# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1841

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

**Page:** 1842

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## [Why \`Tuple{Vararg{T, 2} where T} == Tuple{Any, Any}\`?](https://discourse.julialang.org/t/why-tuple-vararg-t-2-where-t-tuple-any-any/33511)

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**Author:** [@Wenjie](https://discourse.julialang.org/u/Wenjie)\
**Replies:** 2\
**Last updated:** [January 21, 2020, 1:39am UTC](https://discourse.julialang.org/t/why-tuple-vararg-t-2-where-t-tuple-any-any/33511 "2020-01-21T01:39:20Z")

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Why this is the case, instead of being a UnionAll like Arrays?

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## [2d Histogram?](https://discourse.julialang.org/t/2d-histogram/33605)

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**Author:** [@BMval](https://discourse.julialang.org/u/BMval)\
**Replies:** 1\
**Last updated:** [January 21, 2020, 1:16am UTC](https://discourse.julialang.org/t/2d-histogram/33605 "2020-01-21T01:16:07Z")

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Does anybody know, is available 2d Histogram function? thanks

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## [Passing array of pointers to CUDA kernel](https://discourse.julialang.org/t/passing-array-of-pointers-to-cuda-kernel/33570)

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**Author:** [@Michael\_Benton](https://discourse.julialang.org/u/Michael_Benton)\
**Replies:** 2\
**Last updated:** [January 20, 2020, 5:00pm UTC](https://discourse.julialang.org/t/passing-array-of-pointers-to-cuda-kernel/33570 "2020-01-20T17:00:09Z")

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I need to be able to stack arbitrarily sized cuarrays and CuTextures as a single input to a kernel, so I can do operations in the kernel that loop over the data like so: (get GitHub - cdsousa/CuTextures.jl: \[DEPRECATED,…

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## [RFC: Make an abstraction for custom task parallel schedulers (GSoC proposal)](https://discourse.julialang.org/t/rfc-make-an-abstraction-for-custom-task-parallel-schedulers-gsoc-proposal/33284)

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**Author:** [@s417-lama](https://discourse.julialang.org/u/s417-lama)\
**Replies:** 19\
**Last updated:** [January 20, 2020, 8:03pm UTC](https://discourse.julialang.org/t/rfc-make-an-abstraction-for-custom-task-parallel-schedulers-gsoc-proposal/33284 "2020-01-20T20:03:50Z")

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I’m currently thinking of applying for JSoC/GSoC, and I’d like to discuss a project for it, which is about task parallelism. As discussed in reduce overhead of task creation and switching · Issue #33762 · JuliaLang/juli…

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## [Installation of MKL on Julia 1.3.1](https://discourse.julialang.org/t/installation-of-mkl-on-julia-1-3-1/33562)

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**Author:** [@kumarbalachandran](https://discourse.julialang.org/u/kumarbalachandran)\
**Replies:** 2\
**Last updated:** [January 20, 2020, 7:17pm UTC](https://discourse.julialang.org/t/installation-of-mkl-on-julia-1-3-1/33562 "2020-01-20T19:17:48Z")

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The MKL installation on julia-1.3.1 fails on my Dell laptop build MKL Building LibCURL ────────→ \`C:\\Users\\kumar\\.julia\\packages\\LibCURL\\lWJxD\\deps\\build.log\` Building WinRPM ─────────→ \`C:\\Users\\kumar\\.julia\\packag…

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## [Error missing about side-effect on immutable type](https://discourse.julialang.org/t/error-missing-about-side-effect-on-immutable-type/33588)

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**Author:** [@tomtom](https://discourse.julialang.org/u/tomtom)\
**Replies:** 11\
**Last updated:** [January 20, 2020, 4:46pm UTC](https://discourse.julialang.org/t/error-missing-about-side-effect-on-immutable-type/33588 "2020-01-20T16:46:48Z")

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docs mentioned that: Julia function arguments follow a convention sometimes called “pass-by-sharing”… Modifications to mutable values (such as Array s) made within a function will be visible to the caller. I think i…

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## [How to convert an svg file to png with fixed pixel size/resolution](https://discourse.julialang.org/t/how-to-convert-an-svg-file-to-png-with-fixed-pixel-size-resolution/33561)

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**Author:** [@hhaensel](https://discourse.julialang.org/u/hhaensel)\
**Replies:** 1\
**Last updated:** [January 20, 2020, 4:06pm UTC](https://discourse.julialang.org/t/how-to-convert-an-svg-file-to-png-with-fixed-pixel-size-resolution/33561 "2020-01-20T16:06:13Z")

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I wonder how to fix the size of a png when converting svg to png with Rsvg.jl Currently I am using the demo code using Rsvg using Cairo filename\_in = "a4.svg" filename\_out = "a4.png" r = Rsvg.handle\_new\_from\_file(fil…

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## [Make error!](https://discourse.julialang.org/t/make-error/33545)

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**Author:** [@buzz](https://discourse.julialang.org/u/buzz)\
**Replies:** 3\
**Last updated:** [January 20, 2020, 4:11pm UTC](https://discourse.julialang.org/t/make-error/33545 "2020-01-20T16:11:24Z")

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curl: (28) Operation too slow. Less than 1 bytes/sec transferred the last 15 seconds /home/balaji/julia/deps/llvm.mk:575: recipe for target ‘/home/balaji/julia/deps/srccache/LLVM.v8.0.1-4.x86\_64-linux-gnu-gcc4.tar.gz’ f…

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## [Error when trying the first example for LoopVectorization](https://discourse.julialang.org/t/error-when-trying-the-first-example-for-loopvectorization/33586)

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**Author:** [@lesshaste](https://discourse.julialang.org/u/lesshaste)\
**Replies:** 5\
**Last updated:** [January 20, 2020, 3:32pm UTC](https://discourse.julialang.org/t/error-when-trying-the-first-example-for-loopvectorization/33586 "2020-01-20T15:32:45Z")

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I am trying the first example from GitHub - JuliaSIMD/LoopVectorization.jl: Macro(s) for vectorizing loops. . That is: using LoopVectorization, BenchmarkTools function mydot(a, b) s = 0.0 @inbounds @simd for i ∈…

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## [Restoration phase failed](https://discourse.julialang.org/t/restoration-phase-failed/33590)

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**Author:** [@GiuliaM](https://discourse.julialang.org/u/GiuliaM)\
**Replies:** 1\
**Last updated:** [January 20, 2020, 3:27pm UTC](https://discourse.julialang.org/t/restoration-phase-failed/33590 "2020-01-20T15:27:48Z")

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Hi everyone! I try to optimize a nonlinear problem with Ipopt (v0.6.1) using JuMP (v0.20.1). When the algorithm terminates, the output message is: “EXIT: Restoration Failed! Restoration phase converged to a feasible …

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## [JuMP nonlinear optimization not converging for camera calibration code](https://discourse.julialang.org/t/jump-nonlinear-optimization-not-converging-for-camera-calibration-code/33565)

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**Author:** [@brianguenter](https://discourse.julialang.org/u/brianguenter)\
**Replies:** 2\
**Last updated:** [January 20, 2020, 3:25pm UTC](https://discourse.julialang.org/t/jump-nonlinear-optimization-not-converging-for-camera-calibration-code/33565 "2020-01-20T15:25:21Z")

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I am using JuMP optimization to compute distortion correction parameters in camera images. This is a first step toward a more complete camera calibration package. It’s the first time I’ve used JuMP and the optimization…

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## [What is typeof(fun)?](https://discourse.julialang.org/t/what-is-typeof-fun/33523)

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**Author:** [@tomtom](https://discourse.julialang.org/u/tomtom)\
**Replies:** 5\
**Last updated:** [January 20, 2020, 1:57pm UTC](https://discourse.julialang.org/t/what-is-typeof-fun/33523 "2020-01-20T13:57:09Z")

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when I methods(Base.map), I see something like: \[1\] map(::typeof(zero), A::BitArray) in Base at bitarray.jl:1659 what is typeof(zero)? indeed, I found that: julia\> f(x) = 2x f (generic function with 1 method) julia\> …

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## [Should a view of a SharedArray be also shared between workers?](https://discourse.julialang.org/t/should-a-view-of-a-sharedarray-be-also-shared-between-workers/33580)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 3\
**Last updated:** [January 20, 2020, 1:23pm UTC](https://discourse.julialang.org/t/should-a-view-of-a-sharedarray-be-also-shared-between-workers/33580 "2020-01-20T13:23:15Z")

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Consider the following simple example, where we try to fill a view of a SharedArray on a worker (I’ve tested it on julia 1.1.0): using Distributed w = addprocs(1)\[\] using SharedArrays function idid!(v) for i=1:len…

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## [Automatically disconnect idle workers](https://discourse.julialang.org/t/automatically-disconnect-idle-workers/33579)

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**Author:** [@pfarndt](https://discourse.julialang.org/u/pfarndt)\
**Replies:** 0\
**Last updated:** [January 20, 2020, 12:47pm UTC](https://discourse.julialang.org/t/automatically-disconnect-idle-workers/33579 "2020-01-20T12:47:12Z")

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While doing some interactive data analysis (in a Jupyter notebook) I often use a ClusterManagers.ElasticManager in the master process and then connect a couple of remote workers using Distributed.start\_worker(...). Some…

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## [Translate images by subpixel amounts](https://discourse.julialang.org/t/translate-images-by-subpixel-amounts/30248)

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**Author:** [@johnheyer](https://discourse.julialang.org/u/johnheyer)\
**Replies:** 5\
**Last updated:** [January 20, 2020, 11:11am UTC](https://discourse.julialang.org/t/translate-images-by-subpixel-amounts/30248 "2020-01-20T11:11:21Z")

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Hello, I’m trying to translate an image by arbitrary amounts, and am currently doing translations via JuliaImages and CoordinateTransformation packages as such: t = Translation(y\_shift, x\_shift) img = warp(img, t, indi…

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## [ForwardDiff: How to get the derivative part of a dual number](https://discourse.julialang.org/t/forwarddiff-how-to-get-the-derivative-part-of-a-dual-number/33560)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 4\
**Last updated:** [January 20, 2020, 10:00am UTC](https://discourse.julialang.org/t/forwarddiff-how-to-get-the-derivative-part-of-a-dual-number/33560 "2020-01-20T10:00:20Z")

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How do I get the derivative part b (or whatever it is called) of a dual number given by a+b\\epsilon, \\quad \\epsilon^2=0, defined using ForwardDiff package? In particular, with the dual number 3+1\\epsilon given by julia\>…

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## [Jupyter notebook: Use pgf code instead of pdf/svg image for export to latex](https://discourse.julialang.org/t/jupyter-notebook-use-pgf-code-instead-of-pdf-svg-image-for-export-to-latex/33344)

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**Author:** [@karlroyen](https://discourse.julialang.org/u/karlroyen)\
**Replies:** 11\
**Last updated:** [January 20, 2020, 9:58am UTC](https://discourse.julialang.org/t/jupyter-notebook-use-pgf-code-instead-of-pdf-svg-image-for-export-to-latex/33344 "2020-01-20T09:58:00Z")

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When displaying DataFrames in a Jupyter notebook they are nicely rendered using html. When you export the notebook to latex they are nicely exported as latex code creating that table. Is it possible to have the same fun…

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## [Schematic Way to resolve dependency issues in a package development](https://discourse.julialang.org/t/schematic-way-to-resolve-dependency-issues-in-a-package-development/33512)

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**Author:** [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Replies:** 3\
**Last updated:** [January 20, 2020, 9:16am UTC](https://discourse.julialang.org/t/schematic-way-to-resolve-dependency-issues-in-a-package-development/33512 "2020-01-20T09:16:59Z")

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Yesterday I ran into a not-so nice situation with packages and their dependencies. I added a package or updated a package (after \] activate MyPackage an \] update) to my current development status and while locally on my …

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## [Creating a complex matrix from a vector](https://discourse.julialang.org/t/creating-a-complex-matrix-from-a-vector/33555)

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**Author:** [@CPPhysics](https://discourse.julialang.org/u/CPPhysics)\
**Replies:** 8\
**Last updated:** [January 20, 2020, 7:17am UTC](https://discourse.julialang.org/t/creating-a-complex-matrix-from-a-vector/33555 "2020-01-20T07:17:37Z")

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I am sure this is simple but I cannot find the solution. I have a problem where I would like to create a complex matrix out of a real vector. For example, say I have a vector: test = randn(8) And I want to populate a c…

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## [Creating one's own Matrix type](https://discourse.julialang.org/t/creating-ones-own-matrix-type/33553)

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**Author:** [@timueh](https://discourse.julialang.org/u/timueh)\
**Replies:** 6\
**Last updated:** [January 20, 2020, 7:05am UTC](https://discourse.julialang.org/t/creating-ones-own-matrix-type/33553 "2020-01-20T07:05:26Z")

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I have a question related to 13:45 in Alan Edelman’s recent award presentation: In the following two code snippets, is there a deeper difference other than MyMatrix being more descriptive, i.e. the type tells me the typ…

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## [Constructing multi-dimensional array from existing ones](https://discourse.julialang.org/t/constructing-multi-dimensional-array-from-existing-ones/30268)

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**Author:** [@liwt31](https://discourse.julialang.org/u/liwt31)\
**Replies:** 12\
**Last updated:** [January 20, 2020, 6:34am UTC](https://discourse.julialang.org/t/constructing-multi-dimensional-array-from-existing-ones/30268 "2020-01-20T06:34:04Z")

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Hi, I’m a new user from Python. I’m trying to do something like: a, b = np.random.rand(5,5), np.random.rand(5,5) c = np.array(\[a, b\]) to obtain an array with dimension (2, 5, 5). But the following code seems not workin…

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## [\[ANN\] JDF.jl - Experimental Julia DataFrames serialization format](https://discourse.julialang.org/t/ann-jdf-jl-experimental-julia-dataframes-serialization-format/29067)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 3\
**Last updated:** [January 19, 2020, 9:13pm UTC](https://discourse.julialang.org/t/ann-jdf-jl-experimental-julia-dataframes-serialization-format/29067 "2020-01-19T21:13:11Z")

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Saving a DataFrame onto disk is tricky business. This is especially so for large datasets. The current choices are JLD, JLD2, JLSO, Feather, CSV. The first four are preferred to CSV as they are meant to be preserve typ…

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## [Any forest/agricultural/environmental Economist out there?](https://discourse.julialang.org/t/any-forest-agricultural-environmental-economist-out-there/33456)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [January 20, 2020, 4:47am UTC](https://discourse.julialang.org/t/any-forest-agricultural-environmental-economist-out-there/33456 "2020-01-20T04:47:30Z")

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Just out of curiosity, is there any {forest|agricultural|environmental} Economist out there ? For what do you use Julia ?

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## [Will the new DataFrames be memory mapped?](https://discourse.julialang.org/t/will-the-new-dataframes-be-memory-mapped/1022)

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**Author:** [@Fred](https://discourse.julialang.org/u/Fred)\
**Replies:** 11\
**Last updated:** [January 20, 2020, 12:05am UTC](https://discourse.julialang.org/t/will-the-new-dataframes-be-memory-mapped/1022 "2020-01-20T00:05:16Z")

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In Julia, large Arrays can be memory mapped using the function Mmap.mmap(type::Type{Array{T, N}}, dims). But I have to work with large DataFrames (I have to keep columns and rows names and often NA values) in geno-trans…

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## [Where did \`conv\` move to?](https://discourse.julialang.org/t/where-did-conv-move-to/18399)

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**Author:** [@Qqwy](https://discourse.julialang.org/u/Qqwy)\
**Replies:** 18\
**Last updated:** [January 19, 2020, 11:06pm UTC](https://discourse.julialang.org/t/where-did-conv-move-to/18399 "2020-01-19T23:06:25Z")

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Hello there! I finally have a reason to try out Julia. In this case: Testing some things related to digital signal processing. A lot of documentation still refers to Julia 0.7 and similar versions. I was able to find o…

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## [Request to try out mintty as a potential default terminal for Julia on Windows](https://discourse.julialang.org/t/request-to-try-out-mintty-as-a-potential-default-terminal-for-julia-on-windows/33432)

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**Author:** [@viralbshah](https://discourse.julialang.org/u/viralbshah)\
**Replies:** 18\
**Last updated:** [January 19, 2020, 10:50pm UTC](https://discourse.julialang.org/t/request-to-try-out-mintty-as-a-potential-default-terminal-for-julia-on-windows/33432 "2020-01-19T22:50:08Z")

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We have a potential solution now to be able to ship mintty as a default terminal for Julia on Windows. It would be great if users on Windows can try the solution outlined in the issue below, and report in that issue the …

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## [How do i know my package is reading the correct \`Project.toml\` files?](https://discourse.julialang.org/t/how-do-i-know-my-package-is-reading-the-correct-project-toml-files/33499)

<div class="topic-metadata">

**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 8\
**Last updated:** [January 19, 2020, 10:14pm UTC](https://discourse.julialang.org/t/how-do-i-know-my-package-is-reading-the-correct-project-toml-files/33499 "2020-01-19T22:14:46Z")

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I have developed a package MyPackage that has it’s own Project.toml and Manifest.toml files. I’ve dev this from my main environment so that my v1.2 Project.toml file looks like this: (v1.2) pkg\> st Status \`~/.julia/…

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## [Keyword Arguments vs Dict](https://discourse.julialang.org/t/keyword-arguments-vs-dict/33500)

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**Author:** [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)\
**Replies:** 10\
**Last updated:** [January 19, 2020, 9:19pm UTC](https://discourse.julialang.org/t/keyword-arguments-vs-dict/33500 "2020-01-19T21:19:05Z")

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I would like to know if it is a problem to use a Dict parameter for passing options to a method instead of using the keyword arguments mechanism already present in Julia. Basically, I have a method that takes a ten or m…

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## [Advent of Code 2019](https://discourse.julialang.org/t/advent-of-code-2019/31726)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 11\
**Last updated:** [January 19, 2020, 8:03pm UTC](https://discourse.julialang.org/t/advent-of-code-2019/31726 "2020-01-19T20:03:36Z")

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Hello everyone, I created a repository on Github for Advent of Code 2019. I solved the Day One puzzle today. However being in grad school, so I might not have time to solve every problem myself. It would be great if ot…

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## [BaseBenchmarks.jl not in registry?](https://discourse.julialang.org/t/basebenchmarks-jl-not-in-registry/33557)

<div class="topic-metadata">

**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 1\
**Last updated:** [January 19, 2020, 7:59pm UTC](https://discourse.julialang.org/t/basebenchmarks-jl-not-in-registry/33557 "2020-01-19T19:59:11Z")

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When I try to add this package, I get the following error: (v1.3) pkg\> add BaseBenchmarks ERROR: The following package names could not be resolved: \* BaseBenchmarks (not found in project, manifest or registry) Please s…

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