# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1501

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

**Page:** 1502

---

## [Linux users of Julia: Which distro do you use?](https://discourse.julialang.org/t/linux-users-of-julia-which-distro-do-you-use/48913)

<div class="topic-metadata">

**Author:** [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Replies:** 93\
**Last updated:** [February 5, 2021, 7:49am UTC](https://discourse.julialang.org/t/linux-users-of-julia-which-distro-do-you-use/48913 "2021-02-05T07:49:47Z")

</div>

Since Ubuntu 20.10 was just released and Fedora 33 around the corner I am rethinking my setup (coincidentally there is a public holiday on Monday in Austria so I have time to mess around) Any recommendations / cool tipps…

---

## [MethodError: no method matching (::GeometricFlux.var"#adjacency\_matrix#76")](https://discourse.julialang.org/t/methoderror-no-method-matching-geometricflux-var-adjacency-matrix-76/54668)

<div class="topic-metadata">

**Author:** [@rezabayani](https://discourse.julialang.org/u/rezabayani)\
**Replies:** 0\
**Last updated:** [February 5, 2021, 2:59am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-geometricflux-var-adjacency-matrix-76/54668 "2021-02-05T02:59:33Z")

</div>

Hi. This issue is basically the same as the one in GeoemtricFlux.jl issues at Method error when training GCNConv with FeaturedGraph input · Issue #76 · FluxML/GeometricFlux.jl · GitHub. I tried replying there but did not…

---

## [Turn off interactive plotting in GR](https://discourse.julialang.org/t/turn-off-interactive-plotting-in-gr/54650)

<div class="topic-metadata">

**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 10:52pm UTC](https://discourse.julialang.org/t/turn-off-interactive-plotting-in-gr/54650 "2021-02-04T22:52:23Z")

</div>

How do I just save to pdf without showing the plot? Running on on hpc, I call eg plot(stuff); savefig() but I have to suppress these previews somehow to avoid errors from non-existent qt5: connect: Connection refused G…

---

## [Ambiguity with Vararg outer constructor and inner constructor](https://discourse.julialang.org/t/ambiguity-with-vararg-outer-constructor-and-inner-constructor/54622)

<div class="topic-metadata">

**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 8\
**Last updated:** [February 4, 2021, 10:00pm UTC](https://discourse.julialang.org/t/ambiguity-with-vararg-outer-constructor-and-inner-constructor/54622 "2021-02-04T22:00:18Z")

</div>

I have a working Point type that works smoothly in 2D and 3D with various outer constructors: using StaticArrays struct Point{Dim,T} coords::SVector{Dim,T} end # convenience constructors Point{Dim,T}(coords::NTuple{…

---

## [Why does defining a vararg method define a zero argument method?](https://discourse.julialang.org/t/why-does-defining-a-vararg-method-define-a-zero-argument-method/50872)

<div class="topic-metadata">

**Author:** [@CameronBieganek](https://discourse.julialang.org/u/CameronBieganek)\
**Replies:** 32\
**Last updated:** [February 4, 2021, 8:53pm UTC](https://discourse.julialang.org/t/why-does-defining-a-vararg-method-define-a-zero-argument-method/50872 "2021-02-04T20:53:42Z")

</div>

When defining a vararg method, a zero argument method is implicitly created: julia\> foo(args...) = sum(\[args...\]) foo (generic function with 1 method) julia\> foo() ERROR: MethodError: no method matching zero(::Type{Any…

---

## [Add IJulia Error with Artifact ZeroMQ: Unable to Connect to Server](https://discourse.julialang.org/t/add-ijulia-error-with-artifact-zeromq-unable-to-connect-to-server/54649)

<div class="topic-metadata">

**Author:** [@Goose](https://discourse.julialang.org/u/Goose)\
**Replies:** 0\
**Last updated:** [February 4, 2021, 8:41pm UTC](https://discourse.julialang.org/t/add-ijulia-error-with-artifact-zeromq-unable-to-connect-to-server/54649 "2021-02-04T20:41:42Z")

</div>

I’m new to Julia, but I am trying to use the pkg.add(“IJulia”) function and I end up with the error below. Is there something else I need to do? Thanks in advance for you help. julia\> using Pkg julia\> Pkg.add(“IJulia…

---

## [Sum of Flux.params](https://discourse.julialang.org/t/sum-of-flux-params/54608)

<div class="topic-metadata">

**Author:** [@anon74562486](https://discourse.julialang.org/u/anon74562486)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 8:32pm UTC](https://discourse.julialang.org/t/sum-of-flux-params/54608 "2021-02-04T20:32:58Z")

</div>

I tried these two functions to get the l2 regularization term for a NN model: function ℓ₂(a) s = zero(Float32) for i in a s += sum(i.^2) end s end function l₂(a) s = zero(Float32) Lₐ = l…

---

## [Running server with HTTP.jl in async mode?](https://discourse.julialang.org/t/running-server-with-http-jl-in-async-mode/54560)

<div class="topic-metadata">

**Author:** [@DataPsycho](https://discourse.julialang.org/u/DataPsycho)\
**Replies:** 5\
**Last updated:** [February 4, 2021, 6:55pm UTC](https://discourse.julialang.org/t/running-server-with-http-jl-in-async-mode/54560 "2021-02-04T18:55:29Z")

</div>

Hi, I have created a http web service, the concept is taken from the presentation of Quinnj’s MusicAlbum project. 1 thing I am not sure about. If I want to initiate the server with @async mode from the terminal it initi…

---

## [Bounded parameters w/ Optim](https://discourse.julialang.org/t/bounded-parameters-w-optim/54552)

<div class="topic-metadata">

**Author:** [@pyrex41](https://discourse.julialang.org/u/pyrex41)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 6:51pm UTC](https://discourse.julialang.org/t/bounded-parameters-w-optim/54552 "2021-02-04T18:51:13Z")

</div>

I have been working on fitting some non-linear models, and have been using Optim. For models where the parameters space is bounded, one can obviously use Box Constraints. Before I read how to this, however, I had been tr…

---

## [Which Optimization package for large-scale structured nonlinear problems](https://discourse.julialang.org/t/which-optimization-package-for-large-scale-structured-nonlinear-problems/54449)

<div class="topic-metadata">

**Author:** [@egvila](https://discourse.julialang.org/u/egvila)\
**Replies:** 6\
**Last updated:** [February 4, 2021, 6:43pm UTC](https://discourse.julialang.org/t/which-optimization-package-for-large-scale-structured-nonlinear-problems/54449 "2021-02-04T18:43:52Z")

</div>

Hello everyone, As the title says, I would like some insight on what Julia Optimization package would be most appropriate to efficiently solve nonlinear problems with potentially exploitable sparsity structures (e.g. bl…

---

## [How to export data from an array](https://discourse.julialang.org/t/how-to-export-data-from-an-array/54555)

<div class="topic-metadata">

**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 3\
**Last updated:** [February 4, 2021, 6:29pm UTC](https://discourse.julialang.org/t/how-to-export-data-from-an-array/54555 "2021-02-04T18:29:49Z")

</div>

Maybe my question is a little repetitive compared to the last one I posted here. In this model, I would like to export the data that is in i to a .CSV file. When compiling the model the answer I have in .CSV is this: …

---

## [For Loops in Luxor](https://discourse.julialang.org/t/for-loops-in-luxor/54197)

<div class="topic-metadata">

**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 20\
**Last updated:** [February 4, 2021, 5:51pm UTC](https://discourse.julialang.org/t/for-loops-in-luxor/54197 "2021-02-04T17:51:09Z")

</div>

When I create a checker pattern using the rect function, it works perfectly: @svg begin Drawing(2000,2000) background("white") sethue("black") rect(500,0,500,500,:fill) rect(1500,0,500,500,:fill) rect(0,500,500,50…

---

## [(X-Post from Zulip)Hi all! I have a list of Polygons and would like to plot all](https://discourse.julialang.org/t/x-post-from-zulip-hi-all-i-have-a-list-of-polygons-and-would-like-to-plot-all/54625)

<div class="topic-metadata">

**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 5:37pm UTC](https://discourse.julialang.org/t/x-post-from-zulip-hi-all-i-have-a-list-of-polygons-and-would-like-to-plot-all/54625 "2021-02-04T17:37:22Z")

</div>

(X-Post from Zulip) Hi all! I have a list of Polygons and would like to plot all the shapes on the same plot where each shape has a different color. What I have been doing is something like this: using Plots .... fo…

---

## [How to increase BigFloat precision](https://discourse.julialang.org/t/how-to-increase-bigfloat-precision/54634)

<div class="topic-metadata">

**Author:** [@Renan\_Rabelo](https://discourse.julialang.org/u/Renan_Rabelo)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 5:32pm UTC](https://discourse.julialang.org/t/how-to-increase-bigfloat-precision/54634 "2021-02-04T17:32:59Z")

</div>

I need more decimal places with a BigFloat type variable. How to? Thanks!

---

## [What are the best alternatives to JuliaBox?](https://discourse.julialang.org/t/what-are-the-best-alternatives-to-juliabox/37246)

<div class="topic-metadata">

**Author:** [@aerdely](https://discourse.julialang.org/u/aerdely)\
**Replies:** 13\
**Last updated:** [February 4, 2021, 5:31pm UTC](https://discourse.julialang.org/t/what-are-the-best-alternatives-to-juliabox/37246 "2021-02-04T17:31:03Z")

</div>

Since JuliaBox sunset will take place on May 31st :cry: what are the best options to run Julia in the cloud for academic users? I don’t mind to pay a reasonable fee. Thank you in advance.

---

## [Twin Cities Minnesota Meetup group expiring soon](https://discourse.julialang.org/t/twin-cities-minnesota-meetup-group-expiring-soon/54631)

<div class="topic-metadata">

**Author:** [@bradeneliason](https://discourse.julialang.org/u/bradeneliason)\
**Replies:** 0\
**Last updated:** [February 4, 2021, 5:01pm UTC](https://discourse.julialang.org/t/twin-cities-minnesota-meetup-group-expiring-soon/54631 "2021-02-04T17:01:06Z")

</div>

The Twin Cities (Minneapolis-St. Paul, MN) Julia user meetup group is set to expire because it doesn’t have an organizer. There haven’t been any meetings for a long time due to the P word. I might step up, but I’m planni…

---

## [Create dataframe with n columns of strings](https://discourse.julialang.org/t/create-dataframe-with-n-columns-of-strings/36693)

<div class="topic-metadata">

**Author:** [@jonjilla](https://discourse.julialang.org/u/jonjilla)\
**Replies:** 6\
**Last updated:** [February 4, 2021, 4:33pm UTC](https://discourse.julialang.org/t/create-dataframe-with-n-columns-of-strings/36693 "2021-02-04T16:33:54Z")

</div>

I’m sure there is a simple way to do this, but I cannot figure this out. Is there a simple way to create a dataFrame of n columns of all String type? I know I can do this DataFrame(\[String,String,String\],\[:x1, :x2, :x…

---

## [Enumeratezip](https://discourse.julialang.org/t/enumeratezip/54617)

<div class="topic-metadata">

**Author:** [@fgerick](https://discourse.julialang.org/u/fgerick)\
**Replies:** 9\
**Last updated:** [February 4, 2021, 4:23pm UTC](https://discourse.julialang.org/t/enumeratezip/54617 "2021-02-04T16:23:59Z")

</div>

I often would like to use something like enumerate(a,b,c) and get the functionality: a,b,c = rand(10),rand(10),rand(10) for (i,ai,bi,ci) in enumerate(a,b,c) @show i ai bi ci end something that could emulate this is e…

---

## [How to start two (or more) instances of Julia on different CPU cores?](https://discourse.julialang.org/t/how-to-start-two-or-more-instances-of-julia-on-different-cpu-cores/54610)

<div class="topic-metadata">

**Author:** [@Martin](https://discourse.julialang.org/u/Martin)\
**Replies:** 2\
**Last updated:** [February 4, 2021, 2:12pm UTC](https://discourse.julialang.org/t/how-to-start-two-or-more-instances-of-julia-on-different-cpu-cores/54610 "2021-02-04T14:12:48Z")

</div>

I want to start several instances of Julia and run some pretty time consuming (different) simulations. The underlying hardware has several CPU cores and I would like to make sure that each instance uses a different core,…

---

## [Yota.jl getindex error](https://discourse.julialang.org/t/yota-jl-getindex-error/54595)

<div class="topic-metadata">

**Author:** [@DeepQ](https://discourse.julialang.org/u/DeepQ)\
**Replies:** 3\
**Last updated:** [February 4, 2021, 11:36am UTC](https://discourse.julialang.org/t/yota-jl-getindex-error/54595 "2021-02-04T11:36:42Z")

</div>

I am trying to calculate the gradient of this function: using Yota f(x) = sum(getindex(x, \[1 3; 4 2\])) s = rand(2,2) val, g = Yota.grad(f, s) If s = rand(2) my code works but the above code returns this error: \> Fa…

---

## [Linear system problems](https://discourse.julialang.org/t/linear-system-problems/54519)

<div class="topic-metadata">

**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 35\
**Last updated:** [February 4, 2021, 10:57am UTC](https://discourse.julialang.org/t/linear-system-problems/54519 "2021-02-04T10:57:31Z")

</div>

Hello, I’m writing some code that solves A\*x=b, where A can be quite big (say 10000x10000, hopefully bigger in the future). A is not sparse (at least for now) and might be poorly conditioned. Might even have multiple so…

---

## [What do I need to do to a struct to use it in a boolean context?](https://discourse.julialang.org/t/what-do-i-need-to-do-to-a-struct-to-use-it-in-a-boolean-context/54545)

<div class="topic-metadata">

**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 3\
**Last updated:** [February 4, 2021, 10:48am UTC](https://discourse.julialang.org/t/what-do-i-need-to-do-to-a-struct-to-use-it-in-a-boolean-context/54545 "2021-02-04T10:48:26Z")

</div>

What do I need to do to a struct to use it in a boolean context? julia&gt; struct Foo bool::Bool end julia&gt; if Foo(true) println("How do I make this work?") end ERROR: TypeError: non-bool…

---

## [Surprising @fastmath behavior](https://discourse.julialang.org/t/surprising-fastmath-behavior/54600)

<div class="topic-metadata">

**Author:** [@Christian\_Rorvik](https://discourse.julialang.org/u/Christian_Rorvik)\
**Replies:** 3\
**Last updated:** [February 4, 2021, 10:45am UTC](https://discourse.julialang.org/t/surprising-fastmath-behavior/54600 "2021-02-04T10:45:54Z")

</div>

Here’s something that caught me off guard. Example is reduced to trivial code, but I caught this in a much more complex context. function foo(a, b, c) @fastmath x = a \* b + c isnan(x) ? 0.0 : x end code\_native(f…

---

## [How do you invoke a method (like a specific method, not a function)?\`\`\`julia&gt;](https://discourse.julialang.org/t/how-do-you-invoke-a-method-like-a-specific-method-not-a-function-julia-gt/54605)

<div class="topic-metadata">

**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 10:45am UTC](https://discourse.julialang.org/t/how-do-you-invoke-a-method-like-a-specific-method-not-a-function-julia-gt/54605 "2021-02-04T10:45:12Z")

</div>

How do you invoke a method (like a specific method, not a function)? julia&gt; func(a) =5 func (generic function with 1 method) julia&gt; meth = first(methods(func)) func(a) in Main at REPL\[83\]:1 julia&gt; meth(1) ERR…

---

## [Boundary conditions](https://discourse.julialang.org/t/boundary-conditions/54609)

<div class="topic-metadata">

**Author:** [@Rony](https://discourse.julialang.org/u/Rony)\
**Replies:** 0\
**Last updated:** [February 4, 2021, 10:39am UTC](https://discourse.julialang.org/t/boundary-conditions/54609 "2021-02-04T10:39:41Z")

</div>

I want to select particular nodes in my 2D mesh to apply boundary conditions and traction. I saw the examples where the entire left face have been selected. My mesh looks like this. I want to apply constraint in node 1 …

---

## [Performance of structs with incompletely parameterized fields](https://discourse.julialang.org/t/performance-of-structs-with-incompletely-parameterized-fields/54580)

<div class="topic-metadata">

**Author:** [@Deduction42](https://discourse.julialang.org/u/Deduction42)\
**Replies:** 3\
**Last updated:** [February 4, 2021, 9:29am UTC](https://discourse.julialang.org/t/performance-of-structs-with-incompletely-parameterized-fields/54580 "2021-02-04T09:29:08Z")

</div>

Hello, I the performance section, it was stated that we should avoid fields with abstract types struct MyAmbiguousStruct val::AbstractFloat end But what about incompletely parameterized types? How bad is something …

---

## [How to save multiple plot through a loop?](https://discourse.julialang.org/t/how-to-save-multiple-plot-through-a-loop/54575)

<div class="topic-metadata">

**Author:** [@minou92](https://discourse.julialang.org/u/minou92)\
**Replies:** 2\
**Last updated:** [February 4, 2021, 8:46am UTC](https://discourse.julialang.org/t/how-to-save-multiple-plot-through-a-loop/54575 "2021-02-04T08:46:46Z")

</div>

I have been trying to save multiple plots with different names through a loop. I am looking for the Julia equivalent of python script: plt.savefig('ID+str(i).‘png’). I tested this savefig(“C:/Julia\_data/ID”+str(i) “.pd…

---

## [Pkg protocol - delay in updating GeneralRegistry](https://discourse.julialang.org/t/pkg-protocol-delay-in-updating-generalregistry/54521)

<div class="topic-metadata">

**Author:** [@krcools](https://discourse.julialang.org/u/krcools)\
**Replies:** 6\
**Last updated:** [February 4, 2021, 8:09am UTC](https://discourse.julialang.org/t/pkg-protocol-delay-in-updating-generalregistry/54521 "2021-02-04T08:09:34Z")

</div>

I have recently registered new versions of some of my packages. These versions became available immediately on julia-1.3, but are invisible on julia-1.5. I removed the registries subdir of the .julia dir and indeed, whe…

---

## [Seeking advice on contributing to Julia: A faster Lasso solver](https://discourse.julialang.org/t/seeking-advice-on-contributing-to-julia-a-faster-lasso-solver/42023)

<div class="topic-metadata">

**Author:** [@barankarakus](https://discourse.julialang.org/u/barankarakus)\
**Replies:** 9\
**Last updated:** [February 4, 2021, 7:02am UTC](https://discourse.julialang.org/t/seeking-advice-on-contributing-to-julia-a-faster-lasso-solver/42023 "2021-02-04T07:02:31Z")

</div>

Hi there, I’m a Master’s student in Statistics. I’ve recently been researching ‘safe screening rules’ for accelerating Lasso solvers. These can improve computation times by orders of magnitude when the number of feature…

---

## [Embedding julia in C, Segmentation fault when call hcat to concatenate two arrays](https://discourse.julialang.org/t/embedding-julia-in-c-segmentation-fault-when-call-hcat-to-concatenate-two-arrays/54597)

<div class="topic-metadata">

**Author:** [@fanxp](https://discourse.julialang.org/u/fanxp)\
**Replies:** 2\
**Last updated:** [February 4, 2021, 8:07am UTC](https://discourse.julialang.org/t/embedding-julia-in-c-segmentation-fault-when-call-hcat-to-concatenate-two-arrays/54597 "2021-02-04T08:07:47Z")

</div>

Hi, I need to call some julia function in C, but meet some problem. For example, I want to use hcat to concatenate two arrays, but segmentation fault occurs. Below is my source code. #include \<stdlib.h\> #include \<julia…

[Previous page](https://discourse.julialang.org/latest.md?page=1500)

[Next page](https://discourse.julialang.org/latest.md?page=1502)