"Not Enough Arguments" Error in ode23 - code is perfect as far as I know...

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Lauren
Lauren 2014-2-27
编辑： Star Strider 2014-2-27
function kinetics=examquestion1(t,Y)
kinetics=zeros(3,1);
kinetics(1)=-Y(1)*Y(2)+0.1*Y(3);
kinetics(2)=-Y(1)*Y(2)+0.1*Y(3);
kinetics(3)=Y(1)*Y(2)-0.1*Y(3);
[tv,Yv]=ode45(@examquestion1,[0 10],[1;1;0],t);
plot(tv,Yv(:,1),'+',tv,Yv(:,2),'x',tv,Yv(:,3),'o')
hold on
grid
title('Solutions w/k1=1 and k-1=0.1')
text(0.3,14,'-+- A(t)')
text(0.3,10,'-x- B(t)')
text(0.3,-12,'-o- P(t)')
xlabel('time')
hold off
end
Above is my code, error is in line 4 "kinetics(1)=......." I have no clue what to do!! Please help, time is of the essence. Thank you :)
Code is for solving a system of 3 differential equations, representing the kinetics of an A + B = C reaction.

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采纳的回答

Paul
Paul 2014-2-27
Put this in an m-file:
function kinetics=examquestion1(t,Y)
kinetics=zeros(3,1);
kinetics(1)=-Y(1)*Y(2)+0.1*Y(3);
kinetics(2)=-Y(1)*Y(2)+0.1*Y(3);
kinetics(3)=Y(1)*Y(2)-0.1*Y(3);
save it as examquestion1. Then run:
[tv,Yv]=ode45(@examquestion1,[0 10],[1;1;0]);
plot(tv,Yv(:,1),'+',tv,Yv(:,2),'x',tv,Yv(:,3),'o')
hold on
grid
title('Solutions w/k1=1 and k-1=0.1')
text(0.3,14,'-+- A(t)')
text(0.3,10,'-x- B(t)')
text(0.3,-12,'-o- P(t)')
xlabel('time')
hold off

更多回答（1 个）

Star Strider
Star Strider 2014-2-27
编辑：Star Strider 2014-2-27
You can only put a function file inside another function file. If you want your ODE to run in your file, you have to code it as an anonymous function.
You also made a simple typographical error:
[tv,Yv]=ode45(@examquestion1,[0 10],[1;1;0],t);
It will throw an error because of the t.
I reformatted your ODE as an anonymous function (for my convenience only) and this ran without problems:
examquestion1 = @(t,Y) [-Y(1)*Y(2)+0.1*Y(3); -Y(1)*Y(2)+0.1*Y(3); Y(1)*Y(2)-0.1*Y(3)];
[tv,Yv]=ode45(examquestion1,[0 10],[1;1;0]);
Also, with respect to your text statements, see the legend command. It may make what you’re doing easier.

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