# Issue with MethodOfLines.jl Heat equation example

**URL:** <https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411>\
**Category:** New to Julia\
**Tags:** error, differentialequation\
**Created:** [March 21, 2023, 5:49pm UTC](https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411 "2023-03-21T17:49:06Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![dan\_tud](https://avatars.discourse-cdn.com/v4/letter/d/8c91f0/32.png) [@dan\_tud](https://discourse.julialang.org/u/dan_tud)\
**Post date:** [March 21, 2023, 5:49pm UTC](https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411/1 "2023-03-21T17:49:06Z")

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Hi there,

I am new to Julia and I am currently working through the examples for the MethodOfLines.jl package. Whilst running the code for the Heat Equation in 1D with Neumann boundary conditions I seem to get the following error message:  
‘’’  
ERROR: MethodError: no method matching (SciMLBase.PDETimeSeriesSolution{Float64, 1, Dict{Num, Matrix{Float64}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}  
‘’’

The error message is much longer than this. I am currently running Julia 1.8 on vscode, if this is helpful. Thanks for your help!

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**Author:** ![lmiq](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lmiq/32/18314_2.png) [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Post date:** [March 21, 2023, 5:56pm UTC](https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411/2 "2023-03-21T17:56:52Z")

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You are having the same issue as here: [Problems after updating julia 1.8.5 - #8 by lmiq](https://discourse.julialang.org/t/problems-after-updating-julia-1-8-5/96398/8)

(so you can probably follow the updates of that thread)

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**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:** [March 21, 2023, 8:22pm UTC](https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411/3 "2023-03-21T20:22:29Z")

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Yeah it has to do with a recent bump in the road due to updating the return code spec. @xtalax you said you were putting a patch in today?

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**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:** [March 22, 2023, 10:21am UTC](https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411/4 "2023-03-22T10:21:53Z")

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This got patched. MethodOfLines v0.9 should be fine. See [Unable to run heat equation from docs ( ERROR: MethodError: no method matching (SciMLBase.PDETimeSeriesSolution) · Issue #256 · SciML/MethodOfLines.jl · GitHub](https://github.com/SciML/MethodOfLines.jl/issues/256)

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<div class="post-metadata">

**Author:** ![dan\_tud](https://avatars.discourse-cdn.com/v4/letter/d/8c91f0/32.png) [@dan\_tud](https://discourse.julialang.org/u/dan_tud)\
**Post date:** [March 22, 2023, 12:08pm UTC](https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411/5 "2023-03-22T12:08:13Z")

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Thanks Chris, I managed to get it working by using Imiq’s method of starting a new environment, but I’ll update to the new version now too!

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**Author:** ![lmiq](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lmiq/32/18314_2.png) [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Post date:** [March 22, 2023, 12:36pm UTC](https://discourse.julialang.org/t/issue-with-methodoflines-jl-heat-equation-example/96411/6 "2023-03-22T12:36:05Z")

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For all new Julia users, take a look at: [Nice workflows for using and developing Julia 1.9+](https://discourse.julialang.org/t/nice-workflows-for-using-and-developing-julia-1-9/96017)

Particularly since you are using large packages, having a nice workflow with Revise and custom environments will help you a lot.