# Latest

**URL:** https://discourse.julialang.org/latest.md?page=745

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

**Page:** 746

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## [ReverseDiff with Flux model](https://discourse.julialang.org/t/reversediff-with-flux-model/96452)

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**Author:** [@Avec](https://discourse.julialang.org/u/Avec)\
**Replies:** 2\
**Last updated:** [March 23, 2023, 10:04am UTC](https://discourse.julialang.org/t/reversediff-with-flux-model/96452 "2023-03-23T10:04:28Z")

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Hi all, I am trying to get a gradient of a Flux model with a different package than Zygote or ForwardDiff (Zygote cannot get through my real loss function and ForwardDiff is too slow). Since my loss function returns scal…

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## [New to julia : ldapclient output format](https://discourse.julialang.org/t/new-to-julia-ldapclient-output-format/96497)

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**Author:** [@Laurent\_Protois](https://discourse.julialang.org/u/Laurent_Protois)\
**Replies:** 1\
**Last updated:** [March 23, 2023, 9:52am UTC](https://discourse.julialang.org/t/new-to-julia-ldapclient-output-format/96497 "2023-03-23T09:52:56Z")

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In my Julia script : for entry in LDAPClient.each\_entry(chain) uid=“(entry\["uid"\])" nom="(entry\[“gecos”\])” group=“$(entry\[“GTP”\])” println(“$uid;$nom;$group”) end got \[“waynstar84”\];\[“wayne stark”\];\[“-”\] h…

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## [How to find the index of the maximum value of an array that meets certain conditions](https://discourse.julialang.org/t/how-to-find-the-index-of-the-maximum-value-of-an-array-that-meets-certain-conditions/96477)

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**Author:** [@chadagreene](https://discourse.julialang.org/u/chadagreene)\
**Replies:** 8\
**Last updated:** [March 23, 2023, 8:41am UTC](https://discourse.julialang.org/t/how-to-find-the-index-of-the-maximum-value-of-an-array-that-meets-certain-conditions/96477 "2023-03-23T08:41:15Z")

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I’ve got a question involving two parts. I can do each part on its own, but I don’t know the best way to put the two parts together. I want to find the index of the maximum value in an array, limited to elements of the …

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## [Chat with a LLM. Just something to chuckle about](https://discourse.julialang.org/t/chat-with-a-llm-just-something-to-chuckle-about/96483)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 1\
**Last updated:** [March 23, 2023, 8:50am UTC](https://discourse.julialang.org/t/chat-with-a-llm-just-something-to-chuckle-about/96483 "2023-03-23T08:50:49Z")

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## [A problem about multi-threading and IO](https://discourse.julialang.org/t/a-problem-about-multi-threading-and-io/96492)

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**Author:** [@fenyutanchan](https://discourse.julialang.org/u/fenyutanchan)\
**Replies:** 0\
**Last updated:** [March 23, 2023, 5:59am UTC](https://discourse.julialang.org/t/a-problem-about-multi-threading-and-io/96492 "2023-03-23T05:59:10Z")

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I’m trying write a code as make\_random\_string(n::Int)::String = (prod ∘ map)(Char, rand(65:90, n)) function outer\_string(n::Int)::Tuple{String, String} orig\_str = make\_random\_string(n) result\_io = I…

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## [Replace elements of matrix when executing condition](https://discourse.julialang.org/t/replace-elements-of-matrix-when-executing-condition/96465)

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**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 2\
**Last updated:** [March 23, 2023, 6:21am UTC](https://discourse.julialang.org/t/replace-elements-of-matrix-when-executing-condition/96465 "2023-03-23T06:21:48Z")

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Hello. I have next matrix: 200×200 Matrix{Float64}: -3.14652 -3.09094 -3.03716 -2.98602 … -0.311487 -0.311531 -3.12573 -3.07036 -3.01627 -2.96592 -0.311478 -0.311522 -3.10504 -3.05 …

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## [Performance tips for a function which finds n maximums in a matrix](https://discourse.julialang.org/t/performance-tips-for-a-function-which-finds-n-maximums-in-a-matrix/96425)

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**Author:** [@eduardosalaz](https://discourse.julialang.org/u/eduardosalaz)\
**Replies:** 8\
**Last updated:** [March 23, 2023, 5:49am UTC](https://discourse.julialang.org/t/performance-tips-for-a-function-which-finds-n-maximums-in-a-matrix/96425 "2023-03-23T05:49:13Z")

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Hi everyone, I have been trying to squeeze out as much performance as possible out from the following function, which finds the n largest (or maximum) values of a matrix and returns those values and their positions in t…

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## [Wrap and inherit Number](https://discourse.julialang.org/t/wrap-and-inherit-number/4799)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 26\
**Last updated:** [March 23, 2023, 5:14am UTC](https://discourse.julialang.org/t/wrap-and-inherit-number/4799 "2023-03-23T05:14:32Z")

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I’ve seen topics touching this in different constellations, but: How do people create a new type that would magically behave just like any subtype of (say) Number? So for example, if: struct A{T \<: Number} x::T end…

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## [Error: Error during initialization of module CHOLMOD on HPC running Scientific Linux 7](https://discourse.julialang.org/t/error-error-during-initialization-of-module-cholmod-on-hpc-running-scientific-linux-7/92930)

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**Author:** [@austin-putz](https://discourse.julialang.org/u/austin-putz)\
**Replies:** 23\
**Last updated:** [March 23, 2023, 4:50am UTC](https://discourse.julialang.org/t/error-error-during-initialization-of-module-cholmod-on-hpc-running-scientific-linux-7/92930 "2023-03-23T04:50:31Z")

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Hello all, I tried to load Julia on the HPC I use (in the Netherlands managed by Wageningen). I get this error after loading julia and initializing REPL. I guess I don’t even know what to do, any ideas? Has anyone e…

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## [Display fraction over two lines?](https://discourse.julialang.org/t/display-fraction-over-two-lines/96329)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 14\
**Last updated:** [March 23, 2023, 2:12am UTC](https://discourse.julialang.org/t/display-fraction-over-two-lines/96329 "2023-03-23T02:12:31Z")

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Is it possible to display a fraction over two lines ? (In actual code rather than latex documentation)

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## [Partially decompressing Bzip2 files](https://discourse.julialang.org/t/partially-decompressing-bzip2-files/96429)

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**Author:** [@tristian](https://discourse.julialang.org/u/tristian)\
**Replies:** 2\
**Last updated:** [March 23, 2023, 1:00am UTC](https://discourse.julialang.org/t/partially-decompressing-bzip2-files/96429 "2023-03-23T01:00:58Z")

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As the title of the question states, I have a few \*.csv.bzip2 compressed files that are as big as 13GB when decompressed. The files have a structured format and are essentially CSV files. I’d like to read the headers of…

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## [Extracting data vectors in constraint from sum notation in JuMP](https://discourse.julialang.org/t/extracting-data-vectors-in-constraint-from-sum-notation-in-jump/96448)

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**Author:** [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)\
**Replies:** 4\
**Last updated:** [March 22, 2023, 10:25pm UTC](https://discourse.julialang.org/t/extracting-data-vectors-in-constraint-from-sum-notation-in-jump/96448 "2023-03-22T22:25:27Z")

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Dear All, I am working on an optimization problem where I have a variable y\_{i,j} where i,j \\in \[1:n\] = \\{1,2,\\ldots,n\\}. I have a constraint of the form \\sum\_{j \\in \[1:n\]} y\_{j,i} - \\sum\_{j \\in \[1:n\]} y\_{i,j} \\geq b\_…

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## [DynamicalSystems: dynamic rule evaluates to nonzero but trajectory stays at initial condition](https://discourse.julialang.org/t/dynamicalsystems-dynamic-rule-evaluates-to-nonzero-but-trajectory-stays-at-initial-condition/96481)

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**Author:** [@cjoshliu](https://discourse.julialang.org/u/cjoshliu)\
**Replies:** 3\
**Last updated:** [March 22, 2023, 10:25pm UTC](https://discourse.julialang.org/t/dynamicalsystems-dynamic-rule-evaluates-to-nonzero-but-trajectory-stays-at-initial-condition/96481 "2023-03-22T22:25:02Z")

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Hi, I’m new to Julia and trying to find fixed points of an s-species generalized Lotka-Volterra model using DynamicalSystems. My model is d\_t\\vec{u}=\\vec{\\lambda}+\\vec{r}\\cdot\\vec{u}\\cdot (1-\\hat{\\alpha}\\vec{u}) where \\…

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## [Making bound variables from loop in Pluto](https://discourse.julialang.org/t/making-bound-variables-from-loop-in-pluto/96421)

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**Author:** [@mmj](https://discourse.julialang.org/u/mmj)\
**Replies:** 3\
**Last updated:** [March 22, 2023, 9:27pm UTC](https://discourse.julialang.org/t/making-bound-variables-from-loop-in-pluto/96421 "2023-03-22T21:27:45Z")

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Hello. I am attempting to create a Pluto notebook that performs Gaussian elimination on a matrix. I would like the user to insert whatever matrix he desires. What I have done so far is asking the user what are the dimen…

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## [How to detect jumps in a vector mod2pi.(x), when the elements of x are increasing](https://discourse.julialang.org/t/how-to-detect-jumps-in-a-vector-mod2pi-x-when-the-elements-of-x-are-increasing/96475)

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**Author:** [@empet](https://discourse.julialang.org/u/empet)\
**Replies:** 2\
**Last updated:** [March 22, 2023, 9:15pm UTC](https://discourse.julialang.org/t/how-to-detect-jumps-in-a-vector-mod2pi-x-when-the-elements-of-x-are-increasing/96475 "2023-03-22T21:15:34Z")

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After integrating a toral differential equation I get as trajectory coordinates, the vectors x,y, and then calculate: xt = mod2pi.(x) yt = mod2pi.(y) I want to insert a NaN between two consecutive elements of xt a…

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## [Question on multithreading/vectorizing loops](https://discourse.julialang.org/t/question-on-multithreading-vectorizing-loops/95291)

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**Author:** [@Ender\_L](https://discourse.julialang.org/u/Ender_L)\
**Replies:** 9\
**Last updated:** [March 22, 2023, 8:14pm UTC](https://discourse.julialang.org/t/question-on-multithreading-vectorizing-loops/95291 "2023-03-22T20:14:29Z")

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Consider a classic loop parallelization scheme: the outer loop multithreads, and the inner loop vectorizes: tmp = \[Vector{T}(undef, length(B)) for \_ in 1:Threads.nthreads()\] @inbounds Threads.@threads for ii in…

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## [NULL PyObject in package](https://discourse.julialang.org/t/null-pyobject-in-package/96461)

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**Author:** [@asorlik](https://discourse.julialang.org/u/asorlik)\
**Replies:** 2\
**Last updated:** [March 22, 2023, 7:59pm UTC](https://discourse.julialang.org/t/null-pyobject-in-package/96461 "2023-03-22T19:59:29Z")

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I am creating a package and I have gotten the following error in one of my scripts that is called via include(“script\_name.jl”): ERROR: ArgumentError: ref of NULL PyObject The error is coming from a usage of np.gradien…

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## [Dictionary showing invalid keys](https://discourse.julialang.org/t/dictionary-showing-invalid-keys/96422)

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**Author:** [@gxyau](https://discourse.julialang.org/u/gxyau)\
**Replies:** 15\
**Last updated:** [March 22, 2023, 7:37pm UTC](https://discourse.julialang.org/t/dictionary-showing-invalid-keys/96422 "2023-03-22T19:37:57Z")

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Hello there, Been playing around with Julia a bit just to practice some topics. I have recently started using Graphs.jl and found some unexpected behaviour. A MWE and the output has been included below. Long story shor…

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## [ITERATION\_LIMIT with small changes in constraints](https://discourse.julialang.org/t/iteration-limit-with-small-changes-in-constraints/96403)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 3\
**Last updated:** [March 22, 2023, 7:07pm UTC](https://discourse.julialang.org/t/iteration-limit-with-small-changes-in-constraints/96403 "2023-03-22T19:07:40Z")

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I have a linear problem with linear equality and inequality constraints (and interval constraints). It works perfectly with various lower and upper bounds, but specific values trigger this ITERATION\_LIMIT and there is no…

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## [Syntax error with \`using EllipsisNotation: .. as foo\`](https://discourse.julialang.org/t/syntax-error-with-using-ellipsisnotation-as-foo/96464)

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**Author:** [@lmtzx9h4qqnt](https://discourse.julialang.org/u/lmtzx9h4qqnt)\
**Replies:** 4\
**Last updated:** [March 22, 2023, 6:18pm UTC](https://discourse.julialang.org/t/syntax-error-with-using-ellipsisnotation-as-foo/96464 "2023-03-22T18:18:29Z")

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Is there some way to import .. from a package using as? julia\> using EllipsisNotation: .. as foo ERROR: syntax: extra token "foo" after end of expression Stacktrace: \[1\] top-level scope @ none:1 julia\> using Ellips…

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## [\[ANN\] Expronicon v0.8: type-stable rust-like algebra data type & pretty printing Julia expr & more](https://discourse.julialang.org/t/ann-expronicon-v0-8-type-stable-rust-like-algebra-data-type-pretty-printing-julia-expr-more/92647)

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**Author:** [@Roger-luo](https://discourse.julialang.org/u/Roger-luo)\
**Replies:** 3\
**Last updated:** [March 22, 2023, 5:40pm UTC](https://discourse.julialang.org/t/ann-expronicon-v0-8-type-stable-rust-like-algebra-data-type-pretty-printing-julia-expr-more/92647 "2023-03-22T17:40:54Z")

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I’m excited to announce a few new features to the Expronicon package’s recent releases (v0.8), as it starts getting stable I’m going to release a 1.0 version for the next stage if there are no significant changes in the…

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## [Spurious memory allocations within function](https://discourse.julialang.org/t/spurious-memory-allocations-within-function/85430)

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**Author:** [@dwyron](https://discourse.julialang.org/u/dwyron)\
**Replies:** 9\
**Last updated:** [March 22, 2023, 5:25pm UTC](https://discourse.julialang.org/t/spurious-memory-allocations-within-function/85430 "2023-03-22T17:25:44Z")

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Hi everyone, I am trying to reduce memory allocations in a function through preallocations. However, implementing the Perfomance Tips still leaves a significant amount of probably unnecessary allocations, which I can ci…

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## [How can I perform GLM regression on column names with spaces?](https://discourse.julialang.org/t/how-can-i-perform-glm-regression-on-column-names-with-spaces/96442)

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**Author:** [@bertulli](https://discourse.julialang.org/u/bertulli)\
**Replies:** 6\
**Last updated:** [March 22, 2023, 5:06pm UTC](https://discourse.julialang.org/t/how-can-i-perform-glm-regression-on-column-names-with-spaces/96442 "2023-03-22T17:06:37Z")

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Hi all, very noob question but I can’t find an answer. I’m trying to do a linear regression on some data I have: julia\> df\_under\_test\[:, \[instruction\_sym, measure\_power\_sym, binary\_weight\_sym\]\] 1165×3 DataFrame Row │…

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## [Julia solves a two-language problem but the real problem is a 3-wants problem which Julia does not necessarily serve well atm](https://discourse.julialang.org/t/julia-solves-a-two-language-problem-but-the-real-problem-is-a-3-wants-problem-which-julia-does-not-necessarily-serve-well-atm/96295)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 36\
**Last updated:** [March 22, 2023, 5:01pm UTC](https://discourse.julialang.org/t/julia-solves-a-two-language-problem-but-the-real-problem-is-a-3-wants-problem-which-julia-does-not-necessarily-serve-well-atm/96295 "2023-03-22T17:01:31Z")

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Julia solves the two language - write the algo in a slow language and then reimplement it in fast language. However, that is not the biggeest two language. The real problem is this Modeler write code for their models …

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## [PythonCall: Can't get attribute 'CallbackValue'](https://discourse.julialang.org/t/pythoncall-cant-get-attribute-callbackvalue/96456)

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**Author:** [@Jesse\_Lane](https://discourse.julialang.org/u/Jesse_Lane)\
**Replies:** 0\
**Last updated:** [March 22, 2023, 3:46pm UTC](https://discourse.julialang.org/t/pythoncall-cant-get-attribute-callbackvalue/96456 "2023-03-22T15:46:37Z")

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Hello, I have a simulator that I wrote in Julia using Agents.jl and I’m trying to do some reinforcement learning using Ray and using PythonCall for the interop. (I know there are some reinforcement learning packages in…

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## [How does julia prioritize operations and array concatenation?](https://discourse.julialang.org/t/how-does-julia-prioritize-operations-and-array-concatenation/96447)

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**Author:** [@ovt](https://discourse.julialang.org/u/ovt)\
**Replies:** 3\
**Last updated:** [March 22, 2023, 3:38pm UTC](https://discourse.julialang.org/t/how-does-julia-prioritize-operations-and-array-concatenation/96447 "2023-03-22T15:38:47Z")

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Why is it ok to write 1 .-A but not \[A;1 .-A\] ? Somehow, it only works with a space between - and A. Is it because Julia prioritize the A;1 part over the 1 .-A part ? Is there any documentation on how and why julia prio…

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## [How to solve Path Integral Problems with Probabilistic Programming Techniques?](https://discourse.julialang.org/t/how-to-solve-path-integral-problems-with-probabilistic-programming-techniques/96430)

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**Author:** [@GDufenshuoo](https://discourse.julialang.org/u/GDufenshuoo)\
**Replies:** 8\
**Last updated:** [March 22, 2023, 2:45pm UTC](https://discourse.julialang.org/t/how-to-solve-path-integral-problems-with-probabilistic-programming-techniques/96430 "2023-03-22T14:45:34Z")

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Hello everyone, I’m not very familiar with probabilistic programming, so I may not be approaching this problem in the most optimal way. Essentially, I’m trying to solve a problem of the following form: Z \\sim \\int\\int..…

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## [TimeSeries.jl and upsampling](https://discourse.julialang.org/t/timeseries-jl-and-upsampling/88896)

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**Author:** [@olivier](https://discourse.julialang.org/u/olivier)\
**Replies:** 3\
**Last updated:** [March 22, 2023, 3:14pm UTC](https://discourse.julialang.org/t/timeseries-jl-and-upsampling/88896 "2023-03-22T15:14:35Z")

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Hi, I need to be able to resample time series both ways : downsampling and upsimpling. I was able to downsample my time series using both TimeSeries.jl and TimeSeriesResampler.jl But the later doesn’t support upsampli…

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## [Julia VSCode: Is it possible to automatically activate the parent julia environment of the current file?](https://discourse.julialang.org/t/julia-vscode-is-it-possible-to-automatically-activate-the-parent-julia-environment-of-the-current-file/96451)

<div class="topic-metadata">

**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 0\
**Last updated:** [March 22, 2023, 3:08pm UTC](https://discourse.julialang.org/t/julia-vscode-is-it-possible-to-automatically-activate-the-parent-julia-environment-of-the-current-file/96451 "2023-03-22T15:08:17Z")

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I just realized in another discourse thread that this is the feature which I really want. background: I am usually working on several packages in parallel, which I all open in the same vscode workspace (i.e. in one sing…

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## [IndexStyle for pairs iterator?](https://discourse.julialang.org/t/indexstyle-for-pairs-iterator/96450)

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**Author:** [@DNF](https://discourse.julialang.org/u/DNF)\
**Replies:** 0\
**Last updated:** [March 22, 2023, 3:06pm UTC](https://discourse.julialang.org/t/indexstyle-for-pairs-iterator/96450 "2023-03-22T15:06:40Z")

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I was a bit surprised to see that the pairs iterator for Matrix returns CartesianIndices by default. The docstring of pairs includes a section on specifying index style, showing these three signatures: pairs(IndexLinear…

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