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I have a system of ODEs of this form;

Yi=2*Yi*(Y(i-1)-Y(i+1))-Yi;  i=1,2,...n-1;

Please note i,i-1 and i+2 with Y are not index;but subscripts since I can't type subscripts here.

    Y(i-1) is known for only Yi(i=1) and
    Y(i+1) is known for only Yi(i=n-1)

    Initial conditions: Yi(0)=0; for i=1,2,...n-1;

I tried the following codes but got back with errors:

%%Y0 and Yn are known

for i=1:n-1
if i==1
Yt=Y(i+1);
Y=dsolve('DY=2*Y*(Y0-Yt)-Y','Y(0)=0');
elseif i==n-1
Yt1=Y(i-1);
Y=dsolve('DY=2*Y*(Yt1-Yn)-Y','Y(0)=0');
else
Yt1=Y(i-1);
Yt=Y(i+1);
Y=dsolve('DY=2*Y*(Yt1-Yt)-Y','Y(0)=0')
end
end

The following error shows: Error using ==> mupadmex Error in MuPAD command: Index exceeds matrix dimensions.

Error in ==> sym.sym>sym.subsref at 1381 B = mupadmex('symobj::subsref',A.s,inds{:});

Error in ==> testerode at 14 Yt=Y(i+1);

Is there any way to solve this problem using matlab or simulink? Thanks

user2535441
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  • Is there a typo in the first equation you listed? Should the LHS not be `Y(i+1)`?. Otherwise the expression is not in simplest form. – cjh Jun 30 '13 at 14:29
  • @cjh Thanks much for your reply. I have solved the equations using ode15s solver. dsolve couldn't solve the problem since there is no explicit solution. Thanks again. – user2535441 Jun 30 '13 at 23:58

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