# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1439

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

**Page:** 1440

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## [Image not showing in IJulia](https://discourse.julialang.org/t/image-not-showing-in-ijulia/58400)

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**Author:** [@jonathan-durbin](https://discourse.julialang.org/u/jonathan-durbin)\
**Replies:** 2\
**Last updated:** [April 2, 2021, 12:03am UTC](https://discourse.julialang.org/t/image-not-showing-in-ijulia/58400 "2021-04-02T00:03:54Z")

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When I run the example code from the Images Documentation img = Array(reshape(range(0,stop=1,length=10^4), 100, 100)) in a Julia (Jupyter) notebook, I only see the raw output (below), not the image itself. This issue mus…

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## [Does this lose the benefit of QR decomposition?](https://discourse.julialang.org/t/does-this-lose-the-benefit-of-qr-decomposition/58324)

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**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 2\
**Last updated:** [April 1, 2021, 11:49pm UTC](https://discourse.julialang.org/t/does-this-lose-the-benefit-of-qr-decomposition/58324 "2021-04-01T23:49:29Z")

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My understanding is that one can do fast multiplies by the Q matrix of the QR decomposition because it is represented as a sequence of Householder reflections. I want to compute deltai = 3:size(T, 1) δ = Q\[:, d…

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## [Non-convex optimization](https://discourse.julialang.org/t/non-convex-optimization/58227)

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**Author:** [@optimist](https://discourse.julialang.org/u/optimist)\
**Replies:** 2\
**Last updated:** [April 1, 2021, 11:35pm UTC](https://discourse.julialang.org/t/non-convex-optimization/58227 "2021-04-01T23:35:36Z")

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I am solving a non linear optimization using Ipopt. The problem is non-convex but Ipopt gives a good enough answer. The documentation on use of nonlinear parameters and non-linear expressions is somewhat thin. Suppose …

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## [Inverse functions using TaylorSeries.jl](https://discourse.julialang.org/t/inverse-functions-using-taylorseries-jl/43382)

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**Author:** [@dpsanders](https://discourse.julialang.org/u/dpsanders)\
**Replies:** 8\
**Last updated:** [April 1, 2021, 11:24pm UTC](https://discourse.julialang.org/t/inverse-functions-using-taylorseries-jl/43382 "2021-04-01T23:24:06Z")

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Hi @ChrisRackauckas and thread, I’m interested in using AD, and so have been something like 90% successful using TaylorSeries.jl to generate the inverse function to almost any general arbitrary function. For example T…

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## [Simple wildcard search in dataframes](https://discourse.julialang.org/t/simple-wildcard-search-in-dataframes/58401)

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**Author:** [@jonjilla](https://discourse.julialang.org/u/jonjilla)\
**Replies:** 2\
**Last updated:** [April 1, 2021, 10:40pm UTC](https://discourse.julialang.org/t/simple-wildcard-search-in-dataframes/58401 "2021-04-01T22:40:31Z")

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Hello All, This seems like such a trivial thing, but I couldn’t get it to work. I’m simply trying to filter a dataframe column by a wildcard search. What is the right syntax? df = DataFrame(:a =\> \["abcdef","abcdeg","…

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## [Scientific Notation in Plots.jl colorbar](https://discourse.julialang.org/t/scientific-notation-in-plots-jl-colorbar/57793)

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**Author:** [@lsterzinger](https://discourse.julialang.org/u/lsterzinger)\
**Replies:** 8\
**Last updated:** [April 1, 2021, 9:31pm UTC](https://discourse.julialang.org/t/scientific-notation-in-plots-jl-colorbar/57793 "2021-04-01T21:31:30Z")

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Hello, edit: working example using Plots x = rand(10,10) / 1e6 contourf(x) I don’t like how the colorbar’s labels are cut off by the plot edge. Is there a way to tell the plotting package to use scientific notation …

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## [Concurrency violation during garbage collections?](https://discourse.julialang.org/t/concurrency-violation-during-garbage-collections/58391)

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**Author:** [@pixel27](https://discourse.julialang.org/u/pixel27)\
**Replies:** 1\
**Last updated:** [April 1, 2021, 9:13pm UTC](https://discourse.julialang.org/t/concurrency-violation-during-garbage-collections/58391 "2021-04-01T21:13:14Z")

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Really, I guess my question is should I open a bug against Julia for this? It doesn’t appear to be causing issues, and I expect that this will only happen during development. First the stack trace: error in running fi…

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## [No-op function?](https://discourse.julialang.org/t/no-op-function/58392)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 2\
**Last updated:** [April 1, 2021, 8:56pm UTC](https://discourse.julialang.org/t/no-op-function/58392 "2021-04-01T20:56:00Z")

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Is there such a thing as a function that is a no-op (and returns nothing which I guess is always mandatory) for any arguments? Basically noop(args...; kwargs...) = nothing I’m wondering if either something like this…

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## [Drop of performances with Julia 1.6.0 for InterpolationKernels](https://discourse.julialang.org/t/drop-of-performances-with-julia-1-6-0-for-interpolationkernels/58085)

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**Author:** [@emmt](https://discourse.julialang.org/u/emmt)\
**Replies:** 40\
**Last updated:** [April 1, 2021, 8:21pm UTC](https://discourse.julialang.org/t/drop-of-performances-with-julia-1-6-0-for-interpolationkernels/58085 "2021-04-01T20:21:32Z")

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I was happy to switch from Julia 1.5.4 to Julia 1.6.0 but I experienced significant drops of performances for InterpolationKernels by up to a factor 3.6… Below are tables summarizing my tests with BenchmarkTools. The c…

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## [Build\_function from differential equation](https://discourse.julialang.org/t/build-function-from-differential-equation/58276)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 2\
**Last updated:** [April 1, 2021, 8:19pm UTC](https://discourse.julialang.org/t/build-function-from-differential-equation/58276 "2021-04-01T20:19:15Z")

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I tried the example from Symbolics.jl but ran into a problem: using Symbolics function lotka\_volterra!(du, u, p, t) x, y = u α, β, δ, γ = p du\[1\] = dx = α\*x - β\*x\*y du\[2\] = dy = -δ\*y + γ\*x\*y end @variables t du\[…

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## [Plots.jl plot window launched from a signal within Gtk.jl does not open—how to fix?](https://discourse.julialang.org/t/plots-jl-plot-window-launched-from-a-signal-within-gtk-jl-does-not-open-how-to-fix/58384)

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**Author:** [@cdknight](https://discourse.julialang.org/u/cdknight)\
**Replies:** 1\
**Last updated:** [April 1, 2021, 8:18pm UTC](https://discourse.julialang.org/t/plots-jl-plot-window-launched-from-a-signal-within-gtk-jl-does-not-open-how-to-fix/58384 "2021-04-01T20:18:29Z")

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Hi, I’m new here (and to the Julia programming language in general), and hopefully this is the right category. Anyway, I’m attempting to make a GUI to facilitate some visualisation that I’m doing. What I want is to click…

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## [GR can't connect on Windows](https://discourse.julialang.org/t/gr-cant-connect-on-windows/58371)

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**Author:** [@jbreeden](https://discourse.julialang.org/u/jbreeden)\
**Replies:** 4\
**Last updated:** [April 1, 2021, 6:33pm UTC](https://discourse.julialang.org/t/gr-cant-connect-on-windows/58371 "2021-04-01T18:33:34Z")

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I installed Julia 1.6 on Windows a few days ago, and had been using the Plots package with no problems (GR backend only). Now, every time I plot, I get GKS: can't connect to GKS socket application GKS: Open failed in r…

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## [Text disappearing from Juno/Atom](https://discourse.julialang.org/t/text-disappearing-from-juno-atom/55072)

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**Author:** [@SamBrand](https://discourse.julialang.org/u/SamBrand)\
**Replies:** 12\
**Last updated:** [April 1, 2021, 6:29pm UTC](https://discourse.julialang.org/t/text-disappearing-from-juno-atom/55072 "2021-04-01T18:29:18Z")

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Hi everyone, Quite strange error occurring for me since I upgraded julia-client 0.12.6. Bits of text disappear from the screen after I use shift + enter to run highlighted code blocks… sometimes. The actual REPL seems …

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## [Change Plots.jl backend dynamically](https://discourse.julialang.org/t/change-plots-jl-backend-dynamically/58240)

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**Author:** [@HugoTrentesaux](https://discourse.julialang.org/u/HugoTrentesaux)\
**Replies:** 3\
**Last updated:** [April 1, 2021, 6:21pm UTC](https://discourse.julialang.org/t/change-plots-jl-backend-dynamically/58240 "2021-04-01T18:21:34Z")

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I want to plot a figure using all backends. I do this: function plots\_all\_formats() plots("png") plots("html") plots("svg") end function plots(format) # load data # ... if format == "html" …

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## [CUDA : vectorization not working with functions of complex argument](https://discourse.julialang.org/t/cuda-vectorization-not-working-with-functions-of-complex-argument/58375)

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**Author:** [@anscoil](https://discourse.julialang.org/u/anscoil)\
**Replies:** 4\
**Last updated:** [April 1, 2021, 6:13pm UTC](https://discourse.julialang.org/t/cuda-vectorization-not-working-with-functions-of-complex-argument/58375 "2021-04-01T18:13:51Z")

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Hi, Before stating my problem, I would like to say that I’m a fully enthusiastic and convinced Julia user, and to thank the developers for their awesome work. The CUDA module is especially of great help to write fast c…

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## [Recompiling functions with infrequently mutating constant](https://discourse.julialang.org/t/recompiling-functions-with-infrequently-mutating-constant/58368)

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**Author:** [@Deduction42](https://discourse.julialang.org/u/Deduction42)\
**Replies:** 7\
**Last updated:** [April 1, 2021, 4:54pm UTC](https://discourse.julialang.org/t/recompiling-functions-with-infrequently-mutating-constant/58368 "2021-04-01T16:54:39Z")

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I’m writing an application with a whole bunch of vectors of length N that syntactically have elements having a consistent meaning (chemical components in a mixture). Most of the time, I don’t need the names, but on some …

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## [How to migrate version of PooledArrays inside JLD2 file](https://discourse.julialang.org/t/how-to-migrate-version-of-pooledarrays-inside-jld2-file/58369)

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**Author:** [@bluesmoon](https://discourse.julialang.org/u/bluesmoon)\
**Replies:** 3\
**Last updated:** [April 1, 2021, 4:01pm UTC](https://discourse.julialang.org/t/how-to-migrate-version-of-pooledarrays-inside-jld2-file/58369 "2021-04-01T16:01:07Z")

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A while ago I created a JLD2 file with a DataFrame in it. (This is used for unit testing) One of the columns in the DataFrame has a type of PooledArrays.PooledArray{String,UInt32,1,Array{UInt32,1}} When I created the J…

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## [Best Practices for Harmonizing Datasets](https://discourse.julialang.org/t/best-practices-for-harmonizing-datasets/58364)

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**Author:** [@TheCedarPrince](https://discourse.julialang.org/u/TheCedarPrince)\
**Replies:** 5\
**Last updated:** [April 1, 2021, 4:26pm UTC](https://discourse.julialang.org/t/best-practices-for-harmonizing-datasets/58364 "2021-04-01T16:26:44Z")

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Hi everyone! I have a question about data manipulation that is more on the conceptual side: Say you have multiple datasets that you are trying to harmonize. Each dataset requires their own amount of processing to get i…

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## [Range in Earth's coordinates](https://discourse.julialang.org/t/range-in-earths-coordinates/58287)

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**Author:** [@marianoarnaiz](https://discourse.julialang.org/u/marianoarnaiz)\
**Replies:** 12\
**Last updated:** [April 1, 2021, 4:17pm UTC](https://discourse.julialang.org/t/range-in-earths-coordinates/58287 "2021-04-01T16:17:05Z")

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Hi every one! I am looking for an efficient way to generate equally spaced points between two coordinates on Earth’s Surface. Something like: range(point1, point2, length=10) I know there is the GMT wrapper, but it nee…

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## [Plot and plot!](https://discourse.julialang.org/t/plot-and-plot/58372)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 1\
**Last updated:** [April 1, 2021, 3:45pm UTC](https://discourse.julialang.org/t/plot-and-plot/58372 "2021-04-01T15:45:18Z")

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Hi, I wonder how to avoid to duplicate my plot commands (plot then plot!) when I want to add multiples curves using Plots. Here is the MWE that I would like to simplify: using Plots function testplots() them…

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## [$(Main.r) vs $(r) -- confusion](https://discourse.julialang.org/t/main-r-vs-r-confusion/58314)

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**Author:** [@healyp](https://discourse.julialang.org/u/healyp)\
**Replies:** 5\
**Last updated:** [April 1, 2021, 3:07pm UTC](https://discourse.julialang.org/t/main-r-vs-r-confusion/58314 "2021-04-01T15:07:44Z")

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I am trying to write a logging-type macro that will print an informational string depending on a numerical condition. (Yes, I am aware of the Logging module :-).) Using the @assert macro as a starting point I have esse…

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## [Save output from DifferentialEquations](https://discourse.julialang.org/t/save-output-from-differentialequations/58313)

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**Author:** [@Frederic\_Gilt](https://discourse.julialang.org/u/Frederic_Gilt)\
**Replies:** 5\
**Last updated:** [April 1, 2021, 3:05pm UTC](https://discourse.julialang.org/t/save-output-from-differentialequations/58313 "2021-04-01T15:05:40Z")

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Dear all, Using DifferentialEquations I have beautiful results from sol = solve(ensembleprob,SRIW1(),EnsembleThreads(),trajectories=ϕ,saveat=δt); Question is how to save ‘sol’ ?? I have tried io withtout success io =…

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## [Private Package dll gives "Access is denied"](https://discourse.julialang.org/t/private-package-dll-gives-access-is-denied/58295)

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**Author:** [@Brad\_Carman](https://discourse.julialang.org/u/Brad_Carman)\
**Replies:** 4\
**Last updated:** [April 1, 2021, 2:58pm UTC](https://discourse.julialang.org/t/private-package-dll-gives-access-is-denied/58295 "2021-04-01T14:58:07Z")

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I am developing a private package which uses a dll I store in a “lib” folder in my package repository. This dll is from compiled c code and does not require registering and works fine from the development directory. The…

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## [Tuple indexing taking time?](https://discourse.julialang.org/t/tuple-indexing-taking-time/58309)

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**Author:** [@markmbaum](https://discourse.julialang.org/u/markmbaum)\
**Replies:** 25\
**Last updated:** [April 1, 2021, 2:51pm UTC](https://discourse.julialang.org/t/tuple-indexing-taking-time/58309 "2021-04-01T14:51:00Z")

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A fairly general question about a function that I’m working on before I try to summarize what it’s doing. The profile view is below. There are three main red blocks that take up most of the time, each for the same line o…

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## [Multiple-choice (dropdown) arguments](https://discourse.julialang.org/t/multiple-choice-dropdown-arguments/58353)

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**Author:** [@RainerHeintzmann](https://discourse.julialang.org/u/RainerHeintzmann)\
**Replies:** 10\
**Last updated:** [April 1, 2021, 2:46pm UTC](https://discourse.julialang.org/t/multiple-choice-dropdown-arguments/58353 "2021-04-01T14:46:56Z")

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Writing code in julia, I often encounter the need for an argument which can assume a number of different choices. E.g. in IndexFunArrays many functions (e.g. rr(mysize; offset=CtrFT)) have the offset parameter which can …

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## [Radial Basis Surrogate](https://discourse.julialang.org/t/radial-basis-surrogate/58192)

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**Author:** [@Manisha\_07](https://discourse.julialang.org/u/Manisha_07)\
**Replies:** 6\
**Last updated:** [April 1, 2021, 1:43pm UTC](https://discourse.julialang.org/t/radial-basis-surrogate/58192 "2021-04-01T13:43:16Z")

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I am trying to execute the following program but facing the issue. Please help me to resolve this

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## [Error with training decoupled NODEs](https://discourse.julialang.org/t/error-with-training-decoupled-nodes/58311)

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**Author:** [@jvkoch](https://discourse.julialang.org/u/jvkoch)\
**Replies:** 1\
**Last updated:** [April 1, 2021, 12:35pm UTC](https://discourse.julialang.org/t/error-with-training-decoupled-nodes/58311 "2021-04-01T12:35:12Z")

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I’m attempting to train two decoupled neural ODEs simultaneously. Although decoupled, these ODEs interact through a coupled loss function (not shown). I have constructed this in two ways: 1) by writing two separate ODEPr…

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## [Is it reasonable to mimic a Python class with mutable structs?](https://discourse.julialang.org/t/is-it-reasonable-to-mimic-a-python-class-with-mutable-structs/57516)

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**Author:** [@Nicholaswogan](https://discourse.julialang.org/u/Nicholaswogan)\
**Replies:** 16\
**Last updated:** [April 1, 2021, 10:16am UTC](https://discourse.julialang.org/t/is-it-reasonable-to-mimic-a-python-class-with-mutable-structs/57516 "2021-04-01T10:16:10Z")

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Just beginning to learn Julia. I’ve realized that you can mimic a Python class using a module and mutable structs. For example, module MimicPyClass mutable struct Self{T\<:AbstractFloat,D\<:Integer} a::T b::T …

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## [Radial\_surrogates Installations Error](https://discourse.julialang.org/t/radial-surrogates-installations-error/58347)

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**Author:** [@Manisha\_07](https://discourse.julialang.org/u/Manisha_07)\
**Replies:** 5\
**Last updated:** [April 1, 2021, 8:53am UTC](https://discourse.julialang.org/t/radial-surrogates-installations-error/58347 "2021-04-01T08:53:00Z")

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Hello I am trying to add the Radial basis to my Julia but getting this error. Please help me MethodError: no method matching RadialBasis(::Array{Float64,1}, ::Array{Float64,1}, ::Int64, ::Int64) Closest candidates are…

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## [How can I feed sequences of different lengths though a RNN and still have it be differentiable in Flux? (Minimal example included)](https://discourse.julialang.org/t/how-can-i-feed-sequences-of-different-lengths-though-a-rnn-and-still-have-it-be-differentiable-in-flux-minimal-example-included/58340)

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**Author:** [@DevJac](https://discourse.julialang.org/u/DevJac)\
**Replies:** 0\
**Last updated:** [April 1, 2021, 3:05am UTC](https://discourse.julialang.org/t/how-can-i-feed-sequences-of-different-lengths-though-a-rnn-and-still-have-it-be-differentiable-in-flux-minimal-example-included/58340 "2021-04-01T03:05:34Z")

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I have several matrices of several different lengths. I want to feed these matrices though a RNN using Flux, however, I haven’t been able to do so. Everything I’ve tried either uses a lot of memory during the backward pa…

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