# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1585

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

**Page:** 1586

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## [Synchronize the distributed inner loop](https://discourse.julialang.org/t/synchronize-the-distributed-inner-loop/49159)

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**Author:** [@libensvivit](https://discourse.julialang.org/u/libensvivit)\
**Replies:** 3\
**Last updated:** [November 2, 2020, 3:01am UTC](https://discourse.julialang.org/t/synchronize-the-distributed-inner-loop/49159 "2020-11-02T03:01:29Z")

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Hi, I have the following loop nest where I wait for the inner loop to finish before the outer loop proceeds. @time begin for var in 1:10 @sync @distributed for i in 1:100 work(i) end end end If I hav…

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## [BitVector vs Vector{Bool} as default on comparison operations](https://discourse.julialang.org/t/bitvector-vs-vector-bool-as-default-on-comparison-operations/49431)

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**Author:** [@Yamen](https://discourse.julialang.org/u/Yamen)\
**Replies:** 8\
**Last updated:** [November 2, 2020, 2:30am UTC](https://discourse.julialang.org/t/bitvector-vs-vector-bool-as-default-on-comparison-operations/49431 "2020-11-02T02:30:10Z")

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Comparison operations on numeric Vectors return BitVectors by default: const a = rand(100\_000) const b = rand(100\_000) test1(a, b) = a .\> b julia\> @btime test1($a,$b) 24.901 μs (3 allocations: 16.59 KiB) 100000-elem…

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## [Development Workflow for Persistent Julia Sessions](https://discourse.julialang.org/t/development-workflow-for-persistent-julia-sessions/49081)

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**Author:** [@TheCedarPrince](https://discourse.julialang.org/u/TheCedarPrince)\
**Replies:** 15\
**Last updated:** [November 2, 2020, 12:59am UTC](https://discourse.julialang.org/t/development-workflow-for-persistent-julia-sessions/49081 "2020-11-02T00:59:54Z")

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UPDATE: NEW BLOG POST AND VIDEO! By popular demand, I have written up a more formal blog post on this workflow which you can visit here. Furthermore, I also created a companion video which you can see in the blog post or…

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## [Why is the following behaviour not a bug?](https://discourse.julialang.org/t/why-is-the-following-behaviour-not-a-bug/49169)

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**Author:** [@colintbowers](https://discourse.julialang.org/u/colintbowers)\
**Replies:** 19\
**Last updated:** [November 2, 2020, 12:00am UTC](https://discourse.julialang.org/t/why-is-the-following-behaviour-not-a-bug/49169 "2020-11-02T00:00:52Z")

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I just observed the following on v1.4 (so apologies if it is gone on v1.5). julia\> x = \[ rand(0:9, 2) for a = 1:3 \] 3-element Array{Array{Int64,1},1}: \[3, 8\] \[2, 4\] \[3, 1\] julia\> x\[1,1\] 2-element Array{Int64,1}: 3 …

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## [Simple for loop woth if condition in Julia](https://discourse.julialang.org/t/simple-for-loop-woth-if-condition-in-julia/49430)

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**Author:** [@discourserogu](https://discourse.julialang.org/u/discourserogu)\
**Replies:** 5\
**Last updated:** [November 1, 2020, 10:37pm UTC](https://discourse.julialang.org/t/simple-for-loop-woth-if-condition-in-julia/49430 "2020-11-01T22:37:10Z")

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I’m trying to implement the following: res = 0.0 res0= 0.0 for i = 1:10 res = 0.5^i if i==1 res0 = copy(res) end res = copy(res)/res0 println(res) end but when I run it I g…

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## [Broadcast \[possibly missing\] key value pairs from one Dict to another?](https://discourse.julialang.org/t/broadcast-possibly-missing-key-value-pairs-from-one-dict-to-another/49425)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 2\
**Last updated:** [November 1, 2020, 8:57pm UTC](https://discourse.julialang.org/t/broadcast-possibly-missing-key-value-pairs-from-one-dict-to-another/49425 "2020-11-01T20:57:31Z")

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How can I broadcast key value pairs from one Dict to another, whether or not they exist? Tried the following but it doesn’t work: check = Dict() check2 = Dict(:a=\>1,:b=\>"b") check\[keys(check2).=values(check2)\] @test ge…

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## [MultiJuMP failed](https://discourse.julialang.org/t/multijump-failed/49265)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 3\
**Last updated:** [November 1, 2020, 8:48pm UTC](https://discourse.julialang.org/t/multijump-failed/49265 "2020-11-01T20:48:55Z")

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It failed to compile this package ,is there a way to add and use this package for multi objective optimization Thanks

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## [An easy way to call multiple functions from a package?](https://discourse.julialang.org/t/an-easy-way-to-call-multiple-functions-from-a-package/49383)

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**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 4\
**Last updated:** [November 1, 2020, 8:22pm UTC](https://discourse.julialang.org/t/an-easy-way-to-call-multiple-functions-from-a-package/49383 "2020-11-01T20:22:23Z")

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using Distributions; # Currently \[Distributions.tdistpdf, Distributions.tdistlogpdf, Distributions.tdistcdf\] # I want something like Distributions.\[tdistpdf, tdistlogpdf, tdistcdf\] wondering if there is an easy way t…

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## [Unable to make multiple lines in Plots](https://discourse.julialang.org/t/unable-to-make-multiple-lines-in-plots/49401)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 7\
**Last updated:** [November 1, 2020, 7:38pm UTC](https://discourse.julialang.org/t/unable-to-make-multiple-lines-in-plots/49401 "2020-11-01T19:38:49Z")

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I tried to plot 2 lines on the same graph using Plots f(x)=x^2 d(x)=2x plot(f) plot!(d) But when I try to run this I get an error. ERROR: UndefVarError: plot! not defined Stacktrace: \[1\] top-level scope at REPL\[673…

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## [How to check if GLM will be able to run OLS beforehand?](https://discourse.julialang.org/t/how-to-check-if-glm-will-be-able-to-run-ols-beforehand/48432)

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**Author:** [@drarnau](https://discourse.julialang.org/u/drarnau)\
**Replies:** 8\
**Last updated:** [November 1, 2020, 7:32pm UTC](https://discourse.julialang.org/t/how-to-check-if-glm-will-be-able-to-run-ols-beforehand/48432 "2020-11-01T19:32:56Z")

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Dear all, I use the GLM package to compute a simple OLS regression with simulated data inside a loop. In some cases, the simulated data is such that OLS cannot be computed because PosDefException: matrix is not positive…

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## [Stipple questions: multiple access, auth, editable tables, routing](https://discourse.julialang.org/t/stipple-questions-multiple-access-auth-editable-tables-routing/49424)

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**Author:** [@bbrunaud](https://discourse.julialang.org/u/bbrunaud)\
**Replies:** 0\
**Last updated:** [November 1, 2020, 7:31pm UTC](https://discourse.julialang.org/t/stipple-questions-multiple-access-auth-editable-tables-routing/49424 "2020-11-01T19:31:26Z")

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Hello, I’ve been reading as much docs I could find about Stipple. It looks really cool. I want to try it in a project and for that I have the following questions: In the examples I’ve noticed the application state is…

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## [What is being cached in the stale compilation cache?](https://discourse.julialang.org/t/what-is-being-cached-in-the-stale-compilation-cache/49421)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 1\
**Last updated:** [November 1, 2020, 6:43pm UTC](https://discourse.julialang.org/t/what-is-being-cached-in-the-stale-compilation-cache/49421 "2020-11-01T18:43:41Z")

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Julia used to do this a lot in 1.0, its mostly solved since 1.3 IIRC, because we have multiple caches. \[ Info: Recompiling stale cache file /Users/oxinabox/.julia/compiled/v1.0/Revise/M1Qoh.ji for Revise \[295af30f-e4ad-…

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## [Configuring Docker Image of Julia. Julia can't see installed packages](https://discourse.julialang.org/t/configuring-docker-image-of-julia-julia-cant-see-installed-packages/48790)

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**Author:** [@LoganNielsen](https://discourse.julialang.org/u/LoganNielsen)\
**Replies:** 3\
**Last updated:** [November 1, 2020, 6:32pm UTC](https://discourse.julialang.org/t/configuring-docker-image-of-julia-julia-cant-see-installed-packages/48790 "2020-11-01T18:32:54Z")

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Presently I have three files that are referenced in my docker script. I’ll provide the docker script and then the miscellaneous files. Dockerfile # src: https://techytok.com/from-zero-to-julia-using-docker/ FROM julia…

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## [How does Char get stored?](https://discourse.julialang.org/t/how-does-char-get-stored/49366)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 7\
**Last updated:** [October 31, 2020, 7:47pm UTC](https://discourse.julialang.org/t/how-does-char-get-stored/49366 "2020-10-31T19:47:55Z")

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I was basically under the impression that for 4 byte UTF-8 characters Char stored a UInt32 that was the codepoint containing all 4 codeunits. This is clearly not the case, as reinterpret disagrees with the codepoint j…

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## [Histogram of image pixel intensities and the density of a particular intensity](https://discourse.julialang.org/t/histogram-of-image-pixel-intensities-and-the-density-of-a-particular-intensity/49414)

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**Author:** [@Ashwani\_Rathee](https://discourse.julialang.org/u/Ashwani_Rathee)\
**Replies:** 1\
**Last updated:** [November 1, 2020, 5:29pm UTC](https://discourse.julialang.org/t/histogram-of-image-pixel-intensities-and-the-density-of-a-particular-intensity/49414 "2020-11-01T17:29:44Z")

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What I am trying to do: What I able to do as of now: I know the layout thing,pls help with the fraction part how to make that line that tells fraction of representation of a particular intensity in whole spectrum…

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## [Flux relu fails with CUDA gpu](https://discourse.julialang.org/t/flux-relu-fails-with-cuda-gpu/49399)

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**Author:** [@asyrov](https://discourse.julialang.org/u/asyrov)\
**Replies:** 2\
**Last updated:** [November 1, 2020, 4:46pm UTC](https://discourse.julialang.org/t/flux-relu-fails-with-cuda-gpu/49399 "2020-11-01T16:46:16Z")

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I’m getting error “CuArray only supports bits types” when using relu in code like: model = Chain(Dense(2, 2, relu), Dense(2, 1, identity)) |\> gpu All works fine though with: model = Chain(Dense(2, 2, (x) -\> max(0, x),…

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## [Understanding why one function is faster than the other](https://discourse.julialang.org/t/understanding-why-one-function-is-faster-than-the-other/48866)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 16\
**Last updated:** [November 1, 2020, 4:36pm UTC](https://discourse.julialang.org/t/understanding-why-one-function-is-faster-than-the-other/48866 "2020-11-01T16:36:32Z")

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Hi! I wanted to try to learn a bit more about why some functions are faster than others. To do this I decided to use Distances.jl and calculate some Euclidean distances. The code I have used is: using Distances using B…

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## [Plotting fails silently?](https://discourse.julialang.org/t/plotting-fails-silently/49406)

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**Author:** [@Ayush\_Rawat](https://discourse.julialang.org/u/Ayush_Rawat)\
**Replies:** 10\
**Last updated:** [November 1, 2020, 1:44pm UTC](https://discourse.julialang.org/t/plotting-fails-silently/49406 "2020-11-01T13:44:04Z")

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I have a fresh install of Julia(on Catalina), with Plots added via Pkg. Then I try to plot a simple line: using Plots; println("imported") x = 1:10; y = rand(10); # These are the plotting data println("tryna plot"); plo…

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## [No strict ticks found - Plot](https://discourse.julialang.org/t/no-strict-ticks-found-plot/49408)

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**Author:** [@algocompretto](https://discourse.julialang.org/u/algocompretto)\
**Replies:** 2\
**Last updated:** [November 1, 2020, 1:10pm UTC](https://discourse.julialang.org/t/no-strict-ticks-found-plot/49408 "2020-11-01T13:10:26Z")

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Hello! So, my goal with this code is to plot the BR COVID-19 data with a logaritmic scale in y axis. The problem is, it keeps saying that there is an Argument Error and at least one finite value must be provided to forma…

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## [Arrow, Feather, and Parquet](https://discourse.julialang.org/t/arrow-feather-and-parquet/28739)

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**Author:** [@tkf](https://discourse.julialang.org/u/tkf)\
**Replies:** 48\
**Last updated:** [November 1, 2020, 11:02am UTC](https://discourse.julialang.org/t/arrow-feather-and-parquet/28739 "2020-11-01T11:02:16Z")

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Continuing the discussion from JDF - an experimental DataFrame serialization format is ready for beta testing: @ExpandingMan Thank you very much! That’s a great summary and it helps me getting idea of reliability level …

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## [Loading image files not working in Pluto notebook](https://discourse.julialang.org/t/loading-image-files-not-working-in-pluto-notebook/49278)

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**Author:** [@kapple](https://discourse.julialang.org/u/kapple)\
**Replies:** 3\
**Last updated:** [November 1, 2020, 10:27am UTC](https://discourse.julialang.org/t/loading-image-files-not-working-in-pluto-notebook/49278 "2020-11-01T10:27:42Z")

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The following works fine in Julian mode. julia\> using Images julia\> readdir() 2-element Array{String,1}: "Untitled.png" "getimages.jl" julia\> img = load("Untitled.png") 280×382 Array{RGB{N0f8},2} with eltype RGB{Nor…

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## [No documentation for the state of patches for dependencies of Julia](https://discourse.julialang.org/t/no-documentation-for-the-state-of-patches-for-dependencies-of-julia/44735)

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**Author:** [@doronbehar](https://discourse.julialang.org/u/doronbehar)\
**Replies:** 12\
**Last updated:** [November 1, 2020, 10:00am UTC](https://discourse.julialang.org/t/no-documentation-for-the-state-of-patches-for-dependencies-of-julia/44735 "2020-11-01T10:00:37Z")

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I’m trying to package Julia for my distro (NixOS) in the best possible manner. We’d like to use our own dependencies as much as possible, but I’m having trouble figuring out your policy and your status regarding this. He…

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## [ERROR: UndefVarError: depwarn not defined](https://discourse.julialang.org/t/error-undefvarerror-depwarn-not-defined/49394)

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**Author:** [@a88](https://discourse.julialang.org/u/a88)\
**Replies:** 2\
**Last updated:** [November 1, 2020, 2:00am UTC](https://discourse.julialang.org/t/error-undefvarerror-depwarn-not-defined/49394 "2020-11-01T02:00:19Z")

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Hi everyone! So I just recently started using Julia. I managed to install Atom and Juno following the given steps but I keep running into the same problem and so far I couldn’t figure out the solution. Sometimes I get …

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## [How to transition from Emacs / Vim to VSCode?](https://discourse.julialang.org/t/how-to-transition-from-emacs-vim-to-vscode/49373)

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**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 1\
**Last updated:** [November 1, 2020, 1:34am UTC](https://discourse.julialang.org/t/how-to-transition-from-emacs-vim-to-vscode/49373 "2020-11-01T01:34:11Z")

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I’ve used Emacs to start a project with several .jl source files, and I’ve been testing code in the terminal. I’d like to try VSCode. But if I open these .jl files in VSCode simultaneously, VSCode will give auto-completi…

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## [Adding rows](https://discourse.julialang.org/t/adding-rows/49364)

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**Author:** [@r.bhl](https://discourse.julialang.org/u/r.bhl)\
**Replies:** 5\
**Last updated:** [November 1, 2020, 12:34am UTC](https://discourse.julialang.org/t/adding-rows/49364 "2020-11-01T00:34:48Z")

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Hi there! I am a bit new to julia so I have a few a very basic questions: I want to sum 33 rows of an nxm matrix. How can I do so?

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## [How to add all dependencies of a package to global environment?](https://discourse.julialang.org/t/how-to-add-all-dependencies-of-a-package-to-global-environment/19725)

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**Author:** [@marius311](https://discourse.julialang.org/u/marius311)\
**Replies:** 17\
**Last updated:** [October 31, 2020, 10:05pm UTC](https://discourse.julialang.org/t/how-to-add-all-dependencies-of-a-package-to-global-environment/19725 "2020-10-31T22:05:15Z")

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Suppose I have a package A which depends on B and C. If I run add A, then B and C are activate only in A’s environment. This means that if I do using B or using C from the global environment, it will fail. Is there an e…

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## [HTTP, Send headers in HTTP.Response](https://discourse.julialang.org/t/http-send-headers-in-http-response/49389)

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**Author:** [@Jea](https://discourse.julialang.org/u/Jea)\
**Replies:** 0\
**Last updated:** [October 31, 2020, 9:40pm UTC](https://discourse.julialang.org/t/http-send-headers-in-http-response/49389 "2020-10-31T21:40:30Z")

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I want send my headers in the HTTP.Reponse() HTTP.Response(200, "Working") Where i have to send the headers??

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## [Package for limits](https://discourse.julialang.org/t/package-for-limits/49286)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 23\
**Last updated:** [October 31, 2020, 9:37pm UTC](https://discourse.julialang.org/t/package-for-limits/49286 "2020-10-31T21:37:36Z")

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What is a package that can be used to find the limit of a function? I thought ForwardDiff.jl might have this feature but I couldn’t find it in the documentation.

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## [Possible to define a module where one dependency is built after running other stuff first?](https://discourse.julialang.org/t/possible-to-define-a-module-where-one-dependency-is-built-after-running-other-stuff-first/49384)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 6\
**Last updated:** [October 31, 2020, 9:15pm UTC](https://discourse.julialang.org/t/possible-to-define-a-module-where-one-dependency-is-built-after-running-other-stuff-first/49384 "2020-10-31T21:15:00Z")

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I need this module to create a Conda environment whose full path is required by Pkg.build() for another dependency. tmpdir = "/home/me/Desktop/tmp" mkdir(tmpdir) cd(tmpdir) using Pkg Pkg.activate("./") Pkg.add(\["RCall",…

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## [Loop faster than \`reduce\`?](https://discourse.julialang.org/t/loop-faster-than-reduce/48927)

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**Author:** [@stla](https://discourse.julialang.org/u/stla)\
**Replies:** 7\
**Last updated:** [October 31, 2020, 9:12pm UTC](https://discourse.julialang.org/t/loop-faster-than-reduce/48927 "2020-10-31T21:12:56Z")

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Hello, Is there a way to do better than such a loop: for t in 2:n jarray = jack(t, jarray) end I tried jarray = reduce((a, t) -\> jack(t, a), 2:n; init = jarray), but this is slower than the loop.

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