# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=799

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**Page:** 800

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## [Debugging ERROR: ArgumentError: invalid version range](https://discourse.julialang.org/t/debugging-error-argumenterror-invalid-version-range/32979)

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**Author:** [@kevbonham](https://discourse.julialang.org/u/kevbonham)\
**Replies:** 7\
**Last updated:** [January 5, 2020, 5:42pm UTC](https://discourse.julialang.org/t/debugging-error-argumenterror-invalid-version-range/32979 "2020-01-05T17:42:04Z")

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(v1.3) pkg\> activate debug Activating new environment at \`~/repos/scratch/debug/Project.toml\` (debug) pkg\> dev https://github.com/Klepac-Ceraj-Lab/echo\_analysis Updating registry at \`~/.julia/registries/BioJuliaRegist…

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## [Rename registered package](https://discourse.julialang.org/t/rename-registered-package/32994)

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**Author:** [@fipelle](https://discourse.julialang.org/u/fipelle)\
**Replies:** 0\
**Last updated:** [January 5, 2020, 3:23pm UTC](https://discourse.julialang.org/t/rename-registered-package/32994 "2020-01-05T15:23:23Z")

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Hi, I am thinking about renaming a registered package (TSAnalysis.jl) to something more explicit as suggested in a recent discussion. I am not sure what is the latest view on that - I have seen @ChrisRackauckas’ reply …

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## [GMT.jl Installation on Windows 10](https://discourse.julialang.org/t/gmt-jl-installation-on-windows-10/32954)

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**Author:** [@Dervis](https://discourse.julialang.org/u/Dervis)\
**Replies:** 4\
**Last updated:** [January 5, 2020, 4:35am UTC](https://discourse.julialang.org/t/gmt-jl-installation-on-windows-10/32954 "2020-01-05T04:35:41Z")

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Hello, Is there anyone who was able to successfully install GMT.jl? I am trying to run following: However, getting following error: error compiling common\_plot\_xyz: error compiling gmt: could not load library “gmt\_…

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## [SymPy.jl analogue of \`as\_dict\` and \`gens\`](https://discourse.julialang.org/t/sympy-jl-analogue-of-as-dict-and-gens/32972)

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**Author:** [@tdp](https://discourse.julialang.org/u/tdp)\
**Replies:** 3\
**Last updated:** [January 5, 2020, 4:09am UTC](https://discourse.julialang.org/t/sympy-jl-analogue-of-as-dict-and-gens/32972 "2020-01-05T04:09:21Z")

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Hi, What are the SymPy.jl analogues for as\_dict and gens? See below for a minimal piece of code I would like to translate from SymPy to SymPy.jl. This is part of a larger project I am translating from Python to Julia wh…

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## [HTTP.get() doesn't work in parallel function](https://discourse.julialang.org/t/http-get-doesnt-work-in-parallel-function/32956)

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**Author:** [@BMval](https://discourse.julialang.org/u/BMval)\
**Replies:** 5\
**Last updated:** [January 4, 2020, 7:33pm UTC](https://discourse.julialang.org/t/http-get-doesnt-work-in-parallel-function/32956 "2020-01-04T19:33:24Z")

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HTTP.get() doesn’t work in parallel function. Does anybody knows, how to manage HTTP.get() parallel works? Thank you in advance.

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## [Listing all names available in a module](https://discourse.julialang.org/t/listing-all-names-available-in-a-module/32601)

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**Author:** [@gcv](https://discourse.julialang.org/u/gcv)\
**Replies:** 3\
**Last updated:** [January 4, 2020, 7:01pm UTC](https://discourse.julialang.org/t/listing-all-names-available-in-a-module/32601 "2020-01-04T19:01:31Z")

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Is there a way to figure out which names are available in the context of a given module? I want to list all names defined in the module, and imported into the module’s namespace with using, and all modules referenced wit…

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## [Type instability in array concatenation](https://discourse.julialang.org/t/type-instability-in-array-concatenation/32951)

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**Author:** [@fleecy](https://discourse.julialang.org/u/fleecy)\
**Replies:** 3\
**Last updated:** [January 4, 2020, 10:09am UTC](https://discourse.julialang.org/t/type-instability-in-array-concatenation/32951 "2020-01-04T10:09:21Z")

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I have some simple code to make a left-quaternion multiplication matrix: function L\_q(q::Vector{T}) where {T\<:Real} return \[q\[1\] -q\[2:4\]'; q\[2:4\] q\[1\] \* I + SkewSymmetricMatrix(q\[2:4\])\] end But the problem is that …

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## [Is it possible to have variable frame time for each frame in a gif or apng image?](https://discourse.julialang.org/t/is-it-possible-to-have-variable-frame-time-for-each-frame-in-a-gif-or-apng-image/32948)

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**Author:** [@coldinjection](https://discourse.julialang.org/u/coldinjection)\
**Replies:** 1\
**Last updated:** [January 4, 2020, 8:06am UTC](https://discourse.julialang.org/t/is-it-possible-to-have-variable-frame-time-for-each-frame-in-a-gif-or-apng-image/32948 "2020-01-04T08:06:46Z")

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Say I want a specific frame (or multiple frames) to be displayed for a longer period of time in a gif or an apng, the file would be smaller if I specify a longer frame time for this frame instead of having the same ima…

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## [ForwardDiff saving unwanted variable](https://discourse.julialang.org/t/forwarddiff-saving-unwanted-variable/32928)

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**Author:** [@Caio\_Machado](https://discourse.julialang.org/u/Caio_Machado)\
**Replies:** 4\
**Last updated:** [January 4, 2020, 3:12am UTC](https://discourse.julialang.org/t/forwarddiff-saving-unwanted-variable/32928 "2020-01-04T03:12:51Z")

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Hi everyone, I am migrating from Matlab to Julia and I have noticed some weird (perhaps unwanted?) behavior of the ForwardDiff package. using ForwardDiff function eq() function qfun(x) q = x\[1\] + x\[2\]…

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## [How to get buttons to span full height of window using Gtk.jl with Grid layout](https://discourse.julialang.org/t/how-to-get-buttons-to-span-full-height-of-window-using-gtk-jl-with-grid-layout/32946)

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**Author:** [@mantzaris](https://discourse.julialang.org/u/mantzaris)\
**Replies:** 0\
**Last updated:** [January 3, 2020, 10:54pm UTC](https://discourse.julialang.org/t/how-to-get-buttons-to-span-full-height-of-window-using-gtk-jl-with-grid-layout/32946 "2020-01-03T22:54:17Z")

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I am trying to use the Grid layout (with Gtk.jl) but it is behaving differently to what I would expect. I expected that the grid would be set of cells which widgets can be inserted into the fixed cells and stretched in …

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## [Онлайн компилятор Julia](https://discourse.julialang.org/t/julia/22595)

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**Author:** [@11110](https://discourse.julialang.org/u/11110)\
**Replies:** 7\
**Last updated:** [January 3, 2020, 9:00pm UTC](https://discourse.julialang.org/t/julia/22595 "2020-01-03T21:00:05Z")

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Всем привет! Нашёл онлайн компилятор Julia: http://www.compileonline.com/execute\_julia\_online.php Не получается подключать package, добавлять пакеты. При этом можно выводить текст. В чём проблема? Подскажите, есть …

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## [Improve performance of computation graph evaluation](https://discourse.julialang.org/t/improve-performance-of-computation-graph-evaluation/32873)

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**Author:** [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Replies:** 5\
**Last updated:** [January 3, 2020, 8:48pm UTC](https://discourse.julialang.org/t/improve-performance-of-computation-graph-evaluation/32873 "2020-01-03T20:48:58Z")

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Hi, NaiveNASlib.jl uses a run-of-the-mill representation of a computation graph composed of AbstractVertex structs where each vertex is associated with an operation (e.g a neural network layer) as well as its input vert…

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## [Multi-threading bug?](https://discourse.julialang.org/t/multi-threading-bug/32937)

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**Author:** [@gmouts](https://discourse.julialang.org/u/gmouts)\
**Replies:** 7\
**Last updated:** [January 3, 2020, 8:22pm UTC](https://discourse.julialang.org/t/multi-threading-bug/32937 "2020-01-03T20:22:12Z")

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I am trying to make my code to run on multiple threads and I was reading through this. I got the following very weird result: julia\> Threads.nthreads() 6 julia\> Threads.@threads for i = 1:10 println("i = $…

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## [Flux vs Tensorflow training performance comparison?](https://discourse.julialang.org/t/flux-vs-tensorflow-training-performance-comparison/32926)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 5\
**Last updated:** [January 3, 2020, 7:38pm UTC](https://discourse.julialang.org/t/flux-vs-tensorflow-training-performance-comparison/32926 "2020-01-03T19:38:24Z")

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Has anyone done a performance comparison between Flux and Tensorflow, on the speed of training a model? I mean taking some conveniently pre-defined model on some standard dataset (say MNIST) and training it using both li…

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## [Trying to understand communication between workers in simple version of pmap](https://discourse.julialang.org/t/trying-to-understand-communication-between-workers-in-simple-version-of-pmap/32531)

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**Author:** [@Bruno\_Amorim](https://discourse.julialang.org/u/Bruno_Amorim)\
**Replies:** 4\
**Last updated:** [January 3, 2020, 11:39am UTC](https://discourse.julialang.org/t/trying-to-understand-communication-between-workers-in-simple-version-of-pmap/32531 "2020-01-03T11:39:00Z")

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I am trying to understand how different workers can communicate in Julia. In the documentation of previous versions of Julia (\<= v0.6) in the Parallel Computing section, a simple pmap function was given as an example. T…

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## [\[SOLVED\] Unable to use local package](https://discourse.julialang.org/t/solved-unable-to-use-local-package/15946)

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**Author:** [@zaen](https://discourse.julialang.org/u/zaen)\
**Replies:** 7\
**Last updated:** [January 3, 2020, 1:50am UTC](https://discourse.julialang.org/t/solved-unable-to-use-local-package/15946 "2020-01-03T01:50:42Z")

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I’ve got a local copy of a package that I’ve modified to work with Julia 1.0 and would like to send it to someone else. One option is to have them download the original package, make the edits in place, and then use the …

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## [What does \`activate\` really do?](https://discourse.julialang.org/t/what-does-activate-really-do/32898)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 2\
**Last updated:** [January 2, 2020, 10:32pm UTC](https://discourse.julialang.org/t/what-does-activate-really-do/32898 "2020-01-02T22:32:36Z")

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I don’t know why but I am having a terrible time understanding environments in Julia. I really want to understand what activate does and how one should use it. Here is just one of the things I am not wrapping my head aro…

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## [Filter() drop elements of a tuple with singleton doesn't work](https://discourse.julialang.org/t/filter-drop-elements-of-a-tuple-with-singleton-doesnt-work/32896)

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**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 7\
**Last updated:** [January 2, 2020, 10:16pm UTC](https://discourse.julialang.org/t/filter-drop-elements-of-a-tuple-with-singleton-doesnt-work/32896 "2020-01-02T22:16:22Z")

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I want to remove some models in tuple “dropm”, from a list of models “mList”. This fails when the tuple “dropm” is a singleton. It only works if “dropm” is a Vector{string}. I want it to work if “dropm” is a tuple. m…

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## [Does 'gradient' allocate?](https://discourse.julialang.org/t/does-gradient-allocate/32880)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 1\
**Last updated:** [January 2, 2020, 6:10pm UTC](https://discourse.julialang.org/t/does-gradient-allocate/32880 "2020-01-02T18:10:33Z")

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In a call such as g = gradient(loss, ps) , where ps is a Params object (see for instance this line: Flux.jl/train.jl at e92da0cf850a982c425b83c92d6274174e52b02c · FluxML/Flux.jl · GitHub), am I allocating a new vector fo…

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## [Calculating Driving Distance between two waypoints](https://discourse.julialang.org/t/calculating-driving-distance-between-two-waypoints/32866)

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**Author:** [@Dervis](https://discourse.julialang.org/u/Dervis)\
**Replies:** 5\
**Last updated:** [January 2, 2020, 5:50pm UTC](https://discourse.julialang.org/t/calculating-driving-distance-between-two-waypoints/32866 "2020-01-02T17:50:08Z")

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Dear all, I wonder if there is any way to calculate driving distance and driving time between two waypoints? I have checked Googlemaps Distance Matrix API, but I couldn’t find any solid example that is used in Julia. A…

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## [Confused with @time result for simple addtion of arrays](https://discourse.julialang.org/t/confused-with-time-result-for-simple-addtion-of-arrays/32834)

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**Author:** [@balabi](https://discourse.julialang.org/u/balabi)\
**Replies:** 9\
**Last updated:** [January 2, 2020, 4:43pm UTC](https://discourse.julialang.org/t/confused-with-time-result-for-simple-addtion-of-arrays/32834 "2020-01-02T16:43:33Z")

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Hello, I am new to julia. I just installed the latest julia 1.3.1, and then run several small timings. First I define a=\[1,2,3\] Then timing the first time @time a+a it outputs 0.073568 seconds (231.55 k allocations…

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## [Problem installing IJulia for 1.3.1 on Windows 10](https://discourse.julialang.org/t/problem-installing-ijulia-for-1-3-1-on-windows-10/32853)

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**Author:** [@floriano](https://discourse.julialang.org/u/floriano)\
**Replies:** 2\
**Last updated:** [January 2, 2020, 2:42pm UTC](https://discourse.julialang.org/t/problem-installing-ijulia-for-1-3-1-on-windows-10/32853 "2020-01-02T14:42:52Z")

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Good evening, I had Julia 1.2.0 running with IJulia. Now I tried updating to 1.3.1 After installing 1.3.1 I tried to add IJulia, but it fails. Complete fresh installs also do not help. I also cannot reinstall 1.2.0 wit…

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## [Docker image with compiled packages for instant loading!](https://discourse.julialang.org/t/docker-image-with-compiled-packages-for-instant-loading/32871)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 0\
**Last updated:** [January 2, 2020, 12:36pm UTC](https://discourse.julialang.org/t/docker-image-with-compiled-packages-for-instant-loading/32871 "2020-01-02T12:36:47Z")

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I have been learning docker and made this docker image with Julia installed and many data science packages that I use precompiled for instant loading! Check it out here: https://hub.docker.com/r/xiaodaidocker2019/julia-…

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## [Optimizing Calculation in Julia compared to C (New to Julia)](https://discourse.julialang.org/t/optimizing-calculation-in-julia-compared-to-c-new-to-julia/32723)

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**Author:** [@loki](https://discourse.julialang.org/u/loki)\
**Replies:** 25\
**Last updated:** [January 1, 2020, 10:34pm UTC](https://discourse.julialang.org/t/optimizing-calculation-in-julia-compared-to-c-new-to-julia/32723 "2020-01-01T22:34:13Z")

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Hello, just starting to make the switch to Julia from Matlab/C. I’ve been reading up on the speed advantages of Julia and recognize the power that can be wielded in the right hands. I was hoping I could receive some poin…

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## [How to garbage collect pacakges regardless or last used date?](https://discourse.julialang.org/t/how-to-garbage-collect-pacakges-regardless-or-last-used-date/32865)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 6\
**Last updated:** [January 2, 2020, 7:17am UTC](https://discourse.julialang.org/t/how-to-garbage-collect-pacakges-regardless-or-last-used-date/32865 "2020-01-02T07:17:15Z")

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I recall reading somewhere that \]gc is conservative and only remove packages that haven’t been used in the last 1 month. My question how do I do it more aggressively so that I can remove a package that is no longer requ…

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## [Interrupts and \`@spawn\` with \`ccall\`](https://discourse.julialang.org/t/interrupts-and-spawn-with-ccall/32864)

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**Author:** [@ssfrr](https://discourse.julialang.org/u/ssfrr)\
**Replies:** 1\
**Last updated:** [January 2, 2020, 4:43am UTC](https://discourse.julialang.org/t/interrupts-and-spawn-with-ccall/32864 "2020-01-02T04:43:00Z")

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I’m calling some C code many times in a loop, and I expect it to spend a lot of its time blocked. To let other Julia tasks take control while my C code is blocked I’m using @spawn, then fetching the result: fetch(Th…

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## [Why is automerge failing](https://discourse.julialang.org/t/why-is-automerge-failing/32859)

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**Author:** [@colintbowers](https://discourse.julialang.org/u/colintbowers)\
**Replies:** 2\
**Last updated:** [January 2, 2020, 4:32am UTC](https://discourse.julialang.org/t/why-is-automerge-failing/32859 "2020-01-02T04:32:08Z")

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Hi all, I’m trying to submit a minor version increment for my registered package ForecastEval. Unfortunately automerge keeps failing. The PR to JuliaRegistries is here. Originally, I could see from the output that auto…

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## [Unintuitive behavior of package update with --fixed](https://discourse.julialang.org/t/unintuitive-behavior-of-package-update-with-fixed/32855)

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**Author:** [@bicycle1885](https://discourse.julialang.org/u/bicycle1885)\
**Replies:** 2\
**Last updated:** [January 1, 2020, 11:39pm UTC](https://discourse.julialang.org/t/unintuitive-behavior-of-package-update-with-fixed/32855 "2020-01-01T23:39:37Z")

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Hi, I found a weird behavior of the update command in Pkg.jl, which looks a bug to me. But I’m not perfectly sure so let me ask here before filing an issue on the repository. Imagine a situation where you have DataStru…

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## [Artifacts.toml timestamp is in the future](https://discourse.julialang.org/t/artifacts-toml-timestamp-is-in-the-future/32047)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 23\
**Last updated:** [January 1, 2020, 9:42pm UTC](https://discourse.julialang.org/t/artifacts-toml-timestamp-is-in-the-future/32047 "2020-01-01T21:42:57Z")

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What’s up with this? time stamp 2019-12-09 08:40:51 is 0.244783138 s in the future tar: JuliaBinaryWrappers-Wayland\_protocols\_jll.jl-d53533e/Artifacts.toml: time stamp 2019-12-09 08:40:51 is 0.244783138 s in the future …

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## [Fortuna cryptographically secure pseudo random number generator (generator only) available](https://discourse.julialang.org/t/fortuna-cryptographically-secure-pseudo-random-number-generator-generator-only-available/32832)

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**Author:** [@mleisher](https://discourse.julialang.org/u/mleisher)\
**Replies:** 0\
**Last updated:** [December 31, 2019, 11:05pm UTC](https://discourse.julialang.org/t/fortuna-cryptographically-secure-pseudo-random-number-generator-generator-only-available/32832 "2019-12-31T23:05:59Z")

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My first attempt at a working Fortuna PRNG (generator only, no seed file or entropy accumulator) can be found in my collection of tidbits as Fortuna.jl.

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