This question follows from this discussion: https://discourse.julialang.org/t/modify-custom-solver-to-deal-with-multidimensional-arrays/74845 Would it be possible to allow for this? Apparently the routines in `NLSolvers` only accept `AbstractVector`s. `NLsolve` already accepts systems given as multidimensional arrays. So it would be kind of a regression to not allow for that.