MATLAB: Solving non linear delay differential equations with dde23

dde23ddensd

i'm working on a delay differential equation that looks like this: f(y,z,y',z')(t)=a(y,z)(t)+b(y,z)(t-tau) g(y,z,y',z')(t)=c(y,z)(t)+d(y,z)(t-tau) The problem is, in MATLAB, dde23 only solves DDE when the differential terms are isolated (y'=F(t,y,ydel,z,zdel) , z'=G(t,y,ydel,z,zdel)).
Do you know if there's a way to work around it (or perhaps another available tool)? I've tried ddnsd assuming a null delay for delayed differential term but it only accepts non zero delays). Also trying to isolate y' and z' has revealed useless. Thank you

Best Answer

Just solve the system
f(y,z,y',z')(t)=a(y,z)(t)+b(y,z)(t-tau) g(y,z,y',z')(t)=c(y,z)(t)+d(y,z)(t-tau)
for y',z' (two nonlinear equations in the unknowns y' and z').
A possible tool is MATLAB's fsolve.
Best wishes
Torsten.
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