# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1445

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

**Page:** 1446

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## [Optimizing semiclassical simulation for a lattice system](https://discourse.julialang.org/t/optimizing-semiclassical-simulation-for-a-lattice-system/58014)

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**Author:** [@Joh11](https://discourse.julialang.org/u/Joh11)\
**Replies:** 7\
**Last updated:** [March 26, 2021, 4:55pm UTC](https://discourse.julialang.org/t/optimizing-semiclassical-simulation-for-a-lattice-system/58014 "2021-03-26T16:55:13Z")

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Hi everyone, I am currently working on implementing an implementation of semiclassical Monte Carlo for a lattice system (https://github.com/Joh11/semiclassical-monte-carlo). I would like to make my code faster. The bot…

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## [Is \`pkg.julialang.org\` down?](https://discourse.julialang.org/t/is-pkg-julialang-org-down/58015)

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**Author:** [@Impressium](https://discourse.julialang.org/u/Impressium)\
**Replies:** 4\
**Last updated:** [March 26, 2021, 4:09pm UTC](https://discourse.julialang.org/t/is-pkg-julialang-org-down/58015 "2021-03-26T16:09:41Z")

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┌ Warning: could not download https://pkg.julialang.org/registries └ @ Pkg.Types C:\\buildbot\\worker\\package\_win64\\build\\usr\\share\\julia\\stdlib\\v1.6\\Pkg\\src\\Types.jl:976

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## [Symbolics.jl - solve\_for not defined](https://discourse.julialang.org/t/symbolics-jl-solve-for-not-defined/57292)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 3\
**Last updated:** [March 26, 2021, 3:43pm UTC](https://discourse.julialang.org/t/symbolics-jl-solve-for-not-defined/57292 "2021-03-26T15:43:35Z")

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When I tried to use Symbolics.jl to sovle a simple equation, I ran into the error saying that solve\_for was not defined. Below you can see the package status and a screenshot from the docs. Am I wrong, or is something no…

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## [Missing ascii/unicode](https://discourse.julialang.org/t/missing-ascii-unicode/57990)

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**Author:** [@Wei\_Yang](https://discourse.julialang.org/u/Wei_Yang)\
**Replies:** 6\
**Last updated:** [March 26, 2021, 1:55pm UTC](https://discourse.julialang.org/t/missing-ascii-unicode/57990 "2021-03-26T13:55:17Z")

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When I run for i in 1:3000 print(Char(i)) end many of the characters appeared as question marks. I understand that this is most likely an windows OS problem, but just wondering if anyone have encountered this issue be…

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## [Condition for numeric table column type](https://discourse.julialang.org/t/condition-for-numeric-table-column-type/58011)

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**Author:** [@Laco\_Kovac](https://discourse.julialang.org/u/Laco_Kovac)\
**Replies:** 2\
**Last updated:** [March 26, 2021, 1:01pm UTC](https://discourse.julialang.org/t/condition-for-numeric-table-column-type/58011 "2021-03-26T13:01:48Z")

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I am importing data from database, getting DataFrame. I am supposed to import only numeric columns, either Integer or floating point. If the column is nullable, type is a Union of Missing & type, e.g. Union{Missing, Fl…

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## [Help me understand unintuitive behavior of array comparison](https://discourse.julialang.org/t/help-me-understand-unintuitive-behavior-of-array-comparison/57946)

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**Author:** [@levasco](https://discourse.julialang.org/u/levasco)\
**Replies:** 8\
**Last updated:** [March 26, 2021, 1:00pm UTC](https://discourse.julialang.org/t/help-me-understand-unintuitive-behavior-of-array-comparison/57946 "2021-03-26T13:00:16Z")

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julia\> minimum(\[\[1,1e10,1e10\],\[2,0,0\]\]) 3-element Array{Float64,1}: 1.0 1.0e10 1.0e10 I would expect this to return either the same as min.() or a MethodError, but instead only the first elements are compared. Simila…

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## [Tiny associative array (alist-like)](https://discourse.julialang.org/t/tiny-associative-array-alist-like/57937)

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**Author:** [@circonflexe](https://discourse.julialang.org/u/circonflexe)\
**Replies:** 4\
**Last updated:** [March 26, 2021, 12:58pm UTC](https://discourse.julialang.org/t/tiny-associative-array-alist-like/57937 "2021-03-26T12:58:21Z")

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So I need a data structure implementing a tiny associative array from integers to another type T (which type is not completely clear, but assume lists of integers, implemented as Vector{Int}, for now. Or it could be stri…

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## [SDE noise term equal to zero](https://discourse.julialang.org/t/sde-noise-term-equal-to-zero/57816)

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**Author:** [@JuliaCantisan](https://discourse.julialang.org/u/JuliaCantisan)\
**Replies:** 7\
**Last updated:** [March 26, 2021, 12:45pm UTC](https://discourse.julialang.org/t/sde-noise-term-equal-to-zero/57816 "2021-03-26T12:45:24Z")

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Hi everyone, I am dealing with a Stochastic Differential Equation which, in order to solve, I have divided in two: I was wondering if it is correct to set the noise term equal to zero in the first equation, this is: …

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## [Always show exception type in stack trace?](https://discourse.julialang.org/t/always-show-exception-type-in-stack-trace/58010)

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**Author:** [@tpgillam](https://discourse.julialang.org/u/tpgillam)\
**Replies:** 0\
**Last updated:** [March 26, 2021, 11:57am UTC](https://discourse.julialang.org/t/always-show-exception-type-in-stack-trace/58010 "2021-03-26T11:57:14Z")

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I observe that stack traces in Julia do not necessarily show the type of the exception that is thrown. For example: julia\> throw(DomainError("moo")) ERROR: DomainError with moo: ...snip... includes “DomainError” in the…

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## [Nested parametric type?](https://discourse.julialang.org/t/nested-parametric-type/58009)

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**Author:** [@huchiayu0517](https://discourse.julialang.org/u/huchiayu0517)\
**Replies:** 2\
**Last updated:** [March 26, 2021, 11:47am UTC](https://discourse.julialang.org/t/nested-parametric-type/58009 "2021-03-26T11:47:28Z")

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I’m working on a tree code where I have defined the following types: using StaticArrays mutable struct Data{N,T} pos::SVector{N,T} mass::T end mutable struct Node{N,T} center::SVector{N,T} p::Union{Data{N,T}, N…

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## [REPL: RGB colors](https://discourse.julialang.org/t/repl-rgb-colors/58002)

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**Author:** [@ZettEff](https://discourse.julialang.org/u/ZettEff)\
**Replies:** 2\
**Last updated:** [March 26, 2021, 10:43am UTC](https://discourse.julialang.org/t/repl-rgb-colors/58002 "2021-03-26T10:43:34Z")

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Is it possible to represent colors in REPL. The below code does not show the color, but a string representation of the RGB struct. using Colors green = RGB(0.,255,0.) Is it possible / where do I start if I want e.g. a…

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## [DataFrames/CSV: how to read vectors from \*.csv?](https://discourse.julialang.org/t/dataframes-csv-how-to-read-vectors-from-csv/57883)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 9\
**Last updated:** [March 26, 2021, 10:09am UTC](https://discourse.julialang.org/t/dataframes-csv-how-to-read-vectors-from-csv/57883 "2021-03-26T10:09:00Z")

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Dear folks, unfortunately, I fail to read vectors from a \*.csv file. Here is an MWE: using CSV, DataFrames df = DataFrame( A=\[\[1,2,3\], \[4,5,6\]\] ) file = "my\_test.csv" CSV.write(file, df, delim=';') new\_df = DataFrame…

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## [ANN: GitHub action workflow to test if your PR breaks another package (Reverse Dependency Integration Testing)](https://discourse.julialang.org/t/ann-github-action-workflow-to-test-if-your-pr-breaks-another-package-reverse-dependency-integration-testing/57635)

<div class="topic-metadata">

**Author:** [@abelsiqueira](https://discourse.julialang.org/u/abelsiqueira)\
**Replies:** 1\
**Last updated:** [March 26, 2021, 9:57am UTC](https://discourse.julialang.org/t/ann-github-action-workflow-to-test-if-your-pr-breaks-another-package-reverse-dependency-integration-testing/57635 "2021-03-26T09:57:05Z")

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Hi all. At JuliaSmoothOptimizers, we’ve been running a breakage test to see if a PR request to our base package breaks the other packages down the line. This last week I’ve updated it to GitHub Actions and manage to tran…

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## [Tuple as argument for size(AbstractArray)](https://discourse.julialang.org/t/tuple-as-argument-for-size-abstractarray/57533)

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**Author:** [@RainerHeintzmann](https://discourse.julialang.org/u/RainerHeintzmann)\
**Replies:** 36\
**Last updated:** [March 26, 2021, 7:52am UTC](https://discourse.julialang.org/t/tuple-as-argument-for-size-abstractarray/57533 "2021-03-26T07:52:06Z")

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It would be great to have an alternative way of calling size with a tuple of dimensions. Is there a specific reason that this does not exist in Base? The function could look like function size(x::AbstractArray{T},dim:…

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## [Dates.DateTime format in a DataFrame](https://discourse.julialang.org/t/dates-datetime-format-in-a-dataframe/57935)

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**Author:** [@Laco\_Kovac](https://discourse.julialang.org/u/Laco_Kovac)\
**Replies:** 4\
**Last updated:** [March 26, 2021, 7:49am UTC](https://discourse.julialang.org/t/dates-datetime-format-in-a-dataframe/57935 "2021-03-26T07:49:34Z")

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I am fetching content of the table and downloading it CSV (using LibPQ, DataFrames and CSV). This is the code converting DataFrame to CSV: executeResult = execute(conn, "SELECT \* FROM table") frame = DataFrame(executeR…

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## [Can you |\> gpu a GraphConv in GeometricFlux.jl?](https://discourse.julialang.org/t/can-you-gpu-a-graphconv-in-geometricflux-jl/57991)

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**Author:** [@Lian\_Yunlong](https://discourse.julialang.org/u/Lian_Yunlong)\
**Replies:** 0\
**Last updated:** [March 26, 2021, 6:39am UTC](https://discourse.julialang.org/t/can-you-gpu-a-graphconv-in-geometricflux-jl/57991 "2021-03-26T06:39:15Z")

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Dear developers and experts, I am trying to program with Flux.jl for a GNN project. There is a simple question: can I upload a model, form example, GraphConv in GeometricFlux.jl, to GPU via |\> gpu ? I tried this but did…

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## [ProfileView not loading MacOS](https://discourse.julialang.org/t/profileview-not-loading-macos/57970)

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**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 5\
**Last updated:** [March 26, 2021, 6:40am UTC](https://discourse.julialang.org/t/profileview-not-loading-macos/57970 "2021-03-26T06:40:35Z")

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Unfortunately, I can’t seem to get the ProfileView.view() GUI to load on MacOS. I didn’t have any problems adding or precompiling the package. Profile works. The GUI window pops up, but it stays completely blank and I ge…

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## [Plot (GR) with mirror axes](https://discourse.julialang.org/t/plot-gr-with-mirror-axes/57984)

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**Author:** [@ishihama](https://discourse.julialang.org/u/ishihama)\
**Replies:** 1\
**Last updated:** [March 26, 2021, 2:02am UTC](https://discourse.julialang.org/t/plot-gr-with-mirror-axes/57984 "2021-03-26T02:02:46Z")

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I am wondering how to draw the mirror axes in Julia plot with the GR backends. Recently, a major update has been executed and the default setting only draws bottom and left axes only. But my preference is drawing four ax…

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## [Is anyone using Textadept as their editor of choice for Julia?](https://discourse.julialang.org/t/is-anyone-using-textadept-as-their-editor-of-choice-for-julia/41255)

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**Author:** [@timbot](https://discourse.julialang.org/u/timbot)\
**Replies:** 42\
**Last updated:** [March 25, 2021, 11:51pm UTC](https://discourse.julialang.org/t/is-anyone-using-textadept-as-their-editor-of-choice-for-julia/41255 "2021-03-25T23:51:41Z")

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Hello, does anyone here use Textadept as their primary text editor for Julia? I have tried all the usual suspects (Atom, VScode, Emacs, Vim), but I don’t really like using any of them. I came across Textadept today (Te…

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## [Problem with plotting and printing inside a loop](https://discourse.julialang.org/t/problem-with-plotting-and-printing-inside-a-loop/57840)

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**Author:** [@leopdsf](https://discourse.julialang.org/u/leopdsf)\
**Replies:** 6\
**Last updated:** [March 25, 2021, 11:39pm UTC](https://discourse.julialang.org/t/problem-with-plotting-and-printing-inside-a-loop/57840 "2021-03-25T23:39:18Z")

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Hello, there! I’m studying a physical system with the following code: θ = 0.01; dθ = 0.01 ϵ = 1.0 J = 1.0 μ = 1.0 h=0.0 i=1 while θ \< 2 m0 = 0.1 while ϵ \> 0.001 m = μ\*tanh(J/(μ\*θ)\*m0 + h) print(…

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## [Anything like fsspec for Julia?](https://discourse.julialang.org/t/anything-like-fsspec-for-julia/57968)

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**Author:** [@calebwin](https://discourse.julialang.org/u/calebwin)\
**Replies:** 2\
**Last updated:** [March 25, 2021, 11:13pm UTC](https://discourse.julialang.org/t/anything-like-fsspec-for-julia/57968 "2021-03-25T23:13:23Z")

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Is there anything like Python’s fsspec for Julia? I want to be able to read from a file but that file might be living locally, on the Internet, or in S3.

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## [Help with allocations (variable length least squares)](https://discourse.julialang.org/t/help-with-allocations-variable-length-least-squares/57931)

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**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 10\
**Last updated:** [March 25, 2021, 10:21pm UTC](https://discourse.julialang.org/t/help-with-allocations-variable-length-least-squares/57931 "2021-03-25T22:21:05Z")

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Hello, folks. Once again, I’m trying to get rid of allocations. It’s a least squares problem with variable number of equations. I tried creating A and b as SVectors using for loops and ntuples, but only made things wors…

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## [Solarized Dark theme with 1.6.0](https://discourse.julialang.org/t/solarized-dark-theme-with-1-6-0/57941)

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**Author:** [@theogf](https://discourse.julialang.org/u/theogf)\
**Replies:** 8\
**Last updated:** [March 25, 2021, 8:59pm UTC](https://discourse.julialang.org/t/solarized-dark-theme-with-1-6-0/57941 "2021-03-25T20:59:42Z")

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If you noticed like me that some messages are invisible during precompilation with 1.6 when using the Solarized Dark theme in Linux you need to change some of the colors. @dave.f.kleinschmidt proposed the following chan…

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## [Differentiate expressions involving LinearMap](https://discourse.julialang.org/t/differentiate-expressions-involving-linearmap/57945)

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**Author:** [@mpf01](https://discourse.julialang.org/u/mpf01)\
**Replies:** 3\
**Last updated:** [March 25, 2021, 7:53pm UTC](https://discourse.julialang.org/t/differentiate-expressions-involving-linearmap/57945 "2021-03-25T19:53:42Z")

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Is it possible, perhaps by defining an appropriate pullback, to differentiate expressions that involve a LinearMap object? Here’s a small example: using Zygote, LinearMaps m, n = 2, 3; r = ones(m); x = ones(n) A = Line…

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## [Could not load library](https://discourse.julialang.org/t/could-not-load-library/57965)

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**Author:** [@ovt](https://discourse.julialang.org/u/ovt)\
**Replies:** 0\
**Last updated:** [March 25, 2021, 7:17pm UTC](https://discourse.julialang.org/t/could-not-load-library/57965 "2021-03-25T19:17:43Z")

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Hi, I’ve been trying to run this code that I obtained from juliaacademy.com but I have the following error computing c\_sum(a) : ERROR: could not load library "C:\\Users\\myusername\\AppData\\Local\\Temp\\jl\_2ZlYe4PqTE" � …

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## [Help with Performance in JuMP](https://discourse.julialang.org/t/help-with-performance-in-jump/57874)

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**Author:** [@jmcastro2109](https://discourse.julialang.org/u/jmcastro2109)\
**Replies:** 7\
**Last updated:** [March 25, 2021, 7:14pm UTC](https://discourse.julialang.org/t/help-with-performance-in-jump/57874 "2021-03-25T19:14:40Z")

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Hi, I am trying to solve a maximization problem using Gurobi/JuMP and I would really appreciate it if you could help me speed things up. Some background on the problem, essentially I am trying to maximize the expectati…

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## [How can I clear solver attributes in JuMP?](https://discourse.julialang.org/t/how-can-i-clear-solver-attributes-in-jump/57953)

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**Author:** [@NiclasMattsson](https://discourse.julialang.org/u/NiclasMattsson)\
**Replies:** 3\
**Last updated:** [March 25, 2021, 7:05pm UTC](https://discourse.julialang.org/t/how-can-i-clear-solver-attributes-in-jump/57953 "2021-03-25T19:05:34Z")

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I need to solve a JuMP model sequentially using different solvers. Solver 1 has one set of attributes but I’m fine with the defaults for solver 2, at least for now. Unfortunately solver 2 complains about the options I se…

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## [Calling a macro within a macro](https://discourse.julialang.org/t/calling-a-macro-within-a-macro/57766)

<div class="topic-metadata">

**Author:** [@turquoise](https://discourse.julialang.org/u/turquoise)\
**Replies:** 2\
**Last updated:** [March 25, 2021, 6:40pm UTC](https://discourse.julialang.org/t/calling-a-macro-within-a-macro/57766 "2021-03-25T18:40:40Z")

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I have defined a macro called @m.trial which simply escapes its argument and feeds into the @identity macro. The @identity macro is defined as (not escaped at the moment intentionally): macro identity(x) x end @m.t…

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## [Setting number of threads and parsing arguments](https://discourse.julialang.org/t/setting-number-of-threads-and-parsing-arguments/57904)

<div class="topic-metadata">

**Author:** [@mjanun](https://discourse.julialang.org/u/mjanun)\
**Replies:** 6\
**Last updated:** [March 25, 2021, 6:36pm UTC](https://discourse.julialang.org/t/setting-number-of-threads-and-parsing-arguments/57904 "2021-03-25T18:36:34Z")

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I understand that to launch Julia with multithreading from command prompt (on Windows), one has to pass the following command before launching Julia: set JULIA\_NUM\_THREADS=4 I am calling Julia from Excel/VBA using the S…

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## [Error Handling JuMP and CPLEX](https://discourse.julialang.org/t/error-handling-jump-and-cplex/56360)

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**Author:** [@Paul\_McVay](https://discourse.julialang.org/u/Paul_McVay)\
**Replies:** 25\
**Last updated:** [March 25, 2021, 5:56pm UTC](https://discourse.julialang.org/t/error-handling-jump-and-cplex/56360 "2021-03-25T17:56:30Z")

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What is the ideal way to handle CPLEX errors in JuMP and Julia? For example, sometimes I run optimize!(m) and it prints CPLEX Error 1292: Invalid choice of optimization method. However, if I use a try/catch and catch the…

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