# How to force using Tracker (not Zygote) in Flux 0.10

**URL:** <https://discourse.julialang.org/t/how-to-force-using-tracker-not-zygote-in-flux-0-10/33916>\
**Category:** Machine Learning\
**Created:** [January 29, 2020, 5:30am UTC](https://discourse.julialang.org/t/how-to-force-using-tracker-not-zygote-in-flux-0-10/33916 "2020-01-29T05:30:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jaynick](https://avatars.discourse-cdn.com/v4/letter/j/71c47a/32.png) [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Post date:** [January 29, 2020, 5:30am UTC](https://discourse.julialang.org/t/how-to-force-using-tracker-not-zygote-in-flux-0-10/33916/1 "2020-01-29T05:30:14Z")

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I want to try this for debugging. In fact one of the Flux example codes does not even run under 0.10.1, error `mutating arrays not supported`.

I tried doing `using Tracker` before `using Flux`, however it still gives the error with a stacktrace in Zygote, indicating tracker’s gradient() was not used. The code was originally written before 0.10 and is compatible with Tracker.

How to force the use of Tracker under Flux 0.10?

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**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [January 29, 2020, 2:28pm UTC](https://discourse.julialang.org/t/how-to-force-using-tracker-not-zygote-in-flux-0-10/33916/2 "2020-01-29T14:28:56Z")

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[https://github.com/FluxML/Flux.jl/issues/883](https://github.com/FluxML/Flux.jl/issues/883)