I’m simulating a satellite around the earth, and got error:
Symbolic calculations could not initiate. Likely there's a function which is not differentiable by SymEngine.
I think it’s because it cannot differentiate the -\frac 3 2 power. But how could it fail to differentiate something that simple?
using DifferentialEquations, ParameterizedFunctions satellite! = @ode_def Satellite begin dx = vx dy = vy dvx = -GM*(x^2+y^2)^(-3//2) * x dvy = -GM*(x^2+y^2)^(-3//2) * y end GM G = 6.67e-11 M = 5.97e24 elasticity = 1 u0 = [0, 1e7, 5e3, 0] tspan = (0.0,15.0) p = [G*M] prob = ODEProblem(satellite!, u0, tspan, p) sol = solve(prob,Tsit5())