# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1053

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

**Page:** 1054

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## [convert(Regex, ::DateFormat)?](https://discourse.julialang.org/t/convert-regex-dateformat/80335)

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**Author:** [@mgm7734](https://discourse.julialang.org/u/mgm7734)\
**Replies:** 1\
**Last updated:** [May 1, 2022, 5:24pm UTC](https://discourse.julialang.org/t/convert-regex-dateformat/80335 "2022-05-01T17:24:25Z")

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I’m processing some ugly log-files that contain different timestamp formats. So I want to both search for an timestamp embedded in the line with a Regex, and then parse the timestamp if I find it. To keep things DRY, i…

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## [Franklin.jl not building on 1.7.1](https://discourse.julialang.org/t/franklin-jl-not-building-on-1-7-1/79745)

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**Author:** [@liamfdoherty](https://discourse.julialang.org/u/liamfdoherty)\
**Replies:** 2\
**Last updated:** [May 1, 2022, 4:35pm UTC](https://discourse.julialang.org/t/franklin-jl-not-building-on-1-7-1/79745 "2022-05-01T16:35:39Z")

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Hi all, I have previously used Franklin.jl (on 1.6.x) for my personal website, but I have not updated my site since upgrading to Julia 1.7.x. I tried to reinstall Franklin for 1.7.1 today, and get the following error du…

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## [Multiplication of 2 positive numbers gives a negative product](https://discourse.julialang.org/t/multiplication-of-2-positive-numbers-gives-a-negative-product/80323)

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**Author:** [@Brinkhuis](https://discourse.julialang.org/u/Brinkhuis)\
**Replies:** 11\
**Last updated:** [May 1, 2022, 4:25pm UTC](https://discourse.julialang.org/t/multiplication-of-2-positive-numbers-gives-a-negative-product/80323 "2022-05-01T16:25:32Z")

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In Julia 1.7.2 multiplication of 3037000691 and 3037000693 returns the negative product -9223370870501072753. The product I expected is 9223373203208478863. function m(a::BigInt, b::BigInt)::BigInt a \* b end This f…

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## [Interpolation and expression evaluation](https://discourse.julialang.org/t/interpolation-and-expression-evaluation/80283)

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**Author:** [@HJW019](https://discourse.julialang.org/u/HJW019)\
**Replies:** 5\
**Last updated:** [May 1, 2022, 4:19pm UTC](https://discourse.julialang.org/t/interpolation-and-expression-evaluation/80283 "2022-05-01T16:19:29Z")

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Hi: I tried to use interpolation to construct a name of an existing vector and pick the vector for further processing. However, I couldn’t make it to work. The following is an MWE. data2=ones(2); data3=zeros(3); functi…

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## [Check whether an array contains a object](https://discourse.julialang.org/t/check-whether-an-array-contains-a-object/80328)

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**Author:** [@ke\_xu](https://discourse.julialang.org/u/ke_xu)\
**Replies:** 3\
**Last updated:** [May 1, 2022, 3:38pm UTC](https://discourse.julialang.org/t/check-whether-an-array-contains-a-object/80328 "2022-05-01T15:38:52Z")

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Suppose I have an array of some objects, struct Obj v::Int64 end o1 = Obj(1) o2 = Obj(1) os = \[o1\] if use “in” to check if os contains o2 o2 in os it returns true. Because the “in” operator compares elements by “==”…

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## [Why don't objects of my type show in Pluto?](https://discourse.julialang.org/t/why-dont-objects-of-my-type-show-in-pluto/80296)

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**Author:** [@bwanab](https://discourse.julialang.org/u/bwanab)\
**Replies:** 5\
**Last updated:** [May 1, 2022, 2:45pm UTC](https://discourse.julialang.org/t/why-dont-objects-of-my-type-show-in-pluto/80296 "2022-05-01T14:45:04Z")

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I’ve got a type for which I’ve implemented show. When I’ve got an instantiation of the type in a Pluto doc called val, it doesn’t display when I evaluate its name unless I explicitly call show(val) or print(val). In cont…

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## [How to find frequency count for consecutive actions?](https://discourse.julialang.org/t/how-to-find-frequency-count-for-consecutive-actions/78582)

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**Author:** [@xinchin](https://discourse.julialang.org/u/xinchin)\
**Replies:** 10\
**Last updated:** [May 1, 2022, 10:09am UTC](https://discourse.julialang.org/t/how-to-find-frequency-count-for-consecutive-actions/78582 "2022-05-01T10:09:09Z")

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I have a few sizable data sets with rows contains actions of a person in different days. I want to summarize the data as a frequency table that shows the number of times that a specific action followed by another action.…

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## [Cannot change colorbar position](https://discourse.julialang.org/t/cannot-change-colorbar-position/17181)

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**Author:** [@shipengcheng1230](https://discourse.julialang.org/u/shipengcheng1230)\
**Replies:** 6\
**Last updated:** [May 1, 2022, 9:13am UTC](https://discourse.julialang.org/t/cannot-change-colorbar-position/17181 "2022-05-01T09:13:13Z")

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I am trying to change the colorbar position: using Plots # pyplot() plot(rand(10, 2), marker\_z=rand(10), seriestype=:scatter, cb=:top) But the colorbar position won’t move no matter how I specifiy :cb: It is always …

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## [Why doesn't this return the intended value](https://discourse.julialang.org/t/why-doesnt-this-return-the-intended-value/79916)

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**Author:** [@AlexanderChen](https://discourse.julialang.org/u/AlexanderChen)\
**Replies:** 25\
**Last updated:** [May 1, 2022, 8:25am UTC](https://discourse.julialang.org/t/why-doesnt-this-return-the-intended-value/79916 "2022-05-01T08:25:28Z")

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Hi, Background: this is the last part of my implementation of the huffman compression. The good news is, it seems to work the print(decoded\_string) give back the string it decoded before. But it does not return it. it …

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## [Performance and allocation with recursive tree-equations](https://discourse.julialang.org/t/performance-and-allocation-with-recursive-tree-equations/79628)

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**Author:** [@Vik1](https://discourse.julialang.org/u/Vik1)\
**Replies:** 12\
**Last updated:** [May 1, 2022, 8:24am UTC](https://discourse.julialang.org/t/performance-and-allocation-with-recursive-tree-equations/79628 "2022-05-01T08:24:44Z")

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Hi Julia community, I am trying to build a tree-equations structure, which should evaluate as efficiently as possible. I’ve tried many different approaches so far, but can’t get rid of some allocations and some of the b…

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## [@time and @btime report different values?](https://discourse.julialang.org/t/time-and-btime-report-different-values/80087)

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**Author:** [@Seif\_Shebl](https://discourse.julialang.org/u/Seif_Shebl)\
**Replies:** 17\
**Last updated:** [May 1, 2022, 5:55am UTC](https://discourse.julialang.org/t/time-and-btime-report-different-values/80087 "2022-05-01T05:55:23Z")

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When timing the following function, I noticed that the @time macro shows a value, that I assume is correct, whereas @btime shows a different value. This only occurs in Julia 1.8.0-DEV and 1.9.0-DEV. Did I make a mistake? …

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## [Unable to set\_optimizer\_attribute in BilevelJuMP.jl](https://discourse.julialang.org/t/unable-to-set-optimizer-attribute-in-bileveljump-jl/80240)

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**Author:** [@math\_opt](https://discourse.julialang.org/u/math_opt)\
**Replies:** 6\
**Last updated:** [May 1, 2022, 4:49am UTC](https://discourse.julialang.org/t/unable-to-set-optimizer-attribute-in-bileveljump-jl/80240 "2022-05-01T04:49:18Z")

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I am trying to change the MIPGap parameter for Guorbi: using JuMP, Gurobi, BilevelJuMP model = BilevelModel(Gurobi.Optimizer, mode = BilevelJuMP.SOS1Mode()) set\_optimizer\_attribute(model, "MIPGap", 1e-5) Throws error: …

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## [Split dataframe row into multiple rows](https://discourse.julialang.org/t/split-dataframe-row-into-multiple-rows/80214)

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**Author:** [@Elmo](https://discourse.julialang.org/u/Elmo)\
**Replies:** 8\
**Last updated:** [May 1, 2022, 1:16am UTC](https://discourse.julialang.org/t/split-dataframe-row-into-multiple-rows/80214 "2022-05-01T01:16:57Z")

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Hi all, I am pretty new to using DataFrames (but loving it so far), however, I could not find an obvious way to achieve the following transformation in the docs. Suppose I have a dataframe df below: julia\> using DataF…

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## [Pivot\_longer a multidimensional array](https://discourse.julialang.org/t/pivot-longer-a-multidimensional-array/80114)

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**Author:** [@Marco\_Repetto](https://discourse.julialang.org/u/Marco_Repetto)\
**Replies:** 2\
**Last updated:** [May 1, 2022, 1:09am UTC](https://discourse.julialang.org/t/pivot-longer-a-multidimensional-array/80114 "2022-05-01T01:09:36Z")

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I would like to transform a multidimensional array into a matrix of indexes and with the last column being the value itself. In a similar fashion to what pivot\_longer does in R. As an example, this 3-D array: rand(2,2,…

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## [Performance of writing binary files](https://discourse.julialang.org/t/performance-of-writing-binary-files/80278)

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**Author:** [@mkoculak](https://discourse.julialang.org/u/mkoculak)\
**Replies:** 2\
**Last updated:** [April 30, 2022, 9:53pm UTC](https://discourse.julialang.org/t/performance-of-writing-binary-files/80278 "2022-04-30T21:53:07Z")

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I am creating a function to write binary data (a data array) to a file. First, I have just reversed the reading function (which reads data almost one byte at a time) and performed a sequential write, but noticed it took…

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## [Pair{Symbol, Function} slower than equivalent non-parametric type](https://discourse.julialang.org/t/pair-symbol-function-slower-than-equivalent-non-parametric-type/80295)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 4\
**Last updated:** [April 30, 2022, 9:21pm UTC](https://discourse.julialang.org/t/pair-symbol-function-slower-than-equivalent-non-parametric-type/80295 "2022-04-30T21:21:39Z")

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Consider a list of symbol and functions: julia\> macro big\_closure\_list(T, n) esc(:($T\[$(\[:($T(:x, ()-\>$(Symbol(:v, i)))) for i in 1:n\]...)\])) end; julia\> @macroexpand @big\_closure\_list(Pair,…

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## [Perform a multi-column, multi-dimensional search quickly](https://discourse.julialang.org/t/perform-a-multi-column-multi-dimensional-search-quickly/75113)

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**Author:** [@Hikaru\_Matsuoka](https://discourse.julialang.org/u/Hikaru_Matsuoka)\
**Replies:** 9\
**Last updated:** [April 30, 2022, 8:22pm UTC](https://discourse.julialang.org/t/perform-a-multi-column-multi-dimensional-search-quickly/75113 "2022-04-30T20:22:04Z")

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I would like to perform a multi-column search from a multi-dimensional matrix like the one below, is there a fast way to do this? (In the example below, I want to get the rows next to -5.0 3.0 2.0) Test\_matrix = \[-5.0…

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## [What's the largest factors in latency?](https://discourse.julialang.org/t/whats-the-largest-factors-in-latency/80302)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 0\
**Last updated:** [April 30, 2022, 5:57pm UTC](https://discourse.julialang.org/t/whats-the-largest-factors-in-latency/80302 "2022-04-30T17:57:28Z")

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A) For startup of Julia itself B) For running scripts I know some workaround for B) such as -O0 or --compile=min which often goes too far (I’m looking for a middle-ground with as fast startup as Python), is there any r…

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## [Why is this MLP slower in Flux than in TensorFlow?](https://discourse.julialang.org/t/why-is-this-mlp-slower-in-flux-than-in-tensorflow/80272)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 5\
**Last updated:** [April 30, 2022, 3:39pm UTC](https://discourse.julialang.org/t/why-is-this-mlp-slower-in-flux-than-in-tensorflow/80272 "2022-04-30T15:39:57Z")

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I am working with some MLPs and noticed that TensorFlow is much faster than Flux. In the examples below, Flux requires about 20 minutes and TensorFlow requires just over a minute. Am I doing something incorrectly? Thank…

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## [Turing: censored regression example](https://discourse.julialang.org/t/turing-censored-regression-example/53837)

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**Author:** [@drbenvincent](https://discourse.julialang.org/u/drbenvincent)\
**Replies:** 9\
**Last updated:** [April 30, 2022, 3:07pm UTC](https://discourse.julialang.org/t/turing-censored-regression-example/53837 "2022-04-30T15:07:28Z")

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Building upon my previous example of truncated regression, I thought I’d do a worked example of censored regression. To clarify, censoring is where observations below a lower bound and/or observations above an upper boun…

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## [Julia CSV.read stopped working](https://discourse.julialang.org/t/julia-csv-read-stopped-working/80247)

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**Author:** [@jjdegruijter](https://discourse.julialang.org/u/jjdegruijter)\
**Replies:** 32\
**Last updated:** [April 30, 2022, 1:19pm UTC](https://discourse.julialang.org/t/julia-csv-read-stopped-working/80247 "2022-04-30T13:19:29Z")

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I’ve been using CSV.read very often, but yesterday it didn’t work anymore. From another thread on this issue I understand that it may be caused by incompatibility of packages, but I haven’t seen a solution yet. I use ju…

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## [Nvidia Jetson Nano](https://discourse.julialang.org/t/nvidia-jetson-nano/22053)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 39\
**Last updated:** [April 30, 2022, 12:48pm UTC](https://discourse.julialang.org/t/nvidia-jetson-nano/22053 "2022-04-30T12:48:51Z")

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Juilia already runs on the Raspberry Pi. Would this be a good system for prototyping Flux.jl applications? Maybe a bit short on memory.

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## [Installing Julia on jetson nano is it worth it?](https://discourse.julialang.org/t/installing-julia-on-jetson-nano-is-it-worth-it/64865)

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**Author:** [@anon69491625](https://discourse.julialang.org/u/anon69491625)\
**Replies:** 5\
**Last updated:** [April 30, 2022, 12:44pm UTC](https://discourse.julialang.org/t/installing-julia-on-jetson-nano-is-it-worth-it/64865 "2022-04-30T12:44:26Z")

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I have a jetson nano and want to load up linux and add julia to work on cuda coding. I have read that I should NOT install the Julia binaries but to MAKE the julia environment and then it works perfectly. The issue I hav…

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## [Two questions related to using operators in ApproxFun.jl](https://discourse.julialang.org/t/two-questions-related-to-using-operators-in-approxfun-jl/79831)

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**Author:** [@andreasvarga](https://discourse.julialang.org/u/andreasvarga)\
**Replies:** 10\
**Last updated:** [April 30, 2022, 12:32pm UTC](https://discourse.julialang.org/t/two-questions-related-to-using-operators-in-approxfun-jl/79831 "2022-04-30T12:32:01Z")

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I am about to register PeriodicSystems.jl, a new package dedicated to handle linear control systems with periodic time-varying coefficient matrices. For stability analysis, the computation of characteristic exponents of …

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## [Scope of Included Files](https://discourse.julialang.org/t/scope-of-included-files/80264)

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**Author:** [@astrobc1](https://discourse.julialang.org/u/astrobc1)\
**Replies:** 11\
**Last updated:** [April 30, 2022, 11:45am UTC](https://discourse.julialang.org/t/scope-of-included-files/80264 "2022-04-30T11:45:14Z")

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In my understanding, the scope of an included file includes the scope of the file it was include’d in. For example: file1.jl: abstract type AbstractFoo end include("file2.jl") file2.jl: struct Foo \<: AbstractFoo end …

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## [\[ANN\] Introduction to Scientific Programming and Machine Learning with Julia MOOC](https://discourse.julialang.org/t/ann-introduction-to-scientific-programming-and-machine-learning-with-julia-mooc/80277)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 0\
**Last updated:** [April 29, 2022, 10:50pm UTC](https://discourse.julialang.org/t/ann-introduction-to-scientific-programming-and-machine-learning-with-julia-mooc/80277 "2022-04-29T22:50:28Z")

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Dear all, let me announce a new relatively large (15h videos, 15 interactive quizzes with 52 questions, 7 guided exercises), interactive , multi-channel and collaborative course on Introduction to Scientific Programming…

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## [Truncated SVD of extended precision matrix](https://discourse.julialang.org/t/truncated-svd-of-extended-precision-matrix/78989)

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**Author:** [@Samuel3008](https://discourse.julialang.org/u/Samuel3008)\
**Replies:** 6\
**Last updated:** [April 30, 2022, 10:03am UTC](https://discourse.julialang.org/t/truncated-svd-of-extended-precision-matrix/78989 "2022-04-30T10:03:21Z")

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Hi, is anybody aware of a way to compute the truncated SVD of an extended precision (128 bit floats in my case) matrix? For the floats, I’d like to use either MultiFloats.jl (seems faster in my testing, so this would be…

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## [Julia plots layout](https://discourse.julialang.org/t/julia-plots-layout/80221)

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**Author:** [@francesco123212](https://discourse.julialang.org/u/francesco123212)\
**Replies:** 1\
**Last updated:** [April 28, 2022, 9:13pm UTC](https://discourse.julialang.org/t/julia-plots-layout/80221 "2022-04-28T21:13:33Z")

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Hi everyone, I currently am working on a plot with 3 rows of plots, using layout = layout(3,1). My issue is related to the x axis mismatch between the first diagram and the other 2; how should I fix it? thankyou in …

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## [Split DateTime column into separate Date and Time Columns](https://discourse.julialang.org/t/split-datetime-column-into-separate-date-and-time-columns/80228)

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**Author:** [@phantom](https://discourse.julialang.org/u/phantom)\
**Replies:** 20\
**Last updated:** [April 30, 2022, 6:39am UTC](https://discourse.julialang.org/t/split-datetime-column-into-separate-date-and-time-columns/80228 "2022-04-30T06:39:03Z")

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Suppose I have a Dataframe F with a column of DateTime data as follows, Number DateTime Int64 DateTime 1 │73 2022-03-21T20:00:00 2 │80 2022-03-21T19:56:00 …

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## [Odd disappearance of some packages on update](https://discourse.julialang.org/t/odd-disappearance-of-some-packages-on-update/80241)

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**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 6\
**Last updated:** [April 30, 2022, 3:42am UTC](https://discourse.julialang.org/t/odd-disappearance-of-some-packages-on-update/80241 "2022-04-30T03:42:41Z")

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I have a Julia package that uses Optim with autodiff. I believe because of that Calculus and DualNumbers have been part of my environment. I just did a package update and both Calculus and DualNumbers were removed, des…

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