# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1414

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

**Page:** 1415

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## [Should models revert to "unoptimized" if they are modified?](https://discourse.julialang.org/t/should-models-revert-to-unoptimized-if-they-are-modified/59627)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 4\
**Last updated:** [April 23, 2021, 9:22pm UTC](https://discourse.julialang.org/t/should-models-revert-to-unoptimized-if-they-are-modified/59627 "2021-04-23T21:22:05Z")

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If I optimize! a model with GLPK, then add a constraint, I can still access the solution: using JuMP, GLPK, Clp; M = Model(); @variable M A\[1:2\] \>= 0; @constraint M limit1 sum(a for a in A) \<= 1; @objective M Max sum(a …

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## [Calculating specific components of gradients](https://discourse.julialang.org/t/calculating-specific-components-of-gradients/59733)

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**Author:** [@schaerfo](https://discourse.julialang.org/u/schaerfo)\
**Replies:** 4\
**Last updated:** [April 23, 2021, 7:10pm UTC](https://discourse.julialang.org/t/calculating-specific-components-of-gradients/59733 "2021-04-23T19:10:17Z")

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Occasionally, I work with scalar-valued functions that take multiple vectors as arguments. A simple example is: f(\\mathbf{x}, \\mathbf{y}) = e^{-|\\mathbf{x}-\\mathbf{y}|^2} In Julia, this can be coded as: f(x, y) = exp…

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## [Zygote -- include("utils.jl");](https://discourse.julialang.org/t/zygote-include-utils-jl/59429)

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**Author:** [@aquarelleX332](https://discourse.julialang.org/u/aquarelleX332)\
**Replies:** 4\
**Last updated:** [April 23, 2021, 6:51pm UTC](https://discourse.julialang.org/t/zygote-include-utils-jl/59429 "2021-04-23T18:51:10Z")

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Hello, I suspect that the question as follows is most likely trivial and I don’t know if I’m in the right category. I am following Mike Innes’ manual in an attempt to learn how Zygote works inside Flux. At the beginni…

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## [Dataframe (or generally pretty table) without header in Pluto](https://discourse.julialang.org/t/dataframe-or-generally-pretty-table-without-header-in-pluto/59880)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 7\
**Last updated:** [April 23, 2021, 5:42pm UTC](https://discourse.julialang.org/t/dataframe-or-generally-pretty-table-without-header-in-pluto/59880 "2021-04-23T17:42:13Z")

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I am creating a certificate in Pluto, and I am currently displaying tables by putting them in a dataframe, which produces: But the headers, which are not necessary, take up a lot of space. While a problem on its own,…

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## [Pseudo inverse matrix of hessian isn't differentiated](https://discourse.julialang.org/t/pseudo-inverse-matrix-of-hessian-isnt-differentiated/59887)

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**Author:** [@Sunny](https://discourse.julialang.org/u/Sunny)\
**Replies:** 0\
**Last updated:** [April 23, 2021, 5:09pm UTC](https://discourse.julialang.org/t/pseudo-inverse-matrix-of-hessian-isnt-differentiated/59887 "2021-04-23T17:09:30Z")

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I want to compute the grad of pinv(hessian) struct hess\_nn model re params # Define inner constructor method function hess\_nn(model; p = nothing) \_p, re = Flux.destructure(model) if …

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## [How to get row indices and how can I change row indices/row names in a Julia DataFrame?](https://discourse.julialang.org/t/how-to-get-row-indices-and-how-can-i-change-row-indices-row-names-in-a-julia-dataframe/59884)

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**Author:** [@shubh\_b](https://discourse.julialang.org/u/shubh_b)\
**Replies:** 7\
**Last updated:** [April 23, 2021, 5:06pm UTC](https://discourse.julialang.org/t/how-to-get-row-indices-and-how-can-i-change-row-indices-row-names-in-a-julia-dataframe/59884 "2021-04-23T17:06:21Z")

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If I take a Julia DataFrame as below julia\> using DataFrames julia\> df = DataFrame(col1 = \['α', 'β', 'γ'\], col2 = \['A', 'B', 'C'\]) 3×2 DataFrame │ Row │ col1 │ col2 │ │ │ Char │ Char │ ├─────┼──────┼──────┤ │ 1 │ …

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## [Release of docs problem](https://discourse.julialang.org/t/release-of-docs-problem/59871)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 2\
**Last updated:** [April 23, 2021, 4:19pm UTC](https://discourse.julialang.org/t/release-of-docs-problem/59871 "2021-04-23T16:19:46Z")

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I am having problems (again) with the release of the documentation of a new version of a package. THIS is the package. Yesterday night I registered version 0.11.3 and everything seemed to work smoothly: automatic merge…

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## [Accessing array elements too slow?](https://discourse.julialang.org/t/accessing-array-elements-too-slow/59856)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 10\
**Last updated:** [April 23, 2021, 3:54pm UTC](https://discourse.julialang.org/t/accessing-array-elements-too-slow/59856 "2021-04-23T15:54:24Z")

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Hi, I think I could use some help here… As a part of a Monte Carlo code I’m developing in julia+CUDA, I have a function that takes several input parameters, performs a calculation with them, and stores the result in a C…

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## [Simple Parallel Examples for Embarrassingly Simple Problems](https://discourse.julialang.org/t/simple-parallel-examples-for-embarrassingly-simple-problems/8788)

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**Author:** [@ivo\_welch](https://discourse.julialang.org/u/ivo_welch)\
**Replies:** 29\
**Last updated:** [April 23, 2021, 3:45pm UTC](https://discourse.julialang.org/t/simple-parallel-examples-for-embarrassingly-simple-problems/8788 "2021-04-23T15:45:18Z")

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macOS, julia 0.6.2, Feb 2018, captain’s log: I have been playing around with trying to understand (the docs on) parallelism. as an early example, I just want to create, in parallel, a list of function logp1(x::Int64):…

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## [Loading arrays from C calls](https://discourse.julialang.org/t/loading-arrays-from-c-calls/59781)

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**Author:** [@Anton\_Hinneck](https://discourse.julialang.org/u/Anton_Hinneck)\
**Replies:** 10\
**Last updated:** [April 23, 2021, 10:30am UTC](https://discourse.julialang.org/t/loading-arrays-from-c-calls/59781 "2021-04-23T10:30:41Z")

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Hi, I need to work with packages that wrap a C-callable library (\*.so). Code that worked previously now causes segfaults when trying to load arrays. As a test, I compiled a small library called retArray.so containing th…

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## [Check that all fields are concrete types?](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225)

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**Author:** [@Stephen\_Vavasis](https://discourse.julialang.org/u/Stephen_Vavasis)\
**Replies:** 7\
**Last updated:** [April 23, 2021, 2:25pm UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225 "2021-04-23T14:25:21Z")

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I’ve discovered that I may have introduced some performance-sapping code into my project because of the following issue. I have two structs A and B like this: struct A field1::Int end struct B …

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## [Using ProtoBuf to serialize data](https://discourse.julialang.org/t/using-protobuf-to-serialize-data/59396)

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**Author:** [@SpinolaHours](https://discourse.julialang.org/u/SpinolaHours)\
**Replies:** 5\
**Last updated:** [April 23, 2021, 2:06pm UTC](https://discourse.julialang.org/t/using-protobuf-to-serialize-data/59396 "2021-04-23T14:06:58Z")

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Hi there, I’m trying to use ProtoBuf to serialize data but I’m coming across an error I don’t know how to solve: MWE: using ProtoBuf abstract type MyAbstractType end struct MyType \<: MyAbstractType ts::UInt64 …

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## [Multiple CPU threads that use Unified Memory gives a Bus Error](https://discourse.julialang.org/t/multiple-cpu-threads-that-use-unified-memory-gives-a-bus-error/59814)

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**Author:** [@barrettp](https://discourse.julialang.org/u/barrettp)\
**Replies:** 5\
**Last updated:** [April 23, 2021, 2:03pm UTC](https://discourse.julialang.org/t/multiple-cpu-threads-that-use-unified-memory-gives-a-bus-error/59814 "2021-04-23T14:03:20Z")

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I’ve have a function that calls a kernel that uses unified memory. The function allocates and frees the unified memory before and after multiple kernel invocations. I call synchronize() after each kernel call. Without sy…

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## [ArgParse error “too many arguments”](https://discourse.julialang.org/t/argparse-error-too-many-arguments/59859)

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**Author:** [@hei06j](https://discourse.julialang.org/u/hei06j)\
**Replies:** 1\
**Last updated:** [April 23, 2021, 1:37pm UTC](https://discourse.julialang.org/t/argparse-error-too-many-arguments/59859 "2021-04-23T13:37:33Z")

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Hi, I am trying to use ArgParse to read options from command line. It works when I have three options, but when I add another option it throws “too many argument” error. I appreciate your help. using ArgParse function …

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## [PyPlot installation messed up](https://discourse.julialang.org/t/pyplot-installation-messed-up/59855)

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**Author:** [@pg261](https://discourse.julialang.org/u/pg261)\
**Replies:** 1\
**Last updated:** [April 23, 2021, 1:28pm UTC](https://discourse.julialang.org/t/pyplot-installation-messed-up/59855 "2021-04-23T13:28:13Z")

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Hello, I have tried to use PyPlot, and now i think i’ve messed things up. Initially, the installation went fine, and it was possible to import the module. I tried to plot something (my ultimate goal is to plot a matrix…

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## [Julia 1.6 libcurl firewall download issue: Windows Schannel certificate revocation check failure](https://discourse.julialang.org/t/julia-1-6-libcurl-firewall-download-issue-windows-schannel-certificate-revocation-check-failure/58021)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 32\
**Last updated:** [April 23, 2021, 7:56am UTC](https://discourse.julialang.org/t/julia-1-6-libcurl-firewall-download-issue-windows-schannel-certificate-revocation-check-failure/58021 "2021-04-23T07:56:42Z")

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In Julia 1.5.3, I had https-proxy, http\_proxy, html\_proxy, SSL\_CERT\_FILE set in the environment variables. I also had a \_curlrc file with “insecure” in it in my home directory as well as a .condarc to get things workin…

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## [Odd BenchmarkTools timings using @threads and Octavian](https://discourse.julialang.org/t/odd-benchmarktools-timings-using-threads-and-octavian/59838)

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**Author:** [@jlchan](https://discourse.julialang.org/u/jlchan)\
**Replies:** 4\
**Last updated:** [April 23, 2021, 2:54am UTC](https://discourse.julialang.org/t/odd-benchmarktools-timings-using-threads-and-octavian/59838 "2021-04-23T02:54:07Z")

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I’m getting some odd behavior using @threads and Octavian. If I time matmul! and a simple tmap! implementation, I see reasonable speedup. using Octavian using LinearAlgebra A = randn(8,8) x = randn(8,10000) b = simila…

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## [Parametrized function type?](https://discourse.julialang.org/t/parametrized-function-type/59708)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 5\
**Last updated:** [April 23, 2021, 1:33am UTC](https://discourse.julialang.org/t/parametrized-function-type/59708 "2021-04-23T01:33:32Z")

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Is it possible to specify the signature of a function? # mycall : (A -\> B) -\> A -\> B mycall(f::Function{A,B}, a::A)::B where {A,B} = f(a) ERROR: UndefVarError: A not defined

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## [Makie - 3D volume rendering - using Axis3 - questions/issues](https://discourse.julialang.org/t/makie-3d-volume-rendering-using-axis3-questions-issues/59615)

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**Author:** [@Audrius-St](https://discourse.julialang.org/u/Audrius-St)\
**Replies:** 14\
**Last updated:** [April 22, 2021, 7:56pm UTC](https://discourse.julialang.org/t/makie-3d-volume-rendering-using-axis3-questions-issues/59615 "2021-04-22T19:56:52Z")

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Hello, this is my first go at using Julia and GLMakie. The goal is to display a 3D MIP CT image extracted from DICOM data. Julia 1.6 DICOM v0.10.0 AbstractPlotting v0.17.3 GLMakie v0.2.6 Windows 10 x64 Visual Stu…

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## [Handling color in Plots user recipe that produces an image, or indexed color](https://discourse.julialang.org/t/handling-color-in-plots-user-recipe-that-produces-an-image-or-indexed-color/59769)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 2\
**Last updated:** [April 22, 2021, 11:46pm UTC](https://discourse.julialang.org/t/handling-color-in-plots-user-recipe-that-produces-an-image-or-indexed-color/59769 "2021-04-22T23:46:41Z")

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I have a Grid type, and I have a way to plot it in terms of an image (Array{RBGA{...}, 2}), so I define the following user recipe: using Plots using Plots: RGBA using RecipesBase using OffsetArrays struct Grid x::O…

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## [Hcat with matrices as elements](https://discourse.julialang.org/t/hcat-with-matrices-as-elements/59817)

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**Author:** [@FeldrinH](https://discourse.julialang.org/u/FeldrinH)\
**Replies:** 17\
**Last updated:** [April 22, 2021, 9:26pm UTC](https://discourse.julialang.org/t/hcat-with-matrices-as-elements/59817 "2021-04-22T21:26:16Z")

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If I want a matrix with a single row of numbers I can do \[1 2 3 4 5\] or the equivalen function call hcat(1, 2, 3, 4, 5). However, what if I want a matrix with a single row of matrices as elements? If a,b, c, d and e are …

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## [Strange white space dependence with @assert](https://discourse.julialang.org/t/strange-white-space-dependence-with-assert/59825)

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**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 2\
**Last updated:** [April 22, 2021, 9:24pm UTC](https://discourse.julialang.org/t/strange-white-space-dependence-with-assert/59825 "2021-04-22T21:24:15Z")

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Julia syntax is usually insensitive to white space, but I encountered a situation when @assert introduces a strange dependence on white space. Is this a bug? (I’m using Julia 1.6.0.) julia\> t = Int64\[1,2\]; julia\> @asse…

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## [JunoTroubles](https://discourse.julialang.org/t/junotroubles/13994)

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**Author:** [@Neonlights](https://discourse.julialang.org/u/Neonlights)\
**Replies:** 11\
**Last updated:** [April 22, 2021, 8:31pm UTC](https://discourse.julialang.org/t/junotroubles/13994 "2021-04-22T20:31:27Z")

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Woe is me. For I have installed Julia, then tried to set up Atom with Juno, and on starting up the Console REPL this is what I got. What should I do to fix this? I’m a bit troubled that it seems to have failed on a clone…

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## [Processing output from long running process](https://discourse.julialang.org/t/processing-output-from-long-running-process/59824)

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**Author:** [@asyrov](https://discourse.julialang.org/u/asyrov)\
**Replies:** 1\
**Last updated:** [April 22, 2021, 8:07pm UTC](https://discourse.julialang.org/t/processing-output-from-long-running-process/59824 "2021-04-22T20:07:31Z")

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I have long running process, which outputs many things which I do not usually need (or want to transform). I want to run this process capturing, filtering output lines from the process till it finished. In essence, some…

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## [AMPL to jump](https://discourse.julialang.org/t/ampl-to-jump/56760)

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**Author:** [@aaldik](https://discourse.julialang.org/u/aaldik)\
**Replies:** 4\
**Last updated:** [April 22, 2021, 7:31pm UTC](https://discourse.julialang.org/t/ampl-to-jump/56760 "2021-04-22T19:31:29Z")

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Dears I have a question regarding solving a problem that was written in AMPL using Jump. Is there a specific function that allows for translating an ampl file into a recognized file by jump? what is the most efficient w…

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## [Triangular Schur decomposition for a matrix with complex eigenvalues?](https://discourse.julialang.org/t/triangular-schur-decomposition-for-a-matrix-with-complex-eigenvalues/25680)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 5\
**Last updated:** [April 22, 2021, 6:57pm UTC](https://discourse.julialang.org/t/triangular-schur-decomposition-for-a-matrix-with-complex-eigenvalues/25680 "2021-04-22T18:57:16Z")

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Is it possible to compute a (strictly) triangular Schur decomposition for a matrix with complex eigenvalues? With the code below I create such a matrix: T = rand(2,2) λ = rand() + rand()\*im D = \[real(λ) imag(λ); -imag(…

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## [Filter design: MATLAB firls (Least-squares linear-phase FIR filter design) alternative?](https://discourse.julialang.org/t/filter-design-matlab-firls-least-squares-linear-phase-fir-filter-design-alternative/45249)

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**Author:** [@ElectronicTeaCup](https://discourse.julialang.org/u/ElectronicTeaCup)\
**Replies:** 17\
**Last updated:** [April 22, 2021, 6:49pm UTC](https://discourse.julialang.org/t/filter-design-matlab-firls-least-squares-linear-phase-fir-filter-design-alternative/45249 "2021-04-22T18:49:53Z")

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Hi! I am going through a MATLAB based textbook for time frequency analysis of Neural data (MEG/EEG time series data) and got to a chapter which goes through filter construction. It’s primarily going over the usage of the…

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## [RNN is not trained](https://discourse.julialang.org/t/rnn-is-not-trained/59553)

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**Author:** [@Sunny](https://discourse.julialang.org/u/Sunny)\
**Replies:** 6\
**Last updated:** [April 22, 2021, 5:31pm UTC](https://discourse.julialang.org/t/rnn-is-not-trained/59553 "2021-04-22T17:31:10Z")

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I’m trying to reproduce this example but my model won’t train. I use only train dataset to achieve overfitting and get just a line as prediction: using Pandas using Plots using Flux df = read\_csv("airline-passengers.c…

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## [Colorbar position inside layout](https://discourse.julialang.org/t/colorbar-position-inside-layout/59762)

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**Author:** [@AshtonSBradley](https://discourse.julialang.org/u/AshtonSBradley)\
**Replies:** 1\
**Last updated:** [April 22, 2021, 5:30pm UTC](https://discourse.julialang.org/t/colorbar-position-inside-layout/59762 "2021-04-22T17:30:35Z")

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having done (the heatmap is the 4th plot down in a 5x2 layout) cbar = Colorbar(f\[4, 1\]\[2, 1\], vertical=false,height = 20) I get something like this: Is there a way to get the colorbar to sit just below the heatmap…

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## [Unit test equality for arrays?](https://discourse.julialang.org/t/unit-test-equality-for-arrays/8138)

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**Author:** [@fufjvnvnf](https://discourse.julialang.org/u/fufjvnvnf)\
**Replies:** 14\
**Last updated:** [April 22, 2021, 5:28pm UTC](https://discourse.julialang.org/t/unit-test-equality-for-arrays/8138 "2021-04-22T17:28:21Z")

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I am trying to use unit test to test the equality of two arrays, wheres the following test: @test \[2.36248e-314, 2.36248e-314\] ≈ \[0.0, 0.0\] would fail. The two entries in the vector, if compared separately with the sam…

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