# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1490

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

**Page:** 1491

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## [Developing packages - help!](https://discourse.julialang.org/t/developing-packages-help/55299)

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**Author:** [@aditya-kamath](https://discourse.julialang.org/u/aditya-kamath)\
**Replies:** 1\
**Last updated:** [February 15, 2021, 1:15pm UTC](https://discourse.julialang.org/t/developing-packages-help/55299 "2021-02-15T13:15:30Z")

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Hi Everyone, I just installed Juno along with Julia following Chris Rackauckas’ developing for julia tutorial. When I try to dev Surrogates (the package I want to develop) I get this error. ERROR: Unsatisfiable require…

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## [In VSCode-Julia, how to remap "up" key while in the REPL?](https://discourse.julialang.org/t/in-vscode-julia-how-to-remap-up-key-while-in-the-repl/55279)

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**Author:** [@marty0801](https://discourse.julialang.org/u/marty0801)\
**Replies:** 6\
**Last updated:** [February 15, 2021, 12:37pm UTC](https://discourse.julialang.org/t/in-vscode-julia-how-to-remap-up-key-while-in-the-repl/55279 "2021-02-15T12:37:40Z")

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I’d like to use Ctrl-p to load previous commands at the REPL prompt. I assume the correct approach is to modify Keyboard Shortcuts, but I can’t seem to identify the corresponding command. Things I’ve tried: Searched sho…

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## [Nice way to do parallel matrix multiplication](https://discourse.julialang.org/t/nice-way-to-do-parallel-matrix-multiplication/55310)

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**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 0\
**Last updated:** [February 15, 2021, 12:14pm UTC](https://discourse.julialang.org/t/nice-way-to-do-parallel-matrix-multiplication/55310 "2021-02-15T12:14:18Z")

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Hello, I’m trying to do parallel matrix multiplication in a for loop. I’m using Threads.@threads, but this also applies to a GPU version of the code and maybe a distributed (MPI-like) version in the future. Within my c…

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## [@threads tasks and Jupyter interrupt kernel](https://discourse.julialang.org/t/threads-tasks-and-jupyter-interrupt-kernel/55307)

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**Author:** [@dnadlinger](https://discourse.julialang.org/u/dnadlinger)\
**Replies:** 0\
**Last updated:** [February 15, 2021, 11:04am UTC](https://discourse.julialang.org/t/threads-tasks-and-jupyter-interrupt-kernel/55307 "2021-02-15T11:04:08Z")

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I am using Julia inside Jupyter (using IJulia.jl), and have some computationally intensive tasks distributed over several threads using a Threads.@threads for loop. Interrupting the kernel more often than not only seems…

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## [Is it possible to generalize such function to arbitrary tuple size? I couldn't fin](https://discourse.julialang.org/t/is-it-possible-to-generalize-such-function-to-arbitrary-tuple-size-i-couldnt-fin/55305)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 2\
**Last updated:** [February 15, 2021, 10:44am UTC](https://discourse.julialang.org/t/is-it-possible-to-generalize-such-function-to-arbitrary-tuple-size-i-couldnt-fin/55305 "2021-02-15T10:44:13Z")

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Is it possible to generalize such function to arbitrary tuple size? I couldn’t find relevant information in docs. function from\_vec(::Type{MyType{Tuple{T1, T2}}}, x) where {T1, T2} MyType((f(T1, x), f(T2, x))) end Not…

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## [Strange issues fitting GMMs in Turing.jl by extending a fairly simple example](https://discourse.julialang.org/t/strange-issues-fitting-gmms-in-turing-jl-by-extending-a-fairly-simple-example/55232)

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**Author:** [@HarrisonWilde](https://discourse.julialang.org/u/HarrisonWilde)\
**Replies:** 10\
**Last updated:** [February 15, 2021, 9:54am UTC](https://discourse.julialang.org/t/strange-issues-fitting-gmms-in-turing-jl-by-extending-a-fairly-simple-example/55232 "2021-02-15T09:54:29Z")

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I have been extending the Turing example on Bayesian GMMs today in a number of ways, trying it out with non-symmetric 2D Gaussian locations and more clusters than the two in the example I have linked, and namely with som…

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## [Best way to extract parts of arrays in a bigger array](https://discourse.julialang.org/t/best-way-to-extract-parts-of-arrays-in-a-bigger-array/55274)

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**Author:** [@stebett](https://discourse.julialang.org/u/stebett)\
**Replies:** 2\
**Last updated:** [February 15, 2021, 8:38am UTC](https://discourse.julialang.org/t/best-way-to-extract-parts-of-arrays-in-a-bigger-array/55274 "2021-02-15T08:38:41Z")

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Hello everyone, I’m wondering if anybody can find a better solution to this problem: I have 2 arrays of arrays: in the first one there are time series, and in the second one there are timepoints on those time series. M…

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## [Implement AbstractArray so that custom type is returned](https://discourse.julialang.org/t/implement-abstractarray-so-that-custom-type-is-returned/55297)

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**Author:** [@kblissett](https://discourse.julialang.org/u/kblissett)\
**Replies:** 3\
**Last updated:** [February 15, 2021, 8:20am UTC](https://discourse.julialang.org/t/implement-abstractarray-so-that-custom-type-is-returned/55297 "2021-02-15T08:20:20Z")

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I’d like to implement a 3-D vector type like the following: struct Vector3D x::Int y::Int z::Int end Julia has a rich collection of Array operations already defined that I’d love to take advantage of, so I’…

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## [Plotting multivariable function stored in a 2d array](https://discourse.julialang.org/t/plotting-multivariable-function-stored-in-a-2d-array/55288)

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**Author:** [@jigjig](https://discourse.julialang.org/u/jigjig)\
**Replies:** 2\
**Last updated:** [February 15, 2021, 8:11am UTC](https://discourse.julialang.org/t/plotting-multivariable-function-stored-in-a-2d-array/55288 "2021-02-15T08:11:32Z")

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I am trying to plot the solution to a PDE, which is stored as a 2d array. I am wandering if there is a way to plot the solution as a 3d image. Thanks

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## [Checkpointing with Julia](https://discourse.julialang.org/t/checkpointing-with-julia/24026)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 8\
**Last updated:** [February 15, 2021, 7:50am UTC](https://discourse.julialang.org/t/checkpointing-with-julia/24026 "2021-02-15T07:50:59Z")

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The post today by @Xing\_Shi\_Cai leads me to ask - has anyone worked with checkpointing in Julia? A bit of Googling would suggest DMTCP would work http://dmtcp.sourceforge.net/ I guess the real answer is - why don’t I…

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## [Can LaTeXStrings display arrays and DataFrames with LaTeX characters?](https://discourse.julialang.org/t/can-latexstrings-display-arrays-and-dataframes-with-latex-characters/55281)

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**Author:** [@Michael\_Barmann](https://discourse.julialang.org/u/Michael_Barmann)\
**Replies:** 2\
**Last updated:** [February 15, 2021, 3:11am UTC](https://discourse.julialang.org/t/can-latexstrings-display-arrays-and-dataframes-with-latex-characters/55281 "2021-02-15T03:11:01Z")

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I’ve recently discovered the package LaTeXStrings, and am very impressed with it. I was wondering if this package makes it possible to display LaTeX strings within arrays and DataFrames. For example, suppose I have a Dat…

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## [What is the recommended way to do numerical integration in Julia — like \`NIntegrat](https://discourse.julialang.org/t/what-is-the-recommended-way-to-do-numerical-integration-in-julia-like-nintegrat/55237)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 3\
**Last updated:** [February 14, 2021, 11:16pm UTC](https://discourse.julialang.org/t/what-is-the-recommended-way-to-do-numerical-integration-in-julia-like-nintegrat/55237 "2021-02-14T23:16:25Z")

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What is the recommended way to do numerical integration in Julia — like NIntegrate in Mathematica? Note that the original poster on Slack cannot see your response here on Discourse. Consider transcribing the appropriate…

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## [SafeTestsets - how to share test fixture](https://discourse.julialang.org/t/safetestsets-how-to-share-test-fixture/55266)

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**Author:** [@adolgert](https://discourse.julialang.org/u/adolgert)\
**Replies:** 2\
**Last updated:** [February 14, 2021, 11:07pm UTC](https://discourse.julialang.org/t/safetestsets-how-to-share-test-fixture/55266 "2021-02-14T23:07:41Z")

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Using SafeTestsets is a best practice for testing. This kind of TestSet keeps tests from interfering with each other, so I couldn’t define a function setup\_test() outside of @safetestset and use it inside the TestSet. I …

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## [Pkg Automatically adding dependencies](https://discourse.julialang.org/t/pkg-automatically-adding-dependencies/55257)

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**Author:** [@maajdl](https://discourse.julialang.org/u/maajdl)\
**Replies:** 3\
**Last updated:** [February 14, 2021, 8:52pm UTC](https://discourse.julialang.org/t/pkg-automatically-adding-dependencies/55257 "2021-02-14T20:52:05Z")

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Hello I am a beginner-beginner to building a package. I understood what Pkg.add does and more or less why. I am a bit lazy. Would there be a way to Pkg.add automatically, based on the source code? Thanks, Mi…

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## [Large idle memory usage](https://discourse.julialang.org/t/large-idle-memory-usage/20368)

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**Author:** [@NS1](https://discourse.julialang.org/u/NS1)\
**Replies:** 6\
**Last updated:** [February 14, 2021, 7:56pm UTC](https://discourse.julialang.org/t/large-idle-memory-usage/20368 "2021-02-14T19:56:03Z")

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Hi, I found that Julia has quite a large memory footprint in my machine, and wanted to ask if it’s normal. By opening Atom, a Julia process opens, with ~500 MB. When starting julia in the REPL, another process with sim…

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## [Optimization with Optim gives different results each time](https://discourse.julialang.org/t/optimization-with-optim-gives-different-results-each-time/54143)

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**Author:** [@Michael\_Barmann](https://discourse.julialang.org/u/Michael_Barmann)\
**Replies:** 16\
**Last updated:** [February 14, 2021, 7:35pm UTC](https://discourse.julialang.org/t/optimization-with-optim-gives-different-results-each-time/54143 "2021-02-14T19:35:06Z")

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I’m using IPNewton() from the Optim package for an inequality-constrained optimization problem. Strangely, I keep getting different results each time I run the same block of code (without changing anything). For example,…

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## [Is it easy to call Go from Julia? What about Rust? What are the biggest challenges](https://discourse.julialang.org/t/is-it-easy-to-call-go-from-julia-what-about-rust-what-are-the-biggest-challenges/55243)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 6\
**Last updated:** [February 14, 2021, 7:01pm UTC](https://discourse.julialang.org/t/is-it-easy-to-call-go-from-julia-what-about-rust-what-are-the-biggest-challenges/55243 "2021-02-14T19:01:49Z")

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Is it easy to call Go from Julia? What about Rust? What are the biggest challenges? What about the other direction, i.e. them calling Julia? I’m looking for two things. One is that I could do microservices in a modern l…

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## [\[ANN\] CommutativeRings](https://discourse.julialang.org/t/ann-commutativerings/55268)

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**Author:** [@klacru](https://discourse.julialang.org/u/klacru)\
**Replies:** 0\
**Last updated:** [February 14, 2021, 6:09pm UTC](https://discourse.julialang.org/t/ann-commutativerings/55268 "2021-02-14T18:09:38Z")

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This package CommutativeRings supports processing in discrete commutative algebra. It has Galois fields, univariate and multivariate polynomials, matrices and vector spaces over finite fields.

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## [I'm trying to build my documentation but keep getting the following error\`\`\`ERROR](https://discourse.julialang.org/t/im-trying-to-build-my-documentation-but-keep-getting-the-following-error-error/55041)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 2\
**Last updated:** [February 14, 2021, 5:41pm UTC](https://discourse.julialang.org/t/im-trying-to-build-my-documentation-but-keep-getting-the-following-error-error/55041 "2021-02-14T17:41:33Z")

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I’m trying to build my documentation but keep getting the following error ERROR: \`NonlinearSchrodinger=b3fbeaf7-5746-403c-a6b7-06939dc82746\` depends on \`TerminalLoggers\`, but no such entry exists in the manifest. I alr…

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## [Creating a vector from a vector of values and a vector of indices to the first vector](https://discourse.julialang.org/t/creating-a-vector-from-a-vector-of-values-and-a-vector-of-indices-to-the-first-vector/55261)

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**Author:** [@samerb](https://discourse.julialang.org/u/samerb)\
**Replies:** 1\
**Last updated:** [February 14, 2021, 5:25pm UTC](https://discourse.julialang.org/t/creating-a-vector-from-a-vector-of-values-and-a-vector-of-indices-to-the-first-vector/55261 "2021-02-14T17:25:46Z")

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I have a vector x that contains “actual values” and a vector y that contains indices (which are less than or equal to the length of x). I want to create a new vector z whose ith element is x\[y\[i\]\]. I am looking for a one…

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## [How to test multiple parameters with SDE?](https://discourse.julialang.org/t/how-to-test-multiple-parameters-with-sde/55089)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 1\
**Last updated:** [February 14, 2021, 5:03pm UTC](https://discourse.julialang.org/t/how-to-test-multiple-parameters-with-sde/55089 "2021-02-14T17:03:45Z")

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Hello, I would like to find the minimal amount of phages required to distinguish a bacterial population. I have run this model: using DifferentialEquations function growth!(du, u, p, t) μ, κ, φ, ω, η, β = p #=…

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## [Can't parse AM/PM?](https://discourse.julialang.org/t/cant-parse-am-pm/55234)

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**Author:** [@pyrex41](https://discourse.julialang.org/u/pyrex41)\
**Replies:** 5\
**Last updated:** [February 14, 2021, 2:34pm UTC](https://discourse.julialang.org/t/cant-parse-am-pm/55234 "2021-02-14T14:34:45Z")

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I cannot seem to figure out how to parse a datetime string with am/pm: using Dates DateTime("2021-02-01 11:12AM EST", dateformat"y-m-d H:Mp xxx") gives this error: ERROR: ArgumentError: Unable to parse date time. Exp…

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## [How come this is non-allocating?](https://discourse.julialang.org/t/how-come-this-is-non-allocating/55216)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 6\
**Last updated:** [February 14, 2021, 2:20pm UTC](https://discourse.julialang.org/t/how-come-this-is-non-allocating/55216 "2021-02-14T14:20:52Z")

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If found an example which challenges my understanding of what allocations are or are not. If one creates a vector of tuples of different lengths, it is possible to mutate the smaller ones into larger ones without alloca…

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## [Can't access some default units in Unitful.jl](https://discourse.julialang.org/t/cant-access-some-default-units-in-unitful-jl/55235)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 3\
**Last updated:** [February 14, 2021, 1:22pm UTC](https://discourse.julialang.org/t/cant-access-some-default-units-in-unitful-jl/55235 "2021-02-14T13:22:27Z")

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I am trying to use Gauss units for magnetic field: using Unitful B = 1u"Gauss" However, for some strange reason I get the error: ERROR: LoadError: ArgumentError: Symbol Gauss could not be found in unit modules Modul…

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## [Understanding how Julia image and compilation works](https://discourse.julialang.org/t/understanding-how-julia-image-and-compilation-works/55208)

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**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 2\
**Last updated:** [February 14, 2021, 12:32pm UTC](https://discourse.julialang.org/t/understanding-how-julia-image-and-compilation-works/55208 "2021-02-14T12:32:53Z")

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Hey Julianners, Is there a good description on how does julia image → precompile image code compilation: code → runnable code works (and maybe Revise and SnoopCompile interference) Or is my question okay?

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## [JuMP: optimizing in loop with an updated parameter does not work as I expect from experience with AMPL/GAMS behavior](https://discourse.julialang.org/t/jump-optimizing-in-loop-with-an-updated-parameter-does-not-work-as-i-expect-from-experience-with-ampl-gams-behavior/55245)

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**Author:** [@jovansam](https://discourse.julialang.org/u/jovansam)\
**Replies:** 2\
**Last updated:** [February 14, 2021, 11:52am UTC](https://discourse.julialang.org/t/jump-optimizing-in-loop-with-an-updated-parameter-does-not-work-as-i-expect-from-experience-with-ampl-gams-behavior/55245 "2021-02-14T11:52:43Z")

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Hi, When I update a parameter of a predefined model, JuMP does not seem to update the parameter, at least when I call to optimize!. My solution for now is to put the whole model definition in a function as in the first…

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## [Recommended way to cache results of expensive functions?](https://discourse.julialang.org/t/recommended-way-to-cache-results-of-expensive-functions/55239)

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**Author:** [@Shuhua](https://discourse.julialang.org/u/Shuhua)\
**Replies:** 6\
**Last updated:** [February 14, 2021, 9:52am UTC](https://discourse.julialang.org/t/recommended-way-to-cache-results-of-expensive-functions/55239 "2021-02-14T09:52:59Z")

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Suppose that I have a function f: Int --\> Float64 that conducts some expensive computation, but the integer inputs into f typically have only a very small number of possible values. I thus want to cache the results for s…

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## [Flux train multiple models at the same time](https://discourse.julialang.org/t/flux-train-multiple-models-at-the-same-time/55154)

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**Author:** [@anon74562486](https://discourse.julialang.org/u/anon74562486)\
**Replies:** 1\
**Last updated:** [February 14, 2021, 9:47am UTC](https://discourse.julialang.org/t/flux-train-multiple-models-at-the-same-time/55154 "2021-02-14T09:47:48Z")

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What is the best way to train multiple NN models on the same data at the same time? Thank you

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## [VegaLite.jl Grouped Bar Chart with Labels](https://discourse.julialang.org/t/vegalite-jl-grouped-bar-chart-with-labels/55196)

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**Author:** [@sjvrensburg](https://discourse.julialang.org/u/sjvrensburg)\
**Replies:** 2\
**Last updated:** [February 14, 2021, 8:18am UTC](https://discourse.julialang.org/t/vegalite-jl-grouped-bar-chart-with-labels/55196 "2021-02-14T08:18:58Z")

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I am having some issues trying to create a grouped bar chart with labels using VegaLite.jl. From this answer on Discoure, it looks like I should be able to just “sum” two plots. However, the following doesn’t work: usi…

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## [Swift for Tensorflow rationale](https://discourse.julialang.org/t/swift-for-tensorflow-rationale/10563)

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**Author:** [@datnamer](https://discourse.julialang.org/u/datnamer)\
**Replies:** 30\
**Last updated:** [February 14, 2021, 5:20am UTC](https://discourse.julialang.org/t/swift-for-tensorflow-rationale/10563 "2021-02-14T05:20:18Z")

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https://github.com/tensorflow/swift/blob/master/docs/WhySwiftForTensorFlow.md This is interesting and is reminiscent of Julia’s approach in flux. What seems divergent is the lack of multiple dispatch (+1 for Julia) and…

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