# Latest

**URL:** https://discourse.julialang.org/latest.md?page=982

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

**Page:** 983

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## [Does Julia use original PCRE or PCRE2?](https://discourse.julialang.org/t/does-julia-use-original-pcre-or-pcre2/84203)

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**Author:** [@ProvocaTeach](https://discourse.julialang.org/u/ProvocaTeach)\
**Replies:** 1\
**Last updated:** [July 14, 2022, 2:36am UTC](https://discourse.julialang.org/t/does-julia-use-original-pcre-or-pcre2/84203 "2022-07-14T02:36:09Z")

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Does Julia 1.7.3 use the original Perl-compatible regular expressions (PCRE) or the second version (PCRE2)? The Julia docs on regexes say Julia uses PCRE, but they link to the PCRE2 spec while making no mention of the v…

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## [Improving the performance of a sum over a vector of vectors](https://discourse.julialang.org/t/improving-the-performance-of-a-sum-over-a-vector-of-vectors/84150)

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**Author:** [@DanielVandH](https://discourse.julialang.org/u/DanielVandH)\
**Replies:** 10\
**Last updated:** [July 13, 2022, 10:36pm UTC](https://discourse.julialang.org/t/improving-the-performance-of-a-sum-over-a-vector-of-vectors/84150 "2022-07-13T22:36:19Z")

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I want to consider the sum over a vector of vectors. Consider the following benchmarks for a problem involving the sum over some data (getting a log-likelihood): using BenchmarkTools, Random, LoopVectorization Random.se…

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## [How to write nested reducibles in Transducers.jl](https://discourse.julialang.org/t/how-to-write-nested-reducibles-in-transducers-jl/84199)

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**Author:** [@nielsls](https://discourse.julialang.org/u/nielsls)\
**Replies:** 0\
**Last updated:** [July 13, 2022, 9:44pm UTC](https://discourse.julialang.org/t/how-to-write-nested-reducibles-in-transducers-jl/84199 "2022-07-13T21:44:32Z")

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Writing reducibles · Transducers.jl describes how to make a non-iterable collection reducible; e.g. how to use it as input to transducers. But it does not describe how to delegate the reducing operation to another reduci…

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## [Stability issue with MethodOfLines](https://discourse.julialang.org/t/stability-issue-with-methodoflines/84133)

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**Author:** [@marcofrancis](https://discourse.julialang.org/u/marcofrancis)\
**Replies:** 9\
**Last updated:** [July 13, 2022, 6:33pm UTC](https://discourse.julialang.org/t/stability-issue-with-methodoflines/84133 "2022-07-13T18:33:31Z")

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Hi! I’m trying to solve a (I would think) simple PDE with MethodOfLines.jl The PDE in question is: \\partial\_\\tau g(τ,x) = \\frac{1}{2}σ^2\\partial^2\_{x} g(τ,x)+ λ(\\bar{x} - x)\*\\partial\_x g(τ,x) - r\*g(τ,x) g(0,x) = e^{…

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## [Arrow in Plots.jl and PyPlot backend can't change arrowhead placement](https://discourse.julialang.org/t/arrow-in-plots-jl-and-pyplot-backend-cant-change-arrowhead-placement/45511)

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**Author:** [@transarcus](https://discourse.julialang.org/u/transarcus)\
**Replies:** 1\
**Last updated:** [July 13, 2022, 6:19pm UTC](https://discourse.julialang.org/t/arrow-in-plots-jl-and-pyplot-backend-cant-change-arrowhead-placement/45511 "2022-07-13T18:19:42Z")

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Trying to create double headed arrow using pyplot though Plots.jl but arrow(:closed,:both) doesn’t do it. arrow(:closed,:tail) also doesn’t seem to change anything. It works as I would expect with the GR backend. Julia …

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## [How do dynamic text content with Makie and record?](https://discourse.julialang.org/t/how-do-dynamic-text-content-with-makie-and-record/84141)

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**Author:** [@evandro.schulz](https://discourse.julialang.org/u/evandro.schulz)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 6:17pm UTC](https://discourse.julialang.org/t/how-do-dynamic-text-content-with-makie-and-record/84141 "2022-07-13T18:17:45Z")

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I’d want to create a animation of a plot that show the changing in the values in the time. Changing the plot charts, ok. But, I want to chance a text content and the scale of x and y axes per i. How I do it? I cannot ind…

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## [Reading LP/MPS file and using callback](https://discourse.julialang.org/t/reading-lp-mps-file-and-using-callback/68254)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 3\
**Last updated:** [July 13, 2022, 5:50pm UTC](https://discourse.julialang.org/t/reading-lp-mps-file-and-using-callback/68254 "2022-07-13T17:50:55Z")

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Hi All, is there a way to read an lp/MPS file in julia and apply the callback function. Thanks, Manoj Kumar

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## [Bifurcation analysis with history in ODEs](https://discourse.julialang.org/t/bifurcation-analysis-with-history-in-odes/84070)

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**Author:** [@nkoch](https://discourse.julialang.org/u/nkoch)\
**Replies:** 12\
**Last updated:** [July 13, 2022, 5:18pm UTC](https://discourse.julialang.org/t/bifurcation-analysis-with-history-in-odes/84070 "2022-07-13T17:18:18Z")

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Hello, I’m relatively new to using Julia and I am trying to do bifurcation analysis. I have a system of ODEs in which one DE depends on the history of another variable (i.e. du\[2\] depends on history of u\[1\]). From what …

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## [Fast Jaccard Distance between sets of strings?](https://discourse.julialang.org/t/fast-jaccard-distance-between-sets-of-strings/84125)

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**Author:** [@tp2750](https://discourse.julialang.org/u/tp2750)\
**Replies:** 3\
**Last updated:** [July 13, 2022, 5:11pm UTC](https://discourse.julialang.org/t/fast-jaccard-distance-between-sets-of-strings/84125 "2022-07-13T17:11:33Z")

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My friend needs to compute the jaccard distance between sets of strings. The number of sets is hundreds and the number of strings in each set is thousands. The length of the strings is \<= 20. He has thousands of dataset…

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## [Windows not searching contents of \*.jl files](https://discourse.julialang.org/t/windows-not-searching-contents-of-jl-files/84123)

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**Author:** [@thompsonmj](https://discourse.julialang.org/u/thompsonmj)\
**Replies:** 5\
**Last updated:** [July 13, 2022, 3:40pm UTC](https://discourse.julialang.org/t/windows-not-searching-contents-of-jl-files/84123 "2022-07-13T15:40:56Z")

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Not sure if this is a Windows issue or what can be done, but I am using Windows Explorer to search for some old code. It isn’t searching the contents of my \*.jl files, but is returning results for contents of other file …

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## [Return duplicate rows in array with no of times and index of first occurence](https://discourse.julialang.org/t/return-duplicate-rows-in-array-with-no-of-times-and-index-of-first-occurence/84176)

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**Author:** [@ayodyas](https://discourse.julialang.org/u/ayodyas)\
**Replies:** 6\
**Last updated:** [July 13, 2022, 3:25pm UTC](https://discourse.julialang.org/t/return-duplicate-rows-in-array-with-no-of-times-and-index-of-first-occurence/84176 "2022-07-13T15:25:09Z")

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I have a matrix A=\[1,2; 2,3; 3,4;1,2\], I wanted to return duplicated rows (here 1,2), no of repetitions (here 1) and the row index of the first occurrence (here 1st row) I have tried many thing with unique, but nothing…

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## [Using DynamicalSystems: InexactError](https://discourse.julialang.org/t/using-dynamicalsystems-inexacterror/83965)

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**Author:** [@Griffith\_Mendonca](https://discourse.julialang.org/u/Griffith_Mendonca)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 2:44pm UTC](https://discourse.julialang.org/t/using-dynamicalsystems-inexacterror/83965 "2022-07-13T14:44:38Z")

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Dear all, I have a question about the meaning of some output messages from the package DynamicalSystems from https://juliadynamics.github.io/DynamicalSystems.jl/latest/chaos/lyapunovs/. This error message appears when I…

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## [Calculation Pi^Pi^Pi in hexadecimal in High precision](https://discourse.julialang.org/t/calculation-pi-pi-pi-in-hexadecimal-in-high-precision/51785)

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**Author:** [@rbdaus](https://discourse.julialang.org/u/rbdaus)\
**Replies:** 61\
**Last updated:** [July 13, 2022, 2:32pm UTC](https://discourse.julialang.org/t/calculation-pi-pi-pi-in-hexadecimal-in-high-precision/51785 "2022-07-13T14:32:51Z")

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Hello! I have a math question. In Wolfram Language I can type this: BaseForm\[N\[Pi^Pi^Pi, 100000\], 16\] and get VERY FAST the result of up to 100,000 hexadecimal digits for the expression “Pi^Pi^Pi” (a few seconds) B…

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## [Println and ProgressMeter in the same loop](https://discourse.julialang.org/t/println-and-progressmeter-in-the-same-loop/32140)

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**Author:** [@benzwick](https://discourse.julialang.org/u/benzwick)\
**Replies:** 6\
**Last updated:** [July 13, 2022, 2:14pm UTC](https://discourse.julialang.org/t/println-and-progressmeter-in-the-same-loop/32140 "2022-07-13T14:14:16Z")

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I am trying to combine println (or @info for logging) and a ProgressMeter progress bar in a loop like this: using ProgressMeter prog = Progress(10) for i in 1:10 println("value: ", i^2) sleep(0.1) next!(prog…

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## [Using BootStrap package to obtain the distribution of mean/sd](https://discourse.julialang.org/t/using-bootstrap-package-to-obtain-the-distribution-of-mean-sd/84164)

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**Author:** [@AnshPatel7](https://discourse.julialang.org/u/AnshPatel7)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 1:57pm UTC](https://discourse.julialang.org/t/using-bootstrap-package-to-obtain-the-distribution-of-mean-sd/84164 "2022-07-13T13:57:30Z")

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Hi, I’m trying to use the bootstrap function to find the mean and sd of a dataset that I have generated. As an example, the following code gives me the mean, error and bias: A = randn(10) m = bootstrap(mean,A, BasicSa…

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## [Elliptic theta functions](https://discourse.julialang.org/t/elliptic-theta-functions/65742)

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**Author:** [@Gabrielmlando](https://discourse.julialang.org/u/Gabrielmlando)\
**Replies:** 15\
**Last updated:** [July 13, 2022, 1:44pm UTC](https://discourse.julialang.org/t/elliptic-theta-functions/65742 "2022-07-13T13:44:26Z")

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Are elliptic theta functions implemented in Julia? They exist in Mathematica as EllipticTheta, but I need them for heavy numerical calculations.

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## [Header = false not working](https://discourse.julialang.org/t/header-false-not-working/84174)

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**Author:** [@Chiem](https://discourse.julialang.org/u/Chiem)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 1:43pm UTC](https://discourse.julialang.org/t/header-false-not-working/84174 "2022-07-13T13:43:58Z")

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Hello everyone, I have been trying to import my data from a CSV into julia; however, I have been unable to import it without a header. Apparantly you can use header = 0 or header = false; however, neither of these work a…

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## [Performance of value assignment inside functions](https://discourse.julialang.org/t/performance-of-value-assignment-inside-functions/84162)

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**Author:** [@NicolasW](https://discourse.julialang.org/u/NicolasW)\
**Replies:** 3\
**Last updated:** [July 13, 2022, 1:20pm UTC](https://discourse.julialang.org/t/performance-of-value-assignment-inside-functions/84162 "2022-07-13T13:20:55Z")

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I am puzzled by the performance of Julia, somehow it matters if I fully specialize the function argument. Consider the two functions: @noinline @inbounds function update\_gen!(y::AbstractVector{T}, x::AbstractVector{T})…

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## [Least-Angle Regression (LARS) package](https://discourse.julialang.org/t/least-angle-regression-lars-package/68424)

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**Author:** [@Frederic\_Gilt](https://discourse.julialang.org/u/Frederic_Gilt)\
**Replies:** 32\
**Last updated:** [July 13, 2022, 1:03pm UTC](https://discourse.julialang.org/t/least-angle-regression-lars-package/68424 "2022-07-13T13:03:34Z")

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Hello I need LARS method and fortunately a package is (was?) available… Unfortunately is has not been updated since several years, so I download the code, remove the call for ArrayViews package which is outdated and doe…

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## [Struct and vectorised function](https://discourse.julialang.org/t/struct-and-vectorised-function/84159)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 12:51pm UTC](https://discourse.julialang.org/t/struct-and-vectorised-function/84159 "2022-07-13T12:51:21Z")

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struct X; x end struct Y; y end f(::X,::Y) = 1 f.( \[X(1),X(1)\], Y(1) ) This gives an error no method matching length(::Y) Is there a way to tell it that the “.” vectorisation of f() is over the vector of X, …

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## [Create New Package in Julia: Why the test is fail?](https://discourse.julialang.org/t/create-new-package-in-julia-why-the-test-is-fail/84166)

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**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 12:43pm UTC](https://discourse.julialang.org/t/create-new-package-in-julia-why-the-test-is-fail/84166 "2022-07-13T12:43:14Z")

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Hi all, I follow https://julialang.org/contribute/developing\_package/ but when I test the package, it fails, it just the beginning of Hello World, not even complicated. Why is it fails?

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## [\[ANN\] ProtoSyn.jl v1.1: Molecular manipulation and simulation](https://discourse.julialang.org/t/ann-protosyn-jl-v1-1-molecular-manipulation-and-simulation/84158)

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**Author:** [@JosePereiraUA](https://discourse.julialang.org/u/JosePereiraUA)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 12:39pm UTC](https://discourse.julialang.org/t/ann-protosyn-jl-v1-1-molecular-manipulation-and-simulation/84158 "2022-07-13T12:39:24Z")

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Hi everyone! I’m excited to officially share with you ProtoSyn.jl: a new tool for molecular simulation and general manipulation, with a strong emphasis on protein design. I’ve been showcasing ProtoSyn.jl for a while, but…

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## [Matrices vs vectors of vectors performance](https://discourse.julialang.org/t/matrices-vs-vectors-of-vectors-performance/84157)

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**Author:** [@Dario-Rosa85](https://discourse.julialang.org/u/Dario-Rosa85)\
**Replies:** 3\
**Last updated:** [July 13, 2022, 12:35pm UTC](https://discourse.julialang.org/t/matrices-vs-vectors-of-vectors-performance/84157 "2022-07-13T12:35:32Z")

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Coming from Mathematica I have been used on thinking about matrices as lists of lists. Hence, I use the same point of view in Julia and, when I have many vectors to be treated homogeneously, I pack them into vectors of v…

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## [Function that accepts scalars or one element vectors/ arrays](https://discourse.julialang.org/t/function-that-accepts-scalars-or-one-element-vectors-arrays/84040)

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**Author:** [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Replies:** 9\
**Last updated:** [July 13, 2022, 12:23pm UTC](https://discourse.julialang.org/t/function-that-accepts-scalars-or-one-element-vectors-arrays/84040 "2022-07-13T12:23:19Z")

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I would like to restrict a function to accept only argument values which contain only one number, how can this be achieved? My example below accept already scalars, vectors and arrays, but the argument value is not restr…

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## [Request for comments on gmsh documentation](https://discourse.julialang.org/t/request-for-comments-on-gmsh-documentation/84165)

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**Author:** [@gwlagerweij](https://discourse.julialang.org/u/gwlagerweij)\
**Replies:** 0\
**Last updated:** [July 13, 2022, 11:44am UTC](https://discourse.julialang.org/t/request-for-comments-on-gmsh-documentation/84165 "2022-07-13T11:44:43Z")

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Hi all, I have written a small introduction and guide to using gmsh in combination with Julia. This documentation is meant for students of a master-level course on the finite element method for electrical engineers (fur…

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## [Can not use python package although conda status correct](https://discourse.julialang.org/t/can-not-use-python-package-although-conda-status-correct/84155)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 11:32am UTC](https://discourse.julialang.org/t/can-not-use-python-package-although-conda-status-correct/84155 "2022-07-13T11:32:58Z")

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Hello I am using PythonCall and I want to use library simpleitk, (in pure python it always works it is well established package) I added it to Conda.toml all installs but I am unable to load it using pyimport, any help w…

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## [How to find jacobian of neural network model for current variables only and not history variables](https://discourse.julialang.org/t/how-to-find-jacobian-of-neural-network-model-for-current-variables-only-and-not-history-variables/84161)

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**Author:** [@umerzakheer](https://discourse.julialang.org/u/umerzakheer)\
**Replies:** 0\
**Last updated:** [July 13, 2022, 11:10am UTC](https://discourse.julialang.org/t/how-to-find-jacobian-of-neural-network-model-for-current-variables-only-and-not-history-variables/84161 "2022-07-13T11:10:32Z")

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My data for training neural network model contains current variables and also history variables to find best fit for non-linear function. Training perfomance is very good and model can predict data with very low error. M…

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## [Degree modification of multivariate polynomial chaos surrogate model](https://discourse.julialang.org/t/degree-modification-of-multivariate-polynomial-chaos-surrogate-model/84145)

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**Author:** [@chenr86](https://discourse.julialang.org/u/chenr86)\
**Replies:** 2\
**Last updated:** [July 13, 2022, 9:00am UTC](https://discourse.julialang.org/t/degree-modification-of-multivariate-polynomial-chaos-surrogate-model/84145 "2022-07-13T09:00:22Z")

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Hello, I am using Surrogate.jl to build my polynomial choas surrogate model. The model is multivariate, with 4 input parameters, and 1D output. I want to change the parameter op = SurrogatesPolyChaos.GaussOrthoPoly(5) o…

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## [GLFW' GLMakie error](https://discourse.julialang.org/t/glfw-glmakie-error/84153)

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**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 0\
**Last updated:** [July 13, 2022, 8:30am UTC](https://discourse.julialang.org/t/glfw-glmakie-error/84153 "2022-07-13T08:30:59Z")

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Hi all, Ï am using an OS that has no internet. Ï try to use a package, an error occurs: GLFW error API\_UNAVAILABLE ï can run OpenGL example fine

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## [Composite image of multiple channels](https://discourse.julialang.org/t/composite-image-of-multiple-channels/84066)

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**Author:** [@thompsonmj](https://discourse.julialang.org/u/thompsonmj)\
**Replies:** 12\
**Last updated:** [July 13, 2022, 7:39am UTC](https://discourse.julialang.org/t/composite-image-of-multiple-channels/84066 "2022-07-13T07:39:02Z")

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I have 3 images, each a separate channel of the same sample. c1 = rand(100,100) c2 = rand(100,100) c3 = rand(100,100) I’d like to make a custom color gradient for each channel: using Plots pal = palette(:batlow,3) gra…

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