# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1710

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

**Page:** 1711

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## [Problems with using both unregistered and registered modules](https://discourse.julialang.org/t/problems-with-using-both-unregistered-and-registered-modules/41851)

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**Author:** [@Jasper\_Hall](https://discourse.julialang.org/u/Jasper_Hall)\
**Replies:** 2\
**Last updated:** [June 22, 2020, 12:48pm UTC](https://discourse.julialang.org/t/problems-with-using-both-unregistered-and-registered-modules/41851 "2020-06-22T12:48:09Z")

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The actual behaviour of using/include doesn’t seem to match the documentation, so clearly I do ot understand it. Here is a MWE to explain. In a clean environment (new empty folder and fresh REPL) create the following t…

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## [Genetic Algorithms with julia](https://discourse.julialang.org/t/genetic-algorithms-with-julia/41844)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 3\
**Last updated:** [June 22, 2020, 12:03pm UTC](https://discourse.julialang.org/t/genetic-algorithms-with-julia/41844 "2020-06-22T12:03:12Z")

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hello all, I wish to solve a multi objective optimization problem with GA also I have never worked with GA before and I want to learn more about what are the packages that I can find useful? What are the pros of cons of…

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## [Activating an environment that is already active](https://discourse.julialang.org/t/activating-an-environment-that-is-already-active/41852)

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**Author:** [@bernhard](https://discourse.julialang.org/u/bernhard)\
**Replies:** 0\
**Last updated:** [June 22, 2020, 11:28am UTC](https://discourse.julialang.org/t/activating-an-environment-that-is-already-active/41852 "2020-06-22T11:28:54Z")

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I was wondering why activating the environment that is already active takes a fair bit of time. See example. Wouldn’t it make sense to check if the environment is already active and then ‘do nothing’? Or does the activ…

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## [Dynamically mutate type parameter](https://discourse.julialang.org/t/dynamically-mutate-type-parameter/41811)

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**Author:** [@D\_A](https://discourse.julialang.org/u/D_A)\
**Replies:** 6\
**Last updated:** [June 22, 2020, 10:31am UTC](https://discourse.julialang.org/t/dynamically-mutate-type-parameter/41811 "2020-06-22T10:31:20Z")

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Hello, I would like to know if there is a way to mutate the type parameter of an object during runtime (dynamically). MWE: mutable struct Text{Format\<:Union{Integer, AbstractString}} # For MWE, in reality it is like …

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## [Can't load CuArrays](https://discourse.julialang.org/t/cant-load-cuarrays/31214)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 17\
**Last updated:** [June 22, 2020, 10:42am UTC](https://discourse.julialang.org/t/cant-load-cuarrays/31214 "2020-06-22T10:42:08Z")

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Hi, this is ubuntu 18.04 (I think). I have installed julia and the sysop has installed CUDA, but I get using CuArrays \[ Info: CUDAdrv.jl failed to initialize, GPU functionality unavailable (set JULIA\_CUDA\_SILENT or JU…

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## [How to document this](https://discourse.julialang.org/t/how-to-document-this/39217)

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**Author:** [@roble](https://discourse.julialang.org/u/roble)\
**Replies:** 6\
**Last updated:** [June 22, 2020, 9:57am UTC](https://discourse.julialang.org/t/how-to-document-this/39217 "2020-06-22T09:57:58Z")

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I would like to add the documentation of a function to the official documentation page. It should have been a one liner to do this, but now I am somehow stuck… There is already a docstring available. However, I need to …

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## [Parallel optimization/Genetic algorithm/Genetic programming](https://discourse.julialang.org/t/parallel-optimization-genetic-algorithm-genetic-programming/36805)

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**Author:** [@Neurovium](https://discourse.julialang.org/u/Neurovium)\
**Replies:** 4\
**Last updated:** [June 21, 2020, 10:18pm UTC](https://discourse.julialang.org/t/parallel-optimization-genetic-algorithm-genetic-programming/36805 "2020-06-21T22:18:41Z")

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Hi, I was planning to fully port a project to Julia. Checking the evolutionary optimization packages in Julia, I came across a few. It seems that the most mature one, Wallace (GitHub - ChrisTimperley/Wallace.jl: High-pe…

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## [Pmap batch example](https://discourse.julialang.org/t/pmap-batch-example/41849)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 0\
**Last updated:** [June 22, 2020, 9:48am UTC](https://discourse.julialang.org/t/pmap-batch-example/41849 "2020-06-22T09:48:40Z")

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Hi, can someone provide me with a good example of using the batch\_size parameter of the pmap function? I found Parallelism - Understanding pmap and the batch\_size parameter which indicates a performance increase by incr…

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## [Why Bool is a Number?](https://discourse.julialang.org/t/why-bool-is-a-number/41845)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 2\
**Last updated:** [June 22, 2020, 9:13am UTC](https://discourse.julialang.org/t/why-bool-is-a-number/41845 "2020-06-22T09:13:18Z")

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just came across true + 3 == 4, and also true isa Number What is the reason why a boolean gets converted to Int automatically?

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## [Reducing time](https://discourse.julialang.org/t/reducing-time/41721)

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**Author:** [@Avec](https://discourse.julialang.org/u/Avec)\
**Replies:** 4\
**Last updated:** [June 22, 2020, 8:41am UTC](https://discourse.julialang.org/t/reducing-time/41721 "2020-06-22T08:41:07Z")

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Hi everyone, I am trying to get multiplication of a lot of pretty big sparse matrices, I figured out that their special structure allows me to simplify the multiplication into just a computing rows and columns for resul…

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## [Plots small trouble](https://discourse.julialang.org/t/plots-small-trouble/41843)

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**Author:** [@mitsuruk](https://discourse.julialang.org/u/mitsuruk)\
**Replies:** 2\
**Last updated:** [June 22, 2020, 7:26am UTC](https://discourse.julialang.org/t/plots-small-trouble/41843 "2020-06-22T07:26:12Z")

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Hi, I am learning Julialang on Mac and Windwos. I have a small trouble in Plots.jl using Plots, Random plot(rand(50)) Yes, I can get target graph perfect. however, using Plots, Random plot(rand(50)) println(“test…

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## [Triangulation plot triangle plot](https://discourse.julialang.org/t/triangulation-plot-triangle-plot/41665)

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**Author:** [@hyacykcharel](https://discourse.julialang.org/u/hyacykcharel)\
**Replies:** 2\
**Last updated:** [June 22, 2020, 6:01am UTC](https://discourse.julialang.org/t/triangulation-plot-triangle-plot/41665 "2020-06-22T06:01:52Z")

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Im trying to create a triangulation (triangle Plot) plot and dont even know how to do ist can someone help please? using VoronoiDelaunay using GeometricalPredicates using DataFrames, Plots pyplot() #mit unterer Auss…

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## [Round base parameter julia behaviour](https://discourse.julialang.org/t/round-base-parameter-julia-behaviour/41831)

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**Author:** [@cindRoberta](https://discourse.julialang.org/u/cindRoberta)\
**Replies:** 1\
**Last updated:** [June 22, 2020, 4:33am UTC](https://discourse.julialang.org/t/round-base-parameter-julia-behaviour/41831 "2020-06-22T04:33:35Z")

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can someone explain me how the base parameter works on round function: Mathematics · The Julia Language why round(1456.67884565647, digits=5, base=2) results 1456.6875 for example thanks

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## [Evaluate the value of polyvars in SOSModel](https://discourse.julialang.org/t/evaluate-the-value-of-polyvars-in-sosmodel/41836)

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**Author:** [@aliceee](https://discourse.julialang.org/u/aliceee)\
**Replies:** 0\
**Last updated:** [June 22, 2020, 3:21am UTC](https://discourse.julialang.org/t/evaluate-the-value-of-polyvars-in-sosmodel/41836 "2020-06-22T03:21:19Z")

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Hi, I have a question about how to evaluate the values of polyvars in SOSModel. In the following example, there is only one regular JuMP decision variable γ and γ can be evaluated by value(γ). But when I want to check th…

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## [Optimizing a very expensive function evaluated in C++](https://discourse.julialang.org/t/optimizing-a-very-expensive-function-evaluated-in-c/41312)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 15\
**Last updated:** [June 22, 2020, 2:40am UTC](https://discourse.julialang.org/t/optimizing-a-very-expensive-function-evaluated-in-c/41312 "2020-06-22T02:40:26Z")

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I am moving to Julia. I have a function which is implemented in C++ and currently have no time to migrate it to Julia. It depends on lots of parameters. It typically takes 1 hour - 1 week to compute a single value of thi…

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## [Version dependent segfault using ccall](https://discourse.julialang.org/t/version-dependent-segfault-using-ccall/41795)

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**Author:** [@Matt\_Davis](https://discourse.julialang.org/u/Matt_Davis)\
**Replies:** 2\
**Last updated:** [June 21, 2020, 10:55pm UTC](https://discourse.julialang.org/t/version-dependent-segfault-using-ccall/41795 "2020-06-21T22:55:58Z")

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I am running into segmentation faults and/or std::bad\_alloc errors when using the TBLIS C interface. However, the error does not appear on 1.4.x, either built from source or from binaries, but does occur on 1.5.0-beta1 a…

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## [Julia v1.5.0-beta1 is now available](https://discourse.julialang.org/t/julia-v1-5-0-beta1-is-now-available/40381)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 19\
**Last updated:** [June 21, 2020, 9:55pm UTC](https://discourse.julialang.org/t/julia-v1-5-0-beta1-is-now-available/40381 "2020-06-21T21:55:26Z")

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The Julia developers are pleased to announce that Julia v1.5.0 is now in beta, and binaries for the first beta version, 1.5.0-beta1, are available now. You can get them at Download Julia in the “upcoming release” section…

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## [\[ANN\] OptimKit.jl – A blissfully ignorant Julia package for gradient optimization](https://discourse.julialang.org/t/ann-optimkit-jl-a-blissfully-ignorant-julia-package-for-gradient-optimization/41063)

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**Author:** [@juthohaegeman](https://discourse.julialang.org/u/juthohaegeman)\
**Replies:** 8\
**Last updated:** [June 21, 2020, 8:50pm UTC](https://discourse.julialang.org/t/ann-optimkit-jl-a-blissfully-ignorant-julia-package-for-gradient-optimization/41063 "2020-06-21T20:50:32Z")

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OptimKit.jl v0.1.0 was just registered overnight. It is a package for gradient based optimization, and currently supports gradient descent, conjugate gradient and LBFGS. Why did I create another package for this, rather…

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## [ANN: JuliaHub — explore, run, scale](https://discourse.julialang.org/t/ann-juliahub-explore-run-scale/41135)

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**Author:** [@StefanKarpinski](https://discourse.julialang.org/u/StefanKarpinski)\
**Replies:** 34\
**Last updated:** [June 21, 2020, 6:58pm UTC](https://discourse.julialang.org/t/ann-juliahub-explore-run-scale/41135 "2020-06-21T18:58:46Z")

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I’m pleased to announce JuliaHub, a service offered by Julia Computing for exploring the Julia ecosystem, running your Julia code easily in the cloud and scaling it to more and larger machines. The current iteration of t…

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## [Raise the power of polynomials in polyjump](https://discourse.julialang.org/t/raise-the-power-of-polynomials-in-polyjump/41818)

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**Author:** [@aliceee](https://discourse.julialang.org/u/aliceee)\
**Replies:** 1\
**Last updated:** [June 21, 2020, 6:24pm UTC](https://discourse.julialang.org/t/raise-the-power-of-polynomials-in-polyjump/41818 "2020-06-21T18:24:39Z")

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Hi, I’m writing an SOS model using PolyJump: @polyvar B\[1:k,1:pp+1\] @polyvar c0 k = transpose(p\_train\_var)\*vec(B\*vcat(x\_train0\[1,:\],1))\*gamma + c0 when I try to raise the power of polynomial k, by doing this: k^2 I …

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## [Update on latency and the typocalypse](https://discourse.julialang.org/t/update-on-latency-and-the-typocalypse/41753)

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**Author:** [@jeff.bezanson](https://discourse.julialang.org/u/jeff.bezanson)\
**Replies:** 11\
**Last updated:** [June 21, 2020, 3:24pm UTC](https://discourse.julialang.org/t/update-on-latency-and-the-typocalypse/41753 "2020-06-21T15:24:35Z")

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In the last few weeks we’ve managed to merge several latency-related PRs. Let’s take a moment to reflect on where we are. These are times for display(plot(rand(10))) (first time) on my system: v1.4: 19.8 seconds v1.5: …

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## [\[ANN\] PkgPage.jl build a nice webpage for your package in minutes](https://discourse.julialang.org/t/ann-pkgpage-jl-build-a-nice-webpage-for-your-package-in-minutes/41391)

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**Author:** [@tlienart](https://discourse.julialang.org/u/tlienart)\
**Replies:** 20\
**Last updated:** [June 21, 2020, 12:48pm UTC](https://discourse.julialang.org/t/ann-pkgpage-jl-build-a-nice-webpage-for-your-package-in-minutes/41391 "2020-06-21T12:48:48Z")

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Hello! A while back @viralbshah asked me whether it was possible to have a way to create a single-page webpage for packages “really easily” with Franklin, well, here it is. @anon37204545 and I are happy to announce P…

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## [Change the label in plot](https://discourse.julialang.org/t/change-the-label-in-plot/41808)

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**Author:** [@m.lavaiyan](https://discourse.julialang.org/u/m.lavaiyan)\
**Replies:** 6\
**Last updated:** [June 21, 2020, 12:30pm UTC](https://discourse.julialang.org/t/change-the-label-in-plot/41808 "2020-06-21T12:30:37Z")

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Hello, I am looking for an efficient way to change the label from to something like operation1 operation2 operation3 … but not with the manual labeling as bellow. Because for a more number of operations it see…

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## [Asynchronous Makie](https://discourse.julialang.org/t/asynchronous-makie/27127)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 17\
**Last updated:** [June 21, 2020, 11:54am UTC](https://discourse.julialang.org/t/asynchronous-makie/27127 "2020-06-21T11:54:11Z")

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Hi, I wrote a toy CFD solver computing pressure and velocity fields for successive timesteps and I use Makie for plotting the result and store a movie. Although I only plot new frames every 200 timesteps, the plotting …

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## [Free "dev"-ed packages](https://discourse.julialang.org/t/free-dev-ed-packages/41806)

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**Author:** [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Replies:** 6\
**Last updated:** [June 21, 2020, 11:32am UTC](https://discourse.julialang.org/t/free-dev-ed-packages/41806 "2020-06-21T11:32:13Z")

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Suppose I work on several projects that are located in ~/A/, ~/B/, ~/C/, where each folder is a julia environment and has a Project.toml. There are several my packages that are used by all these projects, and the packag…

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## [Docker and shared library loading problem](https://discourse.julialang.org/t/docker-and-shared-library-loading-problem/41807)

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**Author:** [@pauljurczak](https://discourse.julialang.org/u/pauljurczak)\
**Replies:** 4\
**Last updated:** [June 21, 2020, 10:14am UTC](https://discourse.julialang.org/t/docker-and-shared-library-loading-problem/41807 "2020-06-21T10:14:53Z")

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I’m running Julia in Docker container built from ubuntu image with Julia executable on top. Everything runs fine except of loading shared library. Here is the log: paul@desktop:~$ docker run -it julia root@1c3ef9183e75:…

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## [Write a smoother for AlgebraicMultigrid](https://discourse.julialang.org/t/write-a-smoother-for-algebraicmultigrid/41790)

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**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 4\
**Last updated:** [June 21, 2020, 9:07am UTC](https://discourse.julialang.org/t/write-a-smoother-for-algebraicmultigrid/41790 "2020-06-21T09:07:32Z")

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I’m playing around with https://github.com/JuliaLinearAlgebra/AlgebraicMultigrid.jl and would like to write my own smoother, or even just use the Jacobi smoother which is in the package, but not the default. Unfortunatel…

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## [Is the Hessian used in non linear JuMP?](https://discourse.julialang.org/t/is-the-hessian-used-in-non-linear-jump/41804)

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**Author:** [@raphaelchinchilla](https://discourse.julialang.org/u/raphaelchinchilla)\
**Replies:** 3\
**Last updated:** [June 21, 2020, 6:18am UTC](https://discourse.julialang.org/t/is-the-hessian-used-in-non-linear-jump/41804 "2020-06-21T06:18:14Z")

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For non linear optimization, JuMP allows user to create their own function and either use autodiff or specify the derivatives manually: https://jump.dev/JuMP.jl/v0.21.3/nlp/#User-defined-Functions-1 However the documen…

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## [ANN: IsApprox.jl Interface for approximate and exact equality](https://discourse.julialang.org/t/ann-isapprox-jl-interface-for-approximate-and-exact-equality/41786)

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**Author:** [@jlapeyre](https://discourse.julialang.org/u/jlapeyre)\
**Replies:** 5\
**Last updated:** [June 21, 2020, 5:42am UTC](https://discourse.julialang.org/t/ann-isapprox-jl-interface-for-approximate-and-exact-equality/41786 "2020-06-21T05:42:27Z")

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I posted about a preliminary version a few months ago. The package is now registered. From the README: For some applications, LinearAlgebra wants to know if a matrix is exactly Hermitian. Quantum information packages, …

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## [Accessing samples in MCMCChains](https://discourse.julialang.org/t/accessing-samples-in-mcmcchains/41800)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 2\
**Last updated:** [June 21, 2020, 1:38am UTC](https://discourse.julialang.org/t/accessing-samples-in-mcmcchains/41800 "2020-06-21T01:38:31Z")

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I’ve got Turing to sample my model… sort-of. It’s stuck and I’m trying to figure out what the samples look like. The model is a fit of a time-series. So there are parameters that are vectors like Ac which is a 3 vector …

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