I have a differential equation of the kind \dot q_1 = f(q_1, q_2)\\ A(q_1,q_2)\dot q_2=B(q_1,q_2)\dot q_1 where q_1, q_2 are vectors, A is a symmetric, positive-definite real matrix, and B is a real (non-square) matrix. When I use Tsit5 or RK4, the time step dt fluctuates a lot and sometimes the…

Awkward ODE problem

Oscar_Smith October 8, 2022, 3:26pm 5

try FBDF. it’s often really good.

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