# Latest

**URL:** https://discourse.julialang.org/latest.md?page=496

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

**Page:** 497

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## [Gradient check by zygote](https://discourse.julialang.org/t/gradient-check-by-zygote/109225)

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**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 6\
**Last updated:** [January 31, 2024, 10:29pm UTC](https://discourse.julialang.org/t/gradient-check-by-zygote/109225 "2024-01-31T22:29:00Z")

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Hi I am using Julia Gridap library to calculate gradients. I wrote the rules for gradients but when i check the gradients with running finite difference manually. they are different. I check equations multiple time and …

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## [Sparse matrices copy arrays, do not view them](https://discourse.julialang.org/t/sparse-matrices-copy-arrays-do-not-view-them/109505)

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**Author:** [@Enlil50](https://discourse.julialang.org/u/Enlil50)\
**Replies:** 18\
**Last updated:** [January 31, 2024, 9:06pm UTC](https://discourse.julialang.org/t/sparse-matrices-copy-arrays-do-not-view-them/109505 "2024-01-31T21:06:01Z")

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I wrote this program, which preallocates the csc arrays. I have to do a lot of kronecker products and i wanted to re-use this arrays and to write in them. Each iteration would have a different @view inside them, but if…

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## [Why is ' the conjugate transpose of a matrix?](https://discourse.julialang.org/t/why-is-the-conjugate-transpose-of-a-matrix/109450)

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**Author:** [@AwesomeQuest](https://discourse.julialang.org/u/AwesomeQuest)\
**Replies:** 13\
**Last updated:** [January 31, 2024, 9:21pm UTC](https://discourse.julialang.org/t/why-is-the-conjugate-transpose-of-a-matrix/109450 "2024-01-31T21:21:29Z")

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Why is the ' operator the conjugate transpose operator and not just the transpose operator or the conjugate operator?

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## [Switching to Juliaup for installation](https://discourse.julialang.org/t/switching-to-juliaup-for-installation/109525)

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**Author:** [@cby](https://discourse.julialang.org/u/cby)\
**Replies:** 2\
**Last updated:** [January 31, 2024, 8:29pm UTC](https://discourse.julialang.org/t/switching-to-juliaup-for-installation/109525 "2024-01-31T20:29:03Z")

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I’m having trouble figuring out how to switch to Juliaup for installation of a new version of Julia with Visual Studio Code. I ran curl -fsSL https://install.julialang.org | sh julia +1.10 At this point I saw that the…

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## [Callback: solver independent or dependent](https://discourse.julialang.org/t/callback-solver-independent-or-dependent/109423)

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**Author:** [@martina.gherardi](https://discourse.julialang.org/u/martina.gherardi)\
**Replies:** 8\
**Last updated:** [January 31, 2024, 7:46pm UTC](https://discourse.julialang.org/t/callback-solver-independent-or-dependent/109423 "2024-01-31T19:46:59Z")

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Hi, I’m currently diving into my first experience with callbacks and have a few doubts that I hope you can help clarify. The goal is to implement callbacks that add user cuts to the root node (or subsequent nodes) base…

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## [Kronecker doesn't work, kron yes, in this case](https://discourse.julialang.org/t/kronecker-doesnt-work-kron-yes-in-this-case/109474)

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**Author:** [@Enlil50](https://discourse.julialang.org/u/Enlil50)\
**Replies:** 8\
**Last updated:** [January 31, 2024, 7:44pm UTC](https://discourse.julialang.org/t/kronecker-doesnt-work-kron-yes-in-this-case/109474 "2024-01-31T19:44:35Z")

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This is the program I made: import Random using LinearAlgebra N::Int64 = 100 matr\_A = Array{Float64}(undef, N, N) matr\_B = Array{Float64}(undef, N, N) matr\_C = Array{Float64}(undef, N\*N, N\*N) Random.seed!(1) for j = …

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## [Efficient computation of statistics across multiple data frames](https://discourse.julialang.org/t/efficient-computation-of-statistics-across-multiple-data-frames/109471)

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**Author:** [@alex-s-gardner](https://discourse.julialang.org/u/alex-s-gardner)\
**Replies:** 9\
**Last updated:** [January 31, 2024, 6:55pm UTC](https://discourse.julialang.org/t/efficient-computation-of-statistics-across-multiple-data-frames/109471 "2024-01-31T18:55:54Z")

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I have a vector collection of DataFrames that have the same number of rows and same column names and I would like to compute statistics across all data frames to arrive at a data frame that is the same size as a single d…

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## [Nice printing of some values of an array](https://discourse.julialang.org/t/nice-printing-of-some-values-of-an-array/109512)

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**Author:** [@Gravlax](https://discourse.julialang.org/u/Gravlax)\
**Replies:** 5\
**Last updated:** [January 31, 2024, 5:38pm UTC](https://discourse.julialang.org/t/nice-printing-of-some-values-of-an-array/109512 "2024-01-31T17:38:25Z")

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During a simulation, it can be useful to monitor some representative values of an array (mean, max, min, median). With a colleague, we’ve tried to write a function or macro that prints the minimum and maximum value of a…

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## [Why does Meta.parse ignores comments?](https://discourse.julialang.org/t/why-does-meta-parse-ignores-comments/109523)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 6\
**Last updated:** [January 31, 2024, 4:46pm UTC](https://discourse.julialang.org/t/why-does-meta-parse-ignores-comments/109523 "2024-01-31T16:46:02Z")

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I am really surprised that Meta.parse seems to actively kick out some information julia\> Meta.parse(""" function hi() # comment end """) :(function hi() #= none:1 =# #= none:1 =# …

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## [Current State of LP solvers supporting warmstart (start values) in JuMP](https://discourse.julialang.org/t/current-state-of-lp-solvers-supporting-warmstart-start-values-in-jump/109160)

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**Author:** [@BenniHs](https://discourse.julialang.org/u/BenniHs)\
**Replies:** 2\
**Last updated:** [January 31, 2024, 4:45pm UTC](https://discourse.julialang.org/t/current-state-of-lp-solvers-supporting-warmstart-start-values-in-jump/109160 "2024-01-31T16:45:46Z")

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Hi everyone, I have a rather general question on JuMP and LP-Solvers. I am working on an algorithm, where many LPs have to be solved. I want to solve them using the JuMP Framework. There appears to be a lot of potential…

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## [Partitioning a vector](https://discourse.julialang.org/t/partitioning-a-vector/109511)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 7\
**Last updated:** [January 31, 2024, 4:18pm UTC](https://discourse.julialang.org/t/partitioning-a-vector/109511 "2024-01-31T16:18:43Z")

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Dear all, I have a vector: I = 1:55. I need to partition it into 10 subvectors, none of which must be empty and the length of each of which is a random number. What is the best way to do this? Could someone help me?

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## [Bounds check outside loop affects loop performance](https://discourse.julialang.org/t/bounds-check-outside-loop-affects-loop-performance/109524)

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**Author:** [@wheeheee](https://discourse.julialang.org/u/wheeheee)\
**Replies:** 0\
**Last updated:** [January 31, 2024, 4:10pm UTC](https://discourse.julialang.org/t/bounds-check-outside-loop-affects-loop-performance/109524 "2024-01-31T16:10:50Z")

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While playing around with a function, I noticed that adding a bounds check (si\_check) had a drastic impact on its performance. Although for N \<= 18, there is no noticeable performance impact, and the emitted LLVM IR show…

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## [Sparse(kroneckersum). sparse or not?](https://discourse.julialang.org/t/sparse-kroneckersum-sparse-or-not/109521)

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**Author:** [@Enlil50](https://discourse.julialang.org/u/Enlil50)\
**Replies:** 0\
**Last updated:** [January 31, 2024, 2:56pm UTC](https://discourse.julialang.org/t/sparse-kroneckersum-sparse-or-not/109521 "2024-01-31T14:56:53Z")

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I wrote these two sparseArrays functions: using SparseArrays using LinearAlgebra using Kronecker Sz = \[\[0.5, 0\] \[0, -0.5\]\] C = kroneckersum(Sz, Sz) D = sparse(C) display(issparse(D)) display(D) E = kronecker(Sz, Sz) …

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## [Autodiff removing singularity](https://discourse.julialang.org/t/autodiff-removing-singularity/109498)

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**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 5\
**Last updated:** [January 31, 2024, 2:46pm UTC](https://discourse.julialang.org/t/autodiff-removing-singularity/109498 "2024-01-31T14:46:31Z")

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I have a function whose derivative isn’t defined at the origin, but is known ahead of time when approaching from x\>0, which is the limit I want. How can I add a special case to the ForwardDiff dual such that it uses this…

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## [Resolving Julia Warning: dt(2.27e-13) \<= dtmin(2.27e-13) in implementation of dual numbers](https://discourse.julialang.org/t/resolving-julia-warning-dt-2-27e-13-dtmin-2-27e-13-in-implementation-of-dual-numbers/109390)

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**Author:** [@vivekag7](https://discourse.julialang.org/u/vivekag7)\
**Replies:** 4\
**Last updated:** [January 31, 2024, 1:56pm UTC](https://discourse.julialang.org/t/resolving-julia-warning-dt-2-27e-13-dtmin-2-27e-13-in-implementation-of-dual-numbers/109390 "2024-01-31T13:56:24Z")

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Hi Julia Community, I’ve been trying to make a glacier SIA2D forward model compatible with dual numbers using PreallocationTools.jl, however I run into the following warning using the solver RDPK3Sp35: ┌ Warning: dt(2.…

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## [Is there a way to abort a task that does not yield?](https://discourse.julialang.org/t/is-there-a-way-to-abort-a-task-that-does-not-yield/109468)

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**Author:** [@taotree](https://discourse.julialang.org/u/taotree)\
**Replies:** 3\
**Last updated:** [January 31, 2024, 1:16pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-abort-a-task-that-does-not-yield/109468 "2024-01-31T13:16:03Z")

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I searched for running a task with a timeout, but all the answers I found used async tasks which won’t work because the whole point is that the code doesn’t yield. I understand that killing a thread is generally bad, bu…

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## [Image Rotation Algorithm for CUDA and Zygote](https://discourse.julialang.org/t/image-rotation-algorithm-for-cuda-and-zygote/54085)

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**Author:** [@roflmaostc](https://discourse.julialang.org/u/roflmaostc)\
**Replies:** 10\
**Last updated:** [January 31, 2024, 12:29pm UTC](https://discourse.julialang.org/t/image-rotation-algorithm-for-cuda-and-zygote/54085 "2024-01-31T12:29:43Z")

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Hey, today I wanted to use a image rotation algorithm to rotate a 3D array around one dimension (so basically many 2D images). For my applications it needs to be fast and also fully differentiable by Zygote. I tried I…

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## [Should Any have an identity constructor method?](https://discourse.julialang.org/t/should-any-have-an-identity-constructor-method/109500)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 10\
**Last updated:** [January 31, 2024, 10:31am UTC](https://discourse.julialang.org/t/should-any-have-an-identity-constructor-method/109500 "2024-01-31T10:31:00Z")

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Many non-concrete types have constructors, for example we have AbstractFloat(0.3) == 0.3 and Union{Int,Float64}(0.3) == 0.3. Should we also have a method like Any(x) = x? Then we would have map(Any, \[3,4,5\]) == map(ident…

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## [I love you](https://discourse.julialang.org/t/i-love-you/109478)

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**Author:** [@Enlil50](https://discourse.julialang.org/u/Enlil50)\
**Replies:** 2\
**Last updated:** [January 31, 2024, 9:47am UTC](https://discourse.julialang.org/t/i-love-you/109478 "2024-01-31T09:47:41Z")

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This language and all of you. I’m studying physics and I was trying to optimize fortran, C and then C++, but i was stuck between creating the whole programs from the scratch or trying to write 15 function stacked one on …

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## [Distributed: Passing views of an array for read access to workers (using pmap)](https://discourse.julialang.org/t/distributed-passing-views-of-an-array-for-read-access-to-workers-using-pmap/109379)

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**Author:** [@james](https://discourse.julialang.org/u/james)\
**Replies:** 8\
**Last updated:** [January 31, 2024, 9:42am UTC](https://discourse.julialang.org/t/distributed-passing-views-of-an-array-for-read-access-to-workers-using-pmap/109379 "2024-01-31T09:42:42Z")

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I have a large array and want multiple workers to have read access to that array in parallel. Each worker works on a disjoint interval of the array. My plan was to create a view of each of the sections of the array, and…

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## [FinETools Assemby Multiple Dispatch Include Integral Term](https://discourse.julialang.org/t/finetools-assemby-multiple-dispatch-include-integral-term/109502)

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**Author:** [@Domenico\_Lahaye](https://discourse.julialang.org/u/Domenico_Lahaye)\
**Replies:** 0\
**Last updated:** [January 31, 2024, 8:34am UTC](https://discourse.julialang.org/t/finetools-assemby-multiple-dispatch-include-integral-term/109502 "2024-01-31T08:34:15Z")

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Question: does FinETools allow to extend the assembly with a method that during assembly prints e.g. element id? Motivating this question is understanding better how “flexible” / “extensible” FenETools is solve integro-…

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## [What interface bugs have you ran into in the ecosystem?](https://discourse.julialang.org/t/what-interface-bugs-have-you-ran-into-in-the-ecosystem/109001)

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**Author:** [@ckfinite](https://discourse.julialang.org/u/ckfinite)\
**Replies:** 35\
**Last updated:** [January 31, 2024, 8:33am UTC](https://discourse.julialang.org/t/what-interface-bugs-have-you-ran-into-in-the-ecosystem/109001 "2024-01-31T08:33:32Z")

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I’m currently working on the formal design of a statically-checked trait system for Julia building off of our work on subtyping and static typing for Julia. The system as a whole is sadly some ways out yet because of a n…

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## [Type Instability using StaticArrays that I dont get](https://discourse.julialang.org/t/type-instability-using-staticarrays-that-i-dont-get/109499)

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**Author:** [@Christian\_Dengler](https://discourse.julialang.org/u/Christian_Dengler)\
**Replies:** 4\
**Last updated:** [January 31, 2024, 8:03am UTC](https://discourse.julialang.org/t/type-instability-using-staticarrays-that-i-dont-get/109499 "2024-01-31T08:03:30Z")

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Hello, I have a type instability according to @code\_warntype in the following code. To me it seems all types should be inferable though. What would I need to change to make it type stable? using StaticArrays import Lin…

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## [Right way to run external program in parallel?](https://discourse.julialang.org/t/right-way-to-run-external-program-in-parallel/109490)

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**Author:** [@Tetrakai](https://discourse.julialang.org/u/Tetrakai)\
**Replies:** 3\
**Last updated:** [January 31, 2024, 4:21am UTC](https://discourse.julialang.org/t/right-way-to-run-external-program-in-parallel/109490 "2024-01-31T04:21:21Z")

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I could not figure this out all day, until finally this answer saved me: run(\`bash -c """cd temp\_dir && some\_cmd"""\`) Is there a better way to do this? In particular I want to run a program designed to log results s…

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## [Call for Proposals for JuliaCon Global 2024 closes at January 31st 2024 23:59 (CET)](https://discourse.julialang.org/t/call-for-proposals-for-juliacon-global-2024-closes-at-january-31st-2024-23-59-cet/109491)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 0\
**Last updated:** [January 31, 2024, 4:07am UTC](https://discourse.julialang.org/t/call-for-proposals-for-juliacon-global-2024-closes-at-january-31st-2024-23-59-cet/109491 "2024-01-31T04:07:35Z")

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The Call for Proposals for JuliaCon Global 2024 in Eindhoven, the Netherlands, closes at 23:59 (CET) on January 31st. That is less than 18 hours from the time of this post. Please submit your proposals via the link belo…

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## [Create a shortcut to activate / deactivate the plot pane?](https://discourse.julialang.org/t/create-a-shortcut-to-activate-deactivate-the-plot-pane/109489)

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**Author:** [@jojob68](https://discourse.julialang.org/u/jojob68)\
**Replies:** 0\
**Last updated:** [January 31, 2024, 3:35am UTC](https://discourse.julialang.org/t/create-a-shortcut-to-activate-deactivate-the-plot-pane/109489 "2024-01-31T03:35:23Z")

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Is there a way to create a simple shortcut to activate / deactivate the plot pane? I find that the plot pane is useful for quick plots, but if I want to look at one particular plot in detail, zoom in, etc. I often prefe…

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## ['Sol' not defined upon opening Julia?](https://discourse.julialang.org/t/sol-not-defined-upon-opening-julia/109480)

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**Author:** [@deweyfinn](https://discourse.julialang.org/u/deweyfinn)\
**Replies:** 15\
**Last updated:** [January 31, 2024, 3:27am UTC](https://discourse.julialang.org/t/sol-not-defined-upon-opening-julia/109480 "2024-01-31T03:27:43Z")

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Hi. I have this code I am trying to make for graphing the trajectory of a thrown baton. The script involves a mass matrix (of the baton) being multiplied by dydt to show its trajectory. My problem comes from the use of …

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## [Error for install Plots.jl (especially Libtiff\_jll) help me!](https://discourse.julialang.org/t/error-for-install-plots-jl-especially-libtiff-jll-help-me/109484)

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**Author:** [@bellroot](https://discourse.julialang.org/u/bellroot)\
**Replies:** 0\
**Last updated:** [January 31, 2024, 2:02am UTC](https://discourse.julialang.org/t/error-for-install-plots-jl-especially-libtiff-jll-help-me/109484 "2024-01-31T02:02:06Z")

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Hello all, Recently, I upgraded Julia from version 1.9.0 to 1.10.0. After that, an error occurred when I tried to install Plots.jl (\*I am working in an environment where GitHub IP is blocked) Error message is like thi…

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## [Help with Performance in Large Mixed Complementarity Problem](https://discourse.julialang.org/t/help-with-performance-in-large-mixed-complementarity-problem/106052)

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**Author:** [@jmc](https://discourse.julialang.org/u/jmc)\
**Replies:** 23\
**Last updated:** [January 31, 2024, 1:56am UTC](https://discourse.julialang.org/t/help-with-performance-in-large-mixed-complementarity-problem/106052 "2024-01-31T01:56:05Z")

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Hi! I have a complementarity problem in which I am using the new awesome additions to JuMP to solve it. The problem involves a summation over 2^J terms, where J is around 30 and performance is critical. I was wondering…

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## [Why Is There a Significant Slow-down with DuckDB.jl Bridging?](https://discourse.julialang.org/t/why-is-there-a-significant-slow-down-with-duckdb-jl-bridging/109426)

<div class="topic-metadata">

**Author:** [@TheCedarPrince](https://discourse.julialang.org/u/TheCedarPrince)\
**Replies:** 1\
**Last updated:** [January 30, 2024, 11:25pm UTC](https://discourse.julialang.org/t/why-is-there-a-significant-slow-down-with-duckdb-jl-bridging/109426 "2024-01-30T23:25:30Z")

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I did an interesting little exploration with DuckDB.jl + bridging to another local database of a different SQL flavor today (SQLite). Here’s what I did: using BenchmarkTools using DBInterface using DuckDB using HealthSa…

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