# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1225

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

**Page:** 1226

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## [Unrolling of loops with operations on CuArrays](https://discourse.julialang.org/t/unrolling-of-loops-with-operations-on-cuarrays/70468)

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**Author:** [@fedoroff](https://discourse.julialang.org/u/fedoroff)\
**Replies:** 4\
**Last updated:** [October 27, 2021, 5:10pm UTC](https://discourse.julialang.org/t/unrolling-of-loops-with-operations-on-cuarrays/70468 "2021-10-27T17:10:42Z")

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I have a loop where at each iteration I do some vectorial operation over CuArray. For example using CUDA N = 4 a = ones(N) u = CUDA.zeros(1000) @. u = a\[1\] for i=2:N @. u += a\[i\] end As far as I understand, in t…

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## [How to set resolution in GLMakie.mesh()?](https://discourse.julialang.org/t/how-to-set-resolution-in-glmakie-mesh/70492)

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**Author:** [@Simbelmyne](https://discourse.julialang.org/u/Simbelmyne)\
**Replies:** 1\
**Last updated:** [October 27, 2021, 4:56pm UTC](https://discourse.julialang.org/t/how-to-set-resolution-in-glmakie-mesh/70492 "2021-10-27T16:56:01Z")

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Hey, I am trying to change the resolution of a 2D mesh plot: scene = GLMakie.mesh(vertices, faces, color = colors, shading = false, resolution=(500,500)) However, this does not appear to work, it always defaults to 80…

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## [Linear equation with integer digits solution](https://discourse.julialang.org/t/linear-equation-with-integer-digits-solution/70479)

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**Author:** [@Dan\_Micsa](https://discourse.julialang.org/u/Dan_Micsa)\
**Replies:** 3\
**Last updated:** [October 27, 2021, 3:12pm UTC](https://discourse.julialang.org/t/linear-equation-with-integer-digits-solution/70479 "2021-10-27T15:12:15Z")

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I’m new to Julia and I want tot solve this problem with integer, digits solutions: “Each letter represents a different non-zero digit: SEE + SEE = AXES” I create this code and returns an inaccurate solution: using JuM…

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## [IJulia notebook() in Docker container](https://discourse.julialang.org/t/ijulia-notebook-in-docker-container/70462)

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**Author:** [@angelv](https://discourse.julialang.org/u/angelv)\
**Replies:** 2\
**Last updated:** [October 27, 2021, 2:30pm UTC](https://discourse.julialang.org/t/ijulia-notebook-in-docker-container/70462 "2021-10-27T14:30:06Z")

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Hello, for testing purposes I am using a Docker container to run some Julia notebooks. With the project at hand I have no problems to start the Jupyter notebook by using using IJulia notebook() This is not a problem e…

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## [Question about MLJ](https://discourse.julialang.org/t/question-about-mlj/70458)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 6\
**Last updated:** [October 27, 2021, 2:27pm UTC](https://discourse.julialang.org/t/question-about-mlj/70458 "2021-10-27T14:27:27Z")

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I want to make a multivariate probability prediction, and this is my current MLJ model search, but I don’t know if these models are valid. How can I find an efficient prediction model for my data? task(model) = model.is…

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## [List comprehension \`no method matching zero\` issue](https://discourse.julialang.org/t/list-comprehension-no-method-matching-zero-issue/70472)

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**Author:** [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Replies:** 3\
**Last updated:** [October 27, 2021, 1:41pm UTC](https://discourse.julialang.org/t/list-comprehension-no-method-matching-zero-issue/70472 "2021-10-27T13:41:01Z")

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Hello, good morning, I had a following code block failing when I’m doing a loop for get a vector of results in a monte carlo simulation. Can’t understand why I got the issue above: in line below: mc\_estimate = sum(\[in…

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## [Selecting DataFrame columns with Symbol Syntax for columns with non-alphabetical characters](https://discourse.julialang.org/t/selecting-dataframe-columns-with-symbol-syntax-for-columns-with-non-alphabetical-characters/70466)

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**Author:** [@DorianT](https://discourse.julialang.org/u/DorianT)\
**Replies:** 7\
**Last updated:** [October 27, 2021, 1:55pm UTC](https://discourse.julialang.org/t/selecting-dataframe-columns-with-symbol-syntax-for-columns-with-non-alphabetical-characters/70466 "2021-10-27T13:55:54Z")

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using DataFrames df = DataFrame(Firstcolumn = 1:5, Secondcolumn = 1:5) rename!(df, \["Firstcolumn","Second-column"\]) # this works just fine df\[:,:Firstcolumn\] # this does not work df\[:,:Second-column\] # also does n…

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## [VS Code debugging video tutorial](https://discourse.julialang.org/t/vs-code-debugging-video-tutorial/70422)

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**Author:** [@Oto\_Brzobohaty](https://discourse.julialang.org/u/Oto_Brzobohaty)\
**Replies:** 6\
**Last updated:** [October 27, 2021, 12:58pm UTC](https://discourse.julialang.org/t/vs-code-debugging-video-tutorial/70422 "2021-10-27T12:58:46Z")

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Hello, is there any tutorial video showing debugging using VS Code?

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## [The endless packages to add as as a dependency or to resolve](https://discourse.julialang.org/t/the-endless-packages-to-add-as-as-a-dependency-or-to-resolve/70450)

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**Author:** [@Redmusk888](https://discourse.julialang.org/u/Redmusk888)\
**Replies:** 2\
**Last updated:** [October 27, 2021, 12:08pm UTC](https://discourse.julialang.org/t/the-endless-packages-to-add-as-as-a-dependency-or-to-resolve/70450 "2021-10-27T12:08:00Z")

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1.I’m using julia 1.6.3 as my jupyternote kernel. 2.I was learning Linear Algebra on juliaacademy.com .https://juliaacademy.com/courses/937702/lectures/17339511 3.i got the problem below 4.i have been add and reso…

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## [Manually giving gradients in Flux.jl](https://discourse.julialang.org/t/manually-giving-gradients-in-flux-jl/70459)

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**Author:** [@iHany](https://discourse.julialang.org/u/iHany)\
**Replies:** 3\
**Last updated:** [October 27, 2021, 11:14am UTC](https://discourse.julialang.org/t/manually-giving-gradients-in-flux-jl/70459 "2021-10-27T11:14:58Z")

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Hi, I’m solving a Q-learning problem. I’m trying to a gradient of TD error. That is, TD-error = Q^{\\theta}(x, u) - (r(x, u) + \\min\_{v} Q^{\\theta}(x^{+}, v)) where \\theta = (\\theta\_1, ..., \\theta\_N) is the network pa…

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## [Confusion on DifferentialEquations.jl. How many saved timesteps](https://discourse.julialang.org/t/confusion-on-differentialequations-jl-how-many-saved-timesteps/70409)

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**Author:** [@DerOzean](https://discourse.julialang.org/u/DerOzean)\
**Replies:** 5\
**Last updated:** [October 27, 2021, 11:00am UTC](https://discourse.julialang.org/t/confusion-on-differentialequations-jl-how-many-saved-timesteps/70409 "2021-10-27T11:00:42Z")

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Hello everyone, I’m working on a dynamic food web and solving some differential equations. As solver I’m using the DP5 monte carlo method. After successful solving the problem I get for every time steps 4 time the same…

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## [Optim Control the number of search steps during an iteration](https://discourse.julialang.org/t/optim-control-the-number-of-search-steps-during-an-iteration/70457)

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**Author:** [@phy-lxf](https://discourse.julialang.org/u/phy-lxf)\
**Replies:** 0\
**Last updated:** [October 27, 2021, 7:44am UTC](https://discourse.julialang.org/t/optim-control-the-number-of-search-steps-during-an-iteration/70457 "2021-10-27T07:44:57Z")

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When optim.jl uses L-BFGS method to optimize the objective function, the derivative between each step of the optimization process often needs to search 3-4 steps. Can we fix the search step number to 1?

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## [Installing dependencies for separate Project.toml during package development/testing](https://discourse.julialang.org/t/installing-dependencies-for-separate-project-toml-during-package-development-testing/70413)

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**Author:** [@AnHeuermann](https://discourse.julialang.org/u/AnHeuermann)\
**Replies:** 3\
**Last updated:** [October 27, 2021, 9:30am UTC](https://discourse.julialang.org/t/installing-dependencies-for-separate-project-toml-during-package-development-testing/70413 "2021-10-27T09:30:18Z")

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I’m developing a package A wich has some unit tests as well as some examples. I want my unit tests to be fast, so I seperated the examples from my unit tests using an additional Project.toml (this saves me a few minutes…

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## [Cannot install julia on my ssh command line](https://discourse.julialang.org/t/cannot-install-julia-on-my-ssh-command-line/70456)

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**Author:** [@iiisoo](https://discourse.julialang.org/u/iiisoo)\
**Replies:** 3\
**Last updated:** [October 27, 2021, 8:13am UTC](https://discourse.julialang.org/t/cannot-install-julia-on-my-ssh-command-line/70456 "2021-10-27T08:13:04Z")

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## [Searching for updated database tutorial](https://discourse.julialang.org/t/searching-for-updated-database-tutorial/70421)

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**Author:** [@miko](https://discourse.julialang.org/u/miko)\
**Replies:** 2\
**Last updated:** [October 27, 2021, 7:41am UTC](https://discourse.julialang.org/t/searching-for-updated-database-tutorial/70421 "2021-10-27T07:41:03Z")

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It seems that Julia database tutorials that are on the web are outdated. Are there any simple examples of Julia and, say, MySQL.jl usage?

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## [FileIO without filesystem access?](https://discourse.julialang.org/t/fileio-without-filesystem-access/70429)

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**Author:** [@sporklpony](https://discourse.julialang.org/u/sporklpony)\
**Replies:** 3\
**Last updated:** [October 27, 2021, 7:08am UTC](https://discourse.julialang.org/t/fileio-without-filesystem-access/70429 "2021-10-27T07:08:31Z")

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I’d like to use Pluto.jl to create a small utility which processes and uploaded audio file. However, I’m unsure how to convert the uploaded audio file into a format usable with JuliaAudio’s ecosystem and SampledSignals.j…

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## [Save solution and warm start](https://discourse.julialang.org/t/save-solution-and-warm-start/70315)

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**Author:** [@Brock](https://discourse.julialang.org/u/Brock)\
**Replies:** 1\
**Last updated:** [October 27, 2021, 4:50am UTC](https://discourse.julialang.org/t/save-solution-and-warm-start/70315 "2021-10-27T04:50:49Z")

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I am using JuMP and CPLEX to solve an optimization problem. How can I save the best solution found after a certain time limit to a file? How can I then use this file as a warm start during another attempt to solve the …

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## [Errors associated with "using GMT"](https://discourse.julialang.org/t/errors-associated-with-using-gmt/70393)

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**Author:** [@leon](https://discourse.julialang.org/u/leon)\
**Replies:** 28\
**Last updated:** [October 27, 2021, 3:50am UTC](https://discourse.julialang.org/t/errors-associated-with-using-gmt/70393 "2021-10-27T03:50:15Z")

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I just installed the mapping package to my Julia and I can verify that my GMT package was installed: Pkg.status("GMT") Status \`~/.julia/environments/v1.6/Project.toml\` \[5752ebe1\] GMT v0.37.1 However, a simple “…

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## [Weekly small questions thread](https://discourse.julialang.org/t/weekly-small-questions-thread/70438)

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**Author:** [@junelac](https://discourse.julialang.org/u/junelac)\
**Replies:** 1\
**Last updated:** [October 27, 2021, 3:36am UTC](https://discourse.julialang.org/t/weekly-small-questions-thread/70438 "2021-10-27T03:36:24Z")

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Hello, I would suggest to have a weekly small questions thread (maybe in new?) for all the question people could have about any topic related to julia but don’t want to create a thread for them.

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## [Getting union/tuple covariance for maps between parallel type hierarchies](https://discourse.julialang.org/t/getting-union-tuple-covariance-for-maps-between-parallel-type-hierarchies/70060)

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**Author:** [@ablaom](https://discourse.julialang.org/u/ablaom)\
**Replies:** 17\
**Last updated:** [October 27, 2021, 1:44am UTC](https://discourse.julialang.org/t/getting-union-tuple-covariance-for-maps-between-parallel-type-hierarchies/70060 "2021-10-27T01:44:26Z")

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Sorry, this title isn’t great but not sure what to put there :roll\_eyes: I am working on the parallel type hierarchy that’s part of ScientificTypes.jl and we have a function Scitype that maps types to types. I want the …

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## [Documentation not deployed despite make.jl saying it is](https://discourse.julialang.org/t/documentation-not-deployed-despite-make-jl-saying-it-is/70441)

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**Author:** [@biona001](https://discourse.julialang.org/u/biona001)\
**Replies:** 1\
**Last updated:** [October 27, 2021, 1:23am UTC](https://discourse.julialang.org/t/documentation-not-deployed-despite-make-jl-saying-it-is/70441 "2021-10-27T01:23:13Z")

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I think I set up the documentation for my new package correctly. Here’s a screen shot from Github: However, the documentation link is still broken: Home · Knockoffs.jl Does anyone know why? Does this have to do wi…

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## [Cannot read stream serialized with a newer version of Julia](https://discourse.julialang.org/t/cannot-read-stream-serialized-with-a-newer-version-of-julia/70446)

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**Author:** [@iamsuddhasattwa](https://discourse.julialang.org/u/iamsuddhasattwa)\
**Replies:** 2\
**Last updated:** [October 27, 2021, 12:41am UTC](https://discourse.julialang.org/t/cannot-read-stream-serialized-with-a-newer-version-of-julia/70446 "2021-10-27T00:41:05Z")

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I am trying to read a file created in a different machine, and I get this error which seems to be a version mismatch error. My Julia is version 1.5.3. I have no idea how to proceed from this point. julia\> using Serializ…

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## [How to get plot parameters?](https://discourse.julialang.org/t/how-to-get-plot-parameters/70440)

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**Author:** [@pjgorski](https://discourse.julialang.org/u/pjgorski)\
**Replies:** 1\
**Last updated:** [October 27, 2021, 12:13am UTC](https://discourse.julialang.org/t/how-to-get-plot-parameters/70440 "2021-10-27T00:13:10Z")

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We have the plot. Is there a way to get (lookup) plot parameters? Why do I want it? My goal is to create a master legend for subplots. So I need the legend labels to create an empty plot with legend only and I’d like to…

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## [How to improve performance in nested loops](https://discourse.julialang.org/t/how-to-improve-performance-in-nested-loops/70407)

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**Author:** [@claudio20497](https://discourse.julialang.org/u/claudio20497)\
**Replies:** 3\
**Last updated:** [October 26, 2021, 10:34pm UTC](https://discourse.julialang.org/t/how-to-improve-performance-in-nested-loops/70407 "2021-10-26T22:34:50Z")

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Hello, I’m writing a function whose performance suffers because of a nested for-loop. Below is a simplified version of that function. The function f() takes no arguments, and instantiates vecvec a vector of vectors of I…

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## [Find if point is within geojson polygons](https://discourse.julialang.org/t/find-if-point-is-within-geojson-polygons/70416)

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**Author:** [@alex-s-gardner](https://discourse.julialang.org/u/alex-s-gardner)\
**Replies:** 3\
**Last updated:** [October 26, 2021, 10:47pm UTC](https://discourse.julialang.org/t/find-if-point-is-within-geojson-polygons/70416 "2021-10-26T22:47:36Z")

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I am slowly dipping my toe into the Julia waters and I’m hoping someone could point me in the right direction as to how I can determine if a point falls within any of the polygons defined by a geojson file. I’ve found Ge…

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## [Remove single quote from command line](https://discourse.julialang.org/t/remove-single-quote-from-command-line/70434)

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**Author:** [@biona001](https://discourse.julialang.org/u/biona001)\
**Replies:** 1\
**Last updated:** [October 26, 2021, 9:07pm UTC](https://discourse.julialang.org/t/remove-single-quote-from-command-line/70434 "2021-10-26T21:07:31Z")

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Why is there extra single quotes in this command? args = \["--arg1 hi.txt", "--arg2 bye.txt"\] cmd = \`myscript $args\` \`myscript '--arg1 hi.txt' '--arg2 bye.txt'\` How do I get just \`myscript --arg1 hi.txt --arg2 bye.txt…

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## [Understanding dependencies and reproducibility](https://discourse.julialang.org/t/understanding-dependencies-and-reproducibility/70419)

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**Author:** [@shiroghost](https://discourse.julialang.org/u/shiroghost)\
**Replies:** 4\
**Last updated:** [October 26, 2021, 8:30pm UTC](https://discourse.julialang.org/t/understanding-dependencies-and-reproducibility/70419 "2021-10-26T20:30:12Z")

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Hi all, I am trying to understand better reproducibility and the working of the Package manager. Let’s say that I develop a Package “A”, that depends on some third party packages (example CUDA.jl). Now I develop a prog…

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## [Tensor coordinate transforms for linear elasticity](https://discourse.julialang.org/t/tensor-coordinate-transforms-for-linear-elasticity/70326)

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**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 4\
**Last updated:** [October 26, 2021, 3:08pm UTC](https://discourse.julialang.org/t/tensor-coordinate-transforms-for-linear-elasticity/70326 "2021-10-26T15:08:36Z")

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I have a linear elasticity problem in 2D (plane stress) with anisotropic material properties. I can easily calculate the displacement in the (100) plane, but I have difficulty understanding how to get the correct initia…

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## [UnitfulColors.jl](https://discourse.julialang.org/t/unitfulcolors-jl/70226)

<div class="topic-metadata">

**Author:** [@gustaphe](https://discourse.julialang.org/u/gustaphe)\
**Replies:** 2\
**Last updated:** [October 26, 2021, 1:46pm UTC](https://discourse.julialang.org/t/unitfulcolors-jl/70226 "2021-10-26T13:46:52Z")

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I was digging through my ~/.julia/dev/ folder and found this package which I worked on about a year ago. https://github.com/gustaphe/UnitfulColors.jl using UnitfulColors using Unitful, Plots, UnitfulRecipes, Latexify, …

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## [Is there an easy way to get at the history of REPL input?](https://discourse.julialang.org/t/is-there-an-easy-way-to-get-at-the-history-of-repl-input/18025)

<div class="topic-metadata">

**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 23\
**Last updated:** [October 26, 2021, 1:44pm UTC](https://discourse.julialang.org/t/is-there-an-easy-way-to-get-at-the-history-of-repl-input/18025 "2021-10-26T13:44:20Z")

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How does one get easily at the history of the input provided at the prompt? The \*nix shell has a function history which spits out numbered list of commands. Is there something like this in Julia?

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