# Latest **URL:** https://discourse.julialang.org/latest.md?page=630 [Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md) **Page:** 631 --- ## [Instability of perpetual manifolds of coupled oscillators, problem relevant to numerical integration algorithms](https://discourse.julialang.org/t/instability-of-perpetual-manifolds-of-coupled-oscillators-problem-relevant-to-numerical-integration-algorithms/102328)

**Author:** [@Prof\_FG](https://discourse.julialang.org/u/Prof_FG)\ **Replies:** 6\ **Last updated:** [August 1, 2023, 7:10pm UTC](https://discourse.julialang.org/t/instability-of-perpetual-manifolds-of-coupled-oscillators-problem-relevant-to-numerical-integration-algorithms/102328 "2023-08-01T19:10:24Z")

Dear all, I downloaded Julia to try solving numerically a system of nonlinear differential equations, which is based on my article about perpetual points/manifolds, in Journal of Mechanical Science https://doi.org/10.… --- ## [Could (non) @view be made faster? I.e. @view be implicit using read-only arrays?](https://discourse.julialang.org/t/could-non-view-be-made-faster-i-e-view-be-implicit-using-read-only-arrays/102323)

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\ **Replies:** 10\ **Last updated:** [August 1, 2023, 6:58pm UTC](https://discourse.julialang.org/t/could-non-view-be-made-faster-i-e-view-be-implicit-using-read-only-arrays/102323 "2023-08-01T18:58:43Z")

I see the suggestion “use @view/@views” often, to fix a performance problem; possibly for people coming from Python (is it also the default in MATLAB?). I know the difference, and support having a (at least a conception… --- ## [How to use many (non-sticky) tasks while maximizing local storage reuse?](https://discourse.julialang.org/t/how-to-use-many-non-sticky-tasks-while-maximizing-local-storage-reuse/100279)

**Author:** [@pablosanjose](https://discourse.julialang.org/u/pablosanjose)\ **Replies:** 9\ **Last updated:** [August 1, 2023, 12:53pm UTC](https://discourse.julialang.org/t/how-to-use-many-non-sticky-tasks-while-maximizing-local-storage-reuse/100279 "2023-08-01T12:53:08Z")

After reading the WIP blogpost https://github.com/JuliaLang/www.julialang.org/pull/1904, I’m trying to adapt to the new recommended approach to multithreading, now that tasks can migrate between threads. I would like to … --- ## [Speeding up matrix exponential and matrix multiplication](https://discourse.julialang.org/t/speeding-up-matrix-exponential-and-matrix-multiplication/102272)

**Author:** [@eveningsilverfox](https://discourse.julialang.org/u/eveningsilverfox)\ **Replies:** 58\ **Last updated:** [August 1, 2023, 4:21pm UTC](https://discourse.julialang.org/t/speeding-up-matrix-exponential-and-matrix-multiplication/102272 "2023-08-01T16:21:04Z")

I am very new to Julia and trying to convert my python codes to Julia to speed up my work. However, the present Julia version, pasted below, still runs slower than my python version. I see two bottlenecks: (1) the matr… --- ## [How to combine Makie plots in a single figure?](https://discourse.julialang.org/t/how-to-combine-makie-plots-in-a-single-figure/102353)

**Author:** [@Axze-rgb](https://discourse.julialang.org/u/Axze-rgb)\ **Replies:** 16\ **Last updated:** [August 1, 2023, 4:18pm UTC](https://discourse.julialang.org/t/how-to-combine-makie-plots-in-a-single-figure/102353 "2023-08-01T16:18:10Z")

Hello, I really love Makie for all the nice decisions it takes automatically such as great color palettes. That being said, I can’t follow the layout tutorial because Makielayout doesn’t compile, I have been waiting for… --- ## [Byrow function to get the mean of row](https://discourse.julialang.org/t/byrow-function-to-get-the-mean-of-row/102315)

**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\ **Replies:** 10\ **Last updated:** [August 1, 2023, 12:20pm UTC](https://discourse.julialang.org/t/byrow-function-to-get-the-mean-of-row/102315 "2023-08-01T12:20:20Z")

I want to get the row wise mean of two columns of data using byrow function. These two columns are T\_start(s) and T\_stop(s). How should i change code given below ? :point\_down: using HTTP,CSV,DataFrames,InMemoryData… --- ## [How to create a birth/death system with ModelingToolkit.jl?](https://discourse.julialang.org/t/how-to-create-a-birth-death-system-with-modelingtoolkit-jl/102324)

**Author:** [@70Gage70](https://discourse.julialang.org/u/70Gage70)\ **Replies:** 3\ **Last updated:** [August 1, 2023, 3:15pm UTC](https://discourse.julialang.org/t/how-to-create-a-birth-death-system-with-modelingtoolkit-jl/102324 "2023-08-01T15:15:40Z")

This gist of this question is to determine what the canonical workflow is for defining systems with changing numbers of components e.g. growth/death of biological organisms. This issue is discussed is the callback sectio… --- ## [Running tests in package?](https://discourse.julialang.org/t/running-tests-in-package/102354)

**Author:** [@frylock](https://discourse.julialang.org/u/frylock)\ **Replies:** 2\ **Last updated:** [August 1, 2023, 2:49pm UTC](https://discourse.julialang.org/t/running-tests-in-package/102354 "2023-08-01T14:49:25Z")

I have a package, say Neet. (I made it with \] generate Neet.) It is a simple package, and src/Neet.jl contains only: module Neet export is\_great is\_great() = true end I navigate to the ./Neet folder and create another … --- ## [My Windows Julia terminal doesn't show the symbols properly](https://discourse.julialang.org/t/my-windows-julia-terminal-doesnt-show-the-symbols-properly/102352)

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\ **Replies:** 1\ **Last updated:** [August 1, 2023, 1:25pm UTC](https://discourse.julialang.org/t/my-windows-julia-terminal-doesnt-show-the-symbols-properly/102352 "2023-08-01T13:25:13Z")

When I open the Julia terminal from the icon installed on the toolbar when, I see these ? question mark symbol. I think they should be up arrow symbols. What do I do to get the terminal to display the right symbols? --- ## [From multithreading to distributed](https://discourse.julialang.org/t/from-multithreading-to-distributed/101984)

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\ **Replies:** 6\ **Last updated:** [August 1, 2023, 12:51pm UTC](https://discourse.julialang.org/t/from-multithreading-to-distributed/101984 "2023-08-01T12:51:44Z")

I have the following code, that works well: # Dummy function, the real code makes heavy use of ModelingToolkit and DifferentialEquations function rel\_sigma(;λ\_nom) sleep(1) rand() end λ\_noms = sort(unique(vcat(… --- ## [Deep copy of Array in Struct in NamedTuple](https://discourse.julialang.org/t/deep-copy-of-array-in-struct-in-namedtuple/102349)

**Author:** [@DanDoe](https://discourse.julialang.org/u/DanDoe)\ **Replies:** 3\ **Last updated:** [August 1, 2023, 12:17pm UTC](https://discourse.julialang.org/t/deep-copy-of-array-in-struct-in-namedtuple/102349 "2023-08-01T12:17:47Z")

I am creating and returning a NamedTuple cache mystruct = MyStruct{Float64}(42, 42, 42) cache = (; foo, bar, mystruct) return cache where mystruct is an object of the mutable struct MyStruct which contains an array mu… --- ## [Simple debugging: @testset, @debug, @assert](https://discourse.julialang.org/t/simple-debugging-testset-debug-assert/102346)

**Author:** [@ryofurue](https://discourse.julialang.org/u/ryofurue)\ **Replies:** 1\ **Last updated:** [August 1, 2023, 11:25am UTC](https://discourse.julialang.org/t/simple-debugging-testset-debug-assert/102346 "2023-08-01T11:25:50Z")

I want to insert simple test code here and there into my small programs and am wondering what the best practice is. \[What I write below likely includes some error due to my misunderstanding. I’m struggling to understand… --- ## [Combining data of different GCNs in a single file](https://discourse.julialang.org/t/combining-data-of-different-gcns-in-a-single-file/102013)

**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\ **Replies:** 21\ **Last updated:** [August 1, 2023, 10:33am UTC](https://discourse.julialang.org/t/combining-data-of-different-gcns-in-a-single-file/102013 "2023-08-01T10:33:42Z")

**Author:** [@Matheus\_Diogenes\_And](https://discourse.julialang.org/u/Matheus_Diogenes_And)\ **Replies:** 2\ **Last updated:** [August 1, 2023, 12:07pm UTC](https://discourse.julialang.org/t/modeling-objective-function-with-cplexcp-jl/102336 "2023-08-01T12:07:33Z")

Hello everyone. I am trying to use the CPLEXCP.jl. However, I am having some issues when using this library. Follows the code I am executing. This is the link of the github project. using CPLEXCP using MathOptInterface… --- ## [CoupledODEs not defined](https://discourse.julialang.org/t/coupledodes-not-defined/102343)

**Author:** [@Tamojit\_Ghosh](https://discourse.julialang.org/u/Tamojit_Ghosh)\ **Replies:** 1\ **Last updated:** [August 1, 2023, 11:01am UTC](https://discourse.julialang.org/t/coupledodes-not-defined/102343 "2023-08-01T11:01:36Z")

My CoupledODEs function suddenly stopped working. I have DyanamicalSystems Package installed. It is showing error: “UndefVarError: CoupledODEs not defined” --- ## [Concatenation of chains](https://discourse.julialang.org/t/concatenation-of-chains/102344)

**Author:** [@Sahil\_Khan](https://discourse.julialang.org/u/Sahil_Khan)\ **Replies:** 2\ **Last updated:** [August 1, 2023, 9:41am UTC](https://discourse.julialang.org/t/concatenation-of-chains/102344 "2023-08-01T09:41:03Z")

Can we use cat to catenate chains one after another rather than alongside? So in this given case i would like to have chains one after another as a single continuous chain which will make it 2000 rather than two. --- ## [Creating an interpolating 2D lookup table](https://discourse.julialang.org/t/creating-an-interpolating-2d-lookup-table/102303)

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\ **Replies:** 7\ **Last updated:** [August 1, 2023, 8:59am UTC](https://discourse.julialang.org/t/creating-an-interpolating-2d-lookup-table/102303 "2023-08-01T08:59:50Z")

I have the function p=f(a, b) and can generate a grid of values for all valid values of a and b using a simulation. The values of p are steadily increasing with a and steadily decreasing with b. I need a numeric approx… --- ## [How to use Revise to track a local script](https://discourse.julialang.org/t/how-to-use-revise-to-track-a-local-script/102341)

**Author:** [@jinfreedom](https://discourse.julialang.org/u/jinfreedom)\ **Replies:** 3\ **Last updated:** [August 1, 2023, 6:36am UTC](https://discourse.julialang.org/t/how-to-use-revise-to-track-a-local-script/102341 "2023-08-01T06:36:07Z")

Hi, I have a local myfile.jl file that contains some julia code that do some one-time computations. I don’t want to bother to turn it into a package, so I use e.g., include("./myfile.jl") to have access to its variables … --- ## [LlaMa2 architecture in Julia: llama2.jl (300 lines?)](https://discourse.julialang.org/t/llama2-architecture-in-julia-llama2-jl-300-lines/102006)

**Author:** [@Jose\_Diaz](https://discourse.julialang.org/u/Jose_Diaz)\ **Replies:** 2\ **Last updated:** [August 1, 2023, 5:59am UTC](https://discourse.julialang.org/t/llama2-architecture-in-julia-llama2-jl-300-lines/102006 "2023-08-01T05:59:58Z")

Hello! I’m currently porting karpathy/llama2.c to Julia Managed to import all the weights and the config. Created structs with the appropiate types and implemented some of the math too. Now I’m implementing the archite… --- ## [Array/vector comprehension and AbstractTrees Leaves iterator](https://discourse.julialang.org/t/array-vector-comprehension-and-abstracttrees-leaves-iterator/102337)

**Author:** [@pitsianis](https://discourse.julialang.org/u/pitsianis)\ **Replies:** 0\ **Last updated:** [August 1, 2023, 1:18am UTC](https://discourse.julialang.org/t/array-vector-comprehension-and-abstracttrees-leaves-iterator/102337 "2023-08-01T01:18:45Z")

Why the array comprehension behaves differently with the AbstractTrees.Leaves iterator? In the following replacing Leaves(t) with say, range(1,3,3), I do get the 2D array. julia\> using AbstractTrees julia\> t = \[\[1, 2\]… --- ## [Tinkering with REPL settings in \`~/.julia/config/startup.jl\`](https://discourse.julialang.org/t/tinkering-with-repl-settings-in-julia-config-startup-jl/102329)

**Author:** [@frylock](https://discourse.julialang.org/u/frylock)\ **Replies:** 3\ **Last updated:** [July 31, 2023, 11:38pm UTC](https://discourse.julialang.org/t/tinkering-with-repl-settings-in-julia-config-startup-jl/102329 "2023-07-31T23:38:20Z")

I’m using Julia 1.9.2. In the “state of Julia” talk at JuliaCon, a function was mentioned that I wanted to add to my startup: REPL.numbered\_prompt!() … but if I add this to my startup: using REPL REPL.numbered\_prompt!(… --- ## [Stuck with infeasibility certificates in JuMP.jl](https://discourse.julialang.org/t/stuck-with-infeasibility-certificates-in-jump-jl/102210)

**Author:** [@sstroemer](https://discourse.julialang.org/u/sstroemer)\ **Replies:** 1\ **Last updated:** [July 31, 2023, 11:08pm UTC](https://discourse.julialang.org/t/stuck-with-infeasibility-certificates-in-jump-jl/102210 "2023-07-31T23:08:16Z")

I’m trying to work with infeasibility certificates and different solvers. MWE using GLPK: using JuMP import HiGHS, Gurobi, GLPK model = JuMP.Model(() -\> GLPK.Optimizer(; want\_infeasibility\_certificates = true)) @varia… --- ## [Unsupported expression in JuMP](https://discourse.julialang.org/t/unsupported-expression-in-jump/102206)

**Author:** [@jack\_lee](https://discourse.julialang.org/u/jack_lee)\ **Replies:** 1\ **Last updated:** [July 31, 2023, 11:03pm UTC](https://discourse.julialang.org/t/unsupported-expression-in-jump/102206 "2023-07-31T23:03:46Z")

Given a list of sample points ,I want to find a target point which satisfy: the total distance to each points is minimum the largest distance to the target point is minimum function optimize\_factory\_13(xx,yy) mode… --- ## [Which package to use as a dependency for geometric primitives?](https://discourse.julialang.org/t/which-package-to-use-as-a-dependency-for-geometric-primitives/102268)

**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\ **Replies:** 7\ **Last updated:** [July 31, 2023, 9:53pm UTC](https://discourse.julialang.org/t/which-package-to-use-as-a-dependency-for-geometric-primitives/102268 "2023-07-31T21:53:48Z")

I need to create method dispatch on geometric primitives: hypersphere and hyperrectangle (i want to create samplers that randomly sample points uniformly within these primitives). I don’t want to re-define types for the… --- ## [Dispatching on a new composite type that extends an old composite type](https://discourse.julialang.org/t/dispatching-on-a-new-composite-type-that-extends-an-old-composite-type/102334)

**Author:** [@nickbishop](https://discourse.julialang.org/u/nickbishop)\ **Replies:** 4\ **Last updated:** [July 31, 2023, 9:35pm UTC](https://discourse.julialang.org/t/dispatching-on-a-new-composite-type-that-extends-an-old-composite-type/102334 "2023-07-31T21:35:38Z")

I have a situation where I want to check if two 2D vectors are neighbours or not according to some criteria. The initial criteria I considered was to check whether both vectors are within some fixed distance radius of on… --- ## [Loading views from serialized file disconnects memory link](https://discourse.julialang.org/t/loading-views-from-serialized-file-disconnects-memory-link/102335)

**Author:** [@mwhisena](https://discourse.julialang.org/u/mwhisena)\ **Replies:** 0\ **Last updated:** [July 31, 2023, 9:31pm UTC](https://discourse.julialang.org/t/loading-views-from-serialized-file-disconnects-memory-link/102335 "2023-07-31T21:31:10Z")

I have a large matrix of data that I wish to create hundreds of views from. These views help me with setindexing and actually using my data in the program. This works perfectly for me, especially if I want to deepcopy to… --- ## [Creating global variable in a worker](https://discourse.julialang.org/t/creating-global-variable-in-a-worker/102150)

**Author:** [@Jad\_Zeitouni](https://discourse.julialang.org/u/Jad_Zeitouni)\ **Replies:** 8\ **Last updated:** [July 31, 2023, 7:47pm UTC](https://discourse.julialang.org/t/creating-global-variable-in-a-worker/102150 "2023-07-31T19:47:54Z")

I have a vector chains which contains a mutable struct called Chain and a function f!(chain::Chain) which alters chain. I want to distribute each element of chains to a worker so that the worker could return to me a new c… --- ## [Slice, ignoring out of bounds](https://discourse.julialang.org/t/slice-ignoring-out-of-bounds/102286)

**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\ **Replies:** 3\ **Last updated:** [July 31, 2023, 7:43pm UTC](https://discourse.julialang.org/t/slice-ignoring-out-of-bounds/102286 "2023-07-31T19:43:37Z")

I want to slice an array ignoring any out-of-bounds indices. Is there a preferred way to do this? My solution safeslice(a, ixs) = a\[filter(i -\> checkbounds(Bool, a, i), ixs)\] julia\> safeslice(\[10,20,30\], -4:2) 2-elemen… --- ## [Please help me figure out why package dependencies are failing](https://discourse.julialang.org/t/please-help-me-figure-out-why-package-dependencies-are-failing/102313)

**Author:** [@aaroncbader](https://discourse.julialang.org/u/aaroncbader)\ **Replies:** 3\ **Last updated:** [July 31, 2023, 7:35pm UTC](https://discourse.julialang.org/t/please-help-me-figure-out-why-package-dependencies-are-failing/102313 "2023-07-31T19:35:12Z")

To make things easier. I have replaced the names with PkgA, PkgB and PkgC, so it’s easier to see how the packages should depend on each other. PkgB depends on PkgA PkgC also depends on PkgA All three packages are dev… --- ## [Using custom structs with KernelAbstractions](https://discourse.julialang.org/t/using-custom-structs-with-kernelabstractions/102278)

**Author:** [@berk.geveci](https://discourse.julialang.org/u/berk.geveci)\ **Replies:** 6\ **Last updated:** [July 31, 2023, 7:33pm UTC](https://discourse.julialang.org/t/using-custom-structs-with-kernelabstractions/102278 "2023-07-31T19:33:23Z")

Hi folks. I am trying to pass a custom struct to a kernel. I have done this successfully with CUDA.jl and Metal.jl successfully using the Adapt package. I can get the same to work with KernelAbstractions. Here is the re… [Previous page](https://discourse.julialang.org/latest.md?page=629) [Next page](https://discourse.julialang.org/latest.md?page=631)