# Latest

**URL:** https://discourse.julialang.org/latest.md?page=599

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

**Page:** 600

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## [Conditional Constraint Construction Based on Input Data Presence/Absence of Set Combinations in Julia JUMP](https://discourse.julialang.org/t/conditional-constraint-construction-based-on-input-data-presence-absence-of-set-combinations-in-julia-jump/103717)

<div class="topic-metadata">

**Author:** [@Dimi](https://discourse.julialang.org/u/Dimi)\
**Replies:** 6\
**Last updated:** [September 12, 2023, 9:03pm UTC](https://discourse.julialang.org/t/conditional-constraint-construction-based-on-input-data-presence-absence-of-set-combinations-in-julia-jump/103717 "2023-09-12T21:03:20Z")

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Hello everyone. I am currently transitioning from GAMS optimisation to Julia optimisation (in VScode) and trying to figure out the “optimal/fastest” way of constructing conditional constraints based on the presence (or a…

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## [Out of memory when using Makie with large images](https://discourse.julialang.org/t/out-of-memory-when-using-makie-with-large-images/103786)

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**Author:** [@klafyvel](https://discourse.julialang.org/u/klafyvel)\
**Replies:** 2\
**Last updated:** [September 12, 2023, 8:02pm UTC](https://discourse.julialang.org/t/out-of-memory-when-using-makie-with-large-images/103786 "2023-09-12T20:02:07Z")

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Hi, I’m having a problem with a big memory footprint when using CairoMakie to plot big images in the REPL. The code consists of loading four images with load and then plotting them using image! (no treatment whatsoever,…

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## [Reading and writing Arrow column metadata](https://discourse.julialang.org/t/reading-and-writing-arrow-column-metadata/102427)

<div class="topic-metadata">

**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 9\
**Last updated:** [September 12, 2023, 6:52pm UTC](https://discourse.julialang.org/t/reading-and-writing-arrow-column-metadata/102427 "2023-09-12T18:52:27Z")

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I am trying to read and write column metadata for the arrow format. I went to the Arrow, runtest.jl file to try to figure it out, but still am having troubles. If someone can get the MWE working it will help me along. …

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## [JuliaCon 2023 talks are live streaming on YouTube](https://discourse.julialang.org/t/juliacon-2023-talks-are-live-streaming-on-youtube/101956)

<div class="topic-metadata">

**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 27\
**Last updated:** [September 12, 2023, 6:42pm UTC](https://discourse.julialang.org/t/juliacon-2023-talks-are-live-streaming-on-youtube/101956 "2023-09-12T18:42:07Z")

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## [How can I training one function at the time with NeuralPDE?](https://discourse.julialang.org/t/how-can-i-training-one-function-at-the-time-with-neuralpde/103398)

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**Author:** [@Knud\_Sorensen](https://discourse.julialang.org/u/Knud_Sorensen)\
**Replies:** 3\
**Last updated:** [September 12, 2023, 6:32pm UTC](https://discourse.julialang.org/t/how-can-i-training-one-function-at-the-time-with-neuralpde/103398 "2023-09-12T18:32:25Z")

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If you have 2 or more functions as Neural nets, say f and g. And they are coupled by a differential equation. And we already idea how f should look like say we have a mock function f\_m for f How would I? Train f to …

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## [Error when using Unitful and MonteCarloMeasurements with DifferentialEquations](https://discourse.julialang.org/t/error-when-using-unitful-and-montecarlomeasurements-with-differentialequations/103464)

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**Author:** [@rwalters31](https://discourse.julialang.org/u/rwalters31)\
**Replies:** 4\
**Last updated:** [September 12, 2023, 6:26pm UTC](https://discourse.julialang.org/t/error-when-using-unitful-and-montecarlomeasurements-with-differentialequations/103464 "2023-09-12T18:26:42Z")

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I am trying to use both Unitful and MonteCarloMeasurements with DifferentialEquations to better understand the impact of uncertainty on a second order ODE. Using either Untiful or MonteCarloMeasurements alone with Diffe…

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## [Using DiffEqFlux.jl for system identification with partially known system dynamics](https://discourse.julialang.org/t/using-diffeqflux-jl-for-system-identification-with-partially-known-system-dynamics/98197)

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**Author:** [@gsh19](https://discourse.julialang.org/u/gsh19)\
**Replies:** 8\
**Last updated:** [September 12, 2023, 5:51pm UTC](https://discourse.julialang.org/t/using-diffeqflux-jl-for-system-identification-with-partially-known-system-dynamics/98197 "2023-09-12T17:51:03Z")

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Hi everyone. I want to use the DiffEqFlux.jl package to model a system of interest. I have access to a dataset which contains measurements of all system states as well as the external control inputs that act on it. A fir…

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## [Scaling Independent Variables in Composed \`ODESystem\`s](https://discourse.julialang.org/t/scaling-independent-variables-in-composed-odesystem-s/103431)

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**Author:** [@cadojo](https://discourse.julialang.org/u/cadojo)\
**Replies:** 1\
**Last updated:** [September 12, 2023, 5:34pm UTC](https://discourse.julialang.org/t/scaling-independent-variables-in-composed-odesystem-s/103431 "2023-09-12T17:34:39Z")

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I have code that implements the nondimensional form of a simplified three-body problem. The length units are scaled by the distance between the two celestial bodies, a, and the time units are scaled by the orbital period…

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## [OptimizationOptimJL: single function returning objective and gradients](https://discourse.julialang.org/t/optimizationoptimjl-single-function-returning-objective-and-gradients/103704)

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**Author:** [@james3](https://discourse.julialang.org/u/james3)\
**Replies:** 2\
**Last updated:** [September 12, 2023, 5:33pm UTC](https://discourse.julialang.org/t/optimizationoptimjl-single-function-returning-objective-and-gradients/103704 "2023-09-12T17:33:12Z")

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I am using OptimizationOptimJL, and wish to supply my own gradients. There are many common calculations that are shared when evaluating the objective function, and the gradients, so I wish to have a single function that …

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## [Suggestion on what Julia version to install in my class](https://discourse.julialang.org/t/suggestion-on-what-julia-version-to-install-in-my-class/103788)

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**Author:** [@Andrea\_Pagnani](https://discourse.julialang.org/u/Andrea_Pagnani)\
**Replies:** 1\
**Last updated:** [September 12, 2023, 4:04pm UTC](https://discourse.julialang.org/t/suggestion-on-what-julia-version-to-install-in-my-class/103788 "2023-09-12T16:04:06Z")

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Hi there My Julia class on stochastic simulation methods (~ 50 students) is going to start the first weekend of October. As usual to minimize the noise I force everyone to install the same Julia version. Do you think th…

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## [Parameter distribution instead of range in GlobalSensitivity.jl](https://discourse.julialang.org/t/parameter-distribution-instead-of-range-in-globalsensitivity-jl/103755)

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**Author:** [@ANasc](https://discourse.julialang.org/u/ANasc)\
**Replies:** 2\
**Last updated:** [September 12, 2023, 4:00pm UTC](https://discourse.julialang.org/t/parameter-distribution-instead-of-range-in-globalsensitivity-jl/103755 "2023-09-12T16:00:20Z")

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I want to use the eFast method in GlobalSensitivity.jl but where parameters are input as distributions rather than ranges (param\_range asks for a vector of tuples). For example, I’d like to specify that a parameter be sa…

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## [CairoMakie Text Box](https://discourse.julialang.org/t/cairomakie-text-box/103783)

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**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 7\
**Last updated:** [September 12, 2023, 3:57pm UTC](https://discourse.julialang.org/t/cairomakie-text-box/103783 "2023-09-12T15:57:31Z")

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Hello, I could use some advice on how to achieve the following. I am generating a large number of simulation results and I’d like to put somewhere on the plot the parameters for each run. These do not need to be public…

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## [TimeTraveler.jl: a package for running julia code back in time](https://discourse.julialang.org/t/timetraveler-jl-a-package-for-running-julia-code-back-in-time/103478)

<div class="topic-metadata">

**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 15\
**Last updated:** [September 6, 2023, 3:59pm UTC](https://discourse.julialang.org/t/timetraveler-jl-a-package-for-running-julia-code-back-in-time/103478 "2023-09-06T15:59:55Z")

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I created a package to make it easier to work with world-ages and invoke in world. Basically it remembers the world age when any package was loaded. So that you can go and run your code against the defintions in the pa…

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## [Changing runtime precision. A question about FixedPointDecimals](https://discourse.julialang.org/t/changing-runtime-precision-a-question-about-fixedpointdecimals/103775)

<div class="topic-metadata">

**Author:** [@stefkuypers](https://discourse.julialang.org/u/stefkuypers)\
**Replies:** 5\
**Last updated:** [September 12, 2023, 1:07pm UTC](https://discourse.julialang.org/t/changing-runtime-precision-a-question-about-fixedpointdecimals/103775 "2023-09-12T13:07:15Z")

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I’m working on economic simulations and have used the following shortcut in my code: Currency = Fixed(4) Now I’ve run into a situation where I would like to change the precision in some cases. Redefining Currency befor…

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## [Anonymous functions, type stability](https://discourse.julialang.org/t/anonymous-functions-type-stability/103722)

<div class="topic-metadata">

**Author:** [@Leibniz](https://discourse.julialang.org/u/Leibniz)\
**Replies:** 11\
**Last updated:** [September 12, 2023, 12:25pm UTC](https://discourse.julialang.org/t/anonymous-functions-type-stability/103722 "2023-09-12T12:25:20Z")

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For my simulation, I want the user to easily specify a bunch of observable functions like observables = \[(x,p,force) -\> x\[1\], (x,p,force) -\> x\[2\], (x,p,force) -\> p'p\] that are then passed to the simulation and evaluate…

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## [Do we have differentiable sort in Julia?](https://discourse.julialang.org/t/do-we-have-differentiable-sort-in-julia/102713)

<div class="topic-metadata">

**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 14\
**Last updated:** [September 12, 2023, 11:47am UTC](https://discourse.julialang.org/t/do-we-have-differentiable-sort-in-julia/102713 "2023-09-12T11:47:04Z")

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Python has support for fast differentiable sorting which is an implementation of Blondel et al. (2020). I don’t think we have this in Julia at the moment? I have specific use case for ConformalPrediction.jl, but beyond …

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## [Why is 'interactive\_trajectory()' in 'DynamicalSystems.jl' package giving an error?](https://discourse.julialang.org/t/why-is-interactive-trajectory-in-dynamicalsystems-jl-package-giving-an-error/103778)

<div class="topic-metadata">

**Author:** [@Ashu](https://discourse.julialang.org/u/Ashu)\
**Replies:** 5\
**Last updated:** [September 12, 2023, 11:39am UTC](https://discourse.julialang.org/t/why-is-interactive-trajectory-in-dynamicalsystems-jl-package-giving-an-error/103778 "2023-09-12T11:39:36Z")

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Hello, The below given code was working few days back but now it is giving an error UndefVarError: \`interactive\_trajectory\` not defined. using DynamicalSystems using OrdinaryDiffEq using GLMakie function lorenz\_rule!(…

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## [Julia killed with Out of memory error on Linux -- runs fine on MacOS](https://discourse.julialang.org/t/julia-killed-with-out-of-memory-error-on-linux-runs-fine-on-macos/102193)

<div class="topic-metadata">

**Author:** [@nbrantut](https://discourse.julialang.org/u/nbrantut)\
**Replies:** 8\
**Last updated:** [September 12, 2023, 11:14am UTC](https://discourse.julialang.org/t/julia-killed-with-out-of-memory-error-on-linux-runs-fine-on-macos/102193 "2023-09-12T11:14:08Z")

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I have a piece of code that runs smoothly on MacOS but keeps crashing on my Linux (ubuntu 22) workstation. The code is quite involved and it is hard to write a meaningful minimal working example for it – it goes through…

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## [Is there a simple way to parallelize or distribute a function call that updates a local variable within a loop?](https://discourse.julialang.org/t/is-there-a-simple-way-to-parallelize-or-distribute-a-function-call-that-updates-a-local-variable-within-a-loop/103776)

<div class="topic-metadata">

**Author:** [@leoflotor](https://discourse.julialang.org/u/leoflotor)\
**Replies:** 1\
**Last updated:** [September 12, 2023, 11:08am UTC](https://discourse.julialang.org/t/is-there-a-simple-way-to-parallelize-or-distribute-a-function-call-that-updates-a-local-variable-within-a-loop/103776 "2023-09-12T11:08:35Z")

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Hi! I am working on implementing the hill-climbing algorithm to solve the one-dimensional bin packing problem but I got to a bottleneck. The function, which I called main for lack of a better name, repeats the same set …

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## ['ReversePropagation.jl' package](https://discourse.julialang.org/t/reversepropagation-jl-package/103779)

<div class="topic-metadata">

**Author:** [@Ashu](https://discourse.julialang.org/u/Ashu)\
**Replies:** 0\
**Last updated:** [September 12, 2023, 10:11am UTC](https://discourse.julialang.org/t/reversepropagation-jl-package/103779 "2023-09-12T10:11:31Z")

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Hello, I am trying to run an example code given for illustrating the working of ‘ReversePropagation.jl’. But it is neither working in ‘Pluto.jl’ notebook nor in 'VSCode. Could anyone please check if I am making any mist…

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## [Objective function value for all the points in the feasible region](https://discourse.julialang.org/t/objective-function-value-for-all-the-points-in-the-feasible-region/103772)

<div class="topic-metadata">

**Author:** [@Gagan\_Meena](https://discourse.julialang.org/u/Gagan_Meena)\
**Replies:** 9\
**Last updated:** [September 12, 2023, 9:37am UTC](https://discourse.julialang.org/t/objective-function-value-for-all-the-points-in-the-feasible-region/103772 "2023-09-12T09:37:57Z")

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How can we find out the objective function value for all the points in the feasible region for a complex optimization problem using JuMP? Is there a built-in method for doing so? If yes, then please specify the same. I…

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## [Annotated unitful axis in Plots](https://discourse.julialang.org/t/annotated-unitful-axis-in-plots/103732)

<div class="topic-metadata">

**Author:** [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Replies:** 4\
**Last updated:** [September 12, 2023, 8:44am UTC](https://discourse.julialang.org/t/annotated-unitful-axis-in-plots/103732 "2023-09-12T08:44:11Z")

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I’m plotting a function, which accepts a unitful argument. Now, if I want to add an x axis label p = plot!(;xlabel="particle radius") I get an error: ERROR: DimensionError: and μm are not dimensionally compatible. S…

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## [Running two different versions of Julia simultaneously](https://discourse.julialang.org/t/running-two-different-versions-of-julia-simultaneously/103758)

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**Author:** [@cnf](https://discourse.julialang.org/u/cnf)\
**Replies:** 9\
**Last updated:** [September 12, 2023, 8:39am UTC](https://discourse.julialang.org/t/running-two-different-versions-of-julia-simultaneously/103758 "2023-09-12T08:39:47Z")

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Hi, I am using julia1.5.2 (on a linux machine) and noticed that it creates a directory .julia under my home directory and installs downloaded packages there. I have installed julia1.6.7 in a different directory to j…

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## [How do libraries compiled by PackageCompiler.jl interact with Preferences.jl?](https://discourse.julialang.org/t/how-do-libraries-compiled-by-packagecompiler-jl-interact-with-preferences-jl/103479)

<div class="topic-metadata">

**Author:** [@sloede](https://discourse.julialang.org/u/sloede)\
**Replies:** 4\
**Last updated:** [September 12, 2023, 7:26am UTC](https://discourse.julialang.org/t/how-do-libraries-compiled-by-packagecompiler-jl-interact-with-preferences-jl/103479 "2023-09-12T07:26:58Z")

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How do Preferences.jl work together libraries created by PackageCompiler.jl? For example, where do I have to put the Preferences.jl file such that the choice of system MPI library with MPI.jl is respected while compilin…

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## [Error in running julia file](https://discourse.julialang.org/t/error-in-running-julia-file/103765)

<div class="topic-metadata">

**Author:** [@ABHIJITH\_S](https://discourse.julialang.org/u/ABHIJITH_S)\
**Replies:** 2\
**Last updated:** [September 12, 2023, 6:47am UTC](https://discourse.julialang.org/t/error-in-running-julia-file/103765 "2023-09-12T06:47:53Z")

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Encountered a problem while running my first julia file. How do i open the file from the particular directory.

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## [Add Infiltrator.jl to Base?](https://discourse.julialang.org/t/add-infiltrator-jl-to-base/77995)

<div class="topic-metadata">

**Author:** [@CameronBieganek](https://discourse.julialang.org/u/CameronBieganek)\
**Replies:** 15\
**Last updated:** [September 12, 2023, 5:53am UTC](https://discourse.julialang.org/t/add-infiltrator-jl-to-base/77995 "2023-09-12T05:53:14Z")

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I know that folks often ask to add things to Base here on Discourse, and that usually the correct answer is “no”, but I think there’s a very good reason to add Infiltrator.jl to Base Julia. Let me explain. Infiltrator.j…

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## [Day 2 and 3 of JuliaCon 2023 Talks Available on YouTube](https://discourse.julialang.org/t/day-2-and-3-of-juliacon-2023-talks-available-on-youtube/103761)

<div class="topic-metadata">

**Author:** [@ranjan](https://discourse.julialang.org/u/ranjan)\
**Replies:** 2\
**Last updated:** [September 12, 2023, 5:04am UTC](https://discourse.julialang.org/t/day-2-and-3-of-juliacon-2023-talks-available-on-youtube/103761 "2023-09-12T05:04:55Z")

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Hello, The rest of all the JuliaCon talks should uploaded to YouTube and released now. Enjoy! Get in touch with us for any discrepancies. Best, Ranjan Anantharaman Executive Chair, JuliaCon 2023

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## [How to send a response at arbitrary code points in Genie route?](https://discourse.julialang.org/t/how-to-send-a-response-at-arbitrary-code-points-in-genie-route/103766)

<div class="topic-metadata">

**Author:** [@John\_Boik](https://discourse.julialang.org/u/John_Boik)\
**Replies:** 2\
**Last updated:** [September 12, 2023, 3:44am UTC](https://discourse.julialang.org/t/how-to-send-a-response-at-arbitrary-code-points-in-genie-route/103766 "2023-09-12T03:44:35Z")

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I’m trying to use Genie.jl for a fairly simple REST API. Given a route, I would like to be able to send a response at arbitrary code points, depending on conditions. For example, if an exception is raised part way throug…

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## [Using JuMP variables and expressions in conditional statements](https://discourse.julialang.org/t/using-jump-variables-and-expressions-in-conditional-statements/103414)

<div class="topic-metadata">

**Author:** [@AshwinSandeep1](https://discourse.julialang.org/u/AshwinSandeep1)\
**Replies:** 27\
**Last updated:** [September 12, 2023, 3:35am UTC](https://discourse.julialang.org/t/using-jump-variables-and-expressions-in-conditional-statements/103414 "2023-09-12T03:35:52Z")

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Hi all I am trying to construct conditioinal statements using the @NLexpression macro but it seems expressions and even variables can’t be used in this context. Is there a way to do this? My aim is to do the following: …

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## [JuliaCon 2023 Workshop Recordings are Available](https://discourse.julialang.org/t/juliacon-2023-workshop-recordings-are-available/103206)

<div class="topic-metadata">

**Author:** [@ranjan](https://discourse.julialang.org/u/ranjan)\
**Replies:** 8\
**Last updated:** [September 12, 2023, 12:57am UTC](https://discourse.julialang.org/t/juliacon-2023-workshop-recordings-are-available/103206 "2023-09-12T00:57:27Z")

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Hi everyone, The JuliaCon 2023 Workshop recordings are now available: https://www.youtube.com/watch?v=wmCra6roZn4&list=PLP8iPy9hna6T7PRe2sucSonFsrrH-oEZC Stay tuned for the other recordings from the conference! Best, …

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