# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1524

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

**Page:** 1525

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## [No method matching error when calling generic constructor with concrete implementer of abstract type](https://discourse.julialang.org/t/no-method-matching-error-when-calling-generic-constructor-with-concrete-implementer-of-abstract-type/53192)

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**Author:** [@alice](https://discourse.julialang.org/u/alice)\
**Replies:** 15\
**Last updated:** [January 12, 2021, 3:14pm UTC](https://discourse.julialang.org/t/no-method-matching-error-when-calling-generic-constructor-with-concrete-implementer-of-abstract-type/53192 "2021-01-12T15:14:48Z")

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I am trying to implement several algorithms that share a branch-and-bound setup on top, but have different sub problems. To do this, I decided to create abstract types for the sub problems and make the branch-and-bound t…

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## [DataFrames/CSV.read: error on different machines](https://discourse.julialang.org/t/dataframes-csv-read-error-on-different-machines/53211)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 4\
**Last updated:** [January 12, 2021, 3:10pm UTC](https://discourse.julialang.org/t/dataframes-csv-read-error-on-different-machines/53211 "2021-01-12T15:10:55Z")

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Dear folks, I work on one and the same project on two different machines (both Ubuntu, Julia 1.4). The project-related Project.toml and Manifest.toml are in the project folder and I activate them before running my scrip…

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## [Any shortcut to 1:length(myVector)?](https://discourse.julialang.org/t/any-shortcut-to-1-length-myvector/52816)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 34\
**Last updated:** [January 12, 2021, 2:35pm UTC](https://discourse.julialang.org/t/any-shortcut-to-1-length-myvector/52816 "2021-01-12T14:35:54Z")

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Is there any build-in function in Julia to replace 1:length(myVector), i.e. to return a vector of integers from 1 to the length of myVector ? e.g.: myVector =\["a","b","c"\] for i in ???(myVector) println(i) # 1,2,3 …

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## [Meaning and error message of type-parameters](https://discourse.julialang.org/t/meaning-and-error-message-of-type-parameters/53198)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 4\
**Last updated:** [January 12, 2021, 1:43pm UTC](https://discourse.julialang.org/t/meaning-and-error-message-of-type-parameters/53198 "2021-01-12T13:43:18Z")

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Following this thread: We have this example: julia\> struct A{T} i end julia\> A(1) # does not work ERROR: MethodError: no method matching A(::Int64) Stacktrace: \[1\] top-level scope at REPL\[2\]:1 juli…

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## [CUDA.jl Differentiation Error](https://discourse.julialang.org/t/cuda-jl-differentiation-error/53011)

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**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 5\
**Last updated:** [January 12, 2021, 1:28pm UTC](https://discourse.julialang.org/t/cuda-jl-differentiation-error/53011 "2021-01-12T13:28:17Z")

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Dear All, while working on my project (epidemic model, solved using PINN), I tried to port my code to GPU. While function (loss function of my neural network) works and delivers reasonable speed up, while computing grad…

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## [Locating a method defined through a macro](https://discourse.julialang.org/t/locating-a-method-defined-through-a-macro/51764)

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**Author:** [@yha](https://discourse.julialang.org/u/yha)\
**Replies:** 3\
**Last updated:** [January 12, 2021, 12:19pm UTC](https://discourse.julialang.org/t/locating-a-method-defined-through-a-macro/51764 "2021-01-12T12:19:45Z")

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I’ve often encountered a problem figuring out where a method is defined when it’s definition happens through a macro. For example: macro foo() :(bar() = x) end @foo() bar() This gives an UndefVarError with a stac…

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## [Cannot update packages](https://discourse.julialang.org/t/cannot-update-packages/53193)

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**Author:** [@zwwi](https://discourse.julialang.org/u/zwwi)\
**Replies:** 0\
**Last updated:** [January 12, 2021, 11:55am UTC](https://discourse.julialang.org/t/cannot-update-packages/53193 "2021-01-12T11:55:57Z")

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Hello, I am using Julia 1.5.3 under WSL2. I haven’t updated the packages for a couple of months and tried to update them. But I got the following error: (@v1.5) pkg\> up Updating registry at \`~/.julia/registries/Gene…

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## [Second derivative of shape functions in JuAFEM](https://discourse.julialang.org/t/second-derivative-of-shape-functions-in-juafem/53160)

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**Author:** [@FrootLoops](https://discourse.julialang.org/u/FrootLoops)\
**Replies:** 3\
**Last updated:** [January 12, 2021, 8:56am UTC](https://discourse.julialang.org/t/second-derivative-of-shape-functions-in-juafem/53160 "2021-01-12T08:56:23Z")

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Hi, is there already a implemented function, which computes the second derivatives of the shape function at a given point? I am working with PDEs of higher-order and therefore need high order derivates of the used ansa…

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## [SimpleANOVA.jl 0.7.0 - Added repeated measures](https://discourse.julialang.org/t/simpleanova-jl-0-7-0-added-repeated-measures/53188)

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**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 0\
**Last updated:** [January 12, 2021, 7:06am UTC](https://discourse.julialang.org/t/simpleanova-jl-0-7-0-added-repeated-measures/53188 "2021-01-12T07:06:35Z")

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Added repeated measures to my ANOVA package, though without effect sizes at the moment because I’ll need to find a source for the calculations. Both within and among factors, which I believe is more than other available …

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## [DiffEq tolerances on ContinuousCallbacks?](https://discourse.julialang.org/t/diffeq-tolerances-on-continuouscallbacks/53181)

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**Author:** [@klaff](https://discourse.julialang.org/u/klaff)\
**Replies:** 7\
**Last updated:** [January 12, 2021, 6:49am UTC](https://discourse.julialang.org/t/diffeq-tolerances-on-continuouscallbacks/53181 "2021-01-12T06:49:12Z")

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I’m troubleshooting some friction models and trying to understand what I’m seeing. I’ve made a MWE by taking the bouncing ball model from the DiffEq docs and changing the coefficient of restitution to 0.1 instead of 1.0 …

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## [How can I set and get the session of the request from browser in Genie.jl?](https://discourse.julialang.org/t/how-can-i-set-and-get-the-session-of-the-request-from-browser-in-genie-jl/52883)

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**Author:** [@AquaIndigo](https://discourse.julialang.org/u/AquaIndigo)\
**Replies:** 6\
**Last updated:** [January 12, 2021, 4:36am UTC](https://discourse.julialang.org/t/how-can-i-set-and-get-the-session-of-the-request-from-browser-in-genie-jl/52883 "2021-01-12T04:36:58Z")

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Hello, I’m doing my Database course project using Genie as the back-end server, and I’m wondering how to set and save the session. And my efforts are as follows: route("/api/login") do uid = haskey(@params, :id) ? @p…

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## [How to select specific functionality in general pipeline](https://discourse.julialang.org/t/how-to-select-specific-functionality-in-general-pipeline/53184)

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**Author:** [@Satvik](https://discourse.julialang.org/u/Satvik)\
**Replies:** 2\
**Last updated:** [January 12, 2021, 4:23am UTC](https://discourse.julialang.org/t/how-to-select-specific-functionality-in-general-pipeline/53184 "2021-01-12T04:23:03Z")

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Hi, I have several pipelines which have mostly the same behavior with a few differences, and I’m trying to understand the tradeoffs between them. Most of my use cases look something like this: function do\_stuff(pipelin…

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## [The Julia Language on Google News](https://discourse.julialang.org/t/the-julia-language-on-google-news/53128)

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**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 1\
**Last updated:** [January 12, 2021, 4:00am UTC](https://discourse.julialang.org/t/the-julia-language-on-google-news/53128 "2021-01-12T04:00:57Z")

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Hey all! Happy to share that the Julia Languages Official Blog is now a Google News source. You can subscribe/follow us there: https://news.google.com/publications/CAAqBwgKMMT4nwsw0YK4Aw?oc=3&ceid=US:en

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## [How to NOT interpolate on remote worker?](https://discourse.julialang.org/t/how-to-not-interpolate-on-remote-worker/53027)

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**Author:** [@jling](https://discourse.julialang.org/u/jling)\
**Replies:** 3\
**Last updated:** [January 12, 2021, 3:17am UTC](https://discourse.julialang.org/t/how-to-not-interpolate-on-remote-worker/53027 "2021-01-12T03:17:40Z")

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julia\> using Distributed julia\> addprocs(2); julia\> @everywhere a = \[1,2\] julia\> @everywhere println(a) \[1, 2\] From worker 3: \[1, 2\] From worker 2: \[1, 2\] julia\> a = 5 5 julia\> @everywhere println(…

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## [Exploiting parallel Julia's auto-global shipping from inside functions and other submodules?](https://discourse.julialang.org/t/exploiting-parallel-julias-auto-global-shipping-from-inside-functions-and-other-submodules/53185)

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**Author:** [@marius311](https://discourse.julialang.org/u/marius311)\
**Replies:** 1\
**Last updated:** [January 12, 2021, 2:51am UTC](https://discourse.julialang.org/t/exploiting-parallel-julias-auto-global-shipping-from-inside-functions-and-other-submodules/53185 "2021-01-12T02:51:33Z")

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The fact that Julia automatically ships globals from Main to workers for you is a super useful construct, using Distributed addprocs(1) x = \[1,2,3\] @fetch x .+ 1 # x was shipped to worker here @fetch x .+ 2 # x wasn…

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## [PyCall.jl with PermutedDimsArray, StridedSubArray, and ReinterperetArray](https://discourse.julialang.org/t/pycall-jl-with-permuteddimsarray-stridedsubarray-and-reinterperetarray/53146)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 2\
**Last updated:** [January 12, 2021, 12:06am UTC](https://discourse.julialang.org/t/pycall-jl-with-permuteddimsarray-stridedsubarray-and-reinterperetarray/53146 "2021-01-12T00:06:00Z")

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I have been working on Napari.jl which is a Julia package for Napari, a multidimensional image viewer written in Python developed at Chan-Zuckerberg Initiative’s Biohub with many contributors from the field of biological…

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## [Operating on large TIFF stacks without loading whole thing into memory?](https://discourse.julialang.org/t/operating-on-large-tiff-stacks-without-loading-whole-thing-into-memory/51868)

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**Author:** [@ajsc4](https://discourse.julialang.org/u/ajsc4)\
**Replies:** 7\
**Last updated:** [January 11, 2021, 10:36pm UTC](https://discourse.julialang.org/t/operating-on-large-tiff-stacks-without-loading-whole-thing-into-memory/51868 "2021-01-11T22:36:29Z")

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I’m doing some basic image processing on large .tif stacks. For instance, taking the average intensity of each frame. Currently the step that takes by far the longest is loading the stack into memory using: stack = loa…

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## [Julia:alpine + SpecialFunctions issue](https://discourse.julialang.org/t/julia-alpine-specialfunctions-issue/53178)

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**Author:** [@AsafManela](https://discourse.julialang.org/u/AsafManela)\
**Replies:** 2\
**Last updated:** [January 11, 2021, 10:08pm UTC](https://discourse.julialang.org/t/julia-alpine-specialfunctions-issue/53178 "2021-01-11T22:08:14Z")

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Trying to use julia:alpine from docker hub but I’m getting errors when compiling SpecialFunctions.jl: $ docker run -ti --rm julia:alpine \_ \_ \_ \_(\_)\_ | Documentation: https://docs.julialang.o…

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## [Is it a good time for a PyTorch developer to move to Julia? If so, Flux? Knet?](https://discourse.julialang.org/t/is-it-a-good-time-for-a-pytorch-developer-to-move-to-julia-if-so-flux-knet/38453)

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**Author:** [@Alon](https://discourse.julialang.org/u/Alon)\
**Replies:** 52\
**Last updated:** [January 11, 2021, 9:51pm UTC](https://discourse.julialang.org/t/is-it-a-good-time-for-a-pytorch-developer-to-move-to-julia-if-so-flux-knet/38453 "2021-01-11T21:51:35Z")

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For me, the move from Keras to PyTorch was the best decision in my AI career. I am considering moving from Python to Julia because of performance and because the “NumPy” is built-in (as it was in Matlab rest its soul). …

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## [Data-exchange Julia-LabView](https://discourse.julialang.org/t/data-exchange-julia-labview/46315)

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**Author:** [@martincornejo](https://discourse.julialang.org/u/martincornejo)\
**Replies:** 13\
**Last updated:** [January 11, 2021, 9:08pm UTC](https://discourse.julialang.org/t/data-exchange-julia-labview/46315 "2021-01-11T21:08:04Z")

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For an experiment I need for a Julia process to communicate with a LabView process and exchange data every few seconds (1-5 s). Since (I think) there is no package to directly bind Julia and LabView I was thinking of con…

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## [Poor linear relaxation](https://discourse.julialang.org/t/poor-linear-relaxation/53170)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 1\
**Last updated:** [January 11, 2021, 8:12pm UTC](https://discourse.julialang.org/t/poor-linear-relaxation/53170 "2021-01-11T20:12:20Z")

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Dear users, I have a MIP problem whose linear relaxation is very poor. Observe the report of CPLEX below: (Gap greater to 999.99%, then the symbol “–”). Does have any parameter in CPLEX to set to improve these perf…

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## [Ray Tracing for Nuclear Reactor Physics package](https://discourse.julialang.org/t/ray-tracing-for-nuclear-reactor-physics-package/51985)

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**Author:** [@rvignolo](https://discourse.julialang.org/u/rvignolo)\
**Replies:** 4\
**Last updated:** [January 11, 2021, 7:53pm UTC](https://discourse.julialang.org/t/ray-tracing-for-nuclear-reactor-physics-package/51985 "2021-01-11T19:53:10Z")

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Hi! I have just released the RayTracing.jl package, which computes cyclic ray tracing across any unstructured mesh in a rectangular domain. Its results are commonly used in Nuclear Reactor Physics, such as in the Collis…

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## [Julia VS code custom task](https://discourse.julialang.org/t/julia-vs-code-custom-task/53161)

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**Author:** [@mrkosjan](https://discourse.julialang.org/u/mrkosjan)\
**Replies:** 2\
**Last updated:** [January 11, 2021, 7:06pm UTC](https://discourse.julialang.org/t/julia-vs-code-custom-task/53161 "2021-01-11T19:06:19Z")

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Hello, I am trying to setup a vs code task to run a Julia extension command in the active VS code REPL. What I hope to achieve is to bind a hotkey to a task that will run the runtest.jl file in the currently active REPL…

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## [Orthonormalize a matrix in place](https://discourse.julialang.org/t/orthonormalize-a-matrix-in-place/52887)

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**Author:** [@matthiasbe](https://discourse.julialang.org/u/matthiasbe)\
**Replies:** 10\
**Last updated:** [January 11, 2021, 6:21pm UTC](https://discourse.julialang.org/t/orthonormalize-a-matrix-in-place/52887 "2021-01-11T18:21:32Z")

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Hi, For a given matrix M \\in \\mathbb{R}^{m \\times n}, m \\geq n , I would like to orthonormalize the columns of M in place. M \\leftarrow \\texttt{qr}(M)\\texttt{.Q} I see that the function LinearAlgebra.qr! aims at some…

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## [Renumbering PDF files - can this be implemented with PDFIO.jl instead?](https://discourse.julialang.org/t/renumbering-pdf-files-can-this-be-implemented-with-pdfio-jl-instead/53144)

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**Author:** [@dilumaluthge](https://discourse.julialang.org/u/dilumaluthge)\
**Replies:** 8\
**Last updated:** [January 11, 2021, 6:11pm UTC](https://discourse.julialang.org/t/renumbering-pdf-files-can-this-be-implemented-with-pdfio-jl-instead/53144 "2021-01-11T18:11:29Z")

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I often find myself with PDFs in which the physical numbering of the pages does not match the numbering of the PDF. For example, suppose that you have a PDF in which the first twelve pages of the PDF are front matter th…

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## [Having a hard time visualizing LazySets.HPolyHedron & HPolytope](https://discourse.julialang.org/t/having-a-hard-time-visualizing-lazysets-hpolyhedron-hpolytope/52721)

<div class="topic-metadata">

**Author:** [@adropintheriver](https://discourse.julialang.org/u/adropintheriver)\
**Replies:** 1\
**Last updated:** [January 11, 2021, 6:10pm UTC](https://discourse.julialang.org/t/having-a-hard-time-visualizing-lazysets-hpolyhedron-hpolytope/52721 "2021-01-11T18:10:28Z")

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Q.1 what is the right way to render the following a. HPolyhedron/HPolytope b. Set of points (3D) so the code below from Polyhedra docs A = rand(HPolyhedron,dim=3) HPoly = Polytope(constraints\_list(A)) remove\_redunda…

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## [Last mile of BlackBoxOptim](https://discourse.julialang.org/t/last-mile-of-blackboxoptim/53171)

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**Author:** [@zxjroger](https://discourse.julialang.org/u/zxjroger)\
**Replies:** 0\
**Last updated:** [January 11, 2021, 6:05pm UTC](https://discourse.julialang.org/t/last-mile-of-blackboxoptim/53171 "2021-01-11T18:05:17Z")

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I am doing Monte Carlo study of the simulated method of moments estimator for my economic model. Since the objective function is not differentiable, I am using adaptive\_de\_rand\_1\_bin\_radiuslimited in BlackBoxOptim.jl as …

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## [Why are vertices of every LazySets.VPolygon or VPolytope given as 1 D Array and not based on the shape of the object?](https://discourse.julialang.org/t/why-are-vertices-of-every-lazysets-vpolygon-or-vpolytope-given-as-1-d-array-and-not-based-on-the-shape-of-the-object/52719)

<div class="topic-metadata">

**Author:** [@adropintheriver](https://discourse.julialang.org/u/adropintheriver)\
**Replies:** 1\
**Last updated:** [January 11, 2021, 5:49pm UTC](https://discourse.julialang.org/t/why-are-vertices-of-every-lazysets-vpolygon-or-vpolytope-given-as-1-d-array-and-not-based-on-the-shape-of-the-object/52719 "2021-01-11T17:49:32Z")

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A = rand(HPolyhedron,dim=3) Av = tovrep(A) Av.vertices gives an 11-element Array{Array{Float64,1},1} and not a 3 Dimensional array of 11 elements, also how can i convert these vertices to BasicGeometry.Point3d without u…

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## [Exploratory research project workflow](https://discourse.julialang.org/t/exploratory-research-project-workflow/53030)

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**Author:** [@misha\_mikhasenko](https://discourse.julialang.org/u/misha_mikhasenko)\
**Replies:** 26\
**Last updated:** [January 11, 2021, 5:35pm UTC](https://discourse.julialang.org/t/exploratory-research-project-workflow/53030 "2021-01-11T17:35:25Z")

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People scale academic research, what is your workflow in Julia? I mean, how do you develop your project, in which point move functions to the module, when writing tests, how you scale, how you pass parameters between …

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## [Guide for compiling Julia on Windows with portable Cygwin](https://discourse.julialang.org/t/guide-for-compiling-julia-on-windows-with-portable-cygwin/53167)

<div class="topic-metadata">

**Author:** [@heetbeet](https://discourse.julialang.org/u/heetbeet)\
**Replies:** 0\
**Last updated:** [January 11, 2021, 5:10pm UTC](https://discourse.julialang.org/t/guide-for-compiling-julia-on-windows-with-portable-cygwin/53167 "2021-01-11T17:10:00Z")

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This is my personal no-nonsense guide for compiling Julia on Windows. https://gist.github.com/heetbeet/89d34a50c6541d238f680971a1555152

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