# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1669

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

**Page:** 1670

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## [JUMP - Get MIP Gap during optimization](https://discourse.julialang.org/t/jump-get-mip-gap-during-optimization/44258)

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**Author:** [@Tmart](https://discourse.julialang.org/u/Tmart)\
**Replies:** 5\
**Last updated:** [August 5, 2020, 2:05pm UTC](https://discourse.julialang.org/t/jump-get-mip-gap-during-optimization/44258 "2020-08-05T14:05:38Z")

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Hello, I was wondering if it was possible to obtain the value of the MIP Gap at each step of the optimization process. Thank you in advance, KR

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## [Quoting special characters of a url in Cmd objects on Windows](https://discourse.julialang.org/t/quoting-special-characters-of-a-url-in-cmd-objects-on-windows/44324)

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**Author:** [@NiclasMattsson](https://discourse.julialang.org/u/NiclasMattsson)\
**Replies:** 5\
**Last updated:** [August 5, 2020, 1:26pm UTC](https://discourse.julialang.org/t/quoting-special-characters-of-a-url-in-cmd-objects-on-windows/44324 "2020-08-05T13:26:18Z")

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To open a webpage using the default browser in the Windows command line you can use: \> start https://www.google.com/ This works from Julia too if you prefix it with cmd /c: julia\> run(\`cmd /c start https://www.google.…

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## [Circular buffer package?](https://discourse.julialang.org/t/circular-buffer-package/44041)

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**Author:** [@lwabeke](https://discourse.julialang.org/u/lwabeke)\
**Replies:** 3\
**Last updated:** [August 5, 2020, 12:45pm UTC](https://discourse.julialang.org/t/circular-buffer-package/44041 "2020-08-05T12:45:08Z")

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I am working on some code that processes vectors of data of length 6000 elements. When I detect specific criteria, I want to reprocess the last 100 vectors to extract finer details. Thus I want to store the data in a for…

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## [Abstract methods: pattern](https://discourse.julialang.org/t/abstract-methods-pattern/44327)

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**Author:** [@Philippe\_Maincon1](https://discourse.julialang.org/u/Philippe_Maincon1)\
**Replies:** 2\
**Last updated:** [August 5, 2020, 12:31pm UTC](https://discourse.julialang.org/t/abstract-methods-pattern/44327 "2020-08-05T12:31:12Z")

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I want to create a “module general” which provides an abstract type (fruit), to be subtyped in another “module specific”. In the “module general”, I want to provide operations on fruit in general, but which hae to rely …

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## [Can I set @optlevel as a user per module or per function?](https://discourse.julialang.org/t/can-i-set-optlevel-as-a-user-per-module-or-per-function/44192)

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**Author:** [@klaff](https://discourse.julialang.org/u/klaff)\
**Replies:** 10\
**Last updated:** [August 5, 2020, 12:27pm UTC](https://discourse.julialang.org/t/can-i-set-optlevel-as-a-user-per-module-or-per-function/44192 "2020-08-05T12:27:11Z")

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Specifically, I’m playing with rapidly updating plots in a Pluto environment and would like to increase the level of optimizations applied to Plots.jl as a user to see if it changes update rates.

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## [SymPy.jl: how to get non-zero assumptions?](https://discourse.julialang.org/t/sympy-jl-how-to-get-non-zero-assumptions/44313)

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**Author:** [@tomtom](https://discourse.julialang.org/u/tomtom)\
**Replies:** 5\
**Last updated:** [August 5, 2020, 11:49am UTC](https://discourse.julialang.org/t/sympy-jl-how-to-get-non-zero-assumptions/44313 "2020-08-05T11:49:13Z")

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in the following, c should be assumed non-zero for the solution x = 1 /c : import SymPy const sympy = SymPy.sympy julia\> eqn = sympy.sympify("x \* c - 1") c⋅x - 1 julia\> sol = sympy.solve(eqn, SymPy.Sym("x")) 1-element…

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## [How Julia's virtual environment physically store the packages added in the environment?](https://discourse.julialang.org/t/how-julias-virtual-environment-physically-store-the-packages-added-in-the-environment/44314)

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**Author:** [@DataPsycho](https://discourse.julialang.org/u/DataPsycho)\
**Replies:** 5\
**Last updated:** [August 5, 2020, 11:17am UTC](https://discourse.julialang.org/t/how-julias-virtual-environment-physically-store-the-packages-added-in-the-environment/44314 "2020-08-05T11:17:21Z")

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Hi, I am trying to understand the environment in Julia which can be initiated in \] Pkg mode with activate . But when I add a new package with a specific version with add where it physically installed? For example in Pyt…

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## [@code\_warntype, for loops and spurious Union types](https://discourse.julialang.org/t/code-warntype-for-loops-and-spurious-union-types/44318)

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**Author:** [@Raf](https://discourse.julialang.org/u/Raf)\
**Replies:** 5\
**Last updated:** [August 5, 2020, 11:08am UTC](https://discourse.julialang.org/t/code-warntype-for-loops-and-spurious-union-types/44318 "2020-08-05T11:08:02Z")

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If I define some function that includes a for loop and run @code\_warntype on it: function f() for i in 1:10 i end return end @code\_warntype f() The variables listed always contain a Union type: V…

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## [Benchmark of numerical integration packages for multi-dimensional integration](https://discourse.julialang.org/t/benchmark-of-numerical-integration-packages-for-multi-dimensional-integration/44273)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 4\
**Last updated:** [August 5, 2020, 10:33am UTC](https://discourse.julialang.org/t/benchmark-of-numerical-integration-packages-for-multi-dimensional-integration/44273 "2020-08-05T10:33:11Z")

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Hello, I need to integrate a vector valued function F: \\mathbb{R} \\xrightarrow{} \\mathbb{R}^n, with n \\sim 5000 over \[0.0, 1.0\]. I don’t need to very accurate result, an error estimate of 1e-6 is sufficient for my appli…

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## [A rant about C++ containers](https://discourse.julialang.org/t/a-rant-about-c-containers/44269)

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**Author:** [@heetbeet](https://discourse.julialang.org/u/heetbeet)\
**Replies:** 2\
**Last updated:** [August 5, 2020, 9:53am UTC](https://discourse.julialang.org/t/a-rant-about-c-containers/44269 "2020-08-05T09:53:42Z")

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I always forget how much I struggle with C++'s patterns for using their data containers. This is how much code you have to write to find the intersection between two sets: auto intersec = set\<int\>(); std::set\_intersecti…

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## [Import XLSX data](https://discourse.julialang.org/t/import-xlsx-data/44302)

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**Author:** [@dty](https://discourse.julialang.org/u/dty)\
**Replies:** 13\
**Last updated:** [August 5, 2020, 8:55am UTC](https://discourse.julialang.org/t/import-xlsx-data/44302 "2020-08-05T08:55:12Z")

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using XLSX Cs=XLSX.readdata("E:\\\\Julia程序\\\\Cs.xlsx","Sheet1","A1:C24") The above is my code for importing xlsx file (), which is the data type of array (any, 2) and cannot be directly operated with matrix. How can I impo…

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## [Data Races](https://discourse.julialang.org/t/data-races/44185)

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**Author:** [@tisztamo](https://discourse.julialang.org/u/tisztamo)\
**Replies:** 6\
**Last updated:** [August 5, 2020, 8:55am UTC](https://discourse.julialang.org/t/data-races/44185 "2020-08-05T08:55:05Z")

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The updated multithreading docs for v"1.5" says in section “Data-race freedom”: … Additionally, Julia is not memory safe in the presence of a data race. Be very careful about reading a global variable (or closure var…

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## [Xkcd Scientist Tech Help](https://discourse.julialang.org/t/xkcd-scientist-tech-help/44284)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 15\
**Last updated:** [August 5, 2020, 8:31am UTC](https://discourse.julialang.org/t/xkcd-scientist-tech-help/44284 "2020-08-05T08:31:33Z")

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## [Julia data storage](https://discourse.julialang.org/t/julia-data-storage/44283)

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**Author:** [@andrey2185](https://discourse.julialang.org/u/andrey2185)\
**Replies:** 5\
**Last updated:** [August 5, 2020, 8:10am UTC](https://discourse.julialang.org/t/julia-data-storage/44283 "2020-08-05T08:10:21Z")

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Hello, Please advise a reliable, stable and simple package for long-term data storage in a universal cross-platform format? it is desirable to support dataframe

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## [‘UndefVarError: xx not defined’](https://discourse.julialang.org/t/undefvarerror-xx-not-defined/44278)

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**Author:** [@RohitRathore1](https://discourse.julialang.org/u/RohitRathore1)\
**Replies:** 4\
**Last updated:** [August 5, 2020, 7:58am UTC](https://discourse.julialang.org/t/undefvarerror-xx-not-defined/44278 "2020-08-05T07:58:52Z")

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function ackley(x) d = length(xx); c = 2pi; b = 0.2; a = 20; for ii in 1:d xi = xx(ii); sum1 = sum1 + xi^2; sum2 = sum2 + cos(cxi); end sum1 = sum1 + x1^2; sum2 = sum2 + cos(cx2); term1 = -a \* exp(-bsqrt(sum1…

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## [Capturing stdout/stderr from Pkg.test](https://discourse.julialang.org/t/capturing-stdout-stderr-from-pkg-test/44307)

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**Author:** [@felipenoris](https://discourse.julialang.org/u/felipenoris)\
**Replies:** 1\
**Last updated:** [August 5, 2020, 5:26am UTC](https://discourse.julialang.org/t/capturing-stdout-stderr-from-pkg-test/44307 "2020-08-05T05:26:09Z")

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Is it possible to call Pkg.test and make it capture all the output from the test process? I’m trying something like the code below, but the tests run in a sandbox so I guess that’s why I’m unable to capture the output. …

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## [Using package dependencies](https://discourse.julialang.org/t/using-package-dependencies/44303)

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**Author:** [@yarnabrina](https://discourse.julialang.org/u/yarnabrina)\
**Replies:** 4\
**Last updated:** [August 5, 2020, 4:34am UTC](https://discourse.julialang.org/t/using-package-dependencies/44303 "2020-08-05T04:34:36Z")

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Hi! I have recently started to learn Julia, so if it’s too basic question, please bear with me. I’m following Think Julia. In Chapter 4, it is teaching turtle graphics and suggested to download the ThinkJulia package. …

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## [Interactive Tables with IJulia?](https://discourse.julialang.org/t/interactive-tables-with-ijulia/11793)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 1\
**Last updated:** [August 5, 2020, 2:00am UTC](https://discourse.julialang.org/t/interactive-tables-with-ijulia/11793 "2020-08-05T02:00:43Z")

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I was looking for a way to have interactive tables in IJulia, and stumbled over this: https://github.com/quantopian/qgrid I wonder if IJulia bindings for the Qgrid widget would be possible? Or maybe something similar v…

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## [Two type composite struct construction](https://discourse.julialang.org/t/two-type-composite-struct-construction/43727)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 8\
**Last updated:** [August 5, 2020, 12:36am UTC](https://discourse.julialang.org/t/two-type-composite-struct-construction/43727 "2020-08-05T00:36:31Z")

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Hi. I have the following problem/question. I have a struct struct foo{T\<:Integer, U\<:Real} \<: AbstractGraph{T} bar1::T bar2::U end Now, I want to create an instance of foo, where I explicitly define the type U but…

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## [Needs help to build LoopTools using BinaryBuilder](https://discourse.julialang.org/t/needs-help-to-build-looptools-using-binarybuilder/44260)

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**Author:** [@fkguo](https://discourse.julialang.org/u/fkguo)\
**Replies:** 10\
**Last updated:** [August 5, 2020, 12:11am UTC](https://discourse.julialang.org/t/needs-help-to-build-looptools-using-binarybuilder/44260 "2020-08-05T00:11:28Z")

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Hello, There is a package called LoopTools, for which I succeeded in building a .so shared lib locally that I can call in julia. Now I am trying to build it using BinaryBuilder.jl with the following code that was modif…

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## [Setting up testing and code coverage on Travis](https://discourse.julialang.org/t/setting-up-testing-and-code-coverage-on-travis/44241)

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**Author:** [@lgo](https://discourse.julialang.org/u/lgo)\
**Replies:** 4\
**Last updated:** [August 4, 2020, 9:41pm UTC](https://discourse.julialang.org/t/setting-up-testing-and-code-coverage-on-travis/44241 "2020-08-04T21:41:14Z")

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I’ve already got my project on Travis to create the documentation and I wanted to add testing and the corresponding information on code coverage. I’ve added the corresponding testing script and was able to run it locally…

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## [Confused: MbedTLS broken on GitHub Actions with identical code](https://discourse.julialang.org/t/confused-mbedtls-broken-on-github-actions-with-identical-code/44282)

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**Author:** [@fonsp](https://discourse.julialang.org/u/fonsp)\
**Replies:** 1\
**Last updated:** [August 4, 2020, 7:45pm UTC](https://discourse.julialang.org/t/confused-mbedtls-broken-on-github-actions-with-identical-code/44282 "2020-08-04T19:45:30Z")

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My CI tests fail consistently since today, even though no code changed. Comparing the manifests before and after, all dependencies have the same version. The error is: ERROR: LoadError: ArgumentError: Package MbedTLS d…

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## [IJulia cannot connect to server](https://discourse.julialang.org/t/ijulia-cannot-connect-to-server/44279)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 1\
**Last updated:** [August 4, 2020, 7:08pm UTC](https://discourse.julialang.org/t/ijulia-cannot-connect-to-server/44279 "2020-08-04T19:08:20Z")

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I am having trouble connecting to the notebook server with IJulia. When I type notebook(), IJulia starts in the browser. However, when I open a new file, it indicates “Connecting to kernel” at the top. After a few minute…

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## [Serialize or swap file?](https://discourse.julialang.org/t/serialize-or-swap-file/44242)

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**Author:** [@andrey2185](https://discourse.julialang.org/u/andrey2185)\
**Replies:** 4\
**Last updated:** [August 4, 2020, 6:57pm UTC](https://discourse.julialang.org/t/serialize-or-swap-file/44242 "2020-08-04T18:57:37Z")

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Hello! When processing data that does not fit in RAM, what is more efficient - manual serialization or swap file? Splitting the algorithm into subtasks will not work, because at each stage of the calculations, any dat…

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## [Adding legend label to contour plot](https://discourse.julialang.org/t/adding-legend-label-to-contour-plot/44280)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 0\
**Last updated:** [August 4, 2020, 6:49pm UTC](https://discourse.julialang.org/t/adding-legend-label-to-contour-plot/44280 "2020-08-04T18:49:22Z")

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I’m using contour to plot a level set with the command: contour(-3:0.01:3, -3:0.01:3, (x,y) -\> max(abs(x-y), abs(x), abs(y)), levels=\[2.0\], colorbar=false, color = cgrad(\[:blue,:blue\]),lw=2) and I’d like to a leg…

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## [Modifying the input parameters to function in a function while solving differential equations](https://discourse.julialang.org/t/modifying-the-input-parameters-to-function-in-a-function-while-solving-differential-equations/43985)

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**Author:** [@aerorohit](https://discourse.julialang.org/u/aerorohit)\
**Replies:** 4\
**Last updated:** [August 4, 2020, 6:30pm UTC](https://discourse.julialang.org/t/modifying-the-input-parameters-to-function-in-a-function-while-solving-differential-equations/43985 "2020-08-04T18:30:31Z")

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I am new to Julia. Some workshops from this year’s JuliaCon really impressed me and I started exploring… This might be quite a basic question. I am trying to implement a callback while solving an ODE problem. I want the…

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## [Passing function type parameters to a macro](https://discourse.julialang.org/t/passing-function-type-parameters-to-a-macro/44274)

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**Author:** [@Alex\_Ellison](https://discourse.julialang.org/u/Alex_Ellison)\
**Replies:** 2\
**Last updated:** [August 4, 2020, 5:40pm UTC](https://discourse.julialang.org/t/passing-function-type-parameters-to-a-macro/44274 "2020-08-04T17:40:45Z")

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Hey all, I would like to use macros to generate functions with different bodies based on the function’s type parameters. @generated is not an option since ultimately these need to work with CUDA.jl (as far as I can tell…

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## [Best way of \`using\` without bring names into scope?](https://discourse.julialang.org/t/best-way-of-using-without-bring-names-into-scope/44272)

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**Author:** [@afbarnard](https://discourse.julialang.org/u/afbarnard)\
**Replies:** 7\
**Last updated:** [August 4, 2020, 4:54pm UTC](https://discourse.julialang.org/t/best-way-of-using-without-bring-names-into-scope/44272 "2020-08-04T16:54:16Z")

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Is there a way to use a module without bringing its names into scope? I don’t need to extend any methods. Specifically, using A brings type Foo into scope, but other code already defines Foo, so there is a name ambiguit…

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## [Is any package of CFD to simulate the hydrodynamic behaviour?](https://discourse.julialang.org/t/is-any-package-of-cfd-to-simulate-the-hydrodynamic-behaviour/44251)

<div class="topic-metadata">

**Author:** [@PharmCat](https://discourse.julialang.org/u/PharmCat)\
**Replies:** 7\
**Last updated:** [August 4, 2020, 3:48pm UTC](https://discourse.julialang.org/t/is-any-package-of-cfd-to-simulate-the-hydrodynamic-behaviour/44251 "2020-08-04T15:48:38Z")

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Is any package to simulate the hydrodynamic behaviour of a bioreactor with a impeller? PS Something like ANSYS Fluent/THINK Fluid Dynamix.

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## [Unable to build SCIP](https://discourse.julialang.org/t/unable-to-build-scip/44261)

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**Author:** [@musman](https://discourse.julialang.org/u/musman)\
**Replies:** 1\
**Last updated:** [August 4, 2020, 3:45pm UTC](https://discourse.julialang.org/t/unable-to-build-scip/44261 "2020-08-04T15:45:04Z")

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Hi, I am unable to install SCIP package 0.9.4 and receiving the following error. Blockquote add SCIP@v0.9.4 Updating registry at C:\\Users\\usman\\.juliapro\\JuliaPro\_v1.4.2-1\\registries\\JuliaPro Resolving package versi…

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