# How to debug failing DifferentialEquations.solve when called with Dual numbers

**URL:** <https://discourse.julialang.org/t/how-to-debug-failing-differentialequations-solve-when-called-with-dual-numbers/79895>\
**Category:** Numerics\
**Tags:** diffeq, turing, forwarddiff, modelingtoolkit\
**Created:** [April 23, 2022, 2:43pm UTC](https://discourse.julialang.org/t/how-to-debug-failing-differentialequations-solve-when-called-with-dual-numbers/79895 "2022-04-23T14:43:07Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [April 23, 2022, 4:21pm UTC](https://discourse.julialang.org/t/how-to-debug-failing-differentialequations-solve-when-called-with-dual-numbers/79895/2 "2022-04-23T16:21:52Z")

</div>

Why Tsit5? If you hit maxiters, that’s normally a sign of stiffness. See the PSA:

> [@PSA: How to help yourself debug differential equation solving issues](https://discourse.julialang.org/t/psa-how-to-help-yourself-debug-differential-equation-solving-issues/62489):
>
> Debugging differential equation solver issues almost always boils down to doing the same thing, so this is a summary to help you out. For more information on specific issues, check out the FAQ section of the DifferentialEquations.jl documentation which highlights common issues and questions: [https://diffeq.sciml.ai/dev/basics/faq/](https://diffeq.sciml.ai/dev/basics/faq/)How do I debug why the differential equation solver is diverging? dt \<= dtmin. Aborting. There is either an error in your model specification or the true solution i…

---

_[View the full topic](https://discourse.julialang.org/t/how-to-debug-failing-differentialequations-solve-when-called-with-dual-numbers/79895)._