Not much I am afraid. CVODE_BDF() is quite good in general but I doubt it is positive (meaning it keeps the sign of the input vector). Also, around the singularity, the problem is stiff, so AutoTsit5(Rosenbrock23()) could be a first try.
Not much I am afraid. CVODE_BDF() is quite good in general but I doubt it is positive (meaning it keeps the sign of the input vector). Also, around the singularity, the problem is stiff, so AutoTsit5(Rosenbrock23()) could be a first try.