# Latest

**URL:** https://discourse.julialang.org/latest.md?page=789

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

**Page:** 790

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## [Recommended optimizer in OptimizationBBO](https://discourse.julialang.org/t/recommended-optimizer-in-optimizationbbo/94188)

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**Author:** [@magnumopus94](https://discourse.julialang.org/u/magnumopus94)\
**Replies:** 1\
**Last updated:** [February 7, 2023, 11:53am UTC](https://discourse.julialang.org/t/recommended-optimizer-in-optimizationbbo/94188 "2023-02-07T11:53:51Z")

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Hello! I’ve been using the OptimizationBBO.jl recently. In the GitHub page, it is stated that The recommended optimizer is BBO\_adaptive\_de\_rand\_1\_bin\_radiuslimited() May I know why this is the case? On what basis i…

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## [VSCode: minimizing button disappears?](https://discourse.julialang.org/t/vscode-minimizing-button-disappears/94197)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 0\
**Last updated:** [February 7, 2023, 11:49am UTC](https://discourse.julialang.org/t/vscode-minimizing-button-disappears/94197 "2023-02-07T11:49:18Z")

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I’m using VSCode. Sometimes, the expansion/minimization buttons in the upper right corner disappear: and I don’t know how to get out of VSCode… the only way I have found is to kill the VSCode app using the task list (…

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## [MTK: interpolation of observed variables?](https://discourse.julialang.org/t/mtk-interpolation-of-observed-variables/94193)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 1\
**Last updated:** [February 7, 2023, 11:01am UTC](https://discourse.julialang.org/t/mtk-interpolation-of-observed-variables/94193 "2023-02-07T11:01:55Z")

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Suppose I do a simulation of a model using ModelingToolkit.jl, where x is the state, y is an observed variable, and the solution object is sol. Then sol\[x\] sol\[y\] give vectors of the solution of x and y at the time poi…

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## [Grouped Data Frames](https://discourse.julialang.org/t/grouped-data-frames/94116)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 8\
**Last updated:** [February 7, 2023, 8:59am UTC](https://discourse.julialang.org/t/grouped-data-frames/94116 "2023-02-07T08:59:01Z")

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I find querying a JuliaDB IndexedTable is 20% faster than a DataFrame. But selecting a group from a GroupedDataFrame (GDF) is 200 times faster. So I’d like to work more with GDFs. I notice New columns in the und…

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## [ImplicitEquations Plot Return Empty Plot](https://discourse.julialang.org/t/implicitequations-plot-return-empty-plot/94117)

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**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 8\
**Last updated:** [February 7, 2023, 4:38am UTC](https://discourse.julialang.org/t/implicitequations-plot-return-empty-plot/94117 "2023-02-07T04:38:23Z")

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Hi all, there is a problem with plotting using ImplicitEquations: using Plots, ImplicitEquations, LaTeXStrings gr() f(x,y) = y^2 - 3y - 4 - x g(x,y) = x+y plot(f == 0,-5,5, xtick=-7:1:5, xlims=(-7,5), ylims=(-5,5), …

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## [Constrain 2D array variable to contain a value \`x\` number of times](https://discourse.julialang.org/t/constrain-2d-array-variable-to-contain-a-value-x-number-of-times/94180)

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**Author:** [@dash102](https://discourse.julialang.org/u/dash102)\
**Replies:** 3\
**Last updated:** [February 7, 2023, 4:20am UTC](https://discourse.julialang.org/t/constrain-2d-array-variable-to-contain-a-value-x-number-of-times/94180 "2023-02-07T04:20:31Z")

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I am trying to solve for a 2D array x of dimension 4x2 that satisfy the following: x contains integers between 0 and 5 (inclusive) For each column col of x: 1 \<= col\[i\] - col\[i-2\] \<= 2 for i = 3, 4, 7, 8 col\[i\] % …

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## [Named objects in .obj files](https://discourse.julialang.org/t/named-objects-in-obj-files/94185)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 0\
**Last updated:** [February 7, 2023, 3:56am UTC](https://discourse.julialang.org/t/named-objects-in-obj-files/94185 "2023-02-07T03:56:26Z")

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I have .obj format files exported from Blender, which include object names (o keyword). I’d like to retain the association between these object names and the geometry they refer to. As far as I can tell this isn’t curren…

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## [\[Blog\] Map matching](https://discourse.julialang.org/t/blog-map-matching/94184)

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**Author:** [@Wikunia](https://discourse.julialang.org/u/Wikunia)\
**Replies:** 0\
**Last updated:** [February 7, 2023, 3:56am UTC](https://discourse.julialang.org/t/blog-map-matching/94184 "2023-02-07T03:56:15Z")

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Hey everyone, I think some of you might be interested in map matching, the problem of mapping noisy gps tracks to a map. Just wrote a blog post about one algorithm of how this can be achieved which was relatively straig…

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## [Vim Bindings on the horizon?](https://discourse.julialang.org/t/vim-bindings-on-the-horizon/86801)

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**Author:** [@TS-CUBED](https://discourse.julialang.org/u/TS-CUBED)\
**Replies:** 10\
**Last updated:** [February 7, 2023, 2:57am UTC](https://discourse.julialang.org/t/vim-bindings-on-the-horizon/86801 "2023-02-07T02:57:33Z")

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I use either Emacs in Evil mode or the neovim plugin in VSCode, and my shell also uses VIM mode. So the only command line that does not follow that paradigm is Julia. I found a few discussions on github re VIM bindings…

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## [Unable to build PyCall and RCall](https://discourse.julialang.org/t/unable-to-build-pycall-and-rcall/92439)

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**Author:** [@probit2011](https://discourse.julialang.org/u/probit2011)\
**Replies:** 22\
**Last updated:** [February 7, 2023, 2:16am UTC](https://discourse.julialang.org/t/unable-to-build-pycall-and-rcall/92439 "2023-02-07T02:16:50Z")

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Hi, I have been trying to use the Data Science tutorials in Julia Academy. However, when comes the time to instantiate the missing Julia packages from the first Jupyter notebook, the installation fails either because Py…

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## [Julia/Flux creating a model correctly - using Chain Embedding layer reshaping & Dense layers](https://discourse.julialang.org/t/julia-flux-creating-a-model-correctly-using-chain-embedding-layer-reshaping-dense-layers/94089)

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**Author:** [@roeya](https://discourse.julialang.org/u/roeya)\
**Replies:** 3\
**Last updated:** [February 7, 2023, 1:05am UTC](https://discourse.julialang.org/t/julia-flux-creating-a-model-correctly-using-chain-embedding-layer-reshaping-dense-layers/94089 "2023-02-07T01:05:52Z")

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I am trying to follow an old article about word embedding in Julia language with Flux: Julia Word Embedding Layer in Flux - Self Trained - Getting to Know Julia As it is an old outdated article I managed to handle the e…

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## [How to draw survival analysis curve in julia](https://discourse.julialang.org/t/how-to-draw-survival-analysis-curve-in-julia/94171)

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**Author:** [@Nobel\_Chowdary](https://discourse.julialang.org/u/Nobel_Chowdary)\
**Replies:** 3\
**Last updated:** [February 7, 2023, 12:36am UTC](https://discourse.julialang.org/t/how-to-draw-survival-analysis-curve-in-julia/94171 "2023-02-07T00:36:31Z")

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Visualization curves in julia

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## [Unable to install IJulia package](https://discourse.julialang.org/t/unable-to-install-ijulia-package/94163)

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**Author:** [@snowzone5](https://discourse.julialang.org/u/snowzone5)\
**Replies:** 14\
**Last updated:** [February 6, 2023, 10:01pm UTC](https://discourse.julialang.org/t/unable-to-install-ijulia-package/94163 "2023-02-06T22:01:25Z")

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Apologies if this is the wrong area. I was directed here from the IJulia Github page (I got it wrong there also) I am unable install IJulia on Windows 10. Please let me know if I should continue or this topic should m…

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## [Statistics.mean() function with a Matrix containing missing values](https://discourse.julialang.org/t/statistics-mean-function-with-a-matrix-containing-missing-values/94115)

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**Author:** [@austin-putz](https://discourse.julialang.org/u/austin-putz)\
**Replies:** 8\
**Last updated:** [February 6, 2023, 9:52pm UTC](https://discourse.julialang.org/t/statistics-mean-function-with-a-matrix-containing-missing-values/94115 "2023-02-06T21:52:34Z")

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I have a matrix with missing values and I want to calculate the column means. I’m not sure how to drop missing. using Statistics vec = \[1, missing, 2\] mean(vec) # is missing mean(skipmissing(vec) # give 1.5 that …

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## [Reading a large array from an HDF5 file](https://discourse.julialang.org/t/reading-a-large-array-from-an-hdf5-file/23983)

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**Author:** [@huchiayu0517](https://discourse.julialang.org/u/huchiayu0517)\
**Replies:** 14\
**Last updated:** [February 6, 2023, 9:37pm UTC](https://discourse.julialang.org/t/reading-a-large-array-from-an-hdf5-file/23983 "2023-02-06T21:37:14Z")

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I’m trying to read a large 3D array from an HDF5 file. If I just naively read a 3D array, I found that every time I try to access the element (e.g. in a for-loop), I see a lot of unexpected allocations and therefore the …

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## [Symbolics substitute and simplify in a polynomial](https://discourse.julialang.org/t/symbolics-substitute-and-simplify-in-a-polynomial/94160)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 4\
**Last updated:** [February 6, 2023, 8:59pm UTC](https://discourse.julialang.org/t/symbolics-substitute-and-simplify-in-a-polynomial/94160 "2023-02-06T20:59:39Z")

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This is my first time using Symbolics. I have a polynomial that I want to substitute a variable and then simplify the result as shown. julia\> dcs\_P1 = 229.50752 - 321.64369 \* r - 121.01008 \* r^2 + 53.15226 \* r^3 229.50…

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## [Default project activation via Pkg.jl or DrWatson.jl](https://discourse.julialang.org/t/default-project-activation-via-pkg-jl-or-drwatson-jl/94157)

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**Author:** [@mocalvao](https://discourse.julialang.org/u/mocalvao)\
**Replies:** 8\
**Last updated:** [February 6, 2023, 8:43pm UTC](https://discourse.julialang.org/t/default-project-activation-via-pkg-jl-or-drwatson-jl/94157 "2023-02-06T20:43:02Z")

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Right now my, I have several directories, which have Project.toml files because of 2 situations: (1) I have cloned them from Github repos, or (2) I have created them myself as DrWatson.jl “scientific” projects. In ord…

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## [CartesianIndices performance: 3D faster than 2D?](https://discourse.julialang.org/t/cartesianindices-performance-3d-faster-than-2d/94110)

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**Author:** [@lntricate](https://discourse.julialang.org/u/lntricate)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 8:16pm UTC](https://discourse.julialang.org/t/cartesianindices-performance-3d-faster-than-2d/94110 "2023-02-06T20:16:52Z")

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I have encountered a strange occurence when testing the performance of CartesianIndices: using BenchmarkTools function test(t::Tuple) for \_ ∈ CartesianIndices(t) end end @btime test((100,)) # 3.094 ns @btime test(…

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## [How to access variables and expressions faster in jump](https://discourse.julialang.org/t/how-to-access-variables-and-expressions-faster-in-jump/94123)

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**Author:** [@Betristor](https://discourse.julialang.org/u/Betristor)\
**Replies:** 4\
**Last updated:** [February 6, 2023, 7:42pm UTC](https://discourse.julialang.org/t/how-to-access-variables-and-expressions-faster-in-jump/94123 "2023-02-06T19:42:58Z")

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I established a very large model using julia with plenty of variables and expressions. Though not all of these will be meaningful for accessing, I still wrote all into results in dataframe and then saved to csv files. I’…

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## [Case study: Speeding up a logistic regression with RHS prior (Turing vs Numpyro) - any tricks I'm missing?](https://discourse.julialang.org/t/case-study-speeding-up-a-logistic-regression-with-rhs-prior-turing-vs-numpyro-any-tricks-im-missing/87681)

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**Author:** [@svilupp](https://discourse.julialang.org/u/svilupp)\
**Replies:** 38\
**Last updated:** [February 6, 2023, 7:34pm UTC](https://discourse.julialang.org/t/case-study-speeding-up-a-logistic-regression-with-rhs-prior-turing-vs-numpyro-any-tricks-im-missing/87681 "2023-02-06T19:34:06Z")

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Inspired by the recent long discussion on Slack around the performance of Turing, I’ve decided to try to beat my go-to implementation in Numpyro (and failed). I’d appreciate any tips or tricks on how to further speed up…

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## [Does anybody anywhere care about NaN payloads?](https://discourse.julialang.org/t/does-anybody-anywhere-care-about-nan-payloads/94152)

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**Author:** [@Lilith](https://discourse.julialang.org/u/Lilith)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 7:21pm UTC](https://discourse.julialang.org/t/does-anybody-anywhere-care-about-nan-payloads/94152 "2023-02-06T19:21:05Z")

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There are a bunch of different NaN values. NaN and anotherNaN = reinterpret(Float64, reinterpret(UInt64, NaN) + 1) and NaN are two examples. There is a proposal to explicitly disclaim any garuntees about which NaN you re…

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## [Filtering 2D data in Julia](https://discourse.julialang.org/t/filtering-2d-data-in-julia/94122)

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**Author:** [@marianoarnaiz](https://discourse.julialang.org/u/marianoarnaiz)\
**Replies:** 5\
**Last updated:** [February 6, 2023, 7:31pm UTC](https://discourse.julialang.org/t/filtering-2d-data-in-julia/94122 "2023-02-06T19:31:49Z")

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Hi all. Is there are packaga that I can use to filter 2D data? Things like butterworth filtering, derivatives, poly fitting, spectrum computation, etc? I know a lot of this is implemente in GMT.jl by @joa-quim but the …

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## [Google Colab compatibility broken](https://discourse.julialang.org/t/google-colab-compatibility-broken/93004)

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**Author:** [@MilesCranmer](https://discourse.julialang.org/u/MilesCranmer)\
**Replies:** 18\
**Last updated:** [February 6, 2023, 7:04pm UTC](https://discourse.julialang.org/t/google-colab-compatibility-broken/93004 "2023-02-06T19:04:45Z")

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Edit \[Jan 30, 2023\] Looks like all versions of Julia now break :frowning\_face: Main GitHub Issues: Broken inside Google Colab · Issue #48461 · JuliaLang/julia · GitHub Colab update breaks compatibility with JuliaLang …

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## [Precompile error in DifferentialEquations.jl](https://discourse.julialang.org/t/precompile-error-in-differentialequations-jl/94086)

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**Author:** [@jredondo](https://discourse.julialang.org/u/jredondo)\
**Replies:** 11\
**Last updated:** [February 6, 2023, 6:20pm UTC](https://discourse.julialang.org/t/precompile-error-in-differentialequations-jl/94086 "2023-02-06T18:20:17Z")

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Hi all! I’m completely new to Julia and I was trying to set up the example in SciML (Build and run your first simulation with Julia's SciML · Overview of Julia's SciML). However, when I try to do Pkg.add("Differenti…

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## [REPL emits columns when \`show(;allrows=true)\` is executed in Debug Console](https://discourse.julialang.org/t/repl-emits-columns-when-show-allrows-true-is-executed-in-debug-console/94154)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 0\
**Last updated:** [February 6, 2023, 6:04pm UTC](https://discourse.julialang.org/t/repl-emits-columns-when-show-allrows-true-is-executed-in-debug-console/94154 "2023-02-06T18:04:02Z")

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Steps to reproduce: debug some script in vscode where a DataFrame df is generated type show(df,allcols=true) in the Debug Console like show(df,allcols=true) nothing check the output in Terminal and see something lik…

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## [Confusing dispatch problem](https://discourse.julialang.org/t/confusing-dispatch-problem/93760)

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**Author:** [@Euhan](https://discourse.julialang.org/u/Euhan)\
**Replies:** 9\
**Last updated:** [February 6, 2023, 6:01pm UTC](https://discourse.julialang.org/t/confusing-dispatch-problem/93760 "2023-02-06T18:01:37Z")

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I get an unexpected MethodError when running a piece of code. The relevant bit of the error output is: ERROR: LoadError: MethodError: no method matching make\_my\_model(::Int64, ::Int64, ::Int64; no\_inchannels=3) Closest …

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## [JuliaUserGroupMunich: Fall-in-love-with-Julia 101 on Concurrent Programming](https://discourse.julialang.org/t/juliausergroupmunich-fall-in-love-with-julia-101-on-concurrent-programming/93623)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 1\
**Last updated:** [February 6, 2023, 5:24pm UTC](https://discourse.julialang.org/t/juliausergroupmunich-fall-in-love-with-julia-101-on-concurrent-programming/93623 "2023-02-06T17:24:24Z")

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Join us on :spiral\_calendar: Monday 6. February 2023 :clock630: 18:30 CET organized via meetup Fall in love with Julia: Concurrent programming 101 ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Concurrent programming encompasses asyn…

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## [Models with persistent memory usage](https://discourse.julialang.org/t/models-with-persistent-memory-usage/93215)

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**Author:** [@pfarndt](https://discourse.julialang.org/u/pfarndt)\
**Replies:** 3\
**Last updated:** [February 6, 2023, 5:12pm UTC](https://discourse.julialang.org/t/models-with-persistent-memory-usage/93215 "2023-02-06T17:12:16Z")

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I am using Turing a lot but now I have a model which would keep some persistent memory to be computational efficient. A minimal example would be: using Turing, Optim, ForwardDiff mutable struct Acomputer{T \<: Number} …

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## [Using SymPy.jl with two variables](https://discourse.julialang.org/t/using-sympy-jl-with-two-variables/94148)

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**Author:** [@Firstname\_Lastname](https://discourse.julialang.org/u/Firstname_Lastname)\
**Replies:** 1\
**Last updated:** [February 6, 2023, 4:45pm UTC](https://discourse.julialang.org/t/using-sympy-jl-with-two-variables/94148 "2023-02-06T16:45:09Z")

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I ran the following code using SymPy @syms x y f(x,y) = cos(x - y) df(x,y) = sympy.diff(f(x,y),x) df(0,pi/2) # it is supposed to be 1, but an error occurs Please help me to resolve this problem. Thank you.

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## [Converting \`\`\`ComplexF64\`\`\` array to \`\`\`Float64\`\`\` array in-place?](https://discourse.julialang.org/t/converting-complexf64-array-to-float64-array-in-place/94007)

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**Author:** [@bremez](https://discourse.julialang.org/u/bremez)\
**Replies:** 5\
**Last updated:** [February 6, 2023, 4:17pm UTC](https://discourse.julialang.org/t/converting-complexf64-array-to-float64-array-in-place/94007 "2023-02-06T16:17:04Z")

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I have a calculation that manipulates and produces a ComplexF64 array (whose dimension varies by usage in different places in my codebase). I know the final result must be an array of real numbers, or suppose I only care…

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