# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1583

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 1584

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## [BFGS very slow compared to BlackBoxOptim - How to improve performance](https://discourse.julialang.org/t/bfgs-very-slow-compared-to-blackboxoptim-how-to-improve-performance/49253)

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**Author:** [@vsskanth](https://discourse.julialang.org/u/vsskanth)\
**Replies:** 20\
**Last updated:** [November 3, 2020, 3:58pm UTC](https://discourse.julialang.org/t/bfgs-very-slow-compared-to-blackboxoptim-how-to-improve-performance/49253 "2020-11-03T15:58:25Z")

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I am trying to fit a differential equation (using DiffEqParamEstim) with these properties: Lumped parameter linear thermal model with 3 states 8 interpolated external inputs (sampled at 50 Hz) using Interpolations.jl o…

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## [Iterating over String changes its Structure to a an array Characters](https://discourse.julialang.org/t/iterating-over-string-changes-its-structure-to-a-an-array-characters/49417)

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**Author:** [@Jim\_Beck](https://discourse.julialang.org/u/Jim_Beck)\
**Replies:** 6\
**Last updated:** [November 3, 2020, 3:37pm UTC](https://discourse.julialang.org/t/iterating-over-string-changes-its-structure-to-a-an-array-characters/49417 "2020-11-03T15:37:02Z")

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I have a list of strings that I’m attempting to compare to a unique other string. I have a function that compares each string character by character, counting differences at each location. function compareStrings(sequen…

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## [Switch to the folder of open file in VS code](https://discourse.julialang.org/t/switch-to-the-folder-of-open-file-in-vs-code/44813)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 10\
**Last updated:** [November 3, 2020, 3:07pm UTC](https://discourse.julialang.org/t/switch-to-the-folder-of-open-file-in-vs-code/44813 "2020-11-03T15:07:49Z")

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Is there a command to switch to the folder of the current file in VS code? I can see that there is a command to copy the name of the current file, but at least on Windows that path is unusable in Julia since it has si…

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## [IJulia build problems again: solved](https://discourse.julialang.org/t/ijulia-build-problems-again-solved/49530)

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**Author:** [@ctkelley](https://discourse.julialang.org/u/ctkelley)\
**Replies:** 0\
**Last updated:** [November 3, 2020, 2:39pm UTC](https://discourse.julialang.org/t/ijulia-build-problems-again-solved/49530 "2020-11-03T14:39:08Z")

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Reboot solved problems.

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## [Git config pull](https://discourse.julialang.org/t/git-config-pull/49521)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 2\
**Last updated:** [November 3, 2020, 3:04pm UTC](https://discourse.julialang.org/t/git-config-pull/49521 "2020-11-03T15:04:11Z")

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After a recent update, git pull started printing $ git pull …

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## [Converting string to DateTime in DataFrame](https://discourse.julialang.org/t/converting-string-to-datetime-in-dataframe/49524)

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**Author:** [@alunap](https://discourse.julialang.org/u/alunap)\
**Replies:** 5\
**Last updated:** [November 3, 2020, 3:00pm UTC](https://discourse.julialang.org/t/converting-string-to-datetime-in-dataframe/49524 "2020-11-03T15:00:45Z")

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I’m reading in a json file, putting it into DataFrames to clean it up, before dumping into MongoDB (via mongoc). It is almost there, my only problem is that one of the fields is a timestamp, which is coming in as a strin…

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## [Get node indices in NearestNeighbors?](https://discourse.julialang.org/t/get-node-indices-in-nearestneighbors/49252)

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**Author:** [@cgeoga](https://discourse.julialang.org/u/cgeoga)\
**Replies:** 4\
**Last updated:** [November 3, 2020, 2:39pm UTC](https://discourse.julialang.org/t/get-node-indices-in-nearestneighbors/49252 "2020-11-03T14:39:22Z")

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Hey all— I’m building a KDTree using NearestNeighbors.jl like this: using StaticArrays, NearestNeighbors pts = \[SVector{2, Float64}(randn(2)) for \_ in 1:1024\] tree = KDTree(pts, leafsize=25) and I’m trying to find t…

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## [\[ANN\] Telperion.jl - Macro Magic for Properties and Statistical Formulas](https://discourse.julialang.org/t/ann-telperion-jl-macro-magic-for-properties-and-statistical-formulas/49496)

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**Author:** [@joshday](https://discourse.julialang.org/u/joshday)\
**Replies:** 3\
**Last updated:** [November 3, 2020, 2:07pm UTC](https://discourse.julialang.org/t/ann-telperion-jl-macro-magic-for-properties-and-statistical-formulas/49496 "2020-11-03T14:07:07Z")

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Hi everyone, I created a package to help me work with properties in an expression without repeatedly using the dot syntax. The gist is that you can do this: julia\> nt = (x=1, y=2) (x = 1, y = 2) julia\> z = 3 3 julia\>…

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## [How to change vertical to horizontal StringArray?](https://discourse.julialang.org/t/how-to-change-vertical-to-horizontal-stringarray/49522)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 1\
**Last updated:** [November 3, 2020, 1:15pm UTC](https://discourse.julialang.org/t/how-to-change-vertical-to-horizontal-stringarray/49522 "2020-11-03T13:15:27Z")

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How to change vertical to horizontal StringArray ? julia\> plot(rand(3,2),labels=\["a", "b"\]) julia\> plot(rand(3,2),labels=\["a" "b"\]) Works fine only second line. How to change first to second vectors with lalbels ? Pa…

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## [Static arrays being mutated, what is going on?](https://discourse.julialang.org/t/static-arrays-being-mutated-what-is-going-on/49519)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 3\
**Last updated:** [November 3, 2020, 1:03pm UTC](https://discourse.julialang.org/t/static-arrays-being-mutated-what-is-going-on/49519 "2020-11-03T13:03:23Z")

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I do not understand how v3 is the code below is being allowed to mutate. What is going on there? using StaticArrays using BenchmarkTools function test(v1, v2) v3 = zeros(SVector{3,Float64}) for i in 1:10^4 …

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## [When ForwardDiff-ing through an ODE is unstable](https://discourse.julialang.org/t/when-forwarddiff-ing-through-an-ode-is-unstable/49484)

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**Author:** [@Dhruva2](https://discourse.julialang.org/u/Dhruva2)\
**Replies:** 6\
**Last updated:** [November 3, 2020, 1:06pm UTC](https://discourse.julialang.org/t/when-forwarddiff-ing-through-an-ode-is-unstable/49484 "2020-11-03T13:06:01Z")

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DiffEqSensitivity and DiffEqFlux have a selection of great tools to backpropagate in various ways through differential equations, to get gradients with respect to DE parameters. The documentation discusses the numerical …

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## [How to find duplicate rows in String Array (vec)](https://discourse.julialang.org/t/how-to-find-duplicate-rows-in-string-array-vec/49182)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 2\
**Last updated:** [November 3, 2020, 1:01pm UTC](https://discourse.julialang.org/t/how-to-find-duplicate-rows-in-string-array-vec/49182 "2020-11-03T13:01:02Z")

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How to find duplicate rows in String Array (vec) ? Paul

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## [\[ANN\] CameraCalibrations](https://discourse.julialang.org/t/ann-cameracalibrations/49518)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 0\
**Last updated:** [November 3, 2020, 12:23pm UTC](https://discourse.julialang.org/t/ann-cameracalibrations/49518 "2020-11-03T12:23:35Z")

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Hi all, I’ve registered CameraCalibrations, a Julia package for camera calibration. This package uses Matlab’s camera calibration toolbox to detect checkerboards and their corners as well as generate calibration objects…

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## [Julia support for GitHub Codespaces](https://discourse.julialang.org/t/julia-support-for-github-codespaces/46436)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 6\
**Last updated:** [November 3, 2020, 12:18pm UTC](https://discourse.julialang.org/t/julia-support-for-github-codespaces/46436 "2020-11-03T12:18:34Z")

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Just got my beta access to GitHub Codespaces (online VS code in GitHub). Codespaces allows for choosing a container to run in - but while there’s already lot’s of pre-built containers for Python, Java, Perl, Ruby, etc. t…

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## [Unitful dispatch](https://discourse.julialang.org/t/unitful-dispatch/49480)

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**Author:** [@KajWiik](https://discourse.julialang.org/u/KajWiik)\
**Replies:** 13\
**Last updated:** [November 3, 2020, 11:41am UTC](https://discourse.julialang.org/t/unitful-dispatch/49480 "2020-11-03T11:41:50Z")

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Why this works: julia\> function hz(x::typeof(1.0u"Hz")) 2x end hz (generic function with 1 method) and this does not work: julia\> typeof(1.0u"Hz") Quantity{Float64,𝐓^-1,Unitful.FreeUnits{(Hz,),𝐓^-1,nothi…

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## [What do you think of \`(f1 & f2)(x)\`?](https://discourse.julialang.org/t/what-do-you-think-of-f1-f2-x/49459)

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**Author:** [@MarcMush](https://discourse.julialang.org/u/MarcMush)\
**Replies:** 2\
**Last updated:** [November 2, 2020, 3:55pm UTC](https://discourse.julialang.org/t/what-do-you-think-of-f1-f2-x/49459 "2020-11-02T15:55:27Z")

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There might be a thread or a github issue about that but it’s really hard to search for or and and terms, please redirect me if I missed it I’d like to use a syntax that looks like that: f = \<(5) & \>(1) g = isnan | ism…

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## [SVector vs struct performance](https://discourse.julialang.org/t/svector-vs-struct-performance/49503)

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**Author:** [@arnief3](https://discourse.julialang.org/u/arnief3)\
**Replies:** 8\
**Last updated:** [November 3, 2020, 10:46am UTC](https://discourse.julialang.org/t/svector-vs-struct-performance/49503 "2020-11-03T10:46:14Z")

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I am struggling to understand the huge performance difference I am seeing between these two approaches to creating a Vec3 DataType. I would prefer to use a SVector, but only if the performance is comparable. I feel like …

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## [3d histogram plot with PGFPlotsX and StatsBase](https://discourse.julialang.org/t/3d-histogram-plot-with-pgfplotsx-and-statsbase/49413)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 2\
**Last updated:** [November 3, 2020, 8:32am UTC](https://discourse.julialang.org/t/3d-histogram-plot-with-pgfplotsx-and-statsbase/49413 "2020-11-03T08:32:23Z")

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Hi, I would like to do something similiar like this with PGFPlotsX. I´m a newbie in plotting with PGFPlotsX. I tried to it analogously like the example. I use StatsBase for plotting the histogram. Here first the …

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## [Differentials in ModelingToolkit](https://discourse.julialang.org/t/differentials-in-modelingtoolkit/49440)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 6\
**Last updated:** [November 3, 2020, 5:19am UTC](https://discourse.julialang.org/t/differentials-in-modelingtoolkit/49440 "2020-11-03T05:19:35Z")

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I’m trying to find the derivative in ModelingToolkit.jl This is how it was done in SymEngine using SymEngine x=symbols(:x) diff(4x^3,x) would give 3x^2 How would I do the same thing in ModelingToolkit?

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## [Best options to simplify?](https://discourse.julialang.org/t/best-options-to-simplify/49492)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 2\
**Last updated:** [November 3, 2020, 4:01am UTC](https://discourse.julialang.org/t/best-options-to-simplify/49492 "2020-11-03T04:01:34Z")

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What are some packages that work well to simplify? I could not find simplification in SymEngine, and from what I read, none was built as of 2017. SymbolUtilities and ModelingToolkit, do a certain amount of arithmetic bu…

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## [How to find location of Minimum in Interpolation function?](https://discourse.julialang.org/t/how-to-find-location-of-minimum-in-interpolation-function/48528)

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**Author:** [@CosmoProf](https://discourse.julialang.org/u/CosmoProf)\
**Replies:** 11\
**Last updated:** [November 3, 2020, 2:50am UTC](https://discourse.julialang.org/t/how-to-find-location-of-minimum-in-interpolation-function/48528 "2020-11-03T02:50:09Z")

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Hi, when using an Interpolation object to approximate a function with values known over a few dozen discrete data points, how can I find where the (local) minimum of the function is? (Assuming that the minimum is not act…

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## [Symbols in Symbol Utilities](https://discourse.julialang.org/t/symbols-in-symbol-utilities/49498)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 0\
**Last updated:** [November 3, 2020, 2:37am UTC](https://discourse.julialang.org/t/symbols-in-symbol-utilities/49498 "2020-11-03T02:37:14Z")

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I’m trying to use various CAS packages. I tried to follow the instructions for. Symbolic Utils Using SymbolicUtils @syms x diff(x^2+x,x) and I get ERROR: MethodError: no method matching diff(::Term{Number}, ::Sym{Nu…

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## [Fail to building julia](https://discourse.julialang.org/t/fail-to-building-julia/49497)

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**Author:** [@ardsatcg](https://discourse.julialang.org/u/ardsatcg)\
**Replies:** 0\
**Last updated:** [November 3, 2020, 1:59am UTC](https://discourse.julialang.org/t/fail-to-building-julia/49497 "2020-11-03T01:59:46Z")

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git clone is pass, but running ‘make’ isn’t. note: i’ve installed required dependencies

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## [Setting ApproxFun Space , tried several tricks but still receive \*\*ERROR: LoadError: Cannot infer spaces\*\* – specifically when using GeneralizedGenerated.jl for Generalized generated functions](https://discourse.julialang.org/t/setting-approxfun-space-tried-several-tricks-but-still-receive-error-loaderror-cannot-infer-spaces-specifically-when-using-generalizedgenerated-jl-for-generalized-generated-functions/48909)

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**Author:** [@Marc.Cox](https://discourse.julialang.org/u/Marc.Cox)\
**Replies:** 21\
**Last updated:** [October 26, 2020, 7:15pm UTC](https://discourse.julialang.org/t/setting-approxfun-space-tried-several-tricks-but-still-receive-error-loaderror-cannot-infer-spaces-specifically-when-using-generalizedgenerated-jl-for-generalized-generated-functions/48909 "2020-10-26T19:15:20Z")

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Setting ApproxFun Space , tried several tricks but still receive ERROR: LoadError: Cannot infer spaces – specifically when using GeneralizedGenerated.jl for Generalized generated functions # Begin Preamble using Linea…

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## [Multithreading of a simple loop](https://discourse.julialang.org/t/multithreading-of-a-simple-loop/49478)

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**Author:** [@JohnZ](https://discourse.julialang.org/u/JohnZ)\
**Replies:** 6\
**Last updated:** [November 3, 2020, 1:07am UTC](https://discourse.julialang.org/t/multithreading-of-a-simple-loop/49478 "2020-11-03T01:07:58Z")

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Hi, I am trying to use multi-threading to parallelise a simple loop. The actual code is quite complex and I have given a simplified example. The multithreaded version runs slower than the single thread version. I have …

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## [Jaccard distance of each combo of elements in 2 lists](https://discourse.julialang.org/t/jaccard-distance-of-each-combo-of-elements-in-2-lists/49483)

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**Author:** [@lorb24](https://discourse.julialang.org/u/lorb24)\
**Replies:** 2\
**Last updated:** [November 2, 2020, 10:04pm UTC](https://discourse.julialang.org/t/jaccard-distance-of-each-combo-of-elements-in-2-lists/49483 "2020-11-02T22:04:44Z")

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What’s the most efficient way to get the Jaccard distance of each combo of elements in 2 lists? Let’s say I have 2 arrays that look like this: x= "ap p le" "or an ge" "ap pl e" "ap pl e” ”or an ge" "ho ne yc ri sp ap …

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## [Flux con! warning](https://discourse.julialang.org/t/flux-con-warning/49456)

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**Author:** [@Krzysztof\_Langner](https://discourse.julialang.org/u/Krzysztof_Langner)\
**Replies:** 4\
**Last updated:** [November 2, 2020, 9:41pm UTC](https://discourse.julialang.org/t/flux-con-warning/49456 "2020-11-02T21:41:59Z")

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Hi, I’m trying to build simple model which works with MNIST dataset. It works fine, but I get some warning and was wandering if this is something which I can improve Here is the model: Chain( Conv((5, 5), 1=\>8…

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## [Converting .jl file to any kind of markdown](https://discourse.julialang.org/t/converting-jl-file-to-any-kind-of-markdown/36910)

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**Author:** [@erlebach](https://discourse.julialang.org/u/erlebach)\
**Replies:** 3\
**Last updated:** [November 2, 2020, 9:30pm UTC](https://discourse.julialang.org/t/converting-jl-file-to-any-kind-of-markdown/36910 "2020-11-02T21:30:30Z")

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How do I convert a jl file (julia source file) to markdown from within Atom, or from the command line? Once I do that, I can use Pandoc to print the file. It is more complex than using triple quotes around the program. W…

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## [ArchGDAL and GeoArrays error libgdal on windows 10](https://discourse.julialang.org/t/archgdal-and-geoarrays-error-libgdal-on-windows-10/49470)

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**Author:** [@virgile-baudrot](https://discourse.julialang.org/u/virgile-baudrot)\
**Replies:** 3\
**Last updated:** [November 2, 2020, 8:53pm UTC](https://discourse.julialang.org/t/archgdal-and-geoarrays-error-libgdal-on-windows-10/49470 "2020-11-02T20:53:23Z")

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When loading ArchGDAL or GeoArrays, i’ve the following error: ERROR: could not load library "libgdal-26.dll" Sometimes it’s "libgdal-4.dll" \[79e6a3ab\] Adapt v2.3.0 \[c9ce4bd3\] ArchGDAL v0.5.2 \[dce04be8\] ArgCheck v2…

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## [Solving same DiffEq repeatedly but with different initial conditions](https://discourse.julialang.org/t/solving-same-diffeq-repeatedly-but-with-different-initial-conditions/49402)

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**Author:** [@ash](https://discourse.julialang.org/u/ash)\
**Replies:** 2\
**Last updated:** [November 2, 2020, 8:14pm UTC](https://discourse.julialang.org/t/solving-same-diffeq-repeatedly-but-with-different-initial-conditions/49402 "2020-11-02T20:14:46Z")

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I have a set of coupled ODEs that I’d like to solve, which is simple enough using DifferentialEquations.jl. My problem is that I need to solve the same ODE repeatedly for many different initial conditions parametrized by…

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