# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1598

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

**Page:** 1599

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## [Why does delete!() work with sets, but not deleteat!()](https://discourse.julialang.org/t/why-does-delete-work-with-sets-but-not-deleteat/48596)

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**Author:** [@anon60034542](https://discourse.julialang.org/u/anon60034542)\
**Replies:** 10\
**Last updated:** [October 19, 2020, 12:52pm UTC](https://discourse.julialang.org/t/why-does-delete-work-with-sets-but-not-deleteat/48596 "2020-10-19T12:52:52Z")

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If I had the following set: numbers = Set(\[1,2,3,4,5\]) and I do: delete!(3) It will remove the number 3 from the Set, but when I use deleteat!(3) it throws an error, why?

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## [Locally connected layer in Flux](https://discourse.julialang.org/t/locally-connected-layer-in-flux/48624)

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**Author:** [@johnbb](https://discourse.julialang.org/u/johnbb)\
**Replies:** 0\
**Last updated:** [October 19, 2020, 12:00pm UTC](https://discourse.julialang.org/t/locally-connected-layer-in-flux/48624 "2020-10-19T12:00:12Z")

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Has anyone made an implementation of a locally connected layer in Flux similar to the one(s) in Keras?

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## [Flux Can 2-Dimensional Input be fed into MLP columnwise for column output?](https://discourse.julialang.org/t/flux-can-2-dimensional-input-be-fed-into-mlp-columnwise-for-column-output/48622)

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**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 0\
**Last updated:** [October 19, 2020, 11:23am UTC](https://discourse.julialang.org/t/flux-can-2-dimensional-input-be-fed-into-mlp-columnwise-for-column-output/48622 "2020-10-19T11:23:21Z")

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I have an MLP with one output and I am using Flux. Is it possible to have an input of k columns of data and have each column applied to this same MLP so that the output is a column of size k? If so, and if the above r…

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## [\\julia version of \\LaTeX](https://discourse.julialang.org/t/julia-version-of-latex/48585)

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**Author:** [@AlanFreed](https://discourse.julialang.org/u/AlanFreed)\
**Replies:** 5\
**Last updated:** [October 19, 2020, 10:40am UTC](https://discourse.julialang.org/t/julia-version-of-latex/48585 "2020-10-19T10:40:42Z")

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Hi, I’d like to be able to typeset the julia icon in LaTeX documents just like I can for LaTeX via \\LaTeX. I have a crude implementation of % % A macro for typesetting julia % \\usepackage{xcolor} \\newcommand{\\juli…

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## [Generate a positive definite matrix](https://discourse.julialang.org/t/generate-a-positive-definite-matrix/48582)

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**Author:** [@F-YF](https://discourse.julialang.org/u/F-YF)\
**Replies:** 6\
**Last updated:** [October 19, 2020, 10:32am UTC](https://discourse.julialang.org/t/generate-a-positive-definite-matrix/48582 "2020-10-19T10:32:56Z")

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How do I randomly generate a positive definite matrix？ What functions can directly implement this step？

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## [Rethrow error from @async](https://discourse.julialang.org/t/rethrow-error-from-async/48609)

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**Author:** [@kobied](https://discourse.julialang.org/u/kobied)\
**Replies:** 3\
**Last updated:** [October 19, 2020, 9:38am UTC](https://discourse.julialang.org/t/rethrow-error-from-async/48609 "2020-10-19T09:38:48Z")

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hello, I need help understanding why the rethrow from an @async does not work. my test code is as follow: bad\_fun1() = error("this is error from bad\_fun1") function rethrow\_fun1() try bad\_fun1() catch…

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## [Constructing dates from a vector of numbers?](https://discourse.julialang.org/t/constructing-dates-from-a-vector-of-numbers/48546)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 10\
**Last updated:** [October 19, 2020, 6:33am UTC](https://discourse.julialang.org/t/constructing-dates-from-a-vector-of-numbers/48546 "2020-10-19T06:33:50Z")

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I have a solution of a differential equations problem, with a given time vector, say 50 values in the range \[0,10\]. I want to use date along the abscissa axis in the plot. So essentially, I want to associate time 0 from …

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## [How to calculate loss in a given time budget?](https://discourse.julialang.org/t/how-to-calculate-loss-in-a-given-time-budget/48369)

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**Author:** [@Alec\_4](https://discourse.julialang.org/u/Alec_4)\
**Replies:** 6\
**Last updated:** [October 18, 2020, 10:26am UTC](https://discourse.julialang.org/t/how-to-calculate-loss-in-a-given-time-budget/48369 "2020-10-18T10:26:29Z")

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Now i’d like to construct a Dataframe of loss values using different Optimizers in a given processing time budget, which should looks like below. But now my question is how to make this concrete? │ Row │ Optimizer │ 1…

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## [Belgium (Ghent), December 21: User meetup](https://discourse.julialang.org/t/belgium-ghent-december-21-user-meetup/14625)

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**Author:** [@maleadt](https://discourse.julialang.org/u/maleadt)\
**Replies:** 7\
**Last updated:** [October 19, 2020, 6:24am UTC](https://discourse.julialang.org/t/belgium-ghent-december-21-user-meetup/14625 "2020-10-19T06:24:56Z")

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Hi all, We’re organizing a Julia user meetup at Ghent University, Belgium, on the 21st of December. There will be multiple talks, and a reception afterwards for a chance to socialize with fellow Julia users and develope…

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## [The performance of saturating operations or adding intrinsics](https://discourse.julialang.org/t/the-performance-of-saturating-operations-or-adding-intrinsics/48575)

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**Author:** [@kimikage](https://discourse.julialang.org/u/kimikage)\
**Replies:** 10\
**Last updated:** [October 19, 2020, 4:37am UTC](https://discourse.julialang.org/t/the-performance-of-saturating-operations-or-adding-intrinsics/48575 "2020-10-19T04:37:17Z")

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I (we) will support saturating arithmetic in FixedPointNumbers.jl as an experimental feature until the API design is mature. (If you’re interested in the background and API design, you can also see: ) Since the additi…

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## [Execute code in Julia Markdown in VS code](https://discourse.julialang.org/t/execute-code-in-julia-markdown-in-vs-code/48564)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 22\
**Last updated:** [October 19, 2020, 2:15am UTC](https://discourse.julialang.org/t/execute-code-in-julia-markdown-in-vs-code/48564 "2020-10-19T02:15:33Z")

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For a Julia file, I can execute code with Alt+Enter. Is there a similar way, to do the same in a Markdown?

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## [Just switched machines, got "ERROR: expected package \`IfElse \[615f187c\]\` to be registered"](https://discourse.julialang.org/t/just-switched-machines-got-error-expected-package-ifelse-615f187c-to-be-registered/48600)

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**Author:** [@Samuel\_Ainsworth](https://discourse.julialang.org/u/Samuel_Ainsworth)\
**Replies:** 1\
**Last updated:** [October 19, 2020, 1:25am UTC](https://discourse.julialang.org/t/just-switched-machines-got-error-expected-package-ifelse-615f187c-to-be-registered/48600 "2020-10-19T01:25:11Z")

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I just moved my project from one machine running Julia 1.5.1 to another machine running 1.5.2, and tried running \] instantiate. The first time I got an error: ERROR: expected package IfElse \[615f187c\] to be registered, b…

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## [Why can't I get a symbol to interpolate when using ':(for outer $var ...)'](https://discourse.julialang.org/t/why-cant-i-get-a-symbol-to-interpolate-when-using-for-outer-var/45987)

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**Author:** [@frtps](https://discourse.julialang.org/u/frtps)\
**Replies:** 10\
**Last updated:** [October 19, 2020, 12:51am UTC](https://discourse.julialang.org/t/why-cant-i-get-a-symbol-to-interpolate-when-using-for-outer-var/45987 "2020-10-19T00:51:02Z")

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I am auto-generating Julia code and wish to construct an Expr for a for statement for which the iteration variable will be available in the enclosing scope (that’s the spec of the source language). For some reason julia…

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## [Optimal with IPOPTH, Infeasible with Gurobi](https://discourse.julialang.org/t/optimal-with-ipopth-infeasible-with-gurobi/48523)

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**Author:** [@SingingKim](https://discourse.julialang.org/u/SingingKim)\
**Replies:** 4\
**Last updated:** [October 19, 2020, 12:34am UTC](https://discourse.julialang.org/t/optimal-with-ipopth-infeasible-with-gurobi/48523 "2020-10-19T00:34:37Z")

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Hi, I’m working on a bilevel problem that is converted into an equivalent non-convex QCQP by applying strong duality to the lower-level problem (LP). My code returns a (local) optimal solution with Ipopt solver (w/ ma86…

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## [Upload of DataFrame data to databases](https://discourse.julialang.org/t/upload-of-dataframe-data-to-databases/36950)

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**Author:** [@lungben](https://discourse.julialang.org/u/lungben)\
**Replies:** 6\
**Last updated:** [October 19, 2020, 12:18am UTC](https://discourse.julialang.org/t/upload-of-dataframe-data-to-databases/36950 "2020-10-19T00:18:07Z")

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Hi, for evaluation of a possible projet usage I did a comparison of DataFrames.jl to Pandas, with side-by-side examples and timings: Overall, DataFrames.jl performs very well in my experiments, great work! One funct…

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## [BARON ERROR: can't open nl file](https://discourse.julialang.org/t/baron-error-cant-open-nl-file/48456)

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**Author:** [@tpmp](https://discourse.julialang.org/u/tpmp)\
**Replies:** 1\
**Last updated:** [October 18, 2020, 8:40pm UTC](https://discourse.julialang.org/t/baron-error-cant-open-nl-file/48456 "2020-10-18T20:40:49Z")

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I was trying to use BARON to solve some problems. JuMP.jl version: 0.21.5 BARON.jl version: 0.6.5 When I run my program, the following error occurs: C:\\Program Files\\ampl\_mswin64\\baron.exe: can't open C:\\Users\\Lujia\\…

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## [Scope and anonymous functions](https://discourse.julialang.org/t/scope-and-anonymous-functions/48590)

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**Author:** [@Wikunia](https://discourse.julialang.org/u/Wikunia)\
**Replies:** 7\
**Last updated:** [October 18, 2020, 8:06pm UTC](https://discourse.julialang.org/t/scope-and-anonymous-functions/48590 "2020-10-18T20:06:10Z")

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I need help :smiley: What is the difference between: function a() funcs = \[\] i = 1 for j=1:100 push!(funcs, (args...)-\>i) i += 1 end return funcs end b = a()…

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## [Batch training for LSTMs in Flux or Knet](https://discourse.julialang.org/t/batch-training-for-lstms-in-flux-or-knet/47762)

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**Author:** [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Replies:** 5\
**Last updated:** [October 18, 2020, 7:57pm UTC](https://discourse.julialang.org/t/batch-training-for-lstms-in-flux-or-knet/47762 "2020-10-18T19:57:40Z")

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I’m new to Flux so apologies if this is a dumb question/ has already been answered (I cannot figure it out based on a search here and the model zoo) I am trying to train an LSTM on a sequence of choices where more than …

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## [How to use xformatter/yformatter in Plot to change the number to 2M (million) or 2K(thousands)](https://discourse.julialang.org/t/how-to-use-xformatter-yformatter-in-plot-to-change-the-number-to-2m-million-or-2k-thousands/48345)

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**Author:** [@Kantvishu](https://discourse.julialang.org/u/Kantvishu)\
**Replies:** 1\
**Last updated:** [October 18, 2020, 7:48pm UTC](https://discourse.julialang.org/t/how-to-use-xformatter-yformatter-in-plot-to-change-the-number-to-2m-million-or-2k-thousands/48345 "2020-10-18T19:48:51Z")

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Hi in the follwing figure I want to change my x-axis and y-axis number into format 2M (million) or 2K(thousands). How can I do it? I think I have to use xformatter or yformatter command but i don’t know how exactly I ca…

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## [How do I build an executable from my (hello world) simple script?](https://discourse.julialang.org/t/how-do-i-build-an-executable-from-my-hello-world-simple-script/48595)

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**Author:** [@vadrer](https://discourse.julialang.org/u/vadrer)\
**Replies:** 3\
**Last updated:** [October 18, 2020, 7:45pm UTC](https://discourse.julialang.org/t/how-do-i-build-an-executable-from-my-hello-world-simple-script/48595 "2020-10-18T19:45:50Z")

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given that Julia executes as fast as C and internally compiles to machine code (except when in interpreted mode and thus using microlisp) - then I can easily get my binary? looking into command line options with julia -…

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## [Most Accurate/Efficient Interpolation approach for 1D/2D, discrete-continuous hybrid problem](https://discourse.julialang.org/t/most-accurate-efficient-interpolation-approach-for-1d-2d-discrete-continuous-hybrid-problem/48515)

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**Author:** [@CosmoProf](https://discourse.julialang.org/u/CosmoProf)\
**Replies:** 4\
**Last updated:** [October 18, 2020, 7:14pm UTC](https://discourse.julialang.org/t/most-accurate-efficient-interpolation-approach-for-1d-2d-discrete-continuous-hybrid-problem/48515 "2020-10-18T19:14:13Z")

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Hi all, looking for advice on the best way to get very accurate results in finite computing time, for this problem: A discrete grid in x, with f(x) values at each point. For any initial choice of x0, need to interpolate…

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## [Behavior of cd() in Julia script](https://discourse.julialang.org/t/behavior-of-cd-in-julia-script/48532)

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**Author:** [@ZZP12](https://discourse.julialang.org/u/ZZP12)\
**Replies:** 3\
**Last updated:** [October 18, 2020, 7:11pm UTC](https://discourse.julialang.org/t/behavior-of-cd-in-julia-script/48532 "2020-10-18T19:11:37Z")

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Hi, I have a Julia script as below: generate\_default\_project("./default1") make\_julia\_model("./default1/Network.vff", "./default2") println(pwd()) cd("./default2/") println(pwd()) println("run t…

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## [Getting "MethodError: no method matching Model()" when initializing models on JuMP](https://discourse.julialang.org/t/getting-methoderror-no-method-matching-model-when-initializing-models-on-jump/43647)

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**Author:** [@hassanis](https://discourse.julialang.org/u/hassanis)\
**Replies:** 6\
**Last updated:** [October 18, 2020, 6:43pm UTC](https://discourse.julialang.org/t/getting-methoderror-no-method-matching-model-when-initializing-models-on-jump/43647 "2020-10-18T18:43:38Z")

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I’m using JuMP and had several models that were running fine. Now, whenever I try to initialize a model (for example Model(Gurobi.Optimizer)), I get the error: MethodError: no method matching Model(::Type{Gurobi.Optimiz…

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## [What controls if a an operator 1⊕2⊕3 is varadic](https://discourse.julialang.org/t/what-controls-if-a-an-operator-1-2-3-is-varadic/48593)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 3\
**Last updated:** [October 18, 2020, 6:32pm UTC](https://discourse.julialang.org/t/what-controls-if-a-an-operator-1-2-3-is-varadic/48593 "2020-10-18T18:32:31Z")

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Contrast how + parses vs a custom operator: julia\> dump(:(1+2+3)) Expr head: Symbol call args: Array{Any}((4,)) 1: Symbol + 2: Int64 1 3: Int64 2 4: Int64 3 it becomes +(1,2,3) julia\> dump(:(1⊕2⊕3…

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## [Why is there a performance penalty in evaluating the axes of an OffsetArray?](https://discourse.julialang.org/t/why-is-there-a-performance-penalty-in-evaluating-the-axes-of-an-offsetarray/48542)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 5\
**Last updated:** [October 18, 2020, 3:01pm UTC](https://discourse.julialang.org/t/why-is-there-a-performance-penalty-in-evaluating-the-axes-of-an-offsetarray/48542 "2020-10-18T15:01:10Z")

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Currently evaluating the axes of an OffsetArray is considerably slower than that of an Array as the former uses a custom axis type that wraps the axes of the parent. I am trying to understand how to improve the performan…

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## [Gnuplot: how to plot into an existing figure?](https://discourse.julialang.org/t/gnuplot-how-to-plot-into-an-existing-figure/48529)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 12\
**Last updated:** [October 18, 2020, 1:30am UTC](https://discourse.julialang.org/t/gnuplot-how-to-plot-into-an-existing-figure/48529 "2020-10-18T01:30:45Z")

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For the Gnuplot aficionados here: Say I plot once into a terminal. Then I call another function and I would like that plot to be added to that existing terminal. Can I do that? I searched through two Gnuplot books, witho…

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## [Wraping a MKL handle in julia](https://discourse.julialang.org/t/wraping-a-mkl-handle-in-julia/48241)

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**Author:** [@j\_tanu](https://discourse.julialang.org/u/j_tanu)\
**Replies:** 16\
**Last updated:** [October 18, 2020, 2:51pm UTC](https://discourse.julialang.org/t/wraping-a-mkl-handle-in-julia/48241 "2020-10-18T14:51:09Z")

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I am trying to implement mkl two-stage algorithm in Julia. “mkl\_sparse\_?\_create\_csc” function creates a handle for a matrix A in CSC format. In c language, the type of the handle is sparse\_matrix\_t. How to wrap this kind…

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## [Plots doesn't work properly](https://discourse.julialang.org/t/plots-doesnt-work-properly/48579)

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**Author:** [@Inbar\_Maimon](https://discourse.julialang.org/u/Inbar_Maimon)\
**Replies:** 6\
**Last updated:** [October 18, 2020, 2:04pm UTC](https://discourse.julialang.org/t/plots-doesnt-work-properly/48579 "2020-10-18T14:04:56Z")

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Hi there, I’m using Ubuntu 20.04 and julia 1.5.2. I’m trying to use Plots. When typing using Plots the julia terminal raises no complaints. Then I tried plot(1:3, 1:3) and got the message /home/inbar/.julia/packag…

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## [Improving dispatch in an event manager](https://discourse.julialang.org/t/improving-dispatch-in-an-event-manager/48569)

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**Author:** [@Scott\_Hanna](https://discourse.julialang.org/u/Scott_Hanna)\
**Replies:** 1\
**Last updated:** [October 18, 2020, 1:00pm UTC](https://discourse.julialang.org/t/improving-dispatch-in-an-event-manager/48569 "2020-10-18T13:00:23Z")

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Hello all, I’ve recently started building an event manager in Julia as part of a larger project. I’ve done this in OO languages before and I implemented a similar one in Julia. In such an event manager you have events…

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## [Get all Permutations of Array?](https://discourse.julialang.org/t/get-all-permutations-of-array/48578)

<div class="topic-metadata">

**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 2\
**Last updated:** [October 18, 2020, 9:59am UTC](https://discourse.julialang.org/t/get-all-permutations-of-array/48578 "2020-10-18T09:59:01Z")

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Hi I found some old Julia code which states that this used to work: https://en.wikibooks.org/wiki/Julia\_for\_MATLAB\_Users/Core\_Language/Mathematics#perms\_All\_possible\_permutations julia\> perms(a) = reverse(collect(perm…

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