# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1803

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

**Page:** 1804

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## [My crude attempt at the SIR model](https://discourse.julialang.org/t/my-crude-attempt-at-the-sir-model/33919)

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**Author:** [@StevenSiew](https://discourse.julialang.org/u/StevenSiew)\
**Replies:** 29\
**Last updated:** [March 12, 2020, 3:01am UTC](https://discourse.julialang.org/t/my-crude-attempt-at-the-sir-model/33919 "2020-03-12T03:01:38Z")

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Warning! I am nobody with no Medical qualification I literally pulled the parameter values out of thin air Results here are NOT to be used for any serious endeavor S = Array{Float64}(undef,1000) I = Array{Float64}(und…

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## [Setting variable used by multiple functions in a module](https://discourse.julialang.org/t/setting-variable-used-by-multiple-functions-in-a-module/32103)

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**Author:** [@jlchan](https://discourse.julialang.org/u/jlchan)\
**Replies:** 6\
**Last updated:** [January 21, 2020, 8:50am UTC](https://discourse.julialang.org/t/setting-variable-used-by-multiple-functions-in-a-module/32103 "2020-01-21T08:50:26Z")

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I’m trying to find the Julian way to replace the following OOP functionality: if a variable is set when an object is instantiated, then all functions in that instance have access to the variable. It seems like closures …

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## [Surface plot issues](https://discourse.julialang.org/t/surface-plot-issues/35603)

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**Author:** [@Andre\_Mello](https://discourse.julialang.org/u/Andre_Mello)\
**Replies:** 10\
**Last updated:** [March 12, 2020, 1:27am UTC](https://discourse.julialang.org/t/surface-plot-issues/35603 "2020-03-12T01:27:47Z")

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I’m running into multiple small issues on this kind of surface plot. First I’d like to know if I can make it a bit transparent. alpha seems to only affect the colorbar. I’d like to do 1) so that I can have a wireframe …

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## [Can't install IJulia](https://discourse.julialang.org/t/cant-install-ijulia/35858)

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**Author:** [@Lin](https://discourse.julialang.org/u/Lin)\
**Replies:** 0\
**Last updated:** [March 12, 2020, 12:25am UTC](https://discourse.julialang.org/t/cant-install-ijulia/35858 "2020-03-12T00:25:04Z")

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Hi, I am new to start Julia. I see the following error when I was installing IJulia: ERROR: Unable to automatically install 'ZeroMQ' from 'C:\\Users\\user\\.julia\\packa ges\\ZeroMQ\_jll\\1BliR\\Artifacts.toml' Stacktrace: \[…

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## [Including multi-threading functionality in a package](https://discourse.julialang.org/t/including-multi-threading-functionality-in-a-package/35698)

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**Author:** [@joshuanunn](https://discourse.julialang.org/u/joshuanunn)\
**Replies:** 4\
**Last updated:** [March 12, 2020, 12:11am UTC](https://discourse.julialang.org/t/including-multi-threading-functionality-in-a-package/35698 "2020-03-12T00:11:59Z")

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Hi, first post here. Long time python user, so still learning Julia but enjoying so far. What is the general approach to adding multi-threading support into a Julia package? Specifically, I’ve ported a geo-processing li…

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## [Bug in \`reverse!\`?](https://discourse.julialang.org/t/bug-in-reverse/35857)

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**Author:** [@Jean\_Michel](https://discourse.julialang.org/u/Jean_Michel)\
**Replies:** 11\
**Last updated:** [March 12, 2020, 12:10am UTC](https://discourse.julialang.org/t/bug-in-reverse/35857 "2020-03-12T00:10:24Z")

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we have julia\> reverse(1:1:2) 2:-1:1 but julia\> a=1:1:2 1:1:2 julia\> reverse!(a) ERROR: setindex! not defined for StepRange{Int64,Int64} Stacktrace: \[1\] error(::String, ::Type) at ./error.jl:42 \[2\] error\_if\_canonic…

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## [Struct field alignment](https://discourse.julialang.org/t/struct-field-alignment/35856)

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**Author:** [@hros](https://discourse.julialang.org/u/hros)\
**Replies:** 0\
**Last updated:** [March 11, 2020, 10:45pm UTC](https://discourse.julialang.org/t/struct-field-alignment/35856 "2020-03-11T22:45:17Z")

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I am creating a struct which is intended to be passed to C library function using ccall. The C definition uses an alignment attribute. I can use the @calign macro from the CBinding package, but this involves some unwan…

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## [Create external command from string](https://discourse.julialang.org/t/create-external-command-from-string/17568)

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**Author:** [@armstrtw](https://discourse.julialang.org/u/armstrtw)\
**Replies:** 9\
**Last updated:** [March 11, 2020, 10:15pm UTC](https://discourse.julialang.org/t/create-external-command-from-string/17568 "2020-03-11T22:15:21Z")

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are backticks the only way to construct a command for the ‘run’ function: for example: julia\> cmd = “pwd”::String “pwd” julia\> run($cmd) /home/warmstrong Process(pwd, ProcessExited(0)) julia\> what is the \` func…

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## [Adding HDF5: Tree Hash Mismatch! (A Docker-on-Windows problem; solved)](https://discourse.julialang.org/t/adding-hdf5-tree-hash-mismatch-a-docker-on-windows-problem-solved/35817)

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**Author:** [@tuckermcclure](https://discourse.julialang.org/u/tuckermcclure)\
**Replies:** 8\
**Last updated:** [March 11, 2020, 9:32pm UTC](https://discourse.julialang.org/t/adding-hdf5-tree-hash-mismatch-a-docker-on-windows-problem-solved/35817 "2020-03-11T21:32:08Z")

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I’m running Julia v1.3.1 in Ubuntu and trying to \] add HDF5. I’m getting the following error: (sim) pkg\> add HDF5 Resolving package versions... ┌ Error: Tree Hash Mismatch! │ Expected git-tree-sha1: 7d43efbb6eaa156…

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## [Best practice to unstack a dataframe with a lot of columnes?](https://discourse.julialang.org/t/best-practice-to-unstack-a-dataframe-with-a-lot-of-columnes/35851)

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**Author:** [@jling](https://discourse.julialang.org/u/jling)\
**Replies:** 5\
**Last updated:** [March 11, 2020, 9:01pm UTC](https://discourse.julialang.org/t/best-practice-to-unstack-a-dataframe-with-a-lot-of-columnes/35851 "2020-03-11T21:01:54Z")

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so, unlike normal ordering (like what Italy CDC did, JHU people decided to put dates in column names. #first(df\_us, 3) State Country Lat Long 1/22/20 1/23/20 1/24/20 1/25/20 1/26/20 1/27/20 1/28/20 1/29/20 1/30/20 1/3…

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## [Make debug builds of Julia available?](https://discourse.julialang.org/t/make-debug-builds-of-julia-available/35850)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 0\
**Last updated:** [March 11, 2020, 8:13pm UTC](https://discourse.julialang.org/t/make-debug-builds-of-julia-available/35850 "2020-03-11T20:13:40Z")

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I’d like to propose making debug builds of Julia available on \[some of the\] Tier 1 platforms, at least for nightly. When I’ve encountered segfaults in the past, I’ve occasionally bitten the bullet and built it myself. It…

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## [Type stability using reduce](https://discourse.julialang.org/t/type-stability-using-reduce/35816)

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**Author:** [@mpf01](https://discourse.julialang.org/u/mpf01)\
**Replies:** 3\
**Last updated:** [March 11, 2020, 7:26pm UTC](https://discourse.julialang.org/t/type-stability-using-reduce/35816 "2020-03-11T19:26:25Z")

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I’d like to better understand how to ensure type stability when applying a reduce operation on a collection. In the example below, the CrossProd type maintains a collection of objects that represent a “cross product”, wh…

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## [Dataframe identify rows](https://discourse.julialang.org/t/dataframe-identify-rows/35819)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 1\
**Last updated:** [March 11, 2020, 6:42am UTC](https://discourse.julialang.org/t/dataframe-identify-rows/35819 "2020-03-11T06:42:33Z")

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I made a data frame from an xlsx spreadsheet, which has every month from Jan 1976- to Feb 2020 as columns, and as rows these variables. Month-year Population Labour force Employment Full-time employment Part-tim…

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## [Eval code in sandbox. Is it possible?](https://discourse.julialang.org/t/eval-code-in-sandbox-is-it-possible/35848)

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**Author:** [@waralex](https://discourse.julialang.org/u/waralex)\
**Replies:** 0\
**Last updated:** [March 11, 2020, 6:33pm UTC](https://discourse.julialang.org/t/eval-code-in-sandbox-is-it-possible/35848 "2020-03-11T18:33:07Z")

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Hi. Is there any way to eval third-party code with custom environment? For example, if I allow a user of a web interface to write custom Julia’s code to perform data conversion, and then execute this code on the serve…

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## [MATLAB.jl connecting to named engine](https://discourse.julialang.org/t/matlab-jl-connecting-to-named-engine/35847)

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**Author:** [@jonniedie](https://discourse.julialang.org/u/jonniedie)\
**Replies:** 0\
**Last updated:** [March 11, 2020, 5:03pm UTC](https://discourse.julialang.org/t/matlab-jl-connecting-to-named-engine/35847 "2020-03-11T17:03:47Z")

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The matlab.engine API for Python has a method connect\_matlab for connecting to an open, named MATLAB session, which is nice for passing variables back and forth between Python and MATLAB workspaces. I was wondering if an…

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## [Explicitly defining dependent variables vs allowing solver to figure it out](https://discourse.julialang.org/t/explicitly-defining-dependent-variables-vs-allowing-solver-to-figure-it-out/35114)

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**Author:** [@gobs](https://discourse.julialang.org/u/gobs)\
**Replies:** 10\
**Last updated:** [March 11, 2020, 3:20pm UTC](https://discourse.julialang.org/t/explicitly-defining-dependent-variables-vs-allowing-solver-to-figure-it-out/35114 "2020-03-11T15:20:53Z")

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I have an energy system optimisation model with storage. The energy balance for the storage technology looks something like this: e\[t\] = e\[t-1\] + eff \* c\[t\] - d\[t\] The only real decision variables are the charging and…

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## [Read Geopackage Layers to dataframe](https://discourse.julialang.org/t/read-geopackage-layers-to-dataframe/35837)

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**Author:** [@patrickplagowski](https://discourse.julialang.org/u/patrickplagowski)\
**Replies:** 1\
**Last updated:** [March 11, 2020, 3:15pm UTC](https://discourse.julialang.org/t/read-geopackage-layers-to-dataframe/35837 "2020-03-11T15:15:10Z")

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Hi everyone, I started applying ArchGDAL to read geopackage layers. How can one read geopackage layers to dataframes (like geopandas in python)? Motivation: I’d like to avoid for loops and many if/else statements in th…

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## [Converting an array of matrices into a gif](https://discourse.julialang.org/t/converting-an-array-of-matrices-into-a-gif/35741)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 5\
**Last updated:** [March 11, 2020, 2:38pm UTC](https://discourse.julialang.org/t/converting-an-array-of-matrices-into-a-gif/35741 "2020-03-11T14:38:07Z")

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I have an array of 2d matrices and I would like to turn these into a gif. Each of the matrix has an entry from 1 to 8, denoting fixed states. I would like to specify a color for each state, so for example 1 is red, 2 is …

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## [Zygote.jl and PackageCompiler.jl](https://discourse.julialang.org/t/zygote-jl-and-packagecompiler-jl/35839)

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**Author:** [@Peter\_Adelman](https://discourse.julialang.org/u/Peter_Adelman)\
**Replies:** 4\
**Last updated:** [March 11, 2020, 2:17pm UTC](https://discourse.julialang.org/t/zygote-jl-and-packagecompiler-jl/35839 "2020-03-11T14:17:24Z")

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I have been compiling my package for deployment using PackageCompilerX and now PackageCompiler, but recently I added some dependencies (including Zygote) and now it seems to dislike execution after compilation. Ubuntu …

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## [I cant add PyPlot package](https://discourse.julialang.org/t/i-cant-add-pyplot-package/29515)

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**Author:** [@Henoch](https://discourse.julialang.org/u/Henoch)\
**Replies:** 5\
**Last updated:** [March 11, 2020, 2:16pm UTC](https://discourse.julialang.org/t/i-cant-add-pyplot-package/29515 "2020-03-11T14:16:20Z")

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julia\> using Pkg julia\> using PyPlot \[ Info: Precompiling PyPlot \[d330b81b-6aea-500a-939a-2ce795aea3ee\] ERROR: LoadError: LoadError: PyCall not properly installed. Please run Pkg.build("PyCall") Stacktrace: \[1\] top-lev…

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## [Division isn't auto-vectorized when function inlined](https://discourse.julialang.org/t/division-isnt-auto-vectorized-when-function-inlined/35818)

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**Author:** [@non-Jedi](https://discourse.julialang.org/u/non-Jedi)\
**Replies:** 12\
**Last updated:** [March 11, 2020, 1:54pm UTC](https://discourse.julialang.org/t/division-isnt-auto-vectorized-when-function-inlined/35818 "2020-03-11T13:54:34Z")

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I’m attempting to rewrite the benchmarks game spectralnorm implementation without relying on llvmcall for vectorization. I got close to the performance, but it requires awkwardly doing division in a helper function annot…

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## [Project handling for command line scripts](https://discourse.julialang.org/t/project-handling-for-command-line-scripts/35827)

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**Author:** [@simonbyrne](https://discourse.julialang.org/u/simonbyrne)\
**Replies:** 3\
**Last updated:** [March 11, 2020, 12:36pm UTC](https://discourse.julialang.org/t/project-handling-for-command-line-scripts/35827 "2020-03-11T12:36:15Z")

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Is there a good way to specify projects for command line Julia scripts? e.g. I have a script foo.jl that is intended to be called from the command line: how do I ensure that it gets the correct Project.toml file (which, …

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## [ShapeFactory - automate CATIA from Julia](https://discourse.julialang.org/t/shapefactory-automate-catia-from-julia/35834)

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**Author:** [@synxroform](https://discourse.julialang.org/u/synxroform)\
**Replies:** 1\
**Last updated:** [March 11, 2020, 12:29pm UTC](https://discourse.julialang.org/t/shapefactory-automate-catia-from-julia/35834 "2020-03-11T12:29:46Z")

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This library allows you to automate Dassault Systemes Catia. Examples can be found on this github page. Some real world examples here.

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## [Question on Bayesian Inference with Julia, using Turing and/or AdvancedHMC and/or Distributions](https://discourse.julialang.org/t/question-on-bayesian-inference-with-julia-using-turing-and-or-advancedhmc-and-or-distributions/35776)

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**Author:** [@HarrisonWilde](https://discourse.julialang.org/u/HarrisonWilde)\
**Replies:** 11\
**Last updated:** [March 11, 2020, 11:55am UTC](https://discourse.julialang.org/t/question-on-bayesian-inference-with-julia-using-turing-and-or-advancedhmc-and-or-distributions/35776 "2020-03-11T11:55:25Z")

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I am looking to run some experiments in Julia after growing tired of jumping in and out of Stan and suffering from some performance issues that I think Julia could help eliminate. I am looking to do MCMC to learn paramet…

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## [Interpretation of Juno's profiler visualization](https://discourse.julialang.org/t/interpretation-of-junos-profiler-visualization/35810)

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**Author:** [@benninkrs](https://discourse.julialang.org/u/benninkrs)\
**Replies:** 1\
**Last updated:** [March 11, 2020, 10:07am UTC](https://discourse.julialang.org/t/interpretation-of-junos-profiler-visualization/35810 "2020-03-11T10:07:46Z")

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In spite of having used Juno for a while, I have only just recently started using its profiler visualization, which I find very nice. However I do have a couple questions about how to interpret the visualization: The d…

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## [Installing personal packages that depend on other personal packages on Linux](https://discourse.julialang.org/t/installing-personal-packages-that-depend-on-other-personal-packages-on-linux/35832)

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**Author:** [@cndesantana](https://discourse.julialang.org/u/cndesantana)\
**Replies:** 4\
**Last updated:** [March 11, 2020, 9:59am UTC](https://discourse.julialang.org/t/installing-personal-packages-that-depend-on-other-personal-packages-on-linux/35832 "2020-03-11T09:59:41Z")

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Hi people, I have created 2 packages that are at my personal git repository. Package A depends on package B. However, when I try to install package A I get the following error message: Cloning git-repo \`https://cns…

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## [EU Citizen: DAE Solvers and Modeling Tools](https://discourse.julialang.org/t/eu-citizen-dae-solvers-and-modeling-tools/35833)

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**Author:** [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Replies:** 0\
**Last updated:** [March 11, 2020, 9:05am UTC](https://discourse.julialang.org/t/eu-citizen-dae-solvers-and-modeling-tools/35833 "2020-03-11T09:05:04Z")

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If there are any EU citizens who are interested in developing modeling tools (ModelingTookit) and DAE solvers with the MIT Julia Lab, please contact me. We have a partner organization that is putting together a proposal …

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## [Loading COVID-19 CSV data](https://discourse.julialang.org/t/loading-covid-19-csv-data/35820)

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**Author:** [@Glen](https://discourse.julialang.org/u/Glen)\
**Replies:** 2\
**Last updated:** [March 11, 2020, 4:17am UTC](https://discourse.julialang.org/t/loading-covid-19-csv-data/35820 "2020-03-11T04:17:16Z")

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Hi Julians, I am trying to read the latest COVID-19 data to do analysis, from here: https://github.com/CSSEGISandData/COVID-19/blob/master/csse\_covid\_19\_data/csse\_covid\_19\_time\_series/time\_series\_19-covid-Confirmed.csv …

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## [SharedArray of Measurement type](https://discourse.julialang.org/t/sharedarray-of-measurement-type/35756)

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**Author:** [@Hossein\_Haghi](https://discourse.julialang.org/u/Hossein_Haghi)\
**Replies:** 5\
**Last updated:** [March 9, 2020, 4:56pm UTC](https://discourse.julialang.org/t/sharedarray-of-measurement-type/35756 "2020-03-09T16:56:53Z")

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I am trying to put the the output (just one data point) of the solution of an ODE that is solved with uncertainty (measrument.jl) multiple times with different initial conditions within a distributed for loop in a Shared…

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## [Can I make this function even faster?](https://discourse.julialang.org/t/can-i-make-this-function-even-faster/35813)

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**Author:** [@zxjroger](https://discourse.julialang.org/u/zxjroger)\
**Replies:** 5\
**Last updated:** [March 10, 2020, 10:43pm UTC](https://discourse.julialang.org/t/can-i-make-this-function-even-faster/35813 "2020-03-10T22:43:38Z")

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I have the following function which will be evaluated thousands of times in a for loop. This function will generate a vector. Each element in this vector is computed by some algebra of some elements in two different matr…

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