# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1838

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

**Page:** 1839

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## [How to get Julia work for the first time?](https://discourse.julialang.org/t/how-to-get-julia-work-for-the-first-time/33801)

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**Author:** [@DShiu](https://discourse.julialang.org/u/DShiu)\
**Replies:** 12\
**Last updated:** [January 26, 2020, 6:11pm UTC](https://discourse.julialang.org/t/how-to-get-julia-work-for-the-first-time/33801 "2020-01-26T18:11:13Z")

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I am trying to learn Julia by following steps in Quantecon.com: https://julia.quantecon.org/getting\_started\_julia/julia\_environment.html I followed the basic command for Plots, but got an error message. I searched for …

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## [Anonymous nested struct](https://discourse.julialang.org/t/anonymous-nested-struct/33723)

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**Author:** [@Sijun](https://discourse.julialang.org/u/Sijun)\
**Replies:** 12\
**Last updated:** [January 26, 2020, 5:53pm UTC](https://discourse.julialang.org/t/anonymous-nested-struct/33723 "2020-01-26T17:53:06Z")

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By “Anonymous nested struct” I mean defining a struct that has another struct with no name inside: struct ABC name::String data::struct raw::Vector{Float64} value::Int end end I wonder such …

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## [Why is \`\]dev\` downgrading my package?](https://discourse.julialang.org/t/why-is-dev-downgrading-my-package/33748)

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**Author:** [@matthieu](https://discourse.julialang.org/u/matthieu)\
**Replies:** 3\
**Last updated:** [January 26, 2020, 4:39pm UTC](https://discourse.julialang.org/t/why-is-dev-downgrading-my-package/33748 "2020-01-26T16:39:31Z")

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I want to \]dev the latest version of a package released on General. When I \]add the package, the latest version gets downloaded. However, when \]dev it, the package gets downgraded to a previous version. What is happeni…

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## [Dispach on parametric types](https://discourse.julialang.org/t/dispach-on-parametric-types/33807)

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**Author:** [@Maikon\_Araujo](https://discourse.julialang.org/u/Maikon_Araujo)\
**Replies:** 3\
**Last updated:** [January 26, 2020, 4:18pm UTC](https://discourse.julialang.org/t/dispach-on-parametric-types/33807 "2020-01-26T16:18:38Z")

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Is it possible to dispatch on parametric types? Something like that: function f(x::F{Int}) where F end Dispatch on types parameterized on ints. Thank you.

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## [The Julia project will participate in "Google Code In" 2019](https://discourse.julialang.org/t/the-julia-project-will-participate-in-google-code-in-2019/30466)

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**Author:** [@avik](https://discourse.julialang.org/u/avik)\
**Replies:** 37\
**Last updated:** [January 25, 2020, 5:09pm UTC](https://discourse.julialang.org/t/the-julia-project-will-participate-in-google-code-in-2019/30466 "2020-01-25T17:09:27Z")

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Hi All, I am pleased to announce that our project has been accepted to participate in the Google Code In program. This is a contest for 13-17 year olds, introducing them to the world of open source development. The pro…

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## [Registry: support resolving dependencies also when Versions.toml file is empty by using master](https://discourse.julialang.org/t/registry-support-resolving-dependencies-also-when-versions-toml-file-is-empty-by-using-master/33446)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 4\
**Last updated:** [January 25, 2020, 9:25pm UTC](https://discourse.julialang.org/t/registry-support-resolving-dependencies-also-when-versions-toml-file-is-empty-by-using-master/33446 "2020-01-25T21:25:23Z")

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this is a follow up idea on Can Versions.toml point to git branch instead of fixed git commit? concretely does the current registry already work with an empty Versions.toml file in the restricted situation of just addin…

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## [JuliaDB parsing unix epoch field](https://discourse.julialang.org/t/juliadb-parsing-unix-epoch-field/33805)

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**Author:** [@toms](https://discourse.julialang.org/u/toms)\
**Replies:** 0\
**Last updated:** [January 26, 2020, 10:07am UTC](https://discourse.julialang.org/t/juliadb-parsing-unix-epoch-field/33805 "2020-01-26T10:07:36Z")

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Hello Julia community, I’m trying to loadndsparse a csv file with a unix epoch field and turn it into a Julia DateTime . What would be the correct way to do this in Julia? I’ve tried using the colparsers option but am…

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## [Remove blank lines in REPL](https://discourse.julialang.org/t/remove-blank-lines-in-repl/10996)

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**Author:** [@r4f](https://discourse.julialang.org/u/r4f)\
**Replies:** 2\
**Last updated:** [January 26, 2020, 9:34am UTC](https://discourse.julialang.org/t/remove-blank-lines-in-repl/10996 "2020-01-26T09:34:11Z")

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Does anybody know a way to get rid of the blank line in the REPL which appears everytime before an input prompt (except for example when using print(sth))? I like to use julia as a quick calculator-tool from the termina…

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## [Design pattern for correctly overwriting abstract methods (interface methods)](https://discourse.julialang.org/t/design-pattern-for-correctly-overwriting-abstract-methods-interface-methods/33778)

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**Author:** [@essenciary](https://discourse.julialang.org/u/essenciary)\
**Replies:** 6\
**Last updated:** [January 26, 2020, 8:42am UTC](https://discourse.julialang.org/t/design-pattern-for-correctly-overwriting-abstract-methods-interface-methods/33778 "2020-01-26T08:42:22Z")

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I have something like the following situation: module Cache export cache function cache(data) throw(NotImplementedException()) end end module FileCache import Cache function Cache.cache(data) # do cache stuff …

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## [Pyjulia getting around Python executable being it is statically linked to libpython](https://discourse.julialang.org/t/pyjulia-getting-around-python-executable-being-it-is-statically-linked-to-libpython/33797)

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**Author:** [@marinarrd](https://discourse.julialang.org/u/marinarrd)\
**Replies:** 0\
**Last updated:** [January 26, 2020, 3:01am UTC](https://discourse.julialang.org/t/pyjulia-getting-around-python-executable-being-it-is-statically-linked-to-libpython/33797 "2020-01-26T03:01:50Z")

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I have run the command otool -L /usr/bin/python | grep libpython and it returns nothing. I am a little confused about the work arounds suggested in the docs. https://pyjulia.readthedocs.io/en/latest/troubleshooting.h…

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## [Multiplication of submatrices problem](https://discourse.julialang.org/t/multiplication-of-submatrices-problem/33785)

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**Author:** [@ea42gh](https://discourse.julialang.org/u/ea42gh)\
**Replies:** 8\
**Last updated:** [January 26, 2020, 2:03am UTC](https://discourse.julialang.org/t/multiplication-of-submatrices-problem/33785 "2020-01-26T02:03:22Z")

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I was trying to transcribe the algorithm in the appendix of geninv function pseudoinverse(G) # need to restrict types here m,n = size(G) if m \< n transpose=true A=G\*G' n=m else …

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## [Pre-Ordered Book: Mastering Julia 1.0](https://discourse.julialang.org/t/pre-ordered-book-mastering-julia-1-0/33792)

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**Author:** [@dburch](https://discourse.julialang.org/u/dburch)\
**Replies:** 1\
**Last updated:** [January 26, 2020, 1:38am UTC](https://discourse.julialang.org/t/pre-ordered-book-mastering-julia-1-0/33792 "2020-01-26T01:38:59Z")

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I pre-ordered the book Mastering Julia 1.0: Solve complex data processing problems with Julia by Malcolm Sherrington (ordered from Amazon). I got a cancellation notice that my order was cancelled, because Amazon wouldn’t…

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## [The second edition of my book "Julia Programming for Operations Research"](https://discourse.julialang.org/t/the-second-edition-of-my-book-julia-programming-for-operations-research/21262)

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**Author:** [@chkwon](https://discourse.julialang.org/u/chkwon)\
**Replies:** 8\
**Last updated:** [January 26, 2020, 1:07am UTC](https://discourse.julialang.org/t/the-second-edition-of-my-book-julia-programming-for-operations-research/21262 "2020-01-26T01:07:55Z")

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Dear friends, Long waited JuMP v0.19 is now released and I updated my book accordingly. Here is the second edition of my book “Julia Programming for Operations Research” available online. Ten free copies for discourse …

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## [FFT + Measurements](https://discourse.julialang.org/t/fft-measurements/33791)

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**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 1\
**Last updated:** [January 26, 2020, 12:31am UTC](https://discourse.julialang.org/t/fft-measurements/33791 "2020-01-26T00:31:39Z")

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I thought it would be cool if I could calculate the FFT using uncertain data, so I tried using Measurements together with FFTW. I did not get it working. Instead, I wrote a simple FT function which can be used with Meas…

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## [Pitfalls for beginners and the value of convenience and hand-holding](https://discourse.julialang.org/t/pitfalls-for-beginners-and-the-value-of-convenience-and-hand-holding/33441)

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**Author:** [@jules](https://discourse.julialang.org/u/jules)\
**Replies:** 40\
**Last updated:** [January 25, 2020, 10:30pm UTC](https://discourse.julialang.org/t/pitfalls-for-beginners-and-the-value-of-convenience-and-hand-holding/33441 "2020-01-25T22:30:04Z")

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I am soon going to try and give a Julia tutorial in my research group (cognitive neuroscience). It will be for people mostly acquainted with Matlab and R, maybe a few people with some Python experience. I’m therefore thi…

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## [Is there a mechanism in Julia to load modules on demand?](https://discourse.julialang.org/t/is-there-a-mechanism-in-julia-to-load-modules-on-demand/33784)

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**Author:** [@nxtruong](https://discourse.julialang.org/u/nxtruong)\
**Replies:** 6\
**Last updated:** [January 25, 2020, 6:56pm UTC](https://discourse.julialang.org/t/is-there-a-mechanism-in-julia-to-load-modules-on-demand/33784 "2020-01-25T18:56:21Z")

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As I understand, using and import statements must be at the top level. However, sometimes I just want to import a module on-demand, in a function that uses that module. For example, a large module X contains both functio…

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## [Catching the signal SIGWINCH in Julia](https://discourse.julialang.org/t/catching-the-signal-sigwinch-in-julia/33782)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 0\
**Last updated:** [January 25, 2020, 2:29pm UTC](https://discourse.julialang.org/t/catching-the-signal-sigwinch-in-julia/33782 "2020-01-25T14:29:59Z")

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Hi! I am trying to develop a package to create text-based user interfaces in Julia: TextUserInterfaces.jl. However, I need a way to check if the terminal has been resized so I can automatically update the interface. I n…

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## [Automatic Differentiation of arbitrary-order derivatives](https://discourse.julialang.org/t/automatic-differentiation-of-arbitrary-order-derivatives/33774)

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**Author:** [@GregVernon](https://discourse.julialang.org/u/GregVernon)\
**Replies:** 3\
**Last updated:** [January 25, 2020, 9:36am UTC](https://discourse.julialang.org/t/automatic-differentiation-of-arbitrary-order-derivatives/33774 "2020-01-25T09:36:16Z")

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I was wondering if it is possible to programmatically do higher-order automatic differentiation using ForwardDiff (or ReverseDiff). Here’s a MWE that shows a non-optimal way to get specific derivatives (hard-coded): im…

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## [Interactive Vegalite in Jupyter lab](https://discourse.julialang.org/t/interactive-vegalite-in-jupyter-lab/33771)

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**Author:** [@darwindarak](https://discourse.julialang.org/u/darwindarak)\
**Replies:** 2\
**Last updated:** [January 25, 2020, 2:48am UTC](https://discourse.julialang.org/t/interactive-vegalite-in-jupyter-lab/33771 "2020-01-25T02:48:52Z")

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Hi all, I’m having some problems getting interactive plots (simple tooltip) to show up inline in a notebook. The docs say that Jupyter lab should already have the capability, but I can only get it to work if I save the …

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## [Blessed Way for model Serialization](https://discourse.julialang.org/t/blessed-way-for-model-serialization/33768)

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**Author:** [@anoojpatel](https://discourse.julialang.org/u/anoojpatel)\
**Replies:** 0\
**Last updated:** [January 24, 2020, 10:02pm UTC](https://discourse.julialang.org/t/blessed-way-for-model-serialization/33768 "2020-01-24T22:02:43Z")

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I was wondering/looking for clarification on what the best way to serialize models or model weights w.r.t. to necessary non-differentiated against parameters (Batch Norm). I find that directly serializing model object cr…

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## [Environments inheriting remote dependencies](https://discourse.julialang.org/t/environments-inheriting-remote-dependencies/33752)

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**Author:** [@Peter\_Adelman](https://discourse.julialang.org/u/Peter_Adelman)\
**Replies:** 2\
**Last updated:** [January 24, 2020, 8:38pm UTC](https://discourse.julialang.org/t/environments-inheriting-remote-dependencies/33752 "2020-01-24T20:38:47Z")

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If I \]add a github version of a package that I am developing (not the gospel from JuliaRegistries) to a local package (MyPkg), it successfully downloads and uses it for that environment, correctly making Manifest.toml. H…

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## [Swizzling the super type of a foreign Julia type (or: how evil must I be?)](https://discourse.julialang.org/t/swizzling-the-super-type-of-a-foreign-julia-type-or-how-evil-must-i-be/33733)

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**Author:** [@fingolfin](https://discourse.julialang.org/u/fingolfin)\
**Replies:** 2\
**Last updated:** [January 24, 2020, 8:48pm UTC](https://discourse.julialang.org/t/swizzling-the-super-type-of-a-foreign-julia-type-or-how-evil-must-i-be/33733 "2020-01-24T20:48:17Z")

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Hi, so this is a super low-level question for the people who know about or are working on the Julia kernel. tl;dr I need/want to create a “foreign type” MPtr (via the C function jl\_new\_foreign\_type) with no super type,…

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## [Cannot get Gtk.jl onto Repl.it](https://discourse.julialang.org/t/cannot-get-gtk-jl-onto-repl-it/33664)

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**Author:** [@aschimmichanga](https://discourse.julialang.org/u/aschimmichanga)\
**Replies:** 5\
**Last updated:** [January 24, 2020, 7:30pm UTC](https://discourse.julialang.org/t/cannot-get-gtk-jl-onto-repl-it/33664 "2020-01-24T19:30:20Z")

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Why doesn’t Repl.it’s Julia REPL recognize the GTK.jl package? using Pkg Pkg.add("Gtk") using Gtk gives an error

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## [Adding package to JuliaText listing](https://discourse.julialang.org/t/adding-package-to-juliatext-listing/33716)

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**Author:** [@ericproffitt](https://discourse.julialang.org/u/ericproffitt)\
**Replies:** 2\
**Last updated:** [January 24, 2020, 6:26pm UTC](https://discourse.julialang.org/t/adding-package-to-juliatext-listing/33716 "2020-01-24T18:26:56Z")

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Hi all, So I recently updated TopicModelsVB.jl to run on Julia 1.x. I’d like to add it to the JuliaText package listing, how should I go about doing this? Thanks, Eric

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## [ERROR: LoadError: UndefRefError: access to undefined reference](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683)

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**Author:** [@natgeo-wong](https://discourse.julialang.org/u/natgeo-wong)\
**Replies:** 4\
**Last updated:** [January 24, 2020, 5:59pm UTC](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683 "2020-01-24T17:59:41Z")

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So I have the following function function regionextract(data::Array{\<:Real},coord::Array) nlon1 = length(coord\[1\]); nlon2 = size(data,1); nlat1 = length(coord\[2\]); nlat2 = size(data,2); nt = size(data)\[3:en…

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## [Calling Intel MKL as an external library on Mac](https://discourse.julialang.org/t/calling-intel-mkl-as-an-external-library-on-mac/33722)

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**Author:** [@razvangheorghe](https://discourse.julialang.org/u/razvangheorghe)\
**Replies:** 2\
**Last updated:** [January 24, 2020, 4:05pm UTC](https://discourse.julialang.org/t/calling-intel-mkl-as-an-external-library-on-mac/33722 "2020-01-24T16:05:33Z")

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Hi, I’d like to use the Fortran subroutine ZGELSS from MKL in Julia and I’m a bit confused. julia\> versioninfo() Julia Version 1.3.0 Commit 46ce4d7933 (2019-11-26 06:09 UTC) Platform Info: OS: macOS (x86\_64-apple-darw…

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## [VAE in Flux model zoo](https://discourse.julialang.org/t/vae-in-flux-model-zoo/33747)

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**Author:** [@rsteckel](https://discourse.julialang.org/u/rsteckel)\
**Replies:** 0\
**Last updated:** [January 24, 2020, 2:10pm UTC](https://discourse.julialang.org/t/vae-in-flux-model-zoo/33747 "2020-01-24T14:10:44Z")

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I’ve been unable to get the MNIST VAE example in Flux’s model zoo to train. During epoch 1 of training, I get this error: \[ Info: Epoch 1 ERROR: Mutating arrays is not supported Stacktrace: \[1\] (::Zygote.var"#1003#100…

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## [Solving sparse singular linear systems](https://discourse.julialang.org/t/solving-sparse-singular-linear-systems/33401)

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**Author:** [@FHell](https://discourse.julialang.org/u/FHell)\
**Replies:** 3\
**Last updated:** [January 24, 2020, 1:23pm UTC](https://discourse.julialang.org/t/solving-sparse-singular-linear-systems/33401 "2020-01-24T13:23:19Z")

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I have a problem with solving sparse singular linear systems (flow problems on possibly disconnected graphs). I need the minimum norm solution for this. Essentially the sparse version of this: P = \[0.5, -0.5\] M = \[1. -1…

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## [ArrayFire and FFTW dependency Issue](https://discourse.julialang.org/t/arrayfire-and-fftw-dependency-issue/33735)

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**Author:** [@cshen](https://discourse.julialang.org/u/cshen)\
**Replies:** 0\
**Last updated:** [January 24, 2020, 11:22am UTC](https://discourse.julialang.org/t/arrayfire-and-fftw-dependency-issue/33735 "2020-01-24T11:22:00Z")

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Hello, I’ve been trying to install ArrayFire but there seems to be some issue regarding dependencies regarding FFTW (and Zygote). Here with the most recent FFTW@1.2.0: ERROR: Unsatisfiable requirements detected for p…

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## [Solving for eigenvalues of an equation system in ApproxFun.jl](https://discourse.julialang.org/t/solving-for-eigenvalues-of-an-equation-system-in-approxfun-jl/33682)

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**Author:** [@jbmuir](https://discourse.julialang.org/u/jbmuir)\
**Replies:** 3\
**Last updated:** [January 24, 2020, 11:02am UTC](https://discourse.julialang.org/t/solving-for-eigenvalues-of-an-equation-system-in-approxfun-jl/33682 "2020-01-24T11:02:23Z")

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I’m trying to solve an eigenvalue problem for a system of equations using ApproxFun; however I’m getting an implementation error ERROR: Implement Conversion from Chebyshev{Interval{:closed,:closed,Int64},Float64} to Appr…

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