# Latest

**URL:** https://discourse.julialang.org/latest.md?page=173

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

**Page:** 174

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## [Redesigning String, optimising small strings and comparison](https://discourse.julialang.org/t/redesigning-string-optimising-small-strings-and-comparison/119716)

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**Author:** [@tecosaur](https://discourse.julialang.org/u/tecosaur)\
**Replies:** 71\
**Last updated:** [May 3, 2025, 6:26am UTC](https://discourse.julialang.org/t/redesigning-string-optimising-small-strings-and-comparison/119716 "2025-05-03T06:26:33Z")

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Whenever I’ve had to do large-scale string work in Julia, I tend to be less impressed with performance than when doing numerical work. This has produced a niggle, and that niggle as lead to some investigation, which has …

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## [Contiguous Read Non-Contiguous Write vs Non-Contiguous Read Contigous Write Performance](https://discourse.julialang.org/t/contiguous-read-non-contiguous-write-vs-non-contiguous-read-contigous-write-performance/128604)

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**Author:** [@mj2984](https://discourse.julialang.org/u/mj2984)\
**Replies:** 3\
**Last updated:** [May 3, 2025, 12:50am UTC](https://discourse.julialang.org/t/contiguous-read-non-contiguous-write-vs-non-contiguous-read-contigous-write-performance/128604 "2025-05-03T00:50:39Z")

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function permutedims\_custom(Y,X) for idx in range(1,size(Y,2)) @simd for idy in range(1,size(Y,1)) @inbounds Y\[idy,idx\] = X\[idx,idy\] end end end function permutedims\_custom\_2(Y,X) …

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## [Idiomatic way to create non-sticky tasks?](https://discourse.julialang.org/t/idiomatic-way-to-create-non-sticky-tasks/128250)

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**Author:** [@mj2984](https://discourse.julialang.org/u/mj2984)\
**Replies:** 17\
**Last updated:** [May 3, 2025, 12:33am UTC](https://discourse.julialang.org/t/idiomatic-way-to-create-non-sticky-tasks/128250 "2025-05-03T00:33:08Z")

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Hi. I have an application to create an Array of tasks and then launch them asynchronously (preferably in parallel). The time of launching is not necessarily the time of creation hence @spawn is not ideal. Is there a mac…

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## [Problem with running tests in VSCode under Ubuntu (any packages)](https://discourse.julialang.org/t/problem-with-running-tests-in-vscode-under-ubuntu-any-packages/128642)

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**Author:** [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Replies:** 1\
**Last updated:** [May 2, 2025, 10:25pm UTC](https://discourse.julialang.org/t/problem-with-running-tests-in-vscode-under-ubuntu-any-packages/128642 "2025-05-02T22:25:48Z")

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For example: (@v1.11) pkg\> test Revise Testing Revise ... Testing Running tests... ERROR: julia: -t,--threads=\<n\>\[,auto|\<m\>\]; n must be an integer \>= 1 ERROR: Package Revise errored during testing The same er…

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## [Criticism of Julia development experience](https://discourse.julialang.org/t/criticism-of-julia-development-experience/128634)

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**Author:** [@hack3rcon](https://discourse.julialang.org/u/hack3rcon)\
**Replies:** 5\
**Last updated:** [May 2, 2025, 9:02pm UTC](https://discourse.julialang.org/t/criticism-of-julia-development-experience/128634 "2025-05-02T21:02:58Z")

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Hello, I’m just learning Julia and I really like it, but I have a few criticisms: 1- Why are there so few books on learning this language and why has the development team focused all its attention on developing Julia? …

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## [Data engineer](https://discourse.julialang.org/t/data-engineer/128625)

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**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 5\
**Last updated:** [May 2, 2025, 9:05pm UTC](https://discourse.julialang.org/t/data-engineer/128625 "2025-05-02T21:05:55Z")

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while these jobs at my workplace don’t specifically mention julia in the advertisement, i’d encourage anyone here otherwise qualified to apply. message me if you have a question.

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## [Compatibility issue with MultilayerGraphs.jl and CUDA.jl](https://discourse.julialang.org/t/compatibility-issue-with-multilayergraphs-jl-and-cuda-jl/128549)

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**Author:** [@angushushu](https://discourse.julialang.org/u/angushushu)\
**Replies:** 2\
**Last updated:** [May 2, 2025, 8:58pm UTC](https://discourse.julialang.org/t/compatibility-issue-with-multilayergraphs-jl-and-cuda-jl/128549 "2025-05-02T20:58:16Z")

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Hi, I’m trying to run the MultilayerGraphs.jl package on my Windows PC. However, dependency compatibility cannot be resolved. I got the following error. I’m not exactly sure why GPUCompiler requires this high version of …

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## [Is there a Julia package allowing to access json objects like jqlang?](https://discourse.julialang.org/t/is-there-a-julia-package-allowing-to-access-json-objects-like-jqlang/106839)

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**Author:** [@HugoTrentesaux](https://discourse.julialang.org/u/HugoTrentesaux)\
**Replies:** 6\
**Last updated:** [May 2, 2025, 8:47pm UTC](https://discourse.julialang.org/t/is-there-a-julia-package-allowing-to-access-json-objects-like-jqlang/106839 "2025-05-02T20:47:39Z")

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In REPL it’s convenient to use jqlang syntax like curl 'https://\<graphql-api\>' -X POST \\ -H 'content-type: application/json' \\ --data """\<graphql-query\>""" | \\ jq '.data.blocks\[0\].number is there a way to do someth…

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## [Round a float, and force a specific number of decimal places](https://discourse.julialang.org/t/round-a-float-and-force-a-specific-number-of-decimal-places/87547)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 8\
**Last updated:** [May 2, 2025, 8:28pm UTC](https://discourse.julialang.org/t/round-a-float-and-force-a-specific-number-of-decimal-places/87547 "2025-05-02T20:28:23Z")

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Rounding a float to two decimal places, say, does not necessarily create a number with two decimal places. For example round(10.001, digits = 2) produces 10.0 How can I force a specific number of shown decimal places? …

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## [Error when a neural ode is implemented](https://discourse.julialang.org/t/error-when-a-neural-ode-is-implemented/119963)

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**Author:** [@Ashima\_Kalathingal](https://discourse.julialang.org/u/Ashima_Kalathingal)\
**Replies:** 3\
**Last updated:** [May 2, 2025, 8:09pm UTC](https://discourse.julialang.org/t/error-when-a-neural-ode-is-implemented/119963 "2025-05-02T20:09:03Z")

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I am trying to implement a neural ode in Julia. The loss function reduces when training. But after the training the parameters are not updated. It goes back to initial value. When I run the algorithm the following error…

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## [Why mem allocation may surge when function reads single scalar global variable?](https://discourse.julialang.org/t/why-mem-allocation-may-surge-when-function-reads-single-scalar-global-variable/128394)

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**Author:** [@brownlight](https://discourse.julialang.org/u/brownlight)\
**Replies:** 4\
**Last updated:** [May 2, 2025, 7:39pm UTC](https://discourse.julialang.org/t/why-mem-allocation-may-surge-when-function-reads-single-scalar-global-variable/128394 "2025-05-02T19:39:36Z")

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Two functions: pi\_1( ) sums N terms in for loop; N is defined in global scope. pi\_2(nterms) same as pi\_1( ) except that N is passed as a parameter. Output (copied from notebook cells): N = 10\_000\_000 # First run @ti…

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## [Avoid copy when using data for Ptr{T}](https://discourse.julialang.org/t/avoid-copy-when-using-data-for-ptr-t/128602)

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**Author:** [@aitzkora](https://discourse.julialang.org/u/aitzkora)\
**Replies:** 4\
**Last updated:** [May 2, 2025, 7:26pm UTC](https://discourse.julialang.org/t/avoid-copy-when-using-data-for-ptr-t/128602 "2025-05-02T19:26:25Z")

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Hi, I call a fortran code which calls Julia trough a @cfunction using pointers (Ptr{T}), and I want to avoid copying data from Fortran in Julia such as in the following code using Libdl:dlopen, dlsym using Test funct…

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## [Generic API for instantiating lazy values](https://discourse.julialang.org/t/generic-api-for-instantiating-lazy-values/128562)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 11\
**Last updated:** [May 2, 2025, 3:04pm UTC](https://discourse.julialang.org/t/generic-api-for-instantiating-lazy-values/128562 "2025-05-02T15:04:28Z")

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Is there a generic API (ie a function) for requesting a deferred computation of some value? Eg if x is a Base.Generator, I want the array, etc. collect does too much, eg collect(SVector(1, 2, 3)) gives a Vector. Packa…

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## [Tensors.jl and upper convective derivative - Oldroyd - b constitutive model](https://discourse.julialang.org/t/tensors-jl-and-upper-convective-derivative-oldroyd-b-constitutive-model/128341)

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**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 2\
**Last updated:** [May 2, 2025, 2:37pm UTC](https://discourse.julialang.org/t/tensors-jl-and-upper-convective-derivative-oldroyd-b-constitutive-model/128341 "2025-05-02T14:37:58Z")

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Any experience here using Tensors.jl to implement the uppper-convective derivative? Thx.

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## [Mapping Julia’s Astronomy Package Ecosystem: Bridging Gaps and Highlighting Strengths](https://discourse.julialang.org/t/mapping-julia-s-astronomy-package-ecosystem-bridging-gaps-and-highlighting-strengths/128249)

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**Author:** [@The\_Mastermage](https://discourse.julialang.org/u/The_Mastermage)\
**Replies:** 47\
**Last updated:** [May 1, 2025, 9:27pm UTC](https://discourse.julialang.org/t/mapping-julia-s-astronomy-package-ecosystem-bridging-gaps-and-highlighting-strengths/128249 "2025-05-01T21:27:58Z")

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Hi all, I came across comment in the recent discussion on increasing Julia’s adoption. This raises an important point for anyone interested in Julia’s role in astronomy: even when the technical benefits are clear, ad…

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## [US science is taking hits: is Julia affected?](https://discourse.julialang.org/t/us-science-is-taking-hits-is-julia-affected/128543)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 11\
**Last updated:** [May 2, 2025, 2:28pm UTC](https://discourse.julialang.org/t/us-science-is-taking-hits-is-julia-affected/128543 "2025-05-02T14:28:47Z")

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Will US science survive Trump 2.0? How are Julians affected? Has the funding dried up for commercial Julia activities? NIH, for example, has severely cut budgets left and right…

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## [How to set all elements in a lower triangular matrix?](https://discourse.julialang.org/t/how-to-set-all-elements-in-a-lower-triangular-matrix/128603)

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**Author:** [@Abhro](https://discourse.julialang.org/u/Abhro)\
**Replies:** 6\
**Last updated:** [May 2, 2025, 2:05pm UTC](https://discourse.julialang.org/t/how-to-set-all-elements-in-a-lower-triangular-matrix/128603 "2025-05-02T14:05:46Z")

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I have a lower triangular matrix which gets reused. In one of the steps, I have all of the elements (below the diagonal) set to the same value. How do I make Julia understand that I’m not trying to set values above the d…

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## [Debugging MTK with residuals](https://discourse.julialang.org/t/debugging-mtk-with-residuals/128616)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 1\
**Last updated:** [May 2, 2025, 12:38pm UTC](https://discourse.julialang.org/t/debugging-mtk-with-residuals/128616 "2025-05-02T12:38:22Z")

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I have some ModelingToolkit simulation that yields dubious results. No numerical error; just some quantity that becomes negative when it shouldn’t. I have to assume that one of my equations is wrong. Perhaps there is a c…

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## [Predict values using multinomial logistic regression?](https://discourse.julialang.org/t/predict-values-using-multinomial-logistic-regression/128621)

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**Author:** [@Paulogcd](https://discourse.julialang.org/u/Paulogcd)\
**Replies:** 1\
**Last updated:** [May 2, 2025, 11:39am UTC](https://discourse.julialang.org/t/predict-values-using-multinomial-logistic-regression/128621 "2025-05-02T11:39:16Z")

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Dear Julia community :slightly\_smiling\_face:, I have been trying to run a Multinomial logistic regression and to get the estimated results from a certain set of values. I managed to run the regression, but fail to get …

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## [Correct usage of type-dependent constructors](https://discourse.julialang.org/t/correct-usage-of-type-dependent-constructors/128605)

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**Author:** [@albertomercurio](https://discourse.julialang.org/u/albertomercurio)\
**Replies:** 7\
**Last updated:** [May 2, 2025, 11:33am UTC](https://discourse.julialang.org/t/correct-usage-of-type-dependent-constructors/128605 "2025-05-02T11:33:29Z")

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Hello, I need to create a constructor with a parametric type to be able to dispatch. One possible way is the following abstract type MyType end # Singletons occupying 0 bytes struct Type1 \<: MyType end struct Type2 \<:…

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## [How to incorporate state-dependent state constraint in JuMP](https://discourse.julialang.org/t/how-to-incorporate-state-dependent-state-constraint-in-jump/128485)

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**Author:** [@stepanoslejsek](https://discourse.julialang.org/u/stepanoslejsek)\
**Replies:** 9\
**Last updated:** [May 2, 2025, 9:33am UTC](https://discourse.julialang.org/t/how-to-incorporate-state-dependent-state-constraint-in-jump/128485 "2025-05-02T09:33:18Z")

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Hi, I am trying to implement energy-efficient optimal control for vehicles, which includes traffic lights in the setup. The following problem is described as: \\text{minimize}\_{u^+, u^-} \\int\_{0}^{S} \\frac{u^+}{\\eta\_1} …

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## [JLHub documentation vs official, why are they different and which is source of truth?](https://discourse.julialang.org/t/jlhub-documentation-vs-official-why-are-they-different-and-which-is-source-of-truth/128606)

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**Author:** [@marteaua](https://discourse.julialang.org/u/marteaua)\
**Replies:** 3\
**Last updated:** [May 2, 2025, 3:51am UTC](https://discourse.julialang.org/t/jlhub-documentation-vs-official-why-are-they-different-and-which-is-source-of-truth/128606 "2025-05-02T03:51:42Z")

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I noticed that the documentation of inv is richer on Juliahub JLHub doc than the official one. In particular, it specifies that matrix inversion does throw on singular matrices, while the official doesn’t. In practice: …

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## [Strange error in computing trace on product of symbolic matrices in Symbolics.jl](https://discourse.julialang.org/t/strange-error-in-computing-trace-on-product-of-symbolic-matrices-in-symbolics-jl/128598)

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**Author:** [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)\
**Replies:** 2\
**Last updated:** [May 2, 2025, 3:36am UTC](https://discourse.julialang.org/t/strange-error-in-computing-trace-on-product-of-symbolic-matrices-in-symbolics-jl/128598 "2025-05-02T03:36:32Z")

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Dear All, I am a new user of Symbolics.jl and using it to compute trace of product of two symbolic matrices. It seems that if I do not perform a simplify. on the product of the matrices, I get a strange error when compu…

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## [Error if lambdify target function is zero](https://discourse.julialang.org/t/error-if-lambdify-target-function-is-zero/128587)

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**Author:** [@inkie](https://discourse.julialang.org/u/inkie)\
**Replies:** 2\
**Last updated:** [May 1, 2025, 9:34pm UTC](https://discourse.julialang.org/t/error-if-lambdify-target-function-is-zero/128587 "2025-05-01T21:34:56Z")

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Hi guys, im implementing the fourier functions in julia + sympy but when i have an odd function my bn is not working as expected since bn(1) for example is not working giving this error: MethodError: no method matching (…

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## [How to create standalone applications for Windows with a \[G\]UI in Julia 1.11 or 1.12](https://discourse.julialang.org/t/how-to-create-standalone-applications-for-windows-with-a-g-ui-in-julia-1-11-or-1-12/127823)

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**Author:** [@uwestoehr](https://discourse.julialang.org/u/uwestoehr)\
**Replies:** 46\
**Last updated:** [May 1, 2025, 8:31pm UTC](https://discourse.julialang.org/t/how-to-create-standalone-applications-for-windows-with-a-g-ui-in-julia-1-11-or-1-12/127823 "2025-05-01T20:31:13Z")

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As a new user allow me a general question on the state of the art of Julia and how to use it for commercial but OpenSource real-life applications. We design and produce sensors of different types (humidity, temperature …

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## [Package to do graph combinatorics](https://discourse.julialang.org/t/package-to-do-graph-combinatorics/128569)

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**Author:** [@drandran12](https://discourse.julialang.org/u/drandran12)\
**Replies:** 0\
**Last updated:** [April 30, 2025, 12:27pm UTC](https://discourse.julialang.org/t/package-to-do-graph-combinatorics/128569 "2025-04-30T12:27:10Z")

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Hey everyone, I am looking for a package that can do graph combinatorics. For example, suppose I have m distinguishable lines and n distinguishable edges, compute all the possible ways to make the graph. Anyone who kno…

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## [Where on abstract type and parameters](https://discourse.julialang.org/t/where-on-abstract-type-and-parameters/128584)

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**Author:** [@croberts](https://discourse.julialang.org/u/croberts)\
**Replies:** 9\
**Last updated:** [May 1, 2025, 7:19pm UTC](https://discourse.julialang.org/t/where-on-abstract-type-and-parameters/128584 "2025-05-01T19:19:23Z")

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Is there a way to use a type signature that imposes that two arguments are the same subtype of an abstract type and also have the same parameter for some but not necessarily all parameters? For example, the hypothetical…

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## [Distance Correlation in Julia](https://discourse.julialang.org/t/distance-correlation-in-julia/45905)

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**Author:** [@Kokora](https://discourse.julialang.org/u/Kokora)\
**Replies:** 8\
**Last updated:** [May 1, 2025, 3:54pm UTC](https://discourse.julialang.org/t/distance-correlation-in-julia/45905 "2025-05-01T15:54:56Z")

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Hi all, Is there any package in Julia to compute distance correlation just like the package energy in r? Thank you,

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## [Interoperability between Symbolics.jl and MathLink.jl](https://discourse.julialang.org/t/interoperability-between-symbolics-jl-and-mathlink-jl/128596)

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**Author:** [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)\
**Replies:** 2\
**Last updated:** [May 1, 2025, 3:30pm UTC](https://discourse.julialang.org/t/interoperability-between-symbolics-jl-and-mathlink-jl/128596 "2025-05-01T15:30:23Z")

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Dear All, Is interoperability possible between Symbolics.jl and MathLink.jl? I would like to create a symbolic object in Julia, do part of the calculation using Symbolics.jl and then pass some intermediate symbolic obje…

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## [Time Series Analysis in Julia resources?](https://discourse.julialang.org/t/time-series-analysis-in-julia-resources/128597)

<div class="topic-metadata">

**Author:** [@Snowy](https://discourse.julialang.org/u/Snowy)\
**Replies:** 1\
**Last updated:** [May 1, 2025, 3:04pm UTC](https://discourse.julialang.org/t/time-series-analysis-in-julia-resources/128597 "2025-05-01T15:04:59Z")

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Hi all! I’m starting a new job in a few weeks doing forecasting / time series analysis. I’d like to use Julia in my new role. I know R for time series is probably the better choice, but Julia is the language that I’m mo…

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