# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=282

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

**Page:** 283

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## [Where to report error](https://discourse.julialang.org/t/where-to-report-error/100042)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 2\
**Last updated:** [June 8, 2023, 12:14pm UTC](https://discourse.julialang.org/t/where-to-report-error/100042 "2023-06-08T12:14:12Z")

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During precompilation I see this error: ┌ Warning: Module FileIOExt with build ID ffffffff-ffff-ffff-0000-02c424450fe9 is missing from the cache. │ This may mean FileIOExt \[f5f51d8f-5827-5d2e-939b-192fcd6ec70c\] does not…

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## [VSCode server weirdly slow in SSH](https://discourse.julialang.org/t/vscode-server-weirdly-slow-in-ssh/99960)

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**Author:** [@wujinq](https://discourse.julialang.org/u/wujinq)\
**Replies:** 1\
**Last updated:** [June 8, 2023, 2:35am UTC](https://discourse.julialang.org/t/vscode-server-weirdly-slow-in-ssh/99960 "2023-06-08T02:35:04Z")

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I’m currently using the vscode Julia extension when working remotely on Frontera, a supercomputer (CentOS 7). Recently the extension becomes weirdly slow; when I try to execute a code block, it takes about 1 minute to st…

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## [Another world age problem](https://discourse.julialang.org/t/another-world-age-problem/100029)

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**Author:** [@user664303](https://discourse.julialang.org/u/user664303)\
**Replies:** 6\
**Last updated:** [June 8, 2023, 1:40am UTC](https://discourse.julialang.org/t/another-world-age-problem/100029 "2023-06-08T01:40:24Z")

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I’m suffering from a world age problem, that Base.invokelatest does not solve. A MWE demonstrating the problem is as follows: module MyModule export myfun myfun(::Type{Int}) = 3 @generated function genfun(::Type{T}) wh…

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## [Using ntuple() in generated function](https://discourse.julialang.org/t/using-ntuple-in-generated-function/100020)

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**Author:** [@user664303](https://discourse.julialang.org/u/user664303)\
**Replies:** 5\
**Last updated:** [June 8, 2023, 12:48am UTC](https://discourse.julialang.org/t/using-ntuple-in-generated-function/100020 "2023-06-08T00:48:47Z")

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I have found that using ntuple in generated functions produces better code (faster, and with fewer allocations), than constructing the tuple expression manually. Presumably the code that ntuple generates is more inferabl…

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## [When should I choose a struct, mutable struct, Dict, named tuple or DataFrame?](https://discourse.julialang.org/t/when-should-i-choose-a-struct-mutable-struct-dict-named-tuple-or-dataframe/60366)

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**Author:** [@davidwallis](https://discourse.julialang.org/u/davidwallis)\
**Replies:** 17\
**Last updated:** [August 27, 2021, 10:58pm UTC](https://discourse.julialang.org/t/when-should-i-choose-a-struct-mutable-struct-dict-named-tuple-or-dataframe/60366 "2021-08-27T22:58:52Z")

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When should I use a struct, mutable struct, Dict, named tuple or DataFrame in Julia? Mutability and performance must be factors in deciding which data type to use. But when should I use each type?

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## [Optimal column to row major conversion](https://discourse.julialang.org/t/optimal-column-to-row-major-conversion/99989)

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**Author:** [@xgdgsc](https://discourse.julialang.org/u/xgdgsc)\
**Replies:** 7\
**Last updated:** [June 7, 2023, 11:10pm UTC](https://discourse.julialang.org/t/optimal-column-to-row-major-conversion/99989 "2023-06-07T23:10:56Z")

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When converting column major to row major array. When the array dimension become large. It can be tricky to implement fast conversion. Tricks like ENH: Improve performance for copying/relayout of large data · Issue #2165…

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## [Speed-up graphical lasso code](https://discourse.julialang.org/t/speed-up-graphical-lasso-code/100024)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 0\
**Last updated:** [June 7, 2023, 10:09pm UTC](https://discourse.julialang.org/t/speed-up-graphical-lasso-code/100024 "2023-06-07T22:09:53Z")

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Hello, I would like to get you feedback to accelerate my routine glasso for graphical lasso computation (the code follows Friedman et al. 2007 https://arxiv.org/pdf/0708.3517.pdf) where S is the sample covariance matr…

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## [Is there a Julia macro that emulates SAS data step?](https://discourse.julialang.org/t/is-there-a-julia-macro-that-emulates-sas-data-step/100023)

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**Author:** [@mwsohn](https://discourse.julialang.org/u/mwsohn)\
**Replies:** 0\
**Last updated:** [June 7, 2023, 10:02pm UTC](https://discourse.julialang.org/t/is-there-a-julia-macro-that-emulates-sas-data-step/100023 "2023-06-07T22:02:45Z")

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I am wondering whether there is a macro that emulates a SAS data step. Or more specifically a macro that automatically runs through all rows in a DataFrame such that a symbol indicates a column in a DataFrame (as in a @w…

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## [Extra space for specific legend entries](https://discourse.julialang.org/t/extra-space-for-specific-legend-entries/100014)

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**Author:** [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Replies:** 0\
**Last updated:** [June 7, 2023, 5:58pm UTC](https://discourse.julialang.org/t/extra-space-for-specific-legend-entries/100014 "2023-06-07T17:58:49Z")

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PlotlyJS: Is there a trick to add extra space between two legend entries? E.g. a large character at the end of the line with white color.

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## [GPU specifications -- what's the best GPU choice for diffeqGPUs?](https://discourse.julialang.org/t/gpu-specifications-whats-the-best-gpu-choice-for-diffeqgpus/99945)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 9\
**Last updated:** [June 7, 2023, 5:24pm UTC](https://discourse.julialang.org/t/gpu-specifications-whats-the-best-gpu-choice-for-diffeqgpus/99945 "2023-06-07T17:24:58Z")

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I’m looking out specifying a cluster for our IT guys. I’m not a GPU guru and am not up to date on all of the choices. I see there are a lot of options and some GPUs are more optimized for machine learning, etc. I’d li…

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## [How to get all combinations from multiple input arrays?](https://discourse.julialang.org/t/how-to-get-all-combinations-from-multiple-input-arrays/100010)

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**Author:** [@ejmeitz](https://discourse.julialang.org/u/ejmeitz)\
**Replies:** 3\
**Last updated:** [June 7, 2023, 3:49pm UTC](https://discourse.julialang.org/t/how-to-get-all-combinations-from-multiple-input-arrays/100010 "2023-06-07T15:49:25Z")

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Hello, Say I have three input arrays like the ones below (could be arbitrary amount) and I want to generate all possible combinations of values with one entry from each array. The existing functions in Combinatorics.jl …

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## [How does \`--heap\_size\_hint\` relate to improvements for \`Sys.total\_memory()\`?](https://discourse.julialang.org/t/how-does-heap-size-hint-relate-to-improvements-for-sys-total-memory/100006)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 0\
**Last updated:** [June 7, 2023, 2:46pm UTC](https://discourse.julialang.org/t/how-does-heap-size-hint-relate-to-improvements-for-sys-total-memory/100006 "2023-06-07T14:46:27Z")

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Hi there, I am looking to make Julia run smoothly on a kubernetes pod. There seem to be two things which somehow improve stability: Expose constrained memory limits and have the GC use them by maleadt · Pull Request …

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## [BinaryBuilder do not find my binary outputs](https://discourse.julialang.org/t/binarybuilder-do-not-find-my-binary-outputs/99995)

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**Author:** [@Diego\_Javier\_Zea](https://discourse.julialang.org/u/Diego_Javier_Zea)\
**Replies:** 1\
**Last updated:** [June 7, 2023, 11:05am UTC](https://discourse.julialang.org/t/binarybuilder-do-not-find-my-binary-outputs/99995 "2023-06-07T11:05:57Z")

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Hi! It’s the first time I am trying to get a JLL package. I ran the wizard, and everything went well locally. However, the Yggddrasil PR is failing as it looks like it cannot find the binary products. Am I doing somethi…

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## [Animated graph using Makie not working with node\_size or arrow\_size](https://discourse.julialang.org/t/animated-graph-using-makie-not-working-with-node-size-or-arrow-size/99997)

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**Author:** [@Richard](https://discourse.julialang.org/u/Richard)\
**Replies:** 0\
**Last updated:** [June 7, 2023, 12:11pm UTC](https://discourse.julialang.org/t/animated-graph-using-makie-not-working-with-node-size-or-arrow-size/99997 "2023-06-07T12:11:11Z")

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Hi I’m taking first steps with Makie, trying to produce an animated network graph. There are three nodes and I want the edge width, arrow size and node size to vary according to supplied matrices. The static graph wor…

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## [Is this a ternary (?) operator bug?](https://discourse.julialang.org/t/is-this-a-ternary-operator-bug/99998)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 4\
**Last updated:** [June 7, 2023, 1:03pm UTC](https://discourse.julialang.org/t/is-this-a-ternary-operator-bug/99998 "2023-06-07T13:03:30Z")

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julia\> function foo(a,b) a \*= "+1"; b \*= "+2"; return a,b end julia\> function baz() a="";b=""; (true) ? a,b = foo("","") : nothing; println(a,b) end ERROR: syntax: colon expected in "?" expression Stacktrace: \[1\] to…

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## [Faster/performant interpolation of very big arrays](https://discourse.julialang.org/t/faster-performant-interpolation-of-very-big-arrays/99996)

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**Author:** [@eirikeb](https://discourse.julialang.org/u/eirikeb)\
**Replies:** 0\
**Last updated:** [June 7, 2023, 11:49am UTC](https://discourse.julialang.org/t/faster-performant-interpolation-of-very-big-arrays/99996 "2023-06-07T11:49:34Z")

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I have two separate problems relating to interpolation of some dimensions of relatively big arrays. Creating interpolations objects using \`Interpolations.jl’ is a little slow and uses a lot of memory when you create a …

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## [Julia as a bridge between windows and raspberry pi](https://discourse.julialang.org/t/julia-as-a-bridge-between-windows-and-raspberry-pi/99748)

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**Author:** [@RDuarte](https://discourse.julialang.org/u/RDuarte)\
**Replies:** 34\
**Last updated:** [June 7, 2023, 9:50am UTC](https://discourse.julialang.org/t/julia-as-a-bridge-between-windows-and-raspberry-pi/99748 "2023-06-07T09:50:04Z")

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Hello everyone, I’m trying to create project that runs in raspberry pi and windows and I want that Julia works as a bridge between both platforms. I will try to explain. I run Julia in my raspberry pi in order to proc…

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## [How to plot 3d data while using a gradient color depending on the "time" of the point?](https://discourse.julialang.org/t/how-to-plot-3d-data-while-using-a-gradient-color-depending-on-the-time-of-the-point/99988)

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**Author:** [@ultrapoci](https://discourse.julialang.org/u/ultrapoci)\
**Replies:** 2\
**Last updated:** [June 7, 2023, 7:47am UTC](https://discourse.julialang.org/t/how-to-plot-3d-data-while-using-a-gradient-color-depending-on-the-time-of-the-point/99988 "2023-06-07T07:47:25Z")

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Sorry for the confusing title, I’m not really sure how to summarize it. Basically, I have a list of 3D points which are order according the time these points were taken. In a sense, you can think of these as 4D points, w…

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## [How to correctly write package extension code?](https://discourse.julialang.org/t/how-to-correctly-write-package-extension-code/99980)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 6\
**Last updated:** [June 7, 2023, 6:31am UTC](https://discourse.julialang.org/t/how-to-correctly-write-package-extension-code/99980 "2023-06-07T06:31:50Z")

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For example, I have a main package called NeuralNetworks, and an extension called MNIST. Now I want to load MNIST if package MLDatasets.jl is already loaded. I wrote the following code in NeuralNetworks: function loadd…

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## [Tab width in print/println vs printstyled](https://discourse.julialang.org/t/tab-width-in-print-println-vs-printstyled/99917)

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**Author:** [@pbal](https://discourse.julialang.org/u/pbal)\
**Replies:** 4\
**Last updated:** [June 6, 2023, 11:27pm UTC](https://discourse.julialang.org/t/tab-width-in-print-println-vs-printstyled/99917 "2023-06-06T23:27:16Z")

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In Julia 1.9, the tab width is different in println() vs. printstyled(). Version: Version 1.9.0 (2023-05-07) print() and println() are consistent. printstyled() is a different width: julia\> println("123456789\\n\\t\*") …

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## [Unitful.jl without parametrizing types on units?](https://discourse.julialang.org/t/unitful-jl-without-parametrizing-types-on-units/99869)

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**Author:** [@MilesCranmer](https://discourse.julialang.org/u/MilesCranmer)\
**Replies:** 24\
**Last updated:** [June 6, 2023, 8:27pm UTC](https://discourse.julialang.org/t/unitful-jl-without-parametrizing-types-on-units/99869 "2023-06-06T20:27:05Z")

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I am trying to add support for dimensional constraints in SymbolicRegression.jl: https://github.com/MilesCranmer/SymbolicRegression.jl/pull/220. However, I realize now this is going to be impossible with Unitful.jl due t…

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## [Attaching a debugger to a running Julia program and printing local variables](https://discourse.julialang.org/t/attaching-a-debugger-to-a-running-julia-program-and-printing-local-variables/99961)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 1\
**Last updated:** [June 6, 2023, 7:57pm UTC](https://discourse.julialang.org/t/attaching-a-debugger-to-a-running-julia-program-and-printing-local-variables/99961 "2023-06-06T19:57:27Z")

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I have a long-running Julia (nightly) script that seems to enter an infinite loop sometimes after running for several hours. Julia is started with ENABLE\_GDBLISTENER=1 and with -g2. Attaching with GDB (gdb -p PID) works…

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## [Question about the multithreading usage](https://discourse.julialang.org/t/question-about-the-multithreading-usage/99955)

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**Author:** [@jianqixi](https://discourse.julialang.org/u/jianqixi)\
**Replies:** 6\
**Last updated:** [June 6, 2023, 7:21pm UTC](https://discourse.julialang.org/t/question-about-the-multithreading-usage/99955 "2023-06-06T19:21:09Z")

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Hi, I have one question related to the multithreading calculation in Julia. It seems like the @threads for loop is not always safe to get what I want. Here is one simple example of the code: ‘’’ julia A = Any B = Any …

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## [\[CairoMakie\] Mirrored axis sharing](https://discourse.julialang.org/t/cairomakie-mirrored-axis-sharing/99939)

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**Author:** [@fdekerme](https://discourse.julialang.org/u/fdekerme)\
**Replies:** 1\
**Last updated:** [June 6, 2023, 6:57pm UTC](https://discourse.julialang.org/t/cairomakie-mirrored-axis-sharing/99939 "2023-06-06T18:57:27Z")

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Hello, :smiley: Is it possible to do a “Mirrored axis sharing” in CairoMakie, like on this image for example? (from Axes review · Issue #206 · MakieOrg/Makie.jl (github.com) Thank you ! fdekerm

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## [Is there any tutorial (easy) for PyJulia?](https://discourse.julialang.org/t/is-there-any-tutorial-easy-for-pyjulia/99935)

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**Author:** [@cgotelli](https://discourse.julialang.org/u/cgotelli)\
**Replies:** 3\
**Last updated:** [June 6, 2023, 3:15pm UTC](https://discourse.julialang.org/t/is-there-any-tutorial-easy-for-pyjulia/99935 "2023-06-06T15:15:27Z")

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Hello! I have been trying to run a function available in the Julia module “GeoStats” from Python with PyJulia. However, I can’t manage to do it. Is there any tutorial showing how to make PyJulia work with the most recen…

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## [Is it possible to tune garbage collection for interactivity?](https://discourse.julialang.org/t/is-it-possible-to-tune-garbage-collection-for-interactivity/99841)

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**Author:** [@jules](https://discourse.julialang.org/u/jules)\
**Replies:** 6\
**Last updated:** [June 6, 2023, 2:41pm UTC](https://discourse.julialang.org/t/is-it-possible-to-tune-garbage-collection-for-interactivity/99841 "2023-06-06T14:41:47Z")

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200-300 ms intervals of gc are very disruptive when interacting with plots in GLMakie, for example. It would be much better if GC ran more often but only for 5ms or so at a time so that the chance of dropping frames is l…

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## [Find the last index that corresponds to a given condition](https://discourse.julialang.org/t/find-the-last-index-that-corresponds-to-a-given-condition/99942)

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**Author:** [@RDuarte](https://discourse.julialang.org/u/RDuarte)\
**Replies:** 2\
**Last updated:** [June 6, 2023, 2:16pm UTC](https://discourse.julialang.org/t/find-the-last-index-that-corresponds-to-a-given-condition/99942 "2023-06-06T14:16:17Z")

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Hello How can I find the last index that corresponds to a given condition? For example, in matlab i would do: find(f) \<= 1000,1,‘last’) Is there any correspondent function in julia? Thanks in advance

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## [Inference in nested quadgk](https://discourse.julialang.org/t/inference-in-nested-quadgk/99937)

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**Author:** [@lxvm](https://discourse.julialang.org/u/lxvm)\
**Replies:** 0\
**Last updated:** [June 6, 2023, 1:11pm UTC](https://discourse.julialang.org/t/inference-in-nested-quadgk/99937 "2023-06-06T13:11:48Z")

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There have been a handful of threads on this forum regarding long compilation times for nested quadgk calls (e.g. here) and I was wondering what are some of the possible reasons that type inference may be failing in this…

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## [Julia v1.8 -\> v1.9 makes this code 1000x slower](https://discourse.julialang.org/t/julia-v1-8-v1-9-makes-this-code-1000x-slower/99766)

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**Author:** [@user664303](https://discourse.julialang.org/u/user664303)\
**Replies:** 6\
**Last updated:** [June 6, 2023, 12:55pm UTC](https://discourse.julialang.org/t/julia-v1-8-v1-9-makes-this-code-1000x-slower/99766 "2023-06-06T12:55:52Z")

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On upgrading to Julia from 1.8.5. to 1.9.0 I noticed code in one of my packages slow down significantly. It has taken me a long time to get down to the simplest code which replicates the problem, but I have it now. After…

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## [Generate function that calls sequence of functions in order to avoid recompilation](https://discourse.julialang.org/t/generate-function-that-calls-sequence-of-functions-in-order-to-avoid-recompilation/99919)

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**Author:** [@heindelj](https://discourse.julialang.org/u/heindelj)\
**Replies:** 3\
**Last updated:** [June 6, 2023, 12:21pm UTC](https://discourse.julialang.org/t/generate-function-that-calls-sequence-of-functions-in-order-to-avoid-recompilation/99919 "2023-06-06T12:21:55Z")

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I have a type which looks like this: mutable struct FQCTDipole{T\<:Function} \<: AbstractForceField terms::Vector{T} storage::FQCTDipoleStorage results::ForceFieldResults end The only part of this that matter…

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