# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1176

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

**Page:** 1177

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## [Calling Pluto via web api's isn't that the ideal non production sandpit?](https://discourse.julialang.org/t/calling-pluto-via-web-apis-isnt-that-the-ideal-non-production-sandpit/73210)

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**Author:** [@anon69491625](https://discourse.julialang.org/u/anon69491625)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 4:03pm UTC](https://discourse.julialang.org/t/calling-pluto-via-web-apis-isnt-that-the-ideal-non-production-sandpit/73210 "2021-12-16T16:03:25Z")

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About to start coding in julia and making sure my dev foundation makes me a happy bunny. I don’t want to use vscode et al as an ide, they are too noisy for me. I wonder if I can sandbox code in a Pluto NB and call the c…

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## [Checking the symmetry of a matrix](https://discourse.julialang.org/t/checking-the-symmetry-of-a-matrix/73206)

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**Author:** [@Rajesh\_Nakka](https://discourse.julialang.org/u/Rajesh_Nakka)\
**Replies:** 5\
**Last updated:** [December 16, 2021, 3:56pm UTC](https://discourse.julialang.org/t/checking-the-symmetry-of-a-matrix/73206 "2021-12-16T15:56:09Z")

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I am trying to check the symmetry of a matrix which I was expecting to be symmetric. I have printed A^T -A to check the deviation from symmetry. It is actually populated with very small numbers, as shown below. 0.0 …

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## [Is there a lazy version of graph?](https://discourse.julialang.org/t/is-there-a-lazy-version-of-graph/73119)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 7\
**Last updated:** [December 16, 2021, 3:55pm UTC](https://discourse.julialang.org/t/is-there-a-lazy-version-of-graph/73119 "2021-12-16T15:55:06Z")

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I came across an interesting problem recently that can be solved with the shortest path algorithms from Graphs.jl. The only problem is that it takes a “long time” (julia scale :slight\_smile: ) to build the graph because …

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## [Symbolics.jl: Simplify divisions assuming a variable is not zero](https://discourse.julialang.org/t/symbolics-jl-simplify-divisions-assuming-a-variable-is-not-zero/68406)

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**Author:** [@ranocha](https://discourse.julialang.org/u/ranocha)\
**Replies:** 2\
**Last updated:** [September 19, 2021, 12:09pm UTC](https://discourse.julialang.org/t/symbolics-jl-simplify-divisions-assuming-a-variable-is-not-zero/68406 "2021-09-19T12:09:54Z")

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How can I use Symbolics.jl to simplify divisions assuming a variable is not zero? For example, I would like to get 1 from julia\> using Symbolics julia\> @variables x 1-element Vector{Num}: x julia\> simplify(x / x) # …

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## [Sincos slightly slower than sin and cos](https://discourse.julialang.org/t/sincos-slightly-slower-than-sin-and-cos/73207)

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**Author:** [@markmbaum](https://discourse.julialang.org/u/markmbaum)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 3:14pm UTC](https://discourse.julialang.org/t/sincos-slightly-slower-than-sin-and-cos/73207 "2021-12-16T15:14:32Z")

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I have some pieces of code that require lots of sin and cos evaluations and I’m looking for ways to accelerate. I noticed that the sincos function seems slightly slower than calling sin and cos alone. julia\> using Bench…

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## [Function \`apply\`, that calls a function with a tuple of arguments?](https://discourse.julialang.org/t/function-apply-that-calls-a-function-with-a-tuple-of-arguments/72898)

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**Author:** [@bert](https://discourse.julialang.org/u/bert)\
**Replies:** 13\
**Last updated:** [December 12, 2021, 4:03am UTC](https://discourse.julialang.org/t/function-apply-that-calls-a-function-with-a-tuple-of-arguments/72898 "2021-12-12T04:03:33Z")

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Julia makes it very easy to map/broadcast a function over a collection of argument tuples. But I don’t think it makes it so easy to map/broadcast multiple functions over one tuple of arguments. We can do this: f.((1, 2…

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## [PyCall error, number of arguments in a ccall function](https://discourse.julialang.org/t/pycall-error-number-of-arguments-in-a-ccall-function/73143)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 2:18pm UTC](https://discourse.julialang.org/t/pycall-error-number-of-arguments-in-a-ccall-function/73143 "2021-12-16T14:18:56Z")

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I have a script that calls functions from the Python OpenCV module via PyCall. Everything was working fine the other day, not sure what changed in my configuration. I use PyCall with my system python at /usr/bin/python3.…

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## [Mutating array not supported](https://discourse.julialang.org/t/mutating-array-not-supported/73178)

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**Author:** [@gforchini](https://discourse.julialang.org/u/gforchini)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 12:52pm UTC](https://discourse.julialang.org/t/mutating-array-not-supported/73178 "2021-12-16T12:52:25Z")

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I am trying to make a gan in which the generator is generated in a fully parametric way using Flux, StatsBase the discriminator is a very simple neural network for simplicity function Discriminator() return Chain…

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## [Problem with Zygote gradient](https://discourse.julialang.org/t/problem-with-zygote-gradient/72449)

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**Author:** [@mottelet](https://discourse.julialang.org/u/mottelet)\
**Replies:** 10\
**Last updated:** [December 16, 2021, 12:41pm UTC](https://discourse.julialang.org/t/problem-with-zygote-gradient/72449 "2021-12-16T12:41:57Z")

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Hi all, I work with Julia 1.7. Zygote fails to generate/compute my AD gradient in the code below (the loss function itself works well). The message is the following : ERROR: LoadError: Need an adjoint for constructor D…

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## [Same response of NODE for different parameter vectors despite nn results are different](https://discourse.julialang.org/t/same-response-of-node-for-different-parameter-vectors-despite-nn-results-are-different/69608)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 1\
**Last updated:** [December 16, 2021, 12:40pm UTC](https://discourse.julialang.org/t/same-response-of-node-for-different-parameter-vectors-despite-nn-results-are-different/69608 "2021-12-16T12:40:25Z")

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Hi, I’m getting sometimes the same predictions result of my node model for different parameter vectors despite that the neural network return different outputs for the different parameter vectors. Can somebody tell me w…

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## [Stochastic diff eq driven by 1/f noise](https://discourse.julialang.org/t/stochastic-diff-eq-driven-by-1-f-noise/72669)

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**Author:** [@arnelg](https://discourse.julialang.org/u/arnelg)\
**Replies:** 5\
**Last updated:** [December 16, 2021, 12:19pm UTC](https://discourse.julialang.org/t/stochastic-diff-eq-driven-by-1-f-noise/72669 "2021-12-16T12:19:27Z")

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Hi all, I’m new to DifferentialEquations.jl and looking for tips on how model a stochastic process driven by noise that has a 1/f spectrum. Admittedly, this question might be not only on how to use the Julia stochastic d…

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## [Support for MDF format](https://discourse.julialang.org/t/support-for-mdf-format/7162)

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**Author:** [@jayveesea](https://discourse.julialang.org/u/jayveesea)\
**Replies:** 13\
**Last updated:** [December 16, 2021, 12:18pm UTC](https://discourse.julialang.org/t/support-for-mdf-format/7162 "2021-12-16T12:18:14Z")

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It would be great if the MDF format was supported like HDF5 is. Some examples are here for matlab and here (and here) for python. It’s also now supported natively by matlab. Just to be clear, I’m not referring to this…

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## [Testing in Docker: Base.runtests("file") failed 🐋](https://discourse.julialang.org/t/testing-in-docker-base-runtests-file-failed/73060)

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**Author:** [@ImreSamu](https://discourse.julialang.org/u/ImreSamu)\
**Replies:** 1\
**Last updated:** [December 16, 2021, 12:15pm UTC](https://discourse.julialang.org/t/testing-in-docker-base-runtests-file-failed/73060 "2021-12-16T12:15:54Z")

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Question: How can I run : Base.runtests("file") inside docker environments? Any best practice? My test command is failed - with the docker official Julia image. docker run -it --rm --privileged julia:1.7 julia -e …

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## [Defining a macro in a local scope?](https://discourse.julialang.org/t/defining-a-macro-in-a-local-scope/73148)

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**Author:** [@Mark\_Nahabedian](https://discourse.julialang.org/u/Mark_Nahabedian)\
**Replies:** 8\
**Last updated:** [December 16, 2021, 11:57am UTC](https://discourse.julialang.org/t/defining-a-macro-in-a-local-scope/73148 "2021-12-16T11:57:10Z")

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I’m trying to define a macro whose expansion references a local variable. Here’s my example: struct Reference source::Union{Nothing, LineNumberNode} registry::Dict key end let r = Dict() macro ref(…

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## [Resources to help install Julia on large companies](https://discourse.julialang.org/t/resources-to-help-install-julia-on-large-companies/73172)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 11:38am UTC](https://discourse.julialang.org/t/resources-to-help-install-julia-on-large-companies/73172 "2021-12-16T11:38:27Z")

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We are working on a research project in partnership with the industry, and will soon need to transfer the technology to the company that funded the work. Do you have any advise on how to show the IT department of the com…

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## [How to reality-chek a working ODE model made with DifferentialEquations?](https://discourse.julialang.org/t/how-to-reality-chek-a-working-ode-model-made-with-differentialequations/73190)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 1\
**Last updated:** [December 16, 2021, 11:26am UTC](https://discourse.julialang.org/t/how-to-reality-chek-a-working-ode-model-made-with-differentialequations/73190 "2021-12-16T11:26:43Z")

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Hello, I have made a simulation of bacterial infection. I am focusing on the induction of phages. The system works but I am not sure about the results. Even if I activate 400 000 hosts at t=250 (that is, 96.6% of the ba…

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## [Neural SDE vs Neural ODE](https://discourse.julialang.org/t/neural-sde-vs-neural-ode/73189)

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**Author:** [@ignace](https://discourse.julialang.org/u/ignace)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 11:24am UTC](https://discourse.julialang.org/t/neural-sde-vs-neural-ode/73189 "2021-12-16T11:24:10Z")

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May I please ask a question, please redirect me when this is the wrong place to ask :slight\_smile: What is the main (dis)advantage of neural SDEs over neural ODEs? Can they somehow tackle ‘more difficult’ problems or s…

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## [Weird error with CUDA.jl on Julia1.7. Cannot rewrite unknown use of function](https://discourse.julialang.org/t/weird-error-with-cuda-jl-on-julia1-7-cannot-rewrite-unknown-use-of-function/73183)

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**Author:** [@Alexandre\_Chen](https://discourse.julialang.org/u/Alexandre_Chen)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 10:45am UTC](https://discourse.julialang.org/t/weird-error-with-cuda-jl-on-julia1-7-cannot-rewrite-unknown-use-of-function/73183 "2021-12-16T10:45:36Z")

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julia\> a = CuArray(randn(32,32)) 32×32 CuArray{Float64, 2, CUDA.Mem.DeviceBuffer}: -1.18274 0.255296 -0.638661 -0.360422 1.36684 1.33303 -0.0344325 -2.70717 0.781341 0.288144 0.0181823 …

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## [Memory management and PackageCompiler libraries](https://discourse.julialang.org/t/memory-management-and-packagecompiler-libraries/72980)

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**Author:** [@originalsouth](https://discourse.julialang.org/u/originalsouth)\
**Replies:** 8\
**Last updated:** [December 16, 2021, 10:37am UTC](https://discourse.julialang.org/t/memory-management-and-packagecompiler-libraries/72980 "2021-12-16T10:37:33Z")

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Hello, I have a question regarding memory management when retrieving arbitrary sized memory blocks from a library compiled by the PackageCompiler. In https://github.com/originalsouth/RandomPack I have created a dummy p…

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## [Collect model outputs into multi-dimensional array](https://discourse.julialang.org/t/collect-model-outputs-into-multi-dimensional-array/72977)

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**Author:** [@Tengrath](https://discourse.julialang.org/u/Tengrath)\
**Replies:** 5\
**Last updated:** [December 16, 2021, 10:25am UTC](https://discourse.julialang.org/t/collect-model-outputs-into-multi-dimensional-array/72977 "2021-12-16T10:25:42Z")

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Consider the following model which creates an output after every layer ’ function track(model, input) track::Vector{Vector{Float64}} = p = input for layer in model p = layer(p) track = vcat(track, \[p,\]) end …

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## [Variational Inference of Mixture models?](https://discourse.julialang.org/t/variational-inference-of-mixture-models/40031)

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**Author:** [@marty0801](https://discourse.julialang.org/u/marty0801)\
**Replies:** 8\
**Last updated:** [December 16, 2021, 10:06am UTC](https://discourse.julialang.org/t/variational-inference-of-mixture-models/40031 "2021-12-16T10:06:31Z")

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I’m just cutting my teeth on Turing. (BTW, thanks for this amazing software.) Does Turing support VI of mixture models? I attempted advi against a gaussian mixture model, but without success as below. The error occurred…

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## [How can I configure Pkg to use specific git](https://discourse.julialang.org/t/how-can-i-configure-pkg-to-use-specific-git/71420)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 4\
**Last updated:** [December 16, 2021, 9:19am UTC](https://discourse.julialang.org/t/how-can-i-configure-pkg-to-use-specific-git/71420 "2021-12-16T09:19:01Z")

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After I upgrade to MacOS Monterey, my Homebrew installed git does not work. I have uninstalled that git. Now I can use the Xcode git (/usr/bin/git) in the terminal. But when I add/update a github repo, I get the followin…

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## [Why does this allocate? (with example)](https://discourse.julialang.org/t/why-does-this-allocate-with-example/73001)

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**Author:** [@freeman](https://discourse.julialang.org/u/freeman)\
**Replies:** 10\
**Last updated:** [December 16, 2021, 8:55am UTC](https://discourse.julialang.org/t/why-does-this-allocate-with-example/73001 "2021-12-16T08:55:10Z")

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It looks like in a ccall, a string doesn’t allocate but a string view does. Is this expected? Why? To me it’s unexpected. This doesn’t allocate st = "experiment number 1 and 2" fmt = "experiment number %ld %n" function…

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## [MethodError: no method matching isless(::Int64, ::AffExpr)](https://discourse.julialang.org/t/methoderror-no-method-matching-isless-int64-affexpr/69731)

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**Author:** [@Ali9266](https://discourse.julialang.org/u/Ali9266)\
**Replies:** 6\
**Last updated:** [December 16, 2021, 8:37am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-isless-int64-affexpr/69731 "2021-12-16T08:37:56Z")

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I’m receiving an error MethodError: no method matching isless(::Int64, ::AffExpr) while trying to run my code in the constraints “@constraint(model, con8\[k in 1:n,i in 1:m; i==m\], T\_k\[k\]==max(C\_ki\[k,i\]-U\_k\[k\],0))”

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## [When to use pmap vs Threads.@threads?](https://discourse.julialang.org/t/when-to-use-pmap-vs-threads-threads/72805)

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**Author:** [@chelseas](https://discourse.julialang.org/u/chelseas)\
**Replies:** 11\
**Last updated:** [December 16, 2021, 8:28am UTC](https://discourse.julialang.org/t/when-to-use-pmap-vs-threads-threads/72805 "2021-12-16T08:28:31Z")

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Some of my processes may take a minute, and others miliseconds, so load balancing seems like a good idea. Do both do this? Any other things I should know about when using pmap vs. @threads? I’ve tagged jump because I w…

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## [TACC - Four paths to accelerating science on supercomputers](https://discourse.julialang.org/t/tacc-four-paths-to-accelerating-science-on-supercomputers/73187)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 0\
**Last updated:** [December 16, 2021, 8:10am UTC](https://discourse.julialang.org/t/tacc-four-paths-to-accelerating-science-on-supercomputers/73187 "2021-12-16T08:10:07Z")

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Peak performance on supercomputers may be rising unchecked, but getting real improvements in scientific productivity is an altogether different challenge.

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## [Performance when chaining multiple macros](https://discourse.julialang.org/t/performance-when-chaining-multiple-macros/73173)

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**Author:** [@DanielVandH](https://discourse.julialang.org/u/DanielVandH)\
**Replies:** 2\
**Last updated:** [December 16, 2021, 12:22am UTC](https://discourse.julialang.org/t/performance-when-chaining-multiple-macros/73173 "2021-12-16T00:22:42Z")

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I’m aware that macros such as @muladd from MuladdMacro.jl, @views, and @inbounds are occasionally very useful for performance. Might there be any problems with combining them in general? For example, is the following cha…

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## [Julia download links broken?](https://discourse.julialang.org/t/julia-download-links-broken/73171)

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**Author:** [@Lilith](https://discourse.julialang.org/u/Lilith)\
**Replies:** 4\
**Last updated:** [December 15, 2021, 11:47pm UTC](https://discourse.julialang.org/t/julia-download-links-broken/73171 "2021-12-15T23:47:21Z")

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Is it just me or are other folks having an issue where all the julialang-s3.julialang.org... links on are broken? If other folks have this issue I’ll file it on github, but it could just be me.

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## [Is JuliaPro discontinued?](https://discourse.julialang.org/t/is-juliapro-discontinued/67670)

<div class="topic-metadata">

**Author:** [@doctor-phil](https://discourse.julialang.org/u/doctor-phil)\
**Replies:** 16\
**Last updated:** [December 15, 2021, 11:44pm UTC](https://discourse.julialang.org/t/is-juliapro-discontinued/67670 "2021-12-15T23:44:10Z")

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I was trying to update my version of juliapro, but I can’t seem to find the download page anymore. When I click links to it, I am redirected to the juliahub page. I don’t want to work in the cloud or in a web browser, I…

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## [HorseML.jl (formerly LearningHorse.jl)](https://discourse.julialang.org/t/horseml-jl-formerly-learninghorse-jl/73149)

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**Author:** [@QGMW22](https://discourse.julialang.org/u/QGMW22)\
**Replies:** 2\
**Last updated:** [December 15, 2021, 9:36pm UTC](https://discourse.julialang.org/t/horseml-jl-formerly-learninghorse-jl/73149 "2021-12-15T21:36:45Z")

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LearningHorse I’m glad to release new version of this package. please try using this version! Big change Although it is a new version, please note that the package name has also been changed to HorseML because I changed…

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