# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1374

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

**Page:** 1375

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## [How to scale vector filed plots by the norm?](https://discourse.julialang.org/t/how-to-scale-vector-filed-plots-by-the-norm/62186)

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**Author:** [@SebastianM-C](https://discourse.julialang.org/u/SebastianM-C)\
**Replies:** 1\
**Last updated:** [June 1, 2021, 2:05pm UTC](https://discourse.julialang.org/t/how-to-scale-vector-filed-plots-by-the-norm/62186 "2021-06-01T14:05:17Z")

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I am writing a plot recipe for plotting vector fields in a package. I would like to have an arrow plot where the maximum arrow length and arrow size are fixed in Pixel units and all the arrows have their tail length and …

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## [Early termination of ODE integration with callback](https://discourse.julialang.org/t/early-termination-of-ode-integration-with-callback/61035)

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**Author:** [@fkrauer](https://discourse.julialang.org/u/fkrauer)\
**Replies:** 29\
**Last updated:** [June 1, 2021, 1:21pm UTC](https://discourse.julialang.org/t/early-termination-of-ode-integration-with-callback/61035 "2021-06-01T13:21:14Z")

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Hi all I have a simple, epidemiological ODE model with three states: S(usceptibles), I(nfected) and R(ecovered). Transmission is modelled with a periodical, seasonal function. Depending on the initial conditions and par…

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## [JuMP/NumFOCUS contributor survey](https://discourse.julialang.org/t/jump-numfocus-contributor-survey/62141)

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**Author:** [@miles.lubin](https://discourse.julialang.org/u/miles.lubin)\
**Replies:** 2\
**Last updated:** [June 1, 2021, 12:35pm UTC](https://discourse.julialang.org/t/jump-numfocus-contributor-survey/62141 "2021-06-01T12:35:03Z")

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Hi JuMP community, JuMP is participating in a research project being conducted by NumFOCUS. The research is looking into understanding the diversity, inclusion and barriers to participation within NumFOCUS-sponsored pro…

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## [Why doesn't work the module 'const Ref{Task}(@async nothing)' in my package?](https://discourse.julialang.org/t/why-doesnt-work-the-module-const-ref-task-async-nothing-in-my-package/62132)

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**Author:** [@Impressium](https://discourse.julialang.org/u/Impressium)\
**Replies:** 3\
**Last updated:** [June 1, 2021, 12:00pm UTC](https://discourse.julialang.org/t/why-doesnt-work-the-module-const-ref-task-async-nothing-in-my-package/62132 "2021-06-01T12:00:57Z")

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Hey all, why can’t I use a module const like module A const TEST = Ref{Task}(@async nothing) end in a package. (@v1.6) pkg\> update Updating git-repo \`C:\\ProjectName\\packages\\julia\\ProjectName\` Updating \`C:\\Us…

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## [Add a row to a dataframe](https://discourse.julialang.org/t/add-a-row-to-a-dataframe/62170)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 8\
**Last updated:** [June 1, 2021, 10:38am UTC](https://discourse.julialang.org/t/add-a-row-to-a-dataframe/62170 "2021-06-01T10:38:16Z")

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spreadsheet = DataFrame( date=\["Jan 1, 2019"\], #start of the new year #List of Accounts # Start of 2019 #Assets chequing=\[0\], #replace with balance as of Jan 1, 2019 accounts\_reciveable=\[0\], #replace with b…

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## [Problems registering a package](https://discourse.julialang.org/t/problems-registering-a-package/62182)

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**Author:** [@Andrea\_Vigliotti](https://discourse.julialang.org/u/Andrea_Vigliotti)\
**Replies:** 2\
**Last updated:** [June 1, 2021, 9:54am UTC](https://discourse.julialang.org/t/problems-registering-a-package/62182 "2021-06-01T09:54:52Z")

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Hi all I am trying to register this package and the automerge keeps failing saying that guidelines are not met, but I can’t figure out what is wrong this is the pull request this is the part with the error Preco…

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## [Find the maximum for each position of a set of arrays](https://discourse.julialang.org/t/find-the-maximum-for-each-position-of-a-set-of-arrays/62155)

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**Author:** [@maoc](https://discourse.julialang.org/u/maoc)\
**Replies:** 5\
**Last updated:** [May 31, 2021, 10:50pm UTC](https://discourse.julialang.org/t/find-the-maximum-for-each-position-of-a-set-of-arrays/62155 "2021-05-31T22:50:57Z")

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I have an array like this a = \[ rand(1:20,3) for i in 1:2,j in 1:3\] 2×3 Array{Array{Int64,1},2}: 2×3 Array{Array{Int64,1},2}: \[8, 13, 1\] \[12, 4, 9\] \[13, 18, 7\] \[3, 19, 20\] \[8, 3, 11\] \[10, 9, 12\] I would like th…

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## [Fade to transparent](https://discourse.julialang.org/t/fade-to-transparent/62173)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 1\
**Last updated:** [June 1, 2021, 7:30am UTC](https://discourse.julialang.org/t/fade-to-transparent/62173 "2021-06-01T07:30:20Z")

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I have this plot. I want it to fade from opaque to transparent from x=0 to x=100. Is that possible? fig = Figure() Axis(fig\[1,1\]) let xs = 0:.1:100 ys1 = randn(length(xs)) ys2 = randn(length(xs)) yups = m…

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## [\_\_init\_\_ returns nothing in search of documentation](https://discourse.julialang.org/t/init-returns-nothing-in-search-of-documentation/62174)

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**Author:** [@purplishrock](https://discourse.julialang.org/u/purplishrock)\
**Replies:** 1\
**Last updated:** [June 1, 2021, 7:07am UTC](https://discourse.julialang.org/t/init-returns-nothing-in-search-of-documentation/62174 "2021-06-01T07:07:45Z")

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I recently learned there was such a thing an \_\_init\_\_ for modules as described here module initialization But if I put \_\_init\_\_ into the search box it returns absolutely nothing. Aside from the fact that I could have …

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## [What are the currrent options for deep learning on an AMD GPU using Julia?](https://discourse.julialang.org/t/what-are-the-currrent-options-for-deep-learning-on-an-amd-gpu-using-julia/62168)

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**Author:** [@DorianT](https://discourse.julialang.org/u/DorianT)\
**Replies:** 0\
**Last updated:** [June 1, 2021, 12:51am UTC](https://discourse.julialang.org/t/what-are-the-currrent-options-for-deep-learning-on-an-amd-gpu-using-julia/62168 "2021-06-01T00:51:56Z")

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Hello everyone, I am quite new to Julia and the last few days wondering how I should go about my next project which will involve training word embedding models and performing various downstream tasks afterwards. I would…

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## [Tutorial: Efficient and safe approaches to mutation in data parallelism](https://discourse.julialang.org/t/tutorial-efficient-and-safe-approaches-to-mutation-in-data-parallelism/62105)

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**Author:** [@tkf](https://discourse.julialang.org/u/tkf)\
**Replies:** 3\
**Last updated:** [May 31, 2021, 9:55pm UTC](https://discourse.julialang.org/t/tutorial-efficient-and-safe-approaches-to-mutation-in-data-parallelism/62105 "2021-05-31T21:55:48Z")

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Hi, I just wrote another tutorial on data-parallel programming in Julia: Efficient and safe approaches to mutation in data parallelism. This is a sequel of A quick introduction to data parallelism in Julia. As discusse…

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## [Infinite series in Julia](https://discourse.julialang.org/t/infinite-series-in-julia/62151)

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**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 6\
**Last updated:** [May 31, 2021, 7:56pm UTC](https://discourse.julialang.org/t/infinite-series-in-julia/62151 "2021-05-31T19:56:53Z")

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What is the standard approach for computing an infinite series in Julia? Define the sequence of partial sums: s\_{N} \\equiv \\sum\_{j=1}^{N} f(j) In Julia this is: s(N) = sum(f, 1:N) The only way I know is to either com…

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## [C union style for julia](https://discourse.julialang.org/t/c-union-style-for-julia/62149)

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**Author:** [@gitboy16](https://discourse.julialang.org/u/gitboy16)\
**Replies:** 4\
**Last updated:** [May 31, 2021, 7:42pm UTC](https://discourse.julialang.org/t/c-union-style-for-julia/62149 "2021-05-31T19:42:57Z")

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Hi, Is there something equivalent to C union in Julia? Example: union { double b; uint64\_t u64; } u; u.b = d; // use u.u64 here .... I found the following package: Is this the way the community would suggest t…

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## [How to annotate anonymous function parameter type](https://discourse.julialang.org/t/how-to-annotate-anonymous-function-parameter-type/62124)

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**Author:** [@peteole](https://discourse.julialang.org/u/peteole)\
**Replies:** 9\
**Last updated:** [May 31, 2021, 6:53pm UTC](https://discourse.julialang.org/t/how-to-annotate-anonymous-function-parameter-type/62124 "2021-05-31T18:53:49Z")

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Hi, I am wondering how you can annote the signature of a function that is passed as a parameter. For example if I wanted to define a (quite useless) method which returns an array of strings which are computed from an i…

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## [Bug in JuMP](https://discourse.julialang.org/t/bug-in-jump/62129)

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**Author:** [@JohnZ](https://discourse.julialang.org/u/JohnZ)\
**Replies:** 2\
**Last updated:** [May 31, 2021, 6:02pm UTC](https://discourse.julialang.org/t/bug-in-jump/62129 "2021-05-31T18:02:13Z")

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I am running into an unusual error if I specify a method (such as dual simplex, barrier) to use. The solver finds a solution but then I get an error message and Julia exits. The code below reproduces the error. Is this …

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## [Contrasts coding in MixedModels](https://discourse.julialang.org/t/contrasts-coding-in-mixedmodels/62131)

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**Author:** [@Hilary](https://discourse.julialang.org/u/Hilary)\
**Replies:** 1\
**Last updated:** [May 31, 2021, 5:53pm UTC](https://discourse.julialang.org/t/contrasts-coding-in-mixedmodels/62131 "2021-05-31T17:53:38Z")

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Hi guys, I have implemented my SAS Mixed Model on Julia. However, currently there are differences in estimates between SAS and Julia for fixed and random effects. I tried changing the contrasts - maybe this can help t…

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## [Suggestion to slightly improve Julia development](https://discourse.julialang.org/t/suggestion-to-slightly-improve-julia-development/50916)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 94\
**Last updated:** [May 31, 2021, 5:24pm UTC](https://discourse.julialang.org/t/suggestion-to-slightly-improve-julia-development/50916 "2021-05-31T17:24:29Z")

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(This is a discussion I started on Slack but I think this is a better place) Hi! First of all, the Julia community is awesome! Amazing! People are very receptive and really help when the users need. However, I have a s…

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## [StaticArrays and allocations](https://discourse.julialang.org/t/staticarrays-and-allocations/62123)

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**Author:** [@paulmelis](https://discourse.julialang.org/u/paulmelis)\
**Replies:** 27\
**Last updated:** [May 31, 2021, 4:17pm UTC](https://discourse.julialang.org/t/staticarrays-and-allocations/62123 "2021-05-31T16:17:37Z")

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Are there are any guarantees when using StaticArrays that the array values will indeed get stack-allocated? Or is it more like a best-effort guarantee and you may still end up with heap-allocated values? Reason I’m aski…

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## [Using GraphBLAS (from SuiteSparse) to speed up Julia sparse matrix operations](https://discourse.julialang.org/t/using-graphblas-from-suitesparse-to-speed-up-julia-sparse-matrix-operations/62147)

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**Author:** [@viralbshah](https://discourse.julialang.org/u/viralbshah)\
**Replies:** 0\
**Last updated:** [May 31, 2021, 4:56pm UTC](https://discourse.julialang.org/t/using-graphblas-from-suitesparse-to-speed-up-julia-sparse-matrix-operations/62147 "2021-05-31T16:56:53Z")

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I am capturing this conversation from slack here as we integrate GraphBLAS into Julia with permission from @DrTimothyAldenDavis. -viral – Tomas Pevny 7:06 AM I hope people would not mind if I ask a naive question. If…

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## [Julia C constant equivalent](https://discourse.julialang.org/t/julia-c-constant-equivalent/62144)

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**Author:** [@gitboy16](https://discourse.julialang.org/u/gitboy16)\
**Replies:** 4\
**Last updated:** [May 31, 2021, 4:40pm UTC](https://discourse.julialang.org/t/julia-c-constant-equivalent/62144 "2021-05-31T16:40:15Z")

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Hi, What is the equivalent in Julia of 0x8000000000000000ull which is sometimes used in C? Example in C someone could write : (x \>\> 63) | 0x8000000000000000ull Assuming uint64\_t x. Thank you

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## [Variables interfering with each other](https://discourse.julialang.org/t/variables-interfering-with-each-other/62143)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 2\
**Last updated:** [May 31, 2021, 4:13pm UTC](https://discourse.julialang.org/t/variables-interfering-with-each-other/62143 "2021-05-31T16:13:59Z")

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Dear all, I am implementing the divided differences of Newton’ polynomial. However a strange thing happens. I define the x and y values by X and Y variables. Inside the function I define the vector \\Delta Y = Y. But, …

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## [Behavior of kwargs with scatter plot in PyPlot](https://discourse.julialang.org/t/behavior-of-kwargs-with-scatter-plot-in-pyplot/62140)

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**Author:** [@josimar](https://discourse.julialang.org/u/josimar)\
**Replies:** 0\
**Last updated:** [May 31, 2021, 3:18pm UTC](https://discourse.julialang.org/t/behavior-of-kwargs-with-scatter-plot-in-pyplot/62140 "2021-05-31T15:18:46Z")

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I am looking to understand how to pass kwargs to scatter plot using PyPlot. My version control: (@v1.5) pkg\> st Status \`~/.julia/environments/v1.5/Project.toml\` \[c52e3926\] Atom v0.12.30 \[e5e0dc1b\] Juno v0.8.4 \[d3…

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## [Help us understand our users!](https://discourse.julialang.org/t/help-us-understand-our-users/61932)

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**Author:** [@maleadt](https://discourse.julialang.org/u/maleadt)\
**Replies:** 11\
**Last updated:** [May 31, 2021, 2:26pm UTC](https://discourse.julialang.org/t/help-us-understand-our-users/61932 "2021-05-31T14:26:12Z")

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Hi all! Once every while we need to pitch Julia’s GPU programming capabilities with vendors like NVIDIA. Doing so with technical arguments is easy enough, but companies are more easily convinced by an overview of note…

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## [Plots downgraded GR to 0.52 for no good reason](https://discourse.julialang.org/t/plots-downgraded-gr-to-0-52-for-no-good-reason/62115)

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**Author:** [@ChunXi\_Zhang](https://discourse.julialang.org/u/ChunXi_Zhang)\
**Replies:** 10\
**Last updated:** [May 31, 2021, 1:52pm UTC](https://discourse.julialang.org/t/plots-downgraded-gr-to-0-52-for-no-good-reason/62115 "2021-05-31T13:52:21Z")

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I’m a person who does \] up all the time, today I found the Plots.jl is downgrading GR.jl back to 0.52 for no reason. If I go to \] dev Plots, and remove older versions of GR in \[compat\], keeps only the latest 0.57, and \]…

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## [Best way to discretize continuous variable](https://discourse.julialang.org/t/best-way-to-discretize-continuous-variable/62113)

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**Author:** [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Replies:** 2\
**Last updated:** [May 31, 2021, 1:15pm UTC](https://discourse.julialang.org/t/best-way-to-discretize-continuous-variable/62113 "2021-05-31T13:15:04Z")

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I have a continuous variable that I would like to discretize based on the sample quantiles (e.g. top 1%, \>1%-top10%, etc). My intuition was to use the following using StatsBase x = sort(100 .\*rand(100)); # sort just to …

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## [Understanding of implies](https://discourse.julialang.org/t/understanding-of-implies/61978)

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**Author:** [@sogrbilja](https://discourse.julialang.org/u/sogrbilja)\
**Replies:** 14\
**Last updated:** [May 31, 2021, 12:41pm UTC](https://discourse.julialang.org/t/understanding-of-implies/61978 "2021-05-31T12:41:32Z")

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Can someone explain to me how should I read this and which values can variables have? model = Model() @variable(model, x\[1:2\], Bin) @constraint(model, x\[1\] \<= x\[2\]) Should I read it like: this constraint will ensure th…

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## [If b = a, when do changes in a affect b?](https://discourse.julialang.org/t/if-b-a-when-do-changes-in-a-affect-b/61828)

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**Author:** [@Beliavsky](https://discourse.julialang.org/u/Beliavsky)\
**Replies:** 21\
**Last updated:** [May 31, 2021, 12:09pm UTC](https://discourse.julialang.org/t/if-b-a-when-do-changes-in-a-affect-b/61828 "2021-05-31T12:09:55Z")

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If I define array a and set b equal to a, it appears that changes of single elements of a are propagated to b, but changes to the whole array are not. For the code below, I expected b = \[8, 4\] at the end. Why was Julia d…

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## [Setting up differential equations](https://discourse.julialang.org/t/setting-up-differential-equations/62120)

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**Author:** [@Deepa](https://discourse.julialang.org/u/Deepa)\
**Replies:** 1\
**Last updated:** [May 31, 2021, 10:27am UTC](https://discourse.julialang.org/t/setting-up-differential-equations/62120 "2021-05-31T10:27:15Z")

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I’ve the following function function fun(dx,x,p,t) dx\[:,:\] .= mat1\*x + mat2\*x end Here, I’d like to scale mat1\*x + mat2\*x by the values present in a vector scale. In MATLAB I would do (1./scale).\*(mat1\*x + mat2\*x).…

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## [Correctly initializing collection of matrices](https://discourse.julialang.org/t/correctly-initializing-collection-of-matrices/62116)

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**Author:** [@nandoconde](https://discourse.julialang.org/u/nandoconde)\
**Replies:** 5\
**Last updated:** [May 31, 2021, 10:13am UTC](https://discourse.julialang.org/t/correctly-initializing-collection-of-matrices/62116 "2021-05-31T10:13:55Z")

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Hello! I am following suggestions from another post and, instead of having a 3-D array, I am refactoring my code to use a Vector of Matrix so I can use broadcasting on the matrices. Is there a way to initialize the who…

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## [JULIA\_PKG\_SERVER related documentation](https://discourse.julialang.org/t/julia-pkg-server-related-documentation/62117)

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**Author:** [@Skoffer](https://discourse.julialang.org/u/Skoffer)\
**Replies:** 3\
**Last updated:** [May 31, 2021, 10:10am UTC](https://discourse.julialang.org/t/julia-pkg-server-related-documentation/62117 "2021-05-31T10:10:14Z")

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Environmental variable JULIA\_PKG\_SERVER appears rather regularly in questions related to registry update issues (last example is Updating extremly slow today). But where one can find documentation related to this variabl…

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