ode45 function Not enough input arguments error.

2013 10 2
3 个回答
回答已采纳
更新时间：2014 5 22
3 次查看（30 天）

0 个投票

Hello,
I copied a simple tutorial online on how to use an ode45 function. I have checked and double checked everything. I am going insane :) Any help would be greatly appreciated. I continuously receive the error:
*NOTE: I am a novice at MATLAB
if true
>> Animate
Error using Animate (line 5)
Not enough input arguments.
end
Here is my code:
if true
function xdot = Animate(t,x)
xdot = zeros(3,1);
xdot(1) = x(2) * x(3);
xdot(2) = -x(1) * x(3);
xdot(3) = -0.51 * x(1) * x(2);
[t,x] = ode45('Animate',[0 12], [0 1 1], options);
plot(t,x(:,1), '-',t,x(:,2),'-.',t,x(:,3),'.')
end

2 个评论
显示 无 隐藏 无

Susie
Susie 2013-10-2
By the way, the 'if true' and 'end' statements at the beginning and end of my code are just part of the way this comment box formatted my code. Couldn't get rid of them. Those lines are not in my actual MATLAB code.
Thanks
Susie
Susie 2013-10-2
One more thing: my line 5 is 'xdot(1) = x(2) * x(3);'

请先登录，再进行评论。

请先登录，再回答此问题。

 采纳的回答

James Tursa
James Tursa 2013-10-3
编辑：James Tursa 2013-10-3

1 个投票

FYI the doc says 1st argument to ode45 is supposed to be a function handle, not a string (although a string also seems to work). Try this:
[t,x] = ode45(@Animate,[0 12], [0 1 1], options);
plot(t,x(:,1), '-',t,x(:,2),'-.',t,x(:,3),'.')
It looks like the error you are getting is because you are typing in Animate without any arguments.
In any event, I get this plot by typing in the above two lines with your Animate.m function:

更多回答（2 个）

Azzi Abdelmalek
Azzi Abdelmalek 2013-10-2

1 个投票

Your code is correct. Can you precise where is line 5

4 个评论
显示 2更早的评论 隐藏 2更早的评论

Susie
Susie 2013-10-2
My line 5 is xdot(1) = x(2) * x(3);
Susie
Susie 2013-10-2
I have no idea what I am doing wrong. I keep receiving that error message.
Azzi Abdelmalek
Azzi Abdelmalek 2013-10-2
Check if the right function Animate is in the current folder.
Susie
Susie 2013-10-2
I have checked, it is in the current folder. :(

请先登录，再进行评论。

Susie
Susie 2013-10-3

0 个投票

James,
I made that change, but still had the same error. So, I created an x row vector x = [1 5 10]. I'm getting different errors now. Can you post your changes because I'm not getting a plot at all.
Thanks
if true
function xdot = Animate(t,x)
xdot = zeros(3,1);
x = [1 5 10]
xdot(1) = x(2) * x(3);
xdot(2) = -x(1) * x(3);
xdot(3) = -0.51 * x(1) * x(2);
[t,x] = ode45(@Animate,[0 12], [0 1 1]);
plot(t,x(:,1), '-',t,x(:,2),'-.',t,x(:,3),'.')
end

4 个评论
显示 2更早的评论 隐藏 2更早的评论

James Tursa
James Tursa 2013-10-3
I have a file called Animate.m in my current directory, which is:
function xdot = Animate(t,x)
xdot = zeros(3,1);
xdot(1) = x(2) * x(3);
xdot(2) = -x(1) * x(3);
xdot(3) = -0.51 * x(1) * x(2);
end
I then type in the following two lines at the command line (your options variable deleted from the call since you didn't specify what it was) and I get the plot:
[t,x] = ode45('Animate',[0 12], [0 1 1]);
plot(t,x(:,1), '-',t,x(:,2),'-.',t,x(:,3),'.')
Susie
Susie 2013-10-3
<3333333333 !!!!!!!!!!!!!!!!!!!!!!!!!!!!
Thank you!
Joaquim
Joaquim 2014-5-22
编辑：Joaquim 2014-5-22
Hi, I had the same problem when i put >> [Ti,Yi]=solver(ode1,tspan,y0), after defining tspan and y0 in the command prompt.
Anyone can help me? I send the file attached. Thank you

请先登录，再进行评论。

类别

在 帮助中心 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