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ODE45 not enough input arguments

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Tomas van Dorp
Tomas van Dorp le 19 Déc 2016
I have been trying to solve 3 differential equations with ODE 45, but it keeps giving the error that there are not enough input arguments.
This is my function:
function du = Hopelijkgoed(t,u)
Qbin=(5.8333*(10^(-6)));
A=1.8 ;
deltaP=17861 ;
R= 50000;
D=(3.8*(10^(-12)));
d=(35*(10^(-6)));
Vb=0.0001;
Vm=0.00599;
Vd=0.0001;
Qdin=(5.8333*(10^(-6)));
s=3.153600;
a= (deltaP*A)/R; %deltaP= Drukverschil [N/(m^2)], A= Oppervlaktemembraan [m^2], R= Convectie membraan weerstand [(N*m^3)/mol]
b= (D*A)/d; %D= Diffusieconstante [(m^2)/s], A= Oppervlaktemembraan [m^2], d= Dikte membraan loodrecht [m]
du = zeros(3,1);
du(1) = (Qbin+a)*(u(2)/Vb)-((Qbin)*(u(1)/Vm))+s;
du(2) = (Qbin*((u(1)/Vm)-(u(2)/Vb)))+(b*((u(3)/Vd)-(u(2)/Vb)));
du(3) = (-(Qdin*(u(3)/Vd)))+((a-b)*((u(3)/Vd)-(u(2)/Vb)));
end
And this is the script that calls the function:
[T,U]=ode45(@Hopelijkgoed,[0 30],[0.2036 0.004 0]);
figure(1)
plot(T,U)
It keeps giving the error that there is an undefined function or variable 't' if i run the function.
  1 commentaire
Jan
Jan le 19 Déc 2016
Modifié(e) : Jan le 19 Déc 2016
Please post a copy of the complete error message. It contain important details. Most of all the failing line is interesting, because the shown code does not contain the variable "t". This means, that the problem must happen somewhere else.
Use 5.8333e-6 instead of (5.8333*(10^(-6))). The first is a constant, while the 2nd is an expensive power operation.

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Réponses (1)

Sally Al Khamees
Sally Al Khamees le 22 Déc 2016
I was able to execute the code successfully.
To verify, did you follow these steps to execute the code?
  1. Created a function file called "Hopelijkgoed.m" that has the function code.
  2. Created a script "test.m", and copy-pasted the script that calls the function in it. Or used the command window.
  3. executed "test.m", which in turn calls "Hopelijkgoed.m"
I receive "Not enough input arguments" error when I execute "Hopelijkgoed.m" first.
Also, have you tried debugging the code by inserting a break point where the error is and see if the variable "t" is defined before the call.
As Jan Simon suggested, provide the exact error message, or a screenshot of it.

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