# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1709

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

**Page:** 1710

---

## [Packaging: why can't Julia find Test in Travis?](https://discourse.julialang.org/t/packaging-why-cant-julia-find-test-in-travis/41907)

<div class="topic-metadata">

**Author:** [@fusion809](https://discourse.julialang.org/u/fusion809)\
**Replies:** 2\
**Last updated:** [June 23, 2020, 5:48am UTC](https://discourse.julialang.org/t/packaging-why-cant-julia-find-test-in-travis/41907 "2020-06-23T05:48:26Z")

</div>

I’ve got these really basic .travis.yml and test/runtests.jl files and in the Travis log I’m getting the error: $ julia --check-bounds=yes --color=yes -e "if VERSION \< v\\"0.7.0-DEV.5183\\"; Pkg.test(\\"${JL\_PKG}\\", covera…

---

## [Stiff system (of \>100 equations) - Rodas5 - multiple runs - instability or not](https://discourse.julialang.org/t/stiff-system-of-100-equations-rodas5-multiple-runs-instability-or-not/41868)

<div class="topic-metadata">

**Author:** [@Polina](https://discourse.julialang.org/u/Polina)\
**Replies:** 7\
**Last updated:** [June 23, 2020, 4:30am UTC](https://discourse.julialang.org/t/stiff-system-of-100-equations-rodas5-multiple-runs-instability-or-not/41868 "2020-06-23T04:30:38Z")

</div>

Dear all, I have a stiff system of \>100 equations (which I’m not allowed to post anywhere at the moment). I tried solve(my\_prob, Rodas5(autodiff=false),reltol=1e-8,abstol=1e-8,saveat=1.0) # let's call it method1 and …

---

## [How to paste an image from the system clipboard (MS Windows) in a Gtk canvas?](https://discourse.julialang.org/t/how-to-paste-an-image-from-the-system-clipboard-ms-windows-in-a-gtk-canvas/41912)

<div class="topic-metadata">

**Author:** [@frangonve](https://discourse.julialang.org/u/frangonve)\
**Replies:** 0\
**Last updated:** [June 23, 2020, 3:54am UTC](https://discourse.julialang.org/t/how-to-paste-an-image-from-the-system-clipboard-ms-windows-in-a-gtk-canvas/41912 "2020-06-23T03:54:31Z")

</div>

I want to paste an image from the system clipboard (MS Windows) in a Gtk canvas. As far as I know InteractiveUtils.clipboard only works with text. Cheers.

---

## [Safe loop with push! multi-threading](https://discourse.julialang.org/t/safe-loop-with-push-multi-threading/41892)

<div class="topic-metadata">

**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 7\
**Last updated:** [June 23, 2020, 2:36am UTC](https://discourse.julialang.org/t/safe-loop-with-push-multi-threading/41892 "2020-06-23T02:36:01Z")

</div>

Hello, I would like to use multi-threading to speed-up a for loop. For each instance, an expensive computation is done and then the result is pushed at the end of an array. Here is toy example: x = collect(1:10) f(x)…

---

## [How to cite Julia?](https://discourse.julialang.org/t/how-to-cite-julia/41906)

<div class="topic-metadata">

**Author:** [@danielc](https://discourse.julialang.org/u/danielc)\
**Replies:** 1\
**Last updated:** [June 23, 2020, 2:29am UTC](https://discourse.julialang.org/t/how-to-cite-julia/41906 "2020-06-23T02:29:16Z")

</div>

Hello everyone. I use Julia for my research. I’m finishing off a paper and it just occurred to me that I could cite Julia. Is there a paper reference or standard citation that the Julia team prefers for peer reviewed res…

---

## [Random.seed!() doesn't work in Ubuntu machine for parallel running?](https://discourse.julialang.org/t/random-seed-doesnt-work-in-ubuntu-machine-for-parallel-running/41904)

<div class="topic-metadata">

**Author:** [@Jing\_Zhang](https://discourse.julialang.org/u/Jing_Zhang)\
**Replies:** 0\
**Last updated:** [June 23, 2020, 1:02am UTC](https://discourse.julialang.org/t/random-seed-doesnt-work-in-ubuntu-machine-for-parallel-running/41904 "2020-06-23T01:02:48Z")

</div>

I was doing parallel running using multi-cores. Codes are as below. I ran twice of the below codes and Mac gave me the same results. However, when I tried to run the same codes in a Ubuntu machine, different runs gave me…

---

## [Engineering a better activation function for best assembly](https://discourse.julialang.org/t/engineering-a-better-activation-function-for-best-assembly/41897)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 0\
**Last updated:** [June 22, 2020, 11:14pm UTC](https://discourse.julialang.org/t/engineering-a-better-activation-function-for-best-assembly/41897 "2020-06-22T23:14:19Z")

</div>

I’m checking out how complex an activation function can be before it’s (much) slower than ReLU, the simplest kind and standard before new Mish. Maybe not surprisingly f1 is as fast (while maybe it, f2 and f4 are no good…

---

## [Best way to express this algebra between Types](https://discourse.julialang.org/t/best-way-to-express-this-algebra-between-types/41891)

<div class="topic-metadata">

**Author:** [@francesco.alemanno](https://discourse.julialang.org/u/francesco.alemanno)\
**Replies:** 1\
**Last updated:** [June 22, 2020, 10:32pm UTC](https://discourse.julialang.org/t/best-way-to-express-this-algebra-between-types/41891 "2020-06-22T22:32:45Z")

</div>

struct Perturbator rng::AbstractRNG end function (a::Perturbator)() randn(a.rng) end const MultiLike = Union{Tuple,Array} +′(a,b) = a + b -′(a,b) = a - b \*′(a,b) = a \* b /′(a,b) = a / b +′(a::T,b) where T \<: …

---

## [From Julia to VR](https://discourse.julialang.org/t/from-julia-to-vr/4950)

<div class="topic-metadata">

**Author:** [@Loic\_Chappaz](https://discourse.julialang.org/u/Loic_Chappaz)\
**Replies:** 11\
**Last updated:** [June 22, 2020, 9:54pm UTC](https://discourse.julialang.org/t/from-julia-to-vr/4950 "2020-06-22T21:54:15Z")

</div>

Hi all, I am not quite sure this is the best place for this discussion so fee free to let me know and I’ll move that somewhere more appropriate if needed. Put simply, I want to know if there exists already or if some p…

---

## [Emacs and lsp](https://discourse.julialang.org/t/emacs-and-lsp/41890)

<div class="topic-metadata">

**Author:** [@d1cker](https://discourse.julialang.org/u/d1cker)\
**Replies:** 1\
**Last updated:** [June 22, 2020, 8:36pm UTC](https://discourse.julialang.org/t/emacs-and-lsp/41890 "2020-06-22T20:36:19Z")

</div>

Could someone share his lsp config? ( I don’t mind if it’s lsp-mode or eglot)

---

## [Performance of value type construction](https://discourse.julialang.org/t/performance-of-value-type-construction/41603)

<div class="topic-metadata">

**Author:** [@mtfishman](https://discourse.julialang.org/u/mtfishman)\
**Replies:** 1\
**Last updated:** [June 22, 2020, 8:11pm UTC](https://discourse.julialang.org/t/performance-of-value-type-construction/41603 "2020-06-22T20:11:35Z")

</div>

I noticed the following performance discrepancy between making a value type and making the instance of a value type using a runtime value: julia\> using BenchmarkTools julia\> x = "x" "x" julia\> f(x::String) = Val{Symbo…

---

## [LIFO Channels](https://discourse.julialang.org/t/lifo-channels/31343)

<div class="topic-metadata">

**Author:** [@jtackm](https://discourse.julialang.org/u/jtackm)\
**Replies:** 3\
**Last updated:** [June 22, 2020, 7:47pm UTC](https://discourse.julialang.org/t/lifo-channels/31343 "2020-06-22T19:47:03Z")

</div>

I have a parallel computation workflow that uses RemoteChannel-\>Channel to communicate results between master and worker nodes. Channels by default work like a queue (FIFO): using Distributed julia\> shared\_job\_q = Remo…

---

## [Private packages?](https://discourse.julialang.org/t/private-packages/41875)

<div class="topic-metadata">

**Author:** [@jbpatzer](https://discourse.julialang.org/u/jbpatzer)\
**Replies:** 2\
**Last updated:** [June 22, 2020, 6:41pm UTC](https://discourse.julialang.org/t/private-packages/41875 "2020-06-22T18:41:17Z")

</div>

Is it possible to turn a module into a package, compile it with PackageCompiler and then distribute it to selected colleagues without registering it and making it available to everyone and his uncle?

---

## [Passing a String with file name of shared library to ccall](https://discourse.julialang.org/t/passing-a-string-with-file-name-of-shared-library-to-ccall/41799)

<div class="topic-metadata">

**Author:** [@pauljurczak](https://discourse.julialang.org/u/pauljurczak)\
**Replies:** 4\
**Last updated:** [June 22, 2020, 6:22pm UTC](https://discourse.julialang.org/t/passing-a-string-with-file-name-of-shared-library-to-ccall/41799 "2020-06-22T18:22:13Z")

</div>

I have a shared C library with its full name in ENV\["LIBSIMC"\]: julia\> ENV\["LIBSIMC"\] "/home/paul/st/simc/bin/libsimc.so" My call works fine with a literal constant, e.g.: ccall((:logText, "/home/paul/st/simc/bin/libs…

---

## [DifferentialEquations: Confusion regarding time points and values in the solution array](https://discourse.julialang.org/t/differentialequations-confusion-regarding-time-points-and-values-in-the-solution-array/41730)

<div class="topic-metadata">

**Author:** [@Sanji\_Vinsmoke](https://discourse.julialang.org/u/Sanji_Vinsmoke)\
**Replies:** 10\
**Last updated:** [June 19, 2020, 5:54pm UTC](https://discourse.julialang.org/t/differentialequations-confusion-regarding-time-points-and-values-in-the-solution-array/41730 "2020-06-19T17:54:39Z")

</div>

I am a bit confused about the timepoints that the solution array represents. Since the algorithms used to solve are adaptive, the size of solutions might be different. Now, if I say that all my growth rates of species h…

---

## [How to speed up loading libraries](https://discourse.julialang.org/t/how-to-speed-up-loading-libraries/41856)

<div class="topic-metadata">

**Author:** [@dave](https://discourse.julialang.org/u/dave)\
**Replies:** 4\
**Last updated:** [June 22, 2020, 6:11pm UTC](https://discourse.julialang.org/t/how-to-speed-up-loading-libraries/41856 "2020-06-22T18:11:49Z")

</div>

Hello, I’m starting off in Julia and I want to write a program to use a couple of Python libraries that I have. I have a script that I run non-interactively (I use emacs for dev) and it looks like this cat test1.jl @t…

---

## [Specifying column type efficiently in CSV.read for large datasets](https://discourse.julialang.org/t/specifying-column-type-efficiently-in-csv-read-for-large-datasets/41866)

<div class="topic-metadata">

**Author:** [@bray2016](https://discourse.julialang.org/u/bray2016)\
**Replies:** 4\
**Last updated:** [June 22, 2020, 6:07pm UTC](https://discourse.julialang.org/t/specifying-column-type-efficiently-in-csv-read-for-large-datasets/41866 "2020-06-22T18:07:47Z")

</div>

Hello all, Complete Julia noob here. I am trying to figure out how to work with large datasets in Julia. I am trying to import a dataset that has missing values. It seems that Julia defaults to importing all these colum…

---

## [Inefficiency of add\_edge! in SimpleWeightedGraphs](https://discourse.julialang.org/t/inefficiency-of-add-edge-in-simpleweightedgraphs/41832)

<div class="topic-metadata">

**Author:** [@erlebach](https://discourse.julialang.org/u/erlebach)\
**Replies:** 7\
**Last updated:** [June 22, 2020, 5:37pm UTC](https://discourse.julialang.org/t/inefficiency-of-add-edge-in-simpleweightedgraphs/41832 "2020-06-22T17:37:39Z")

</div>

I have a master graph with 250,000 nodes, and a variable called homes which is a Vector of Vectors of size 4, with values between 1 and 100,000. The idea is that many vector of size 4 has a corresponding dense graph, whi…

---

## [CUDNNError when using Flux within a Task](https://discourse.julialang.org/t/cudnnerror-when-using-flux-within-a-task/39199)

<div class="topic-metadata">

**Author:** [@jonathan-laurent](https://discourse.julialang.org/u/jonathan-laurent)\
**Replies:** 15\
**Last updated:** [June 22, 2020, 5:33pm UTC](https://discourse.julialang.org/t/cudnnerror-when-using-flux-within-a-task/39199 "2020-06-22T17:33:40Z")

</div>

I have been trying to release a Flux backend for my AlphaZero.jl library, but I am encountering a mysterious CUDNN error (CUDNN\_STATUS\_INTERNAL\_ERROR). Here is some info: The error happens consistently at every run, a…

---

## [\[ANN\] DFTK.jl - A pure-Julia implementation of density-functional theory](https://discourse.julialang.org/t/ann-dftk-jl-a-pure-julia-implementation-of-density-functional-theory/40806)

<div class="topic-metadata">

**Author:** [@mfh](https://discourse.julialang.org/u/mfh)\
**Replies:** 7\
**Last updated:** [June 22, 2020, 5:16pm UTC](https://discourse.julialang.org/t/ann-dftk-jl-a-pure-julia-implementation-of-density-functional-theory/40806 "2020-06-22T17:16:40Z")

</div>

DFTK, the density-functional toolkit, is a Julia package @antoine-levitt and me started about a year ago and now we feel it is time to announce it to the community! The aim of the package is to become a platform for met…

---

## [Complex vector math performance: StructArray of CuArrays vs CuArrays](https://discourse.julialang.org/t/complex-vector-math-performance-structarray-of-cuarrays-vs-cuarrays/40576)

<div class="topic-metadata">

**Author:** [@ozmaden](https://discourse.julialang.org/u/ozmaden)\
**Replies:** 2\
**Last updated:** [June 22, 2020, 4:40pm UTC](https://discourse.julialang.org/t/complex-vector-math-performance-structarray-of-cuarrays-vs-cuarrays/40576 "2020-06-22T16:40:45Z")

</div>

Hi there! I’m benchmarking a GPU implementation of a function performing downconversion of a signal given a carrier signal replica. The original form of the function in the library looks like this: julia\> function downc…

---

## [Suppress output when using Weave](https://discourse.julialang.org/t/suppress-output-when-using-weave/41857)

<div class="topic-metadata">

**Author:** [@eaubanel](https://discourse.julialang.org/u/eaubanel)\
**Replies:** 1\
**Last updated:** [June 22, 2020, 4:07pm UTC](https://discourse.julialang.org/t/suppress-output-when-using-weave/41857 "2020-06-22T16:07:35Z")

</div>

I noticed that I can’t suppress output using a semicolon when creating a document using Weave. For example: #' Test Weave's handling of output suppression via ; c = rand(); #' should show no output. Here’s what the HTM…

---

## [Installing JuliaPro](https://discourse.julialang.org/t/installing-juliapro/41693)

<div class="topic-metadata">

**Author:** [@trodger88](https://discourse.julialang.org/u/trodger88)\
**Replies:** 4\
**Last updated:** [June 22, 2020, 3:36pm UTC](https://discourse.julialang.org/t/installing-juliapro/41693 "2020-06-22T15:36:30Z")

</div>

When attempting to start JuliaPro after installation I get the message "7234:0618/142137.028535:FATAL:atom\_main\_delegate.cc(194)\] Running as root without --no-sandbox is not supported. See 638180 - chromium - An open-so…

---

## [Error messages from Gtk callbacks are not being shown](https://discourse.julialang.org/t/error-messages-from-gtk-callbacks-are-not-being-shown/38412)

<div class="topic-metadata">

**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 3\
**Last updated:** [June 22, 2020, 3:27pm UTC](https://discourse.julialang.org/t/error-messages-from-gtk-callbacks-are-not-being-shown/38412 "2020-06-22T15:27:26Z")

</div>

I’m developing a Gkt.jl application, and errors that happen inside a callback are not being displayed. For example, if you run this code and click the button multiple times: using Gtk w = Gtk.Window() b = Gtk.Button("h…

---

## [How to get lowered names of functions with kwargs to precompile](https://discourse.julialang.org/t/how-to-get-lowered-names-of-functions-with-kwargs-to-precompile/41861)

<div class="topic-metadata">

**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 1\
**Last updated:** [June 22, 2020, 2:44pm UTC](https://discourse.julialang.org/t/how-to-get-lowered-names-of-functions-with-kwargs-to-precompile/41861 "2020-06-22T14:44:59Z")

</div>

Hi! I have a lot of functions in a package that has keywords arguments and I want to precompile them. However, I am not sure how can I get the lowered name. For example: julia\> function teste(::Val{:a}; b = 1, c = 2) …

---

## [Have you used the IIS/conflict-refiner feature of a solver? How would you like to access it from JuMP?](https://discourse.julialang.org/t/have-you-used-the-iis-conflict-refiner-feature-of-a-solver-how-would-you-like-to-access-it-from-jump/41862)

<div class="topic-metadata">

**Author:** [@dourouc05](https://discourse.julialang.org/u/dourouc05)\
**Replies:** 0\
**Last updated:** [June 22, 2020, 1:51pm UTC](https://discourse.julialang.org/t/have-you-used-the-iis-conflict-refiner-feature-of-a-solver-how-would-you-like-to-access-it-from-jump/41862 "2020-06-22T13:51:42Z")

</div>

Hi all, Right now, the plumbing work has been performed in the JuMP ecosystem to let you access the IIS/conflict-refiner functionality of your solver. More precisely, there is a low-level interface in MathOptInterface t…

---

## [Tensor Contractions for N-dimensional tensors](https://discourse.julialang.org/t/tensor-contractions-for-n-dimensional-tensors/41810)

<div class="topic-metadata">

**Author:** [@morkip](https://discourse.julialang.org/u/morkip)\
**Replies:** 5\
**Last updated:** [June 22, 2020, 1:29pm UTC](https://discourse.julialang.org/t/tensor-contractions-for-n-dimensional-tensors/41810 "2020-06-22T13:29:10Z")

</div>

I am working with exponentially sized tensors (exponential in a given variable N, for my case to the basis 4). Up to now, I stored the tensors linearly indexed, that is in a vector from 1:4^N. Contractions where therefor…

---

## [Logarithm of Symbolic Polynomial](https://discourse.julialang.org/t/logarithm-of-symbolic-polynomial/25729)

<div class="topic-metadata">

**Author:** [@alulushi](https://discourse.julialang.org/u/alulushi)\
**Replies:** 11\
**Last updated:** [June 22, 2020, 1:23pm UTC](https://discourse.julialang.org/t/logarithm-of-symbolic-polynomial/25729 "2020-06-22T13:23:38Z")

</div>

Hi all, I’m new to Julia and have been using it for about a week, so apologies if the answer to this is obvious and I just haven’t been able to work it out. The project that I’m using Julia for requires taking the logar…

---

## [When to return an explicit \`nothing\` from a function?](https://discourse.julialang.org/t/when-to-return-an-explicit-nothing-from-a-function/41846)

<div class="topic-metadata">

**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 9\
**Last updated:** [June 22, 2020, 1:15pm UTC](https://discourse.julialang.org/t/when-to-return-an-explicit-nothing-from-a-function/41846 "2020-06-22T13:15:28Z")

</div>

After making a few minor modifications to a function, I was surprised that my program went from a few hundred allocations to millions. It turns out that even though I never used the return value of the function (the las…

---

## [Is it possible to make this function work in Julia?](https://discourse.julialang.org/t/is-it-possible-to-make-this-function-work-in-julia/41835)

<div class="topic-metadata">

**Author:** [@reb](https://discourse.julialang.org/u/reb)\
**Replies:** 3\
**Last updated:** [June 22, 2020, 1:01pm UTC](https://discourse.julialang.org/t/is-it-possible-to-make-this-function-work-in-julia/41835 "2020-06-22T13:01:28Z")

</div>

Sorry this takes so much verbiage. I know that most of the functions I need to write will have several variables already defined prior to the definition of the function. The value of these variables must be accessible …

[Previous page](https://discourse.julialang.org/latest.md?page=1708)

[Next page](https://discourse.julialang.org/latest.md?page=1710)