Define an ODE which depends on an external function with the @ode_def macro

[ChrisRackauckas]

This is a duplicate of another thread which has the answer:

How to define a system of ODEs with @ode_def and update the value of a variable using a function that depends on time?

You need to @register_symbolic it so that way it’s kept as a node in the symbolic graph. using DifferentialEquations using ParameterizedFunctions # Solve odeFB odeFB = @ode_def begin dGp = ((Vmax * Ge * Gp)/(Km + Gp)) - (k4 * Gp) - (k2 * A * Gp) + (km2 * A) + (km4 * Gi) dGi = (k4 * Gp) - (k5 * Gi) - (km4 * Gi) + (km5 * A) dA = - (k3 * A) + (k5 * Gi) - (km5 * A) end Vmax Ge Km k2 k3 k4 k5 km2 km4 km5 x0 = ones(length(odeFB.syms)) p = (1400, 24.15, 1100, 5.3, 4, 2, 2.3, 5.3, 2, 2.…