# Trying to solve a second order differential equation. Your advices

**URL:** <https://discourse.julialang.org/t/trying-to-solve-a-second-order-differential-equation-your-advices/41162>\
**Category:** Optimization (Mathematical)\
**Created:** [June 10, 2020, 9:04pm UTC](https://discourse.julialang.org/t/trying-to-solve-a-second-order-differential-equation-your-advices/41162 "2020-06-10T21:04:51Z")\
**Posts on this page:** 1\
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**Author:** ![aquarelle332](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aquarelle332/32/20816_2.png) [@aquarelle332](https://discourse.julialang.org/u/aquarelle332)\
**Post date:** [June 22, 2020, 10:23pm UTC](https://discourse.julialang.org/t/trying-to-solve-a-second-order-differential-equation-your-advices/41162/13 "2020-06-22T22:23:06Z")

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With OrdinaryDiffEq v5.39.1 (Julia-1.4.2), I tried a couple of solvers (Kvaerno3, KenCarp3, Rodas4, Rosenbrock23) but I obtained an error like:

```julia
DimensionMismatch("W: (Base.OneTo(2), Base.OneTo(2)), mass matrix: (Base.OneTo(2),)")
in expression starting at line 36

```

Where can I focus my attention? Is it linked to [https://github.com/SciML/DiffEqBase.jl/pull/536](https://github.com/SciML/DiffEqBase.jl/pull/536) ?

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