# Latest

**URL:** https://discourse.julialang.org/latest.md?page=670

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

**Page:** 671

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## [How to re-define a variable completely?](https://discourse.julialang.org/t/how-to-re-define-a-variable-completely/100322)

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**Author:** [@Lukas\_Hebing](https://discourse.julialang.org/u/Lukas_Hebing)\
**Replies:** 35\
**Last updated:** [June 15, 2023, 9:15am UTC](https://discourse.julialang.org/t/how-to-re-define-a-variable-completely/100322 "2023-06-15T09:15:02Z")

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When I define a wrong (or unuseful) type to a variable declaration I get an error as expected: my\_var::Int64 = 3.2 However, when I continue to work in the REPL, it is impossible to re-define the variable: my\_var = 3.2…

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## [Compiled program from PackageCompiler is much slower than REPL?](https://discourse.julialang.org/t/compiled-program-from-packagecompiler-is-much-slower-than-repl/42640)

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**Author:** [@linlinlin](https://discourse.julialang.org/u/linlinlin)\
**Replies:** 3\
**Last updated:** [June 15, 2023, 8:31am UTC](https://discourse.julialang.org/t/compiled-program-from-packagecompiler-is-much-slower-than-repl/42640 "2023-06-15T08:31:43Z")

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Hi, Community members. Recently, I want to compile my code to an executable program, but I have the speed problem. I develop my program based on a package JuliaGrid. In this package, it calls many other packages, like…

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## [Optimizing code with array assignments](https://discourse.julialang.org/t/optimizing-code-with-array-assignments/99857)

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**Author:** [@fergu](https://discourse.julialang.org/u/fergu)\
**Replies:** 12\
**Last updated:** [June 15, 2023, 7:48am UTC](https://discourse.julialang.org/t/optimizing-code-with-array-assignments/99857 "2023-06-15T07:48:49Z")

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TL;DR I have some performance critical code that I am trying to optimize as it will otherwise take unacceptably long to run. Testing seems to suggest that the main culprit is assignments to arrays rather than the computa…

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## [m/Julia - an alternative to r/Julia](https://discourse.julialang.org/t/m-julia-an-alternative-to-r-julia/100377)

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**Author:** [@AdamWysokinski](https://discourse.julialang.org/u/AdamWysokinski)\
**Replies:** 0\
**Last updated:** [June 15, 2023, 7:15am UTC](https://discourse.julialang.org/t/m-julia-an-alternative-to-r-julia/100377 "2023-06-15T07:15:15Z")

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Hi all, Considering the situation of Reddit and the blackout of the Julia subreddit, I’ve created the kbin Julia magazine. kbin is a federated alternative to Reddit, similar to lemmy or beehav. https://kbin.social/m/Ju…

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## [JuliaUserGroupMunich: Intro to JuliaClimate + JuliaOcean by Gael Forget](https://discourse.julialang.org/t/juliausergroupmunich-intro-to-juliaclimate-juliaocean-by-gael-forget/99757)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 4\
**Last updated:** [June 15, 2023, 6:59am UTC](https://discourse.julialang.org/t/juliausergroupmunich-intro-to-juliaclimate-juliaocean-by-gael-forget/99757 "2023-06-15T06:59:49Z")

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Join us online :spiral\_calendar: Monday 12. June 2023 :clock630: 18:30 CEST organized via meetup special extra session JuliaClimate + JuliaOcean by Gael Forget ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ I am glad to welcome Gael…

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## [(The future of) HTML Parsing in Julia](https://discourse.julialang.org/t/the-future-of-html-parsing-in-julia/100337)

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**Author:** [@algunion](https://discourse.julialang.org/u/algunion)\
**Replies:** 3\
**Last updated:** [June 15, 2023, 3:41am UTC](https://discourse.julialang.org/t/the-future-of-html-parsing-in-julia/100337 "2023-06-15T03:41:07Z")

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Hello world, I am writing this here hoping to find someone more knowledgeable than me on the Julia ecosystem around web / HTML. My context in a few words: I am working on a larger project that involves lots of HTML man…

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## [Array issue with optimzing a function with quadgk](https://discourse.julialang.org/t/array-issue-with-optimzing-a-function-with-quadgk/41837)

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**Author:** [@shoshievass](https://discourse.julialang.org/u/shoshievass)\
**Replies:** 12\
**Last updated:** [June 15, 2023, 3:07am UTC](https://discourse.julialang.org/t/array-issue-with-optimzing-a-function-with-quadgk/41837 "2023-06-15T03:07:44Z")

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I’m trying to minimize a function that involves an integral, the integrand of which is one of the optimizing parameters. I can compute the function and get the gradient with Zygote, but I’m getting an odd conversion erro…

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## [First run of ModelingToolkit + DE solve() is extremely slow](https://discourse.julialang.org/t/first-run-of-modelingtoolkit-de-solve-is-extremely-slow/100350)

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**Author:** [@70Gage70](https://discourse.julialang.org/u/70Gage70)\
**Replies:** 6\
**Last updated:** [June 15, 2023, 3:05am UTC](https://discourse.julialang.org/t/first-run-of-modelingtoolkit-de-solve-is-extremely-slow/100350 "2023-06-15T03:05:08Z")

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The code in question takes some interpolants of wind/water vector fields (in the MWE I have replaced these with interpolations of a constant), then constructs a Clump, which is a system of two first order ODEs for the x,…

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## [Lowpass with Hann window](https://discourse.julialang.org/t/lowpass-with-hann-window/100227)

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**Author:** [@ryofurue](https://discourse.julialang.org/u/ryofurue)\
**Replies:** 21\
**Last updated:** [June 15, 2023, 2:42am UTC](https://discourse.julialang.org/t/lowpass-with-hann-window/100227 "2023-06-15T02:42:38Z")

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I’m not familiar with “signal processing” business. I’m from a different discipline. That means I’m not familiar with the jargon in Filters - filter design and filtering · DSP.jl . I need to apply simple lowpass filters…

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## [Return the ith iteration value of a variable in a for loop when the broken from the outside using @async](https://discourse.julialang.org/t/return-the-ith-iteration-value-of-a-variable-in-a-for-loop-when-the-broken-from-the-outside-using-async/100301)

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**Author:** [@phantom](https://discourse.julialang.org/u/phantom)\
**Replies:** 7\
**Last updated:** [June 15, 2023, 1:10am UTC](https://discourse.julialang.org/t/return-the-ith-iteration-value-of-a-variable-in-a-for-loop-when-the-broken-from-the-outside-using-async/100301 "2023-06-15T01:10:13Z")

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Hi sorry if I am being dense here. I would like the option of terminating a for loop from outside the function. If the loop is completed it should return the value of the variable being modified. However if the loop …

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## [Installing Julia from within R/Python](https://discourse.julialang.org/t/installing-julia-from-within-r-python/100363)

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**Author:** [@biona001](https://discourse.julialang.org/u/biona001)\
**Replies:** 1\
**Last updated:** [June 15, 2023, 12:41am UTC](https://discourse.julialang.org/t/installing-julia-from-within-r-python/100363 "2023-06-15T00:41:56Z")

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Hi community, I’m trying to write a Python/R wrapper for my Julia package. Initially I was following DifferentialEquations.jl’s example via diffeqr and diffeqpy, but I’m encountering major obstacles because: I want R/P…

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## [Simulating a system of ODES in Julia with ODEProblem](https://discourse.julialang.org/t/simulating-a-system-of-odes-in-julia-with-odeproblem/100285)

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**Author:** [@KZ-Spectra](https://discourse.julialang.org/u/KZ-Spectra)\
**Replies:** 4\
**Last updated:** [June 15, 2023, 12:12am UTC](https://discourse.julialang.org/t/simulating-a-system-of-odes-in-julia-with-odeproblem/100285 "2023-06-15T00:12:17Z")

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I am using ODEProblem to solve a system of ODEs: https://mathb.in/75542 such that u\_1 = u\_N = 0. To do this, I wrote the code shown at the end of the post to generate this solution: https://i.imgur.com/wQC8aTj.png I exp…

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## [Installation of Julia on SCO OpenServer](https://discourse.julialang.org/t/installation-of-julia-on-sco-openserver/84239)

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**Author:** [@Jim](https://discourse.julialang.org/u/Jim)\
**Replies:** 58\
**Last updated:** [June 14, 2023, 11:42pm UTC](https://discourse.julialang.org/t/installation-of-julia-on-sco-openserver/84239 "2023-06-14T23:42:08Z")

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I downloaded the Unix binary, gunzip, tar xvf, and chmod to execute. No errors, it just doesn’t do anything. What did I miss?

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## [Is there a Symbolics.jl interface to Ipopt (or similar)?](https://discourse.julialang.org/t/is-there-a-symbolics-jl-interface-to-ipopt-or-similar/100149)

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**Author:** [@votroto](https://discourse.julialang.org/u/votroto)\
**Replies:** 17\
**Last updated:** [June 14, 2023, 10:49pm UTC](https://discourse.julialang.org/t/is-there-a-symbolics-jl-interface-to-ipopt-or-similar/100149 "2023-06-14T22:49:05Z")

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Hello, is there an interface to Ipopt which can accept Symbolics functions? There is NLPModelsIpopt, which accepts NLPModels. Going via ADNLPModels seems unnecessary as Symbolics can already provide all the hessians, ja…

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## [Do I need to re-dowload packages when I downgrade Julia?](https://discourse.julialang.org/t/do-i-need-to-re-dowload-packages-when-i-downgrade-julia/100356)

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**Author:** [@bertulli](https://discourse.julialang.org/u/bertulli)\
**Replies:** 3\
**Last updated:** [June 14, 2023, 10:35pm UTC](https://discourse.julialang.org/t/do-i-need-to-re-dowload-packages-when-i-downgrade-julia/100356 "2023-06-14T22:35:43Z")

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Hi all! I am having some troubles using PackageCompiler recently (whereas it worked fine with Julia 1.8 ~6 months ago), so I thought I needed to downgrade my Julia installation. I tried juliaup and worked fine, installi…

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## [Stability of Julia between versions](https://discourse.julialang.org/t/stability-of-julia-between-versions/100001)

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**Author:** [@JuliaBoomer](https://discourse.julialang.org/u/JuliaBoomer)\
**Replies:** 12\
**Last updated:** [June 14, 2023, 10:04pm UTC](https://discourse.julialang.org/t/stability-of-julia-between-versions/100001 "2023-06-14T22:04:53Z")

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Hello, I am working on an optimization tool coded in Julia in its version 1.3.1. Until a few months ago, I regularly encountered stability issues, with the tool apparently becoming obsolete after some updates. I would l…

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## [Automatic transformation of constrained distributions in Turing.jl](https://discourse.julialang.org/t/automatic-transformation-of-constrained-distributions-in-turing-jl/100369)

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**Author:** [@sandy6502](https://discourse.julialang.org/u/sandy6502)\
**Replies:** 0\
**Last updated:** [June 14, 2023, 9:53pm UTC](https://discourse.julialang.org/t/automatic-transformation-of-constrained-distributions-in-turing-jl/100369 "2023-06-14T21:53:11Z")

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This is a question about automatic transformation of constrained distributions. The docs on compiler design say “Random variables whose distributions have a constrained support are transformed using a bijector from Bije…

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## [Find whether a Julia script has the output redirected to the screen or a pipe?](https://discourse.julialang.org/t/find-whether-a-julia-script-has-the-output-redirected-to-the-screen-or-a-pipe/100365)

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**Author:** [@RaulDurand](https://discourse.julialang.org/u/RaulDurand)\
**Replies:** 2\
**Last updated:** [June 14, 2023, 9:48pm UTC](https://discourse.julialang.org/t/find-whether-a-julia-script-has-the-output-redirected-to-the-screen-or-a-pipe/100365 "2023-06-14T21:48:31Z")

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How do I find whether a Julia script running in the terminal has the output (stdout) redirected to the screen or a pipe? $ ./julia\_script # outputs to the terminal $ ./julia\_script | command # pipes the output

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## [Optimizing an objective function with a vector containing constants, variables, and functions of variables using JuMP](https://discourse.julialang.org/t/optimizing-an-objective-function-with-a-vector-containing-constants-variables-and-functions-of-variables-using-jump/100366)

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**Author:** [@Hyrum\_Hansen](https://discourse.julialang.org/u/Hyrum_Hansen)\
**Replies:** 3\
**Last updated:** [June 14, 2023, 9:42pm UTC](https://discourse.julialang.org/t/optimizing-an-objective-function-with-a-vector-containing-constants-variables-and-functions-of-variables-using-jump/100366 "2023-06-14T21:42:24Z")

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I’m working on a set of optimization problems where I need to maximize something that looks a lot like a quadratic form but isn’t. The following example is one such problem: Maximize f^TAf where f = \[1, x, x^2\] and A i…

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## [Plots.jl plot in Tk.jl canvas](https://discourse.julialang.org/t/plots-jl-plot-in-tk-jl-canvas/100362)

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**Author:** [@AdamWysokinski](https://discourse.julialang.org/u/AdamWysokinski)\
**Replies:** 0\
**Last updated:** [June 14, 2023, 8:11pm UTC](https://discourse.julialang.org/t/plots-jl-plot-in-tk-jl-canvas/100362 "2023-06-14T20:11:00Z")

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Hi, Is it possible to draw Plots.jl plot in the Tk.jl canvas? If so, could you please send me an example code? Thanks! Adam

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## [Parallel Optimization with Surrogates.jl](https://discourse.julialang.org/t/parallel-optimization-with-surrogates-jl/93586)

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**Author:** [@Dreycen\_Foiles](https://discourse.julialang.org/u/Dreycen_Foiles)\
**Replies:** 6\
**Last updated:** [June 14, 2023, 8:08pm UTC](https://discourse.julialang.org/t/parallel-optimization-with-surrogates-jl/93586 "2023-06-14T20:08:36Z")

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I’m thinking about using Surrogates.jl to optimize a process in my lab using the Gaussian processes for Bayesian optimization. It’s easier for me to run multiple experiments at once, so I was wondering if it was possible…

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## [Sorted Attributes in XML.jl?](https://discourse.julialang.org/t/sorted-attributes-in-xml-jl/100168)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 8\
**Last updated:** [June 14, 2023, 7:59pm UTC](https://discourse.julialang.org/t/sorted-attributes-in-xml-jl/100168 "2023-06-14T19:59:54Z")

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Hello! I saw the newly released XML.jl and I am really excited about it. I wonder if it is possible to “enforce” attribute ordering? I have a case in which I want to produce and XML which is meant to be both human read…

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## [Element by element wise multiplication and addition/subtraction of 3d matrices](https://discourse.julialang.org/t/element-by-element-wise-multiplication-and-addition-subtraction-of-3d-matrices/100178)

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**Author:** [@smac](https://discourse.julialang.org/u/smac)\
**Replies:** 19\
**Last updated:** [June 14, 2023, 7:28pm UTC](https://discourse.julialang.org/t/element-by-element-wise-multiplication-and-addition-subtraction-of-3d-matrices/100178 "2023-06-14T19:28:40Z")

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Hello, I’m new to Julia, with prior experience of fortran and Matlab. I have a 3d magnetohydrodynamics code which does all the time stepping + spatial derivatives using 3d matrices, with the operations carried out using…

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## [How to select rows of differently sized matrices based on an approximate value within a column of each matrix](https://discourse.julialang.org/t/how-to-select-rows-of-differently-sized-matrices-based-on-an-approximate-value-within-a-column-of-each-matrix/100343)

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**Author:** [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Replies:** 6\
**Last updated:** [June 14, 2023, 7:27pm UTC](https://discourse.julialang.org/t/how-to-select-rows-of-differently-sized-matrices-based-on-an-approximate-value-within-a-column-of-each-matrix/100343 "2023-06-14T19:27:35Z")

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A bit hard to explain in the title. I have saved the output of hundreds of runs from a solver (from DifferentialEquations). The overall run time is the same between the runs (start and end time are the same), but the sol…

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## [Makie: Unable to position Legend](https://discourse.julialang.org/t/makie-unable-to-position-legend/99769)

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**Author:** [@VictorSeven](https://discourse.julialang.org/u/VictorSeven)\
**Replies:** 3\
**Last updated:** [June 14, 2023, 7:21pm UTC](https://discourse.julialang.org/t/makie-unable-to-position-legend/99769 "2023-06-14T19:21:20Z")

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Hi all, I am trying to get a figure done with Makie. I am having trouble setting the position of my legend so it does not intersect with the lines. I have checked Legend · Makie , but that only says that I can use combi…

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## [Comparing the subsetted elements of a 3d matrix](https://discourse.julialang.org/t/comparing-the-subsetted-elements-of-a-3d-matrix/100355)

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**Author:** [@smac](https://discourse.julialang.org/u/smac)\
**Replies:** 2\
**Last updated:** [June 14, 2023, 6:59pm UTC](https://discourse.julialang.org/t/comparing-the-subsetted-elements-of-a-3d-matrix/100355 "2023-06-14T18:59:59Z")

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Hello, I originally posted this earlier today as part of an earlier question submitted to the community, but I think maybe it should be a “new” post. So I am cutting and pasting the most important parts of the message he…

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## [Disable a particular simplification when using ModelingToolkit.jl](https://discourse.julialang.org/t/disable-a-particular-simplification-when-using-modelingtoolkit-jl/100344)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 6\
**Last updated:** [June 14, 2023, 6:36pm UTC](https://discourse.julialang.org/t/disable-a-particular-simplification-when-using-modelingtoolkit-jl/100344 "2023-06-14T18:36:36Z")

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I have a particular example, written minimally as: using ModelingToolkit @variables t # independent variable (time) dDt = Differential(t) # define an operator for the differentiation w.r.t. time const norma…

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## [JuliaCon 2023 Updates: Schedule, Housing and Social Events!](https://discourse.julialang.org/t/juliacon-2023-updates-schedule-housing-and-social-events/100349)

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**Author:** [@ranjan](https://discourse.julialang.org/u/ranjan)\
**Replies:** 0\
**Last updated:** [June 14, 2023, 5:31pm UTC](https://discourse.julialang.org/t/juliacon-2023-updates-schedule-housing-and-social-events/100349 "2023-06-14T17:31:47Z")

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Hello, This is your friendly neighborhood JuliaCon organizer. Just wanted to bring some updates to you: We released a new version of the schedule: https://pretalx.com/juliacon2023/schedule/. It has a bunch of changes…

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## [How to reset the elements of a 3x3 matrix without any memory allocation?](https://discourse.julialang.org/t/how-to-reset-the-elements-of-a-3x3-matrix-without-any-memory-allocation/100257)

<div class="topic-metadata">

**Author:** [@Ethan\_Diao](https://discourse.julialang.org/u/Ethan_Diao)\
**Replies:** 18\
**Last updated:** [June 14, 2023, 5:17pm UTC](https://discourse.julialang.org/t/how-to-reset-the-elements-of-a-3x3-matrix-without-any-memory-allocation/100257 "2023-06-14T17:17:54Z")

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I want to set the element value of a 3x3 matrix to newly calculated values in a small function that gets called a lot of times. I’ve tried broadcasted assignment to a temporary 3x3 matrix, but that seems to introduce a f…

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## [Bring Julia code to embedded hardware (ARM)](https://discourse.julialang.org/t/bring-julia-code-to-embedded-hardware-arm/19979)

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**Author:** [@asprionj](https://discourse.julialang.org/u/asprionj)\
**Replies:** 92\
**Last updated:** [June 14, 2023, 4:38pm UTC](https://discourse.julialang.org/t/bring-julia-code-to-embedded-hardware-arm/19979 "2023-06-14T16:38:31Z")

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I’m using Julia as framework for simulation of physical systems and prototyping for signal-processing and control algorithms. Of course, the latter should eventually run on some embedded hardware (in my case, it will be …

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