How to solve "Subscripted assignment dimension mismatch"?

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ZHUOREN XU 2017-3-28

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回答： Santhana Raj 2017-3-31

tspan=[0 3]; % time span

X0=[0.0 0.0 10 0 0 0]'; % initial postitions/angles and derivatives thereof Angular_velocity=00:10:400;%rotor_speed*2*pi/60; % in rad/sec PAR0=[Angular_velocity]; %omega

 for i=1:10(Angular_velocity)
%run ode45 refering to the function dXdt
options = odeset('RelTol',1e-2,'AbsTol',1e-2);
options = odeset(options,'OutputFcn',@odeplot,'OutputSel',[1 2 3]);
[t,X(:,:,i)]= ode23(@mymodel_working,tspan,X0,options,PAR0);
end
%break X matrix down into column vectors of changing values with t 
x1(:,i)=X(:,1);
x2(:,i)=X(:,2);
x3(:,i)=X(:,3);
x4(:,i)=X(:,4);
x5(:,i)=X(:,5);
x6(:,i)=X(:,6);
% x7=X(:,7);

figure plot(t,x3,'-b')

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Answer 1

Santhana Raj 2017-3-31

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I see that the X is a 3dimentional matrix. And in the code where you split it up into multiple x, you are accessing X as a 2D matrix.

I assume this is the problem. If so, then change the lines to :

x1=X(:,:,1);

Note that now x1 is a 2D matrix and not a column matrix. The index i is not required as anyway you are outside the loop and the value of i is fixed to 10;

I also would like to point to you that the ODE is running 10 times without any change in its input. it is gonna give the same result.