# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1264

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

**Page:** 1265

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## [Why with @threads, the execution time is worse?](https://discourse.julialang.org/t/why-with-threads-the-execution-time-is-worse/68160)

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**Author:** [@Amro](https://discourse.julialang.org/u/Amro)\
**Replies:** 19\
**Last updated:** [September 16, 2021, 9:44pm UTC](https://discourse.julialang.org/t/why-with-threads-the-execution-time-is-worse/68160 "2021-09-16T21:44:37Z")

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I am running the below code on 6 physical core computer: using SparseArrays; using LinearAlgebra; using .Threads using BenchmarkTools dt = 0.001; tmin = 0; tmax = 5; timeSim = tmin:dt:tmax; NodeVoltage = zeros(…

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## [What is the best tool to use for weighting matrices](https://discourse.julialang.org/t/what-is-the-best-tool-to-use-for-weighting-matrices/68218)

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**Author:** [@Nenndul](https://discourse.julialang.org/u/Nenndul)\
**Replies:** 8\
**Last updated:** [September 16, 2021, 8:18pm UTC](https://discourse.julialang.org/t/what-is-the-best-tool-to-use-for-weighting-matrices/68218 "2021-09-16T20:18:10Z")

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I have a problem that involves combining several matrices with a weighted average to optimize for a given feature, such as the average value of over the data in the resulting matrix. The setup is essentially like this. …

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## [How to choose which parameters to estimate in parameter estimation when using diffeqflux.sciml\_train and BBO?](https://discourse.julialang.org/t/how-to-choose-which-parameters-to-estimate-in-parameter-estimation-when-using-diffeqflux-sciml-train-and-bbo/68280)

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**Author:** [@shwetank\_verma](https://discourse.julialang.org/u/shwetank_verma)\
**Replies:** 1\
**Last updated:** [September 16, 2021, 7:52pm UTC](https://discourse.julialang.org/t/how-to-choose-which-parameters-to-estimate-in-parameter-estimation-when-using-diffeqflux-sciml-train-and-bbo/68280 "2021-09-16T19:52:26Z")

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Hey everyone, I am trying to do parameter estimation for a set of differential equations using diffeqflux\_sciml\_train and BBO. However, I would like to choose which parameters I want to estimate and which ones I don’t wa…

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## [Matrix factorization with Symbolics.jl](https://discourse.julialang.org/t/matrix-factorization-with-symbolics-jl/68266)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 3\
**Last updated:** [September 16, 2021, 7:51pm UTC](https://discourse.julialang.org/t/matrix-factorization-with-symbolics-jl/68266 "2021-09-16T19:51:56Z")

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I want to factorize a small matrix of integers symbolically with Symbols.jl. For examble A = \[0 1; 1 0\] How do I get symbolically the spectral decomposition? I could not find a way to specify a symbolic 1 with Symbolic…

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## [Defining function as scalar vs fusing with two Ref's, significant speed difference](https://discourse.julialang.org/t/defining-function-as-scalar-vs-fusing-with-two-refs-significant-speed-difference/68273)

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**Author:** [@cosmia](https://discourse.julialang.org/u/cosmia)\
**Replies:** 1\
**Last updated:** [September 16, 2021, 6:26pm UTC](https://discourse.julialang.org/t/defining-function-as-scalar-vs-fusing-with-two-refs-significant-speed-difference/68273 "2021-09-16T18:26:50Z")

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I wonder why there are significant differences in performance between these two functions. The core functions are the tt and tt1, one in which I use @. to broadcast the results, and the other where I write everything as …

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## [Propagating Nothing when a parameter is Nothing generically](https://discourse.julialang.org/t/propagating-nothing-when-a-parameter-is-nothing-generically/68270)

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**Author:** [@Bob2](https://discourse.julialang.org/u/Bob2)\
**Replies:** 6\
**Last updated:** [September 16, 2021, 5:41pm UTC](https://discourse.julialang.org/t/propagating-nothing-when-a-parameter-is-nothing-generically/68270 "2021-09-16T17:41:50Z")

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I want something like this for a collection of a couple dozen small functions. f(a::Nothing, b) = nothing f(a, b::Nothing) = nothing f(a::Nothing, b::Nothing) = nothing f(a, b) = a + b But I wish to do so without addi…

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## [Package for multi label classification](https://discourse.julialang.org/t/package-for-multi-label-classification/46156)

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**Author:** [@Rajeev\_Gangal](https://discourse.julialang.org/u/Rajeev_Gangal)\
**Replies:** 2\
**Last updated:** [September 16, 2021, 5:11pm UTC](https://discourse.julialang.org/t/package-for-multi-label-classification/46156 "2021-09-16T17:11:35Z")

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What’s the best ML package to use for multi-label classification in Julia? Hopefully, it will have multiple algorithms. Else, do suggest particular packages too. MLJ? Flux? or TensorFlow etc

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## [NamedVecs.jl - Is this a good idea?](https://discourse.julialang.org/t/namedvecs-jl-is-this-a-good-idea/68275)

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**Author:** [@Per](https://discourse.julialang.org/u/Per)\
**Replies:** 4\
**Last updated:** [September 16, 2021, 4:41pm UTC](https://discourse.julialang.org/t/namedvecs-jl-is-this-a-good-idea/68275 "2021-09-16T16:41:49Z")

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The Julia ecosystem is reaching a size where, if something seems like a good idea, there’s probably a package for it. And conversely, if there is no package, then there’s probably a reason why such a package is not a goo…

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## [Multiple camera views on same scene in Makie](https://discourse.julialang.org/t/multiple-camera-views-on-same-scene-in-makie/68274)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 3\
**Last updated:** [September 16, 2021, 4:22pm UTC](https://discourse.julialang.org/t/multiple-camera-views-on-same-scene-in-makie/68274 "2021-09-16T16:22:03Z")

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I’d like to have two views of the same scene / data in Makie. Below is code for the output that I want, but I would like to just have one call to scatter! (for example). using Makie: Makie, Observable using GLMakie: GLM…

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## [Matrix division \\ for sparse and singular matrices](https://discourse.julialang.org/t/matrix-division-for-sparse-and-singular-matrices/68253)

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**Author:** [@blob](https://discourse.julialang.org/u/blob)\
**Replies:** 7\
**Last updated:** [September 16, 2021, 3:26pm UTC](https://discourse.julialang.org/t/matrix-division-for-sparse-and-singular-matrices/68253 "2021-09-16T15:26:30Z")

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It seems that the behaviour of matrix division \\ is inconsistent if sparse matrices are used: using LinearAlgebra, SparseArrays A1=\[1 1 ;0 0.0\] B1=\[4; 0.0\] x1=A1\\B1 #Error: LAPACKException(2) x2=sparse(A1)\\sparse(B1…

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## [Capture the stdout output of a ccall?](https://discourse.julialang.org/t/capture-the-stdout-output-of-a-ccall/68262)

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**Author:** [@carstenbauer](https://discourse.julialang.org/u/carstenbauer)\
**Replies:** 4\
**Last updated:** [September 16, 2021, 2:41pm UTC](https://discourse.julialang.org/t/capture-the-stdout-output-of-a-ccall/68262 "2021-09-16T14:41:31Z")

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I’m ccalling a function in a shared lib which writes something to stdout (i.e. it appears it the terminal). Is it possible to capture this text output? Among other things, I tried mktemp() do path, io redirect\_stdou…

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## [Multiple Outputs (Tuple) from IfElse with VectorizationBase](https://discourse.julialang.org/t/multiple-outputs-tuple-from-ifelse-with-vectorizationbase/68255)

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**Author:** [@disberd](https://discourse.julialang.org/u/disberd)\
**Replies:** 3\
**Last updated:** [September 16, 2021, 2:36pm UTC](https://discourse.julialang.org/t/multiple-outputs-tuple-from-ifelse-with-vectorizationbase/68255 "2021-09-16T14:36:08Z")

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Hi there, I am trying to experiment a bit with VectorizationBase to create functions that can be used inside the @turbo macro from LoopVectorization. I have a use case where my computation can be significantly sped up …

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## [Notebook in vscode: what is the status now?](https://discourse.julialang.org/t/notebook-in-vscode-what-is-the-status-now/68243)

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**Author:** [@Chong\_Wang](https://discourse.julialang.org/u/Chong_Wang)\
**Replies:** 0\
**Last updated:** [September 16, 2021, 5:15am UTC](https://discourse.julialang.org/t/notebook-in-vscode-what-is-the-status-now/68243 "2021-09-16T05:15:27Z")

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In vscode notebooks, the autocompletion seldom works for me. There are several situations: Jupyter extension, Julia extension not installed. Jupyter extension, Julia extension installed. Kernel handled by jupyte…

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## [Julia server keeps crashing in vscode after I added MKL.jl](https://discourse.julialang.org/t/julia-server-keeps-crashing-in-vscode-after-i-added-mkl-jl/68259)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 2\
**Last updated:** [September 16, 2021, 12:52pm UTC](https://discourse.julialang.org/t/julia-server-keeps-crashing-in-vscode-after-i-added-mkl-jl/68259 "2021-09-16T12:52:01Z")

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I keep receiving this error: fatal: error thrown and no exception handler available. InitError(mod=:IntelOpenMP\_jll, error=ErrorException("Artifact "IntelOpenMP" was not installed correctly. Try \`using Pkg; Pkg.instanti…

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## [LibSSH2\_jll fails to precompile](https://discourse.julialang.org/t/libssh2-jll-fails-to-precompile/68247)

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**Author:** [@clarakoehne](https://discourse.julialang.org/u/clarakoehne)\
**Replies:** 1\
**Last updated:** [September 16, 2021, 11:48am UTC](https://discourse.julialang.org/t/libssh2-jll-fails-to-precompile/68247 "2021-09-16T11:48:19Z")

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Hey there, I’m trying to compile a project using the PackageCompiler module. The compilation is part of a conda build process, i.e. I’m trying to make and upload a bioconda package from my project. However, I get the fo…

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## [Plotting by multiple factors](https://discourse.julialang.org/t/plotting-by-multiple-factors/68237)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 4\
**Last updated:** [September 16, 2021, 11:42am UTC](https://discourse.julialang.org/t/plotting-by-multiple-factors/68237 "2021-09-16T11:42:25Z")

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Hi all, I have a dataset with three factors and one dependent variable. In the example below, how do I get all of the linear data in the top plot and all of the exponential data in the bottom plot. I tried changing the …

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## [MethodError: no method matching DMatrix](https://discourse.julialang.org/t/methoderror-no-method-matching-dmatrix/68202)

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**Author:** [@Billpete002](https://discourse.julialang.org/u/Billpete002)\
**Replies:** 2\
**Last updated:** [September 16, 2021, 10:41am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-dmatrix/68202 "2021-09-16T10:41:14Z")

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Hi All, After fixing my one-hot encoding issue I’ve split my code into test and train but I am struggling to get XGBoost’s DMatrix to run. All of my variables are numeric (with the exception of my label, which I did tes…

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## [Better documentation for properties vs. fields](https://discourse.julialang.org/t/better-documentation-for-properties-vs-fields/68173)

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**Author:** [@nandoconde](https://discourse.julialang.org/u/nandoconde)\
**Replies:** 7\
**Last updated:** [September 16, 2021, 9:38am UTC](https://discourse.julialang.org/t/better-documentation-for-properties-vs-fields/68173 "2021-09-16T09:38:57Z")

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Background I found myself often using the quite uncomfortable fieldnames(typeof(x)) Searching for something unrelated, I found in an old thread this magic: propertynames(x) Which turns out to be a fantastic alternati…

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## [Running a pre-trained BERT on twitter data using Flux.jl Transformer.jl](https://discourse.julialang.org/t/running-a-pre-trained-bert-on-twitter-data-using-flux-jl-transformer-jl/67721)

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**Author:** [@Storopoli](https://discourse.julialang.org/u/Storopoli)\
**Replies:** 17\
**Last updated:** [September 16, 2021, 9:24am UTC](https://discourse.julialang.org/t/running-a-pre-trained-bert-on-twitter-data-using-flux-jl-transformer-jl/67721 "2021-09-16T09:24:41Z")

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Hi everybody! I have 8k labelled twitter data with either a 0 or 1 (binary classification). MLJ.jl with classical machine learning has not very good performance with the problem. I am trying to fit a pre-trained BERT t…

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## [How to nest \`@auto\_hash\_equals\` & \`@with\_kw\`?](https://discourse.julialang.org/t/how-to-nest-auto-hash-equals-with-kw/33121)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 2\
**Last updated:** [September 16, 2021, 7:12am UTC](https://discourse.julialang.org/t/how-to-nest-auto-hash-equals-with-kw/33121 "2021-09-16T07:12:09Z")

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How to nest the 2 macros? If I have both AutoHashEquals.@auto\_hash\_equals & Parameters.@with\_kw applied onto a type definition. Either @auto\_hash\_equals @with\_kw or @with\_kw @auto\_hash\_equals is not working: julia\> @aut…

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## [Histogram Bin Width Control With Plots.jl](https://discourse.julialang.org/t/histogram-bin-width-control-with-plots-jl/68063)

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**Author:** [@cmdenis](https://discourse.julialang.org/u/cmdenis)\
**Replies:** 5\
**Last updated:** [September 16, 2021, 5:44am UTC](https://discourse.julialang.org/t/histogram-bin-width-control-with-plots-jl/68063 "2021-09-16T05:44:46Z")

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Hello, I am using Plots.jl to make a histogram. I would like to have control over the bin size, but I can’t seem to find anything specifically saying how to do this in the documentation (or in other posts). I have an a…

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## [Best practice for the conversion from a vector of dictionaries to a dataframe](https://discourse.julialang.org/t/best-practice-for-the-conversion-from-a-vector-of-dictionaries-to-a-dataframe/68244)

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**Author:** [@iHany](https://discourse.julialang.org/u/iHany)\
**Replies:** 1\
**Last updated:** [September 16, 2021, 5:54am UTC](https://discourse.julialang.org/t/best-practice-for-the-conversion-from-a-vector-of-dictionaries-to-a-dataframe/68244 "2021-09-16T05:54:55Z")

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I’d like to know whether there is a convenient way of converting from a vector of dictionaries to a dataframe. For example, julia\> my\_dict = Dict("a" =\> \[1, 2, 3\], "b" =\> \[4\]) my\_dictDict{String, Vector{Int64}} with 2 e…

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## [Kemp and Kemp (1991) Poisson random variates implementation](https://discourse.julialang.org/t/kemp-and-kemp-1991-poisson-random-variates-implementation/68233)

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**Author:** [@pjentsch0](https://discourse.julialang.org/u/pjentsch0)\
**Replies:** 0\
**Last updated:** [September 15, 2021, 10:20pm UTC](https://discourse.julialang.org/t/kemp-and-kemp-1991-poisson-random-variates-implementation/68233 "2021-09-15T22:20:51Z")

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Currently, the sampler in Distributions.jl for poisson random variates is PoissonADSampler, which implements the algorithm from J.H. Ahrens, U. Dieter (1982). I found the paper, “Poisson Random Variate Generation” from …

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## [Searching for the counterpart to the gaussian\_pyramid](https://discourse.julialang.org/t/searching-for-the-counterpart-to-the-gaussian-pyramid/68203)

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**Author:** [@trilobit](https://discourse.julialang.org/u/trilobit)\
**Replies:** 2\
**Last updated:** [September 16, 2021, 5:27am UTC](https://discourse.julialang.org/t/searching-for-the-counterpart-to-the-gaussian-pyramid/68203 "2021-09-16T05:27:30Z")

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using Images, TestImages img=testimage("mandrill") mosaic(gaussian\_pyramid(img,5, 1.2, 0), nrow=1) Searching for the simple counterpart. A function for upsample and sharpen (not “kron”).

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## [Memory usage with mmap file](https://discourse.julialang.org/t/memory-usage-with-mmap-file/59883)

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**Author:** [@KKesgin](https://discourse.julialang.org/u/KKesgin)\
**Replies:** 17\
**Last updated:** [September 16, 2021, 3:38am UTC](https://discourse.julialang.org/t/memory-usage-with-mmap-file/59883 "2021-09-16T03:38:55Z")

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Hi All I’m accessing a very large binary file randomly on windows. I don’t dare to put in all the code but I managed to replicate the behavior with a small loop. Could someone please explain to me why this is causing in…

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## [Rew file format in MOI.FileFormats / JuMP](https://discourse.julialang.org/t/rew-file-format-in-moi-fileformats-jump/68238)

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**Author:** [@obar](https://discourse.julialang.org/u/obar)\
**Replies:** 2\
**Last updated:** [September 16, 2021, 1:54am UTC](https://discourse.julialang.org/t/rew-file-format-in-moi-fileformats-jump/68238 "2021-09-16T01:54:35Z")

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Would it be possible to include support for .rew model file formats in JuMP? It is sometimes useful to share models where a risk of leaking proprietary information is present (e.g. here) and .mps files contain constrain…

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## [ERROR: MethodError: no method matching adjoint(::DateTime)](https://discourse.julialang.org/t/error-methoderror-no-method-matching-adjoint-datetime/68230)

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**Author:** [@jhgorse](https://discourse.julialang.org/u/jhgorse)\
**Replies:** 3\
**Last updated:** [September 16, 2021, 12:42am UTC](https://discourse.julialang.org/t/error-methoderror-no-method-matching-adjoint-datetime/68230 "2021-09-16T00:42:00Z")

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Hello, I am struggling with Julia’s less than MATLAB capability for transposing matrices (row data). I parse a file into a temporary vector. I transpose the vector and append to the matrix. Neither before nor after the…

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## [Chose what browser to launch Pluto in](https://discourse.julialang.org/t/chose-what-browser-to-launch-pluto-in/58488)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 5\
**Last updated:** [September 15, 2021, 11:48pm UTC](https://discourse.julialang.org/t/chose-what-browser-to-launch-pluto-in/58488 "2021-09-15T23:48:50Z")

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I believe that I can add a kwarg in my Pluto.run() command to chose the browser to launch the notebook in. I can however not find anything about it over at github, and because there is no comprehensive documentations I d…

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## [How load date on SQLite](https://discourse.julialang.org/t/how-load-date-on-sqlite/68231)

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**Author:** [@Rafael\_Brus](https://discourse.julialang.org/u/Rafael_Brus)\
**Replies:** 1\
**Last updated:** [September 15, 2021, 11:35pm UTC](https://discourse.julialang.org/t/how-load-date-on-sqlite/68231 "2021-09-15T23:35:10Z")

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How load date on SQLite? using SQLite, Dates, DataFrames df = DataFrame(Column1 = \[1,2,3\], Column2 = \[today(),today()- Dates.Day(10),today()- Dates.Day(20)\]) SQLite.load!(df, db, "Test", temp=false) Thi…

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## [Gurobi not using barrier method](https://discourse.julialang.org/t/gurobi-not-using-barrier-method/68078)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 9\
**Last updated:** [September 15, 2021, 11:11pm UTC](https://discourse.julialang.org/t/gurobi-not-using-barrier-method/68078 "2021-09-15T23:11:16Z")

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Hi, I have a model (the LP mentioned in my earlier post), that, when solved from Julia, logs indicate that Gurobi uses a primal simplex algorithm, but when I dump the MPS and solve it from the command-line, gurobi\_cl us…

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