ODE45 not enough input arguments

1 次查看（过去 30 天）
Tomas van Dorp
Tomas van Dorp 2016-12-19
回答： Sally Al Khamees 2016-12-22
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 个评论
Jan
Jan 2016-12-19
编辑：Jan 2016-12-19
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.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Sally Al Khamees
Sally Al Khamees 2016-12-22
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.

类别

在 Help Center 和 File Exchange 中查找有关 Ordinary Differential Equations 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by