ode45 not enough input argument

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saramatlab
saramatlab 2014-9-8
编辑： saramatlab 2014-9-9
Hi everyone, i have a problem with an ode function, i show you the code:
%Ode function:
function dTdt=ode1(t,T,d,e)
dTdt=d-e*T
return
%main code
T0=293;
T1=400;
Tf2=293;
a=0.2;
tchange=(T1-T0)/a;
for t=1:(tchange)+1
Tf(t)=T0+a*(t-1);
d=(Tf(t)-Tf2)/(R*C)
e=-2/(R*C)
[t,T] = ode45(ode1,[0 336],293,d,e)
end
Matlab says to me:
Error using ode1 (line 2) Not enough input arguments.
Error in Untitled (line 27) [t,T] = ode45(ode1,[0 336],293,d,e)
i know that i have to put some value for d and e, but how can i do if they change every step because they are in a for cycle? What else is wrong? Please please help me, i can't do anything by myself!

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采纳的回答

Mischa Kim
Mischa Kim 2014-9-8
saramatlab, use
function my_ode()
%main code
T0 = 293;
T1 = 300;
Tf2 = 293;
a = 0.2;
R = 1; % not defined in your code
C = 1; % not defined in your code
tchange = (T1-T0)/a;
for ii = 1:(tchange)+1
Tf(ii) = T0 + a*(ii-1);
d = (Tf(ii) - Tf2)/(R*C);
e = -2/(R*C);
% d and e need to be passed as parameters
[t,T] = ode45(@ode1,[0 336],293,[],[d,e]);
end
end
function dTdt = ode1(t,T,param)
d = param(1);
e = param(2);
dTdt = d - e*T;
end
Put both functions in the same function file and name it my_ode.m. The code is in no way optimized, but runs properly.
  1 个评论
saramatlab
saramatlab 2014-9-8
编辑：saramatlab 2014-9-9
Thank you so much, it works!!! :):):) Can i ask you another one question? i've to compare my solution with one other,i have to check that at the end my ode function this relationship: a*t+293=400 is true.
t is the same variable that i have in the ode, how can i put in my ode function this relationship so that t is the same for both the equation?

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更多回答（2 个）

Andy L
Andy L 2014-9-8
编辑：Andy L 2014-9-8
You need to vectorise your inputs to ode1 as below:
%Ode function:
function dTdt = ode1(t,T,d,e)
becomes
function dTdt = ode1(t,Y)
Y(1) = T;
Y(2) = d;
Y(3) = e;
Check example 1 in this link ode45
  3 个评论
显示 1更早的评论
Andy L
Andy L 2014-9-8
A few things to consider:
  • When is T declared?
  • When is Y declared?
  • Should T be a vector?
  • How are you storing the results of your optimisations?
saramatlab
saramatlab 2014-9-8
T is the variable that i want to calculate with the differential equation, it's a temperature profile and i only know its initial value. I am not storing the results beacuse i'm not able to :(

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saramatlab
saramatlab 2014-9-9
Can i ask you another one question? i've to compare my solution with one other,i have to check that at the end my ode function this relationship: a*t+293=400 is true.
t is the same variable that i have in the ode, how can i put in my ode function this relationship so that t is the same for both the equation?

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