# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1301

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

**Page:** 1302

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## [Segmentation fault, EDIT: Signal 6 - has somebody a clue?](https://discourse.julialang.org/t/segmentation-fault-edit-signal-6-has-somebody-a-clue/66206)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 7\
**Last updated:** [August 12, 2021, 3:08pm UTC](https://discourse.julialang.org/t/segmentation-fault-edit-signal-6-has-somebody-a-clue/66206 "2021-08-12T15:08:06Z")

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Hi there, I am using IRTools to manipulate some intermediate representation, so this may be quite deep into julia. Out of a sudden, I have no clue what is going on, I get the following segmentation fault signal 6: sig…

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## [Performance depends dramatically on compilation order](https://discourse.julialang.org/t/performance-depends-dramatically-on-compilation-order/58425)

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**Author:** [@fverdugo](https://discourse.julialang.org/u/fverdugo)\
**Replies:** 6\
**Last updated:** [August 12, 2021, 2:25pm UTC](https://discourse.julialang.org/t/performance-depends-dramatically-on-compilation-order/58425 "2021-08-12T14:25:23Z")

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Using ProfileView, I have realized that our code base Gridap.jl suffers from runtime dispatch at some performance critical parts. Luckily, I have been able to reduce the problem to a simple MWE and even found a workaroun…

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## [Chebyshev Coefficients for 1/(1+x^2); interpretation of equations in paper](https://discourse.julialang.org/t/chebyshev-coefficients-for-1-1-x-2-interpretation-of-equations-in-paper/66001)

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**Author:** [@blackeneth](https://discourse.julialang.org/u/blackeneth)\
**Replies:** 6\
**Last updated:** [August 12, 2021, 2:04pm UTC](https://discourse.julialang.org/t/chebyshev-coefficients-for-1-1-x-2-interpretation-of-equations-in-paper/66001 "2021-08-12T14:04:40Z")

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I need to calculate C2k from the paper, Modification of of Owen’s Method for Computing the Bivariate Normal Integral (DM Borth, 1973). The relevant bit of math is here: Note the sentence, Letting\\ C\_{2k} \\ be\\ the…

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## [Package for fitting a curve and storing the function](https://discourse.julialang.org/t/package-for-fitting-a-curve-and-storing-the-function/66135)

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**Author:** [@juliauser](https://discourse.julialang.org/u/juliauser)\
**Replies:** 7\
**Last updated:** [August 12, 2021, 2:08pm UTC](https://discourse.julialang.org/t/package-for-fitting-a-curve-and-storing-the-function/66135 "2021-08-12T14:08:53Z")

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I have a set of point x and y and I would like to find the best (polynomial?) fit and store it so that I can use it as a function. Polynomials.jl creates the fit but not the function (evaluating the function at a point …

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## [Unit testing for macros?](https://discourse.julialang.org/t/unit-testing-for-macros/66230)

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**Author:** [@tbenst](https://discourse.julialang.org/u/tbenst)\
**Replies:** 3\
**Last updated:** [August 12, 2021, 1:50pm UTC](https://discourse.julialang.org/t/unit-testing-for-macros/66230 "2021-08-12T13:50:50Z")

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Suppose I write some complicated macro: "Return exact same expression." macro flawed\_identity(ex) @assert ex.head != :(=) "oops we don't support head of :=" ex end and I write some tests: @testset "identity" b…

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## [Multi column indexing](https://discourse.julialang.org/t/multi-column-indexing/66265)

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**Author:** [@jpmorr](https://discourse.julialang.org/u/jpmorr)\
**Replies:** 4\
**Last updated:** [August 12, 2021, 1:41pm UTC](https://discourse.julialang.org/t/multi-column-indexing/66265 "2021-08-12T13:41:54Z")

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I’m still new to Julia but there’s still some basics that I’m still clearly not understanding. Take the following example which has confused me all morning. storage\_indx\_mult = hcat(\[12, 165, 55, 66, 89, 101, 2\], \[68, …

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## [How to splat named tuples into functions?](https://discourse.julialang.org/t/how-to-splat-named-tuples-into-functions/66263)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 1\
**Last updated:** [August 12, 2021, 12:12pm UTC](https://discourse.julialang.org/t/how-to-splat-named-tuples-into-functions/66263 "2021-08-12T12:12:09Z")

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I’d like to be able to do something like this: using NLsolve function f!(F, x) F\[1\] = (x\[1\]+3)\*(x\[2\]^3-7)+18 F\[2\] = sin(x\[2\]\*exp(x\[1\])-1) end opts = (method=:newton, autodiff=:forward) # i'd like to be able t…

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## [Implementing interface on custom types](https://discourse.julialang.org/t/implementing-interface-on-custom-types/66250)

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**Author:** [@Daneel](https://discourse.julialang.org/u/Daneel)\
**Replies:** 3\
**Last updated:** [August 12, 2021, 11:43am UTC](https://discourse.julialang.org/t/implementing-interface-on-custom-types/66250 "2021-08-12T11:43:00Z")

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Is it possible to implement an interface on a simple custom type so that many common functions will work on it? I’m trying to improve my knowledge of Julia. Let’s say we have the following simple custom type. mutable st…

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## [Dash.jl slider doesn't display labels](https://discourse.julialang.org/t/dash-jl-slider-doesnt-display-labels/66253)

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**Author:** [@Iulian.Cioarca](https://discourse.julialang.org/u/Iulian.Cioarca)\
**Replies:** 1\
**Last updated:** [August 12, 2021, 11:16am UTC](https://discourse.julialang.org/t/dash-jl-slider-doesnt-display-labels/66253 "2021-08-12T11:16:24Z")

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I was messing around with dcc\_slider and observed that labels are missing if the marks argument is constructed using an array of Floats, with zero as decimal (ex: 0.0:10.0). The labels are displayed fine if I use either …

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## [Julia 1.6.2 not eq comparison operator bug](https://discourse.julialang.org/t/julia-1-6-2-not-eq-comparison-operator-bug/66252)

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**Author:** [@hobbymarks](https://discourse.julialang.org/u/hobbymarks)\
**Replies:** 2\
**Last updated:** [August 12, 2021, 10:00am UTC](https://discourse.julialang.org/t/julia-1-6-2-not-eq-comparison-operator-bug/66252 "2021-08-12T10:00:39Z")

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When I want to use the Not-equals comparison operator,I must copy from the julia help documentation. If it is not obtained by copying, even if I input according to the suggestions of the document, and the characters dis…

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## [Binary-read fixed-length String](https://discourse.julialang.org/t/binary-read-fixed-length-string/66080)

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**Author:** [@ryofurue](https://discourse.julialang.org/u/ryofurue)\
**Replies:** 8\
**Last updated:** [August 12, 2021, 8:34am UTC](https://discourse.julialang.org/t/binary-read-fixed-length-string/66080 "2021-08-12T08:34:03Z")

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I was wondering how to read a fixed-length character string from a binary file. My file is formatted like this: Int32|4-byte string|array of Float32's . . . The string consists of just four plain ASCII characters wit…

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## [Dot operation broadcast for a "StaticSparseVector"](https://discourse.julialang.org/t/dot-operation-broadcast-for-a-staticsparsevector/66124)

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**Author:** [@Philippe\_Maincon1](https://discourse.julialang.org/u/Philippe_Maincon1)\
**Replies:** 5\
**Last updated:** [August 12, 2021, 7:35am UTC](https://discourse.julialang.org/t/dot-operation-broadcast-for-a-staticsparsevector/66124 "2021-08-12T07:35:23Z")

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For various reasons, I want to create a static sparse vector (SSV) type. In contrast to what is done (for matrices) in LuxurySparse.jl, I want the sparsity structure to be part of the data type. I do that by using a re…

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## [Are there Julia + MPI applications on Supercomputer?](https://discourse.julialang.org/t/are-there-julia-mpi-applications-on-supercomputer/66240)

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**Author:** [@CRquantum](https://discourse.julialang.org/u/CRquantum)\
**Replies:** 5\
**Last updated:** [August 12, 2021, 7:06am UTC](https://discourse.julialang.org/t/are-there-julia-mpi-applications-on-supercomputer/66240 "2021-08-12T07:06:44Z")

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I am come from modern Fortran with nuclear quantum Monte Carlo (QMC) applications, which, seems many codes are written in modern Fortran. For example, some codes such as Green’s Function Monte Carlo (GFMC) for Carbon 12…

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## [Transforming arbitrary Julia code to lazy evaluation](https://discourse.julialang.org/t/transforming-arbitrary-julia-code-to-lazy-evaluation/66239)

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**Author:** [@tbenst](https://discourse.julialang.org/u/tbenst)\
**Replies:** 4\
**Last updated:** [August 12, 2021, 3:51am UTC](https://discourse.julialang.org/t/transforming-arbitrary-julia-code-to-lazy-evaluation/66239 "2021-08-12T03:51:01Z")

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I’ve been experimenting with methods for transforming arbitrary Julia code for lazy evaluation (repo at https://github.com/tbenst/Thunks.jl). Here’s an example of what I’d like to be able to do in a fraction of a second: …

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## [Query optimizer support for indicator constraints](https://discourse.julialang.org/t/query-optimizer-support-for-indicator-constraints/66244)

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**Author:** [@SupplyChef](https://discourse.julialang.org/u/SupplyChef)\
**Replies:** 1\
**Last updated:** [August 12, 2021, 3:39am UTC](https://discourse.julialang.org/t/query-optimizer-support-for-indicator-constraints/66244 "2021-08-12T03:39:30Z")

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Hello, Is there a way to query if a solver supports indicator constraints? I’d like to write a function that produces a model that uses indicator constraints if they are supported and reverts to a big-M constraints if n…

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## [Jitter R function equivalent in Julia?](https://discourse.julialang.org/t/jitter-r-function-equivalent-in-julia/43457)

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**Author:** [@pauloat](https://discourse.julialang.org/u/pauloat)\
**Replies:** 26\
**Last updated:** [August 12, 2021, 2:40am UTC](https://discourse.julialang.org/t/jitter-r-function-equivalent-in-julia/43457 "2021-08-12T02:40:15Z")

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hi, I wanted to know if there’s an equivalent function to R’s jitter() that add noise to a value or vector of values. Thanks you.

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## [Help to get my slow Julia code to run as fast as Rust/Java/Lisp](https://discourse.julialang.org/t/help-to-get-my-slow-julia-code-to-run-as-fast-as-rust-java-lisp/65741)

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**Author:** [@renatoathaydes](https://discourse.julialang.org/u/renatoathaydes)\
**Replies:** 100\
**Last updated:** [August 6, 2021, 1:54am UTC](https://discourse.julialang.org/t/help-to-get-my-slow-julia-code-to-run-as-fast-as-rust-java-lisp/65741 "2021-08-06T01:54:53Z")

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Hi there! I had included some Julia code in a benchmark I’ve run to see how it performs compared to a few other languages. Given what other people say, Julia should be very fast, but the program I wrote is much slower t…

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## [Arrow.jl reading compressed(lz4 and zstd) arrow/feather format may have memory leak](https://discourse.julialang.org/t/arrow-jl-reading-compressed-lz4-and-zstd-arrow-feather-format-may-have-memory-leak/52177)

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**Author:** [@jesseventura](https://discourse.julialang.org/u/jesseventura)\
**Replies:** 3\
**Last updated:** [August 12, 2021, 1:47am UTC](https://discourse.julialang.org/t/arrow-jl-reading-compressed-lz4-and-zstd-arrow-feather-format-may-have-memory-leak/52177 "2021-08-12T01:47:19Z")

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refer to memory leaking when reading compressed arrow files · Issue #80 · apache/arrow-julia · GitHub I found only when i have a compressed arrow format(lz4 or zstd) , the memory leak problem occurs. uncompressed forma…

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## [Julia without libc (or bundled with non-glibc)](https://discourse.julialang.org/t/julia-without-libc-or-bundled-with-non-glibc/66238)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 1\
**Last updated:** [August 12, 2021, 1:01am UTC](https://discourse.julialang.org/t/julia-without-libc-or-bundled-with-non-glibc/66238 "2021-08-12T01:01:58Z")

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What does it take to run Julia without libc? Not fully baremetal, might be a later goal… Very few languages run without libc, e.g. glibc. Zig is an exception but also works with. One option is to bundle with another li…

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## [Which reference is undefined here?](https://discourse.julialang.org/t/which-reference-is-undefined-here/65707)

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**Author:** [@trg818](https://discourse.julialang.org/u/trg818)\
**Replies:** 10\
**Last updated:** [August 11, 2021, 11:38pm UTC](https://discourse.julialang.org/t/which-reference-is-undefined-here/65707 "2021-08-11T23:38:30Z")

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Hi, I’m still quite new to Julia and am trying to make a simple plot. Please consider the following: zth=Vector{Vector{Float64}}(undef,length(DaT)) tth=Vector{Vector{Float64}}(undef,length(DaT)) ... zthcnvplot=plot(tit…

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## [How to sample from a truncated distribution without allocating too much memory](https://discourse.julialang.org/t/how-to-sample-from-a-truncated-distribution-without-allocating-too-much-memory/66232)

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**Author:** [@Frisus95](https://discourse.julialang.org/u/Frisus95)\
**Replies:** 1\
**Last updated:** [August 11, 2021, 10:12pm UTC](https://discourse.julialang.org/t/how-to-sample-from-a-truncated-distribution-without-allocating-too-much-memory/66232 "2021-08-11T22:12:59Z")

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Hello everyone! I’m writing a code that samples millions of times from a truncated distribution. Everything works well and is also enough fast, but I am not satisfied with the memory allocations and the gc time, in my …

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## [Creating an array of symmetric matrix variables in \`JuMP\`](https://discourse.julialang.org/t/creating-an-array-of-symmetric-matrix-variables-in-jump/66229)

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**Author:** [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)\
**Replies:** 2\
**Last updated:** [August 11, 2021, 9:13pm UTC](https://discourse.julialang.org/t/creating-an-array-of-symmetric-matrix-variables-in-jump/66229 "2021-08-11T21:13:23Z")

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Dear All, I am trying to create an array of symmetric matrix variables in JuMP, i.e., an array of matrix variables X\_i\\in\\mathbf{S}^n for i\\in\\{1,2,\\ldots,N\\}. If I had only one symmetric matrix variable X\\in\\mathbf{S}^…

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## [Get training data from saved machine](https://discourse.julialang.org/t/get-training-data-from-saved-machine/66114)

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**Author:** [@Vishal\_Sharma1](https://discourse.julialang.org/u/Vishal_Sharma1)\
**Replies:** 1\
**Last updated:** [August 11, 2021, 9:13pm UTC](https://discourse.julialang.org/t/get-training-data-from-saved-machine/66114 "2021-08-11T21:13:08Z")

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Using MLJ, after saving and retrieving a machine - Is there any method to retrieve the training data that was used to train this machine. I am unable to find any such method in documentation.

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## [Parameterized subtying syntax strangeness](https://discourse.julialang.org/t/parameterized-subtying-syntax-strangeness/66226)

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**Author:** [@Joseph\_Campolongo](https://discourse.julialang.org/u/Joseph_Campolongo)\
**Replies:** 0\
**Last updated:** [August 11, 2021, 8:27pm UTC](https://discourse.julialang.org/t/parameterized-subtying-syntax-strangeness/66226 "2021-08-11T20:27:03Z")

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Given two syntactically different but semantically equal (?) type definitions, one fails with an invalid subtyping error, while the other succeeds. Can someone explain why this is happening? julia\> abstract type F{X} e…

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## [Download/unzip a .zip file](https://discourse.julialang.org/t/download-unzip-a-zip-file/21271)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 3\
**Last updated:** [August 11, 2021, 7:51pm UTC](https://discourse.julialang.org/t/download-unzip-a-zip-file/21271 "2021-08-11T19:51:08Z")

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I set out to download/unzip a .zip file from a URL today and never thought it would be such a problem. I get an error when installing ZipFile.jl and there seems to be a lot of complaints about that package anyways. Can s…

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## [Can You use Julia on Neuromorphic computer](https://discourse.julialang.org/t/can-you-use-julia-on-neuromorphic-computer/66166)

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**Author:** [@development\_mentor](https://discourse.julialang.org/u/development_mentor)\
**Replies:** 5\
**Last updated:** [August 11, 2021, 6:53pm UTC](https://discourse.julialang.org/t/can-you-use-julia-on-neuromorphic-computer/66166 "2021-08-11T18:53:22Z")

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Hello, I have a hypothetical question. Is it possible to use Julia on a different architecture of a computer?

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## [Personal Statement](https://discourse.julialang.org/t/personal-statement/65818)

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**Author:** [@klacru](https://discourse.julialang.org/u/klacru)\
**Replies:** 11\
**Last updated:** [August 11, 2021, 6:11pm UTC](https://discourse.julialang.org/t/personal-statement/65818 "2021-08-11T18:11:06Z")

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Dear Julia community, most of you have a scientific background, I guess, and many of you keep or shall keep their promotional certificates in their hands. The mine is now close to forty years old. I can’t say, I made mu…

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## [Is there any padding function available to pad a matrix or array?](https://discourse.julialang.org/t/is-there-any-padding-function-available-to-pad-a-matrix-or-array/8521)

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**Author:** [@tosalonijain](https://discourse.julialang.org/u/tosalonijain)\
**Replies:** 7\
**Last updated:** [August 11, 2021, 4:54pm UTC](https://discourse.julialang.org/t/is-there-any-padding-function-available-to-pad-a-matrix-or-array/8521 "2021-08-11T16:54:53Z")

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If yes, Please share, if not than also a response would be appreciated.

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## [Julia v1.7.0-beta3 installs old Turing version](https://discourse.julialang.org/t/julia-v1-7-0-beta3-installs-old-turing-version/66185)

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**Author:** [@stst](https://discourse.julialang.org/u/stst)\
**Replies:** 4\
**Last updated:** [August 11, 2021, 4:53pm UTC](https://discourse.julialang.org/t/julia-v1-7-0-beta3-installs-old-turing-version/66185 "2021-08-11T16:53:57Z")

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\] add Turing in the REPL of a fresh Julia v1.7.0-beta3 install on Windows with an emtpy .julia folder installs Turing v0.15.1 instead of the most recent v0.17.0. \] add Turing@v0.17.0 results in an unsatisfiable requirem…

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## [Pgfplotsx TypeError after fresh install](https://discourse.julialang.org/t/pgfplotsx-typeerror-after-fresh-install/58596)

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**Author:** [@OlafTeichert](https://discourse.julialang.org/u/OlafTeichert)\
**Replies:** 9\
**Last updated:** [August 11, 2021, 3:50pm UTC](https://discourse.julialang.org/t/pgfplotsx-typeerror-after-fresh-install/58596 "2021-08-11T15:50:16Z")

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I just reinstalled Julia on a new laptop and am getting an error when using the pgfsplotsx backend. Here is a minimum reproducible example: using Plots pgfplotsx() plot(\[1,2,3,4,5\]) Resulting in the following error me…

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