MATLAB: Not sure why vector changes assignment when using ode45

ode45

I am going to simplify the problem out of context as I believe this will be easier to understand, obviously I will be corrected if this is actually unhelpful.
There's 3 m files. Main, secondfun, thirdfun.
In main I have defined an 8 element vector i.e.
vector=[var1 var2 var3 var4 var5 var6 var7 var8]
In main I then call the second function with vector as one of the inputs i.e.
[out1, out2]=secondfun(in1, in2, in3, vector)
Where secondfun m file has secondfun(x,y,z,vector):
y0=[vector(1);vector(2);vector(3)]
[~,out3]=ode45(@thirdfun,t,y0,vector)
and thirdfun, thirdfun(~,vector) has:
out3=zeros(3,1);
out3(1)=(vector(5)-vector(1))/vector(7);      *****
out3(2)=(vector(5)-vector(2))/vector(8);
out3(3)=(vector(4)-vector(3))/vector(6);
So running this I get the error that on the second line in thirdfun: Index exceeds matrix dimensions.
I narrowed this error down to where I'm using ode45 in secondfun. Before that line the vector function is a 8 element row vector as it should be. After that line it's turned into y0 only (3 element column vector), i.e. it's being passed into secondfun fine as far as I understand but I don't understand where or how it's being redefined as that?
Any advice on this would be much appreciated.
Thanks.

Best Answer

[~,out3]=ode45(@thirdfun,t,y0,vector)
This isn't the right way to pass a third input (beyond the two that ode45 passes into the integrand function automatically) into thirdfun, which is what I assume is your intention. Instead vector is being interpreted as the options input to ode45.
There's an example on the ode45 documentation page showing one technique for passing additional parameters into the integrand function and a link (in the description of the odefun input on the documentation page) that describes a few other techniques.
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