Error thrown when attempting Parameter Identifiability


I’m really excited to dig around the Parameter Identifiability in ODE Models, that I came across in ModelingToolkit.jl as well as in Overview of Julia’s SciML documentation. I have tried the same on my ODE model, but face some bottlenecks with certain equations involving exponents.

The error thrown is :
MethodError: no method matching ^(::Nemo.QQMPolyRingElem, ::Rational{Int64})

I have troubleshooted my code and found that the below equation with decimal exponent is the root cause of error:

x1    ~  423.1*(x2^0.2561)

But I’m left with no choice to alter my equation, since it is fitted out of data. Can’t such type of equations be handled in parameter identifiability? I could simulate the model, solving my system of equations with the above mentioned equation as well…and this issue arises only when I go for parameter identifiability.

Can I know why this occurs and how can it be resolved?
Thanks in advance!

No, it can only do rational polynomial equations.

Thanks for the info!