Matlab’s bvp4c allows the user to specify ODE-BVP problems which contain an unknown parameter, and then to specify the problem by providing an extra boundary condition. E.g. for a second order ODE, we might have an extra unknown parameter, lambda, in the ODE, but then specify 3 boundary conditions rather than the usual two. This is handy for a wide range of problems.
Is there any functionality like this in DifferentialEquations.jl?