# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1641

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

**Page:** 1642

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## [Static Arrays in pure Julia](https://discourse.julialang.org/t/static-arrays-in-pure-julia/46030)

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**Author:** [@Renan\_Rabelo](https://discourse.julialang.org/u/Renan_Rabelo)\
**Replies:** 2\
**Last updated:** [September 3, 2020, 11:22pm UTC](https://discourse.julialang.org/t/static-arrays-in-pure-julia/46030 "2020-09-03T23:22:17Z")

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Before Julia I used to code in Java, and Java has static arrays (immutable size). I know for sure that static arrays are way faster than dynamic ones, so how can I use they in pure Julia? I found a package called “Stat…

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## [How do I build a car's factory pipeline with RemoteChannel?](https://discourse.julialang.org/t/how-do-i-build-a-cars-factory-pipeline-with-remotechannel/46018)

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**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 5\
**Last updated:** [September 3, 2020, 9:54pm UTC](https://discourse.julialang.org/t/how-do-i-build-a-cars-factory-pipeline-with-remotechannel/46018 "2020-09-03T21:54:44Z")

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I’m currently playing with RemoteChannel, and trying to make a text book example of parallelism, that is, a pipeline. My toy example is a car factory with 3 stages clean\_car, paint and pay\_taxes. I can build the primiti…

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## [Using JuMPeR](https://discourse.julialang.org/t/using-jumper/46000)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 1\
**Last updated:** [September 3, 2020, 8:58pm UTC](https://discourse.julialang.org/t/using-jumper/46000 "2020-09-03T20:58:19Z")

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I look for articles that talk about robust optimization using JuMPeR. Can someone refer me? Thank you!

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## [How process with Conda.add pakacge](https://discourse.julialang.org/t/how-process-with-conda-add-pakacge/46022)

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**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 1\
**Last updated:** [September 3, 2020, 8:43pm UTC](https://discourse.julialang.org/t/how-process-with-conda-add-pakacge/46022 "2020-09-03T20:43:42Z")

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How to proceed to add a package through Coda.add. I am receiving the following alert and I don’t know how to proceed Julia\> Conda.add("scipy.optimize") \[ Info: Running \`conda install -y scipy.optimize\` in root environme…

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## [ODE AutoTsit5(Rodas5()) switching bug (depends from tolerance history)](https://discourse.julialang.org/t/ode-autotsit5-rodas5-switching-bug-depends-from-tolerance-history/45288)

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**Author:** [@peatlux](https://discourse.julialang.org/u/peatlux)\
**Replies:** 8\
**Last updated:** [September 3, 2020, 7:42pm UTC](https://discourse.julialang.org/t/ode-autotsit5-rodas5-switching-bug-depends-from-tolerance-history/45288 "2020-09-03T19:42:00Z")

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I want to solve my coupled DiffEq with different algorithms, because i don’t know the specific characteristics of it. But i know that it can exhibit stiff behaviour in some cases. I need to solve it many times in a param…

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## [Providing More Initial Parameter Values than there are Parameters in the Function Being Optimized](https://discourse.julialang.org/t/providing-more-initial-parameter-values-than-there-are-parameters-in-the-function-being-optimized/45585)

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**Author:** [@donkeysaddle](https://discourse.julialang.org/u/donkeysaddle)\
**Replies:** 9\
**Last updated:** [September 3, 2020, 5:51pm UTC](https://discourse.julialang.org/t/providing-more-initial-parameter-values-than-there-are-parameters-in-the-function-being-optimized/45585 "2020-09-03T17:51:45Z")

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Why does the “extra” parameter value affect the optimization? Apologies if this is in the Optim documentation - I didn’t see it. For example: using Optim f(x) = (1.0 - x\[1\])^2 + 100.0 \* (x\[2\] - x\[1\]^2)^2 x0 = \[0.0, 0.…

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## [Unable to automatically install 'CompilerSupportLibraries'](https://discourse.julialang.org/t/unable-to-automatically-install-compilersupportlibraries/36669)

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**Author:** [@aliceee](https://discourse.julialang.org/u/aliceee)\
**Replies:** 39\
**Last updated:** [September 3, 2020, 4:38pm UTC](https://discourse.julialang.org/t/unable-to-automatically-install-compilersupportlibraries/36669 "2020-09-03T16:38:09Z")

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Hi! I’m new to Julia and I was trying to install the package “Distributions”. After running Pkg.add("Distributions"), I got the following error Resolving package versions... Unable to automatically install 'CompilerSupp…

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## [Julia is crashing. What to do with the error?](https://discourse.julialang.org/t/julia-is-crashing-what-to-do-with-the-error/46008)

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**Author:** [@Impressium](https://discourse.julialang.org/u/Impressium)\
**Replies:** 4\
**Last updated:** [September 3, 2020, 2:57pm UTC](https://discourse.julialang.org/t/julia-is-crashing-what-to-do-with-the-error/46008 "2020-09-03T14:57:53Z")

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I’m using some JSON3, JSON, PyCall and Tasks and get such a bug? Does anyone know what it means? Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Tha…

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## [How to deal with multiple processes trying to load the same file (and crash)?](https://discourse.julialang.org/t/how-to-deal-with-multiple-processes-trying-to-load-the-same-file-and-crash/46005)

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**Author:** [@volkerkarle](https://discourse.julialang.org/u/volkerkarle)\
**Replies:** 3\
**Last updated:** [September 3, 2020, 2:52pm UTC](https://discourse.julialang.org/t/how-to-deal-with-multiple-processes-trying-to-load-the-same-file-and-crash/46005 "2020-09-03T14:52:14Z")

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hey folks, Right now I have the issue that multiple jobs on a cluster try to load the same data (my data is saved using JLD) and there is a problem with the disk, as a result the jobs fail. How can I deal with this issu…

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## [Extend \`mod\` first argument to Gaussian integers?](https://discourse.julialang.org/t/extend-mod-first-argument-to-gaussian-integers/45975)

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**Author:** [@scheinerman](https://discourse.julialang.org/u/scheinerman)\
**Replies:** 4\
**Last updated:** [September 3, 2020, 1:53pm UTC](https://discourse.julialang.org/t/extend-mod-first-argument-to-gaussian-integers/45975 "2020-09-03T13:53:08Z")

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Would folks find it useful if mod(z,m) worked when z is a Gaussian integer? This is easy enough to implement: import Base.mod function mod(z::Complex{T}, m::Integer) where T\<:Integer a,b = reim(z) return mod(a…

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## [Zygote + CUDA: scalar getindex with custom activation function using multiplication](https://discourse.julialang.org/t/zygote-cuda-scalar-getindex-with-custom-activation-function-using-multiplication/45997)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 3\
**Last updated:** [September 3, 2020, 1:40pm UTC](https://discourse.julialang.org/t/zygote-cuda-scalar-getindex-with-custom-activation-function-using-multiplication/45997 "2020-09-03T13:40:35Z")

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This simple model training does not work because of the custom activation function: julia\> using CUDA,Flux julia\> CUDA.allowscalar(false) julia\> const c = 100 100 julia\> f(x) = σ(x)\*2\*c f (generic function with 1 met…

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## [Using LSTM with Conv layers](https://discourse.julialang.org/t/using-lstm-with-conv-layers/46007)

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**Author:** [@nantonel](https://discourse.julialang.org/u/nantonel)\
**Replies:** 0\
**Last updated:** [September 3, 2020, 1:32pm UTC](https://discourse.julialang.org/t/using-lstm-with-conv-layers/46007 "2020-09-03T13:32:16Z")

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I was wondering what is the best practice to use a LSTM (or any RNN) together with some convolutional layers using Flux and in general how to unite recurrent networks with other blocks. Say I have this simple problem wh…

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## [IJulia do not run](https://discourse.julialang.org/t/ijulia-do-not-run/45409)

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**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 49\
**Last updated:** [September 3, 2020, 8:16am UTC](https://discourse.julialang.org/t/ijulia-do-not-run/45409 "2020-09-03T08:16:17Z")

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I manage to install IJulia, but when I want to run the notebook () command, I get the following alerts: (@v1.5) pkg\> add IJulia Updating registry at \`C:\\Users\\hermesr\\.julia\\registries\\General\` Resolving package ve…

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## [Fastest way to broadcast reductions of SubArrays](https://discourse.julialang.org/t/fastest-way-to-broadcast-reductions-of-subarrays/45913)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 1\
**Last updated:** [September 3, 2020, 7:51am UTC](https://discourse.julialang.org/t/fastest-way-to-broadcast-reductions-of-subarrays/45913 "2020-09-03T07:51:19Z")

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I have an array arr whose subarrays correspond to the column-groups given in colinds. Below is an example of division that does what I want without creating any subarrays or broadcasting. The desired result is given by…

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## [How to apply a function only to the second column of a matrix](https://discourse.julialang.org/t/how-to-apply-a-function-only-to-the-second-column-of-a-matrix/45988)

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**Author:** [@StevenSiew](https://discourse.julialang.org/u/StevenSiew)\
**Replies:** 2\
**Last updated:** [September 3, 2020, 6:54am UTC](https://discourse.julialang.org/t/how-to-apply-a-function-only-to-the-second-column-of-a-matrix/45988 "2020-09-03T06:54:30Z")

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How to apply a function only to the second column of a matrix The only way I know of is this. Is there an easier way to apply the sin function to only the second column of a matrix? julia\> m = \[1. 2. 3.; 4. 5. 6.; 7. 8…

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## [Obtain frequency response from digital filter with DSP.jl](https://discourse.julialang.org/t/obtain-frequency-response-from-digital-filter-with-dsp-jl/44618)

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**Author:** [@marcpabst](https://discourse.julialang.org/u/marcpabst)\
**Replies:** 4\
**Last updated:** [September 2, 2020, 4:59am UTC](https://discourse.julialang.org/t/obtain-frequency-response-from-digital-filter-with-dsp-jl/44618 "2020-09-02T04:59:33Z")

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Hi, I have a simple and potentially very stupid question. I use DSP.jl to construct a filter via digitalfilter(), which leaves me with a filter kernel I can apply to my signal. If I wanted to take a look at the respons…

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## [Failing to precompile LibPQ](https://discourse.julialang.org/t/failing-to-precompile-libpq/34890)

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**Author:** [@alejandromerchan](https://discourse.julialang.org/u/alejandromerchan)\
**Replies:** 1\
**Last updated:** [September 3, 2020, 12:34am UTC](https://discourse.julialang.org/t/failing-to-precompile-libpq/34890 "2020-09-03T00:34:54Z")

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I added LibPQ on my Windows 10 machine, but I’m getting a weird error using LibPQ ERROR: LoadError: InitError: ArgumentError: Unknown time zone "America/Los\_Angeles" Stacktrace: \[1\] (::TimeZones.var"#3#4"{String})() at…

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## [The filter function is non-intuitive](https://discourse.julialang.org/t/the-filter-function-is-non-intuitive/45674)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 25\
**Last updated:** [September 2, 2020, 9:30pm UTC](https://discourse.julialang.org/t/the-filter-function-is-non-intuitive/45674 "2020-09-02T21:30:08Z")

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So this is the current behaviour of the filter function, when given a function that returns a boolean and a collection (taken from the documentation): julia\> a = 1:10 1:10 julia\> filter(isodd, a) 5-element Array{Int64,…

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## [Cpu name from Julia](https://discourse.julialang.org/t/cpu-name-from-julia/45964)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 4\
**Last updated:** [September 2, 2020, 9:10pm UTC](https://discourse.julialang.org/t/cpu-name-from-julia/45964 "2020-09-02T21:10:10Z")

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Hi, Is it possible to get the cpu name with Julia ? I tried CpuId.jl but it returns a lot of information which I am not able extract…

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## [Parallel loading of packages, to help e.g. Queryverse (VegaLite), time-to-first plot](https://discourse.julialang.org/t/parallel-loading-of-packages-to-help-e-g-queryverse-vegalite-time-to-first-plot/45700)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 5\
**Last updated:** [September 2, 2020, 3:43pm UTC](https://discourse.julialang.org/t/parallel-loading-of-packages-to-help-e-g-queryverse-vegalite-time-to-first-plot/45700 "2020-09-02T15:43:19Z")

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First I want to say, time-to-first-plot isn’t really an issue (I consider it a solved problem if you know what you’re doing, using right packages/options), e.g. in about a sec. on Julia 1.6 (you can excpect this speed so…

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## [Need help with building constraints](https://discourse.julialang.org/t/need-help-with-building-constraints/45911)

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**Author:** [@sogrbilja](https://discourse.julialang.org/u/sogrbilja)\
**Replies:** 9\
**Last updated:** [September 2, 2020, 8:20pm UTC](https://discourse.julialang.org/t/need-help-with-building-constraints/45911 "2020-09-02T20:20:34Z")

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I am trying to fit images to A4 piece of paper, I am getting infeasible solution but I don’t understand why. params = Dict() params\["ROWS"\] = 1:297 params\["COLS"\] = 1:210 params\["TOTAL"\] = 210 \* 297 params\["I…

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## [Empty list in sum create an error](https://discourse.julialang.org/t/empty-list-in-sum-create-an-error/45962)

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**Author:** [@cotepascal76](https://discourse.julialang.org/u/cotepascal76)\
**Replies:** 6\
**Last updated:** [September 2, 2020, 7:14pm UTC](https://discourse.julialang.org/t/empty-list-in-sum-create-an-error/45962 "2020-09-02T19:14:31Z")

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I would to define a constraint in jump using this compact notation like: sum( sum( Flow\[p,j\] for j in A\[p\] if j == "TT" ) for p in pars) ) the problem is that for a given p, there may be no “TT” in A\[p\] list and in …

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## [Does it make sense for @orderby and @groupby not to commute?](https://discourse.julialang.org/t/does-it-make-sense-for-orderby-and-groupby-not-to-commute/45920)

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**Author:** [@conditionality](https://discourse.julialang.org/u/conditionality)\
**Replies:** 2\
**Last updated:** [September 2, 2020, 6:05pm UTC](https://discourse.julialang.org/t/does-it-make-sense-for-orderby-and-groupby-not-to-commute/45920 "2020-09-02T18:05:39Z")

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I have a dataframe which I want to group by some column value, and within each group I want the rows sorted by another column. I can do an @orderby |\> @groupby, however I feel like a @groupby |\> @orderby should make equa…

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## [No line number for: syntax: unexpected ")"](https://discourse.julialang.org/t/no-line-number-for-syntax-unexpected/45604)

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**Author:** [@jleman](https://discourse.julialang.org/u/jleman)\
**Replies:** 9\
**Last updated:** [September 2, 2020, 6:03pm UTC](https://discourse.julialang.org/t/no-line-number-for-syntax-unexpected/45604 "2020-09-02T18:03:55Z")

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Is there a way to get syntax messages like this to show a line number? syntax: unexpected “)”

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## [\[ANN\] GMAT.jl: Run NASA's General Mission Analysis Tool from Julia](https://discourse.julialang.org/t/ann-gmat-jl-run-nasas-general-mission-analysis-tool-from-julia/45959)

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**Author:** [@helgee](https://discourse.julialang.org/u/helgee)\
**Replies:** 2\
**Last updated:** [September 2, 2020, 4:54pm UTC](https://discourse.julialang.org/t/ann-gmat-jl-run-nasas-general-mission-analysis-tool-from-julia/45959 "2020-09-02T16:54:53Z")

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Hi folks, I want to announce another small but exciting package: https://github.com/JuliaSpace/GMAT.jl This package allows you to run scripts written for NASA’s General Mission Analysis Tool from the convenience of yo…

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## [\[ANN\] Chess.jl v0.2.0](https://discourse.julialang.org/t/ann-chess-jl-v0-2-0/45958)

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**Author:** [@Tord](https://discourse.julialang.org/u/Tord)\
**Replies:** 3\
**Last updated:** [September 2, 2020, 4:25pm UTC](https://discourse.julialang.org/t/ann-chess-jl-v0-2-0/45958 "2020-09-02T16:25:18Z")

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I’m happy to annouce version 0.2.0 of Chess.jl, my Julia chess programming library: https://github.com/romstad/Chess.jl The main changes are: License changed from AGPLv3 to MIT. This was a hard decision, since I have…

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## [More accurate evalpoly](https://discourse.julialang.org/t/more-accurate-evalpoly/45932)

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**Author:** [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)\
**Replies:** 8\
**Last updated:** [September 2, 2020, 4:24pm UTC](https://discourse.julialang.org/t/more-accurate-evalpoly/45932 "2020-09-02T16:24:21Z")

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In my quest for a better exp function, I discovered that having a more accurate evalpoly function is necessary if you want low error. Our builtin version is very fast (1 flop per degree), but has an unfortunately high ma…

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## [How to use NamedDimsArrays(NamedDims.jl) as containers for JuMP Variables?](https://discourse.julialang.org/t/how-to-use-nameddimsarrays-nameddims-jl-as-containers-for-jump-variables/45961)

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**Author:** [@GerhardTotschnig](https://discourse.julialang.org/u/GerhardTotschnig)\
**Replies:** 0\
**Last updated:** [September 2, 2020, 3:41pm UTC](https://discourse.julialang.org/t/how-to-use-nameddimsarrays-nameddims-jl-as-containers-for-jump-variables/45961 "2020-09-02T15:41:01Z")

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I am planning to develop a very large power system model. In AMPL it took 1-2h to generate the model and 12h to solve the model with cplex. In JuMP one can use symbols to create DenseAxisArrays of Variables and Constrai…

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## [Julia in x32 mode?! Precompiling Plots slow (or any package) with --compile=min](https://discourse.julialang.org/t/julia-in-x32-mode-precompiling-plots-slow-or-any-package-with-compile-min/45948)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 6\
**Last updated:** [September 2, 2020, 2:35pm UTC](https://discourse.julialang.org/t/julia-in-x32-mode-precompiling-plots-slow-or-any-package-with-compile-min/45948 "2020-09-02T14:35:20Z")

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On Julia 1.6 using Plots is taking forever (EDIT: now done, took 21 minutes) to precompile so I ran strace on the Julia process: strace: Process 4845 attached strace: \[ Process PID=4845 runs in x32 mode. \] \[hung foreve…

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## [How to replace list of char in string array?](https://discourse.julialang.org/t/how-to-replace-list-of-char-in-string-array/45951)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 2\
**Last updated:** [September 2, 2020, 2:33pm UTC](https://discourse.julialang.org/t/how-to-replace-list-of-char-in-string-array/45951 "2020-09-02T14:33:26Z")

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I have a list of chars julia\> usuwam 96×1 Array{Any,2}: "\\"" """ "A" "/" ... and i need to repalce all from string Array: julia\> string.(dane\[:,5\]) 1074762-element Array{String,1}: "TEST" "VENDISERVISSp.zo.o." …

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