vm.*n)
dhdt= (A_h.*Vm.*(1-h)) - (B_h.*Vm.*h)
dzdt=[dVmdt; dmdt; dndt; dhdt]

end of function this was my main function:

if true
  initial_conditions= [0,9]
  tspan=[0 100];
  [t,z] = ode45 ('part1',tspan,initial_conditions)
end

but i get this error and I don't know why:

Index exceeds matrix dimensions.

Error in part1 (line 8) m=z(2);

Error in odearguments (line 90) f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Error in ode45 (line 115) odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin); end

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Star Strider 2017-4-12

‘i get this error and I don't know why’

Neither do we, because you did not post the code to ‘part1’.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Rollin Baker 2017-4-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/334937-why-is-there-an-error-when-i-call-my-function#answer_263087

You are seeing this error because you are trying to access 'z(2)', but 'z' only contains one element. It seems that you are expecting the 'ode45' function to return multiple solutions.

Since we don't have access to 'part1', it would be hard for anyone to figure out why this is happening, but I would begin by confirming that the solutions from 'ode45' are what you expect. This should be a good starting point to reach your solution.

I hope this was helpful. Good luck on your project!