Solve a differential system in one file

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abc abc 2015-5-12

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https://ww2.mathworks.cn/matlabcentral/answers/216390-solve-a-differential-system-in-one-file

评论： abc abc 2015-5-12

Hi i'm trying to solve this :

function dy = vdp1000(t,y)
dy = zeros(2,1);    % a column vector
dy(1) = y(2);
dy(2) = 1000*(1 - y(1)^2)*y(2) - y(1);
end
[[T,Y]=ode15s(@vdp1000,[0 3000], [2 0]);
plot(T,Y(:,1),'-o')

but it does not work and i would like it work without command window but matlab answers me :

Error: File: vdp1000.m Line: 9 Column: 1 This statement is not inside any function. (It follows the END that terminates the definition of the function "vdp1000".)

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Answer 1

Torsten 2015-5-12

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https://ww2.mathworks.cn/matlabcentral/answers/216390-solve-a-differential-system-in-one-file#answer_178833

在 MATLAB Online 中打开

function driver
[T,Y]=ode15s(@vdp1000,[0 3000], [2 0]);
plot(T,Y(:,1),'-o')
function dy = vdp1000(t,y)
dy = zeros(2,1);    % a column vector
dy(1) = y(2);
dy(2) = 1000*(1 - y(1)^2)*y(2) - y(1);

Best wishes

Torsten.

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abc abc 2015-5-12

在 MATLAB Online 中打开

thank you for your answer but matlab answers me :

Warning: File: vdp1000.m Line: 4 Column: 15
Function with duplicate name "vdp1000" cannot be called. 
Error using vdp1000
Too many input arguments.
Error in odearguments (line 87)
f0 = feval(ode,t0,y0,args{:});   % ODE15I sets args{1} to yp0.
Error in ode15s (line 148)
[neq, tspan, ntspan, next, t0, tfinal, tdir, y0, f0, odeArgs, odeFcn, ...
Error in vdp1000 (line 2)
[T,Y]=ode15s(@vdp1000,[0 3000], [2 0]);