# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=336

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**Page:** 337

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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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## [Speeding up DDE that interpolates past value at 3 indices](https://discourse.julialang.org/t/speeding-up-dde-that-interpolates-past-value-at-3-indices/67970)

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**Author:** [@Amarantine](https://discourse.julialang.org/u/Amarantine)\
**Replies:** 7\
**Last updated:** [September 15, 2021, 9:25pm UTC](https://discourse.julialang.org/t/speeding-up-dde-that-interpolates-past-value-at-3-indices/67970 "2021-09-15T21:25:34Z")

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On the example for DDE, there is a section talking about speeding up interpolation at a specific index. However, I’m wondering if I can do similar things with more than one, like 3, indices. I have a large model with 150…

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## [How to compute density of conditional probability from data](https://discourse.julialang.org/t/how-to-compute-density-of-conditional-probability-from-data/68208)

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**Author:** [@SteffenPL](https://discourse.julialang.org/u/SteffenPL)\
**Replies:** 6\
**Last updated:** [September 15, 2021, 5:22pm UTC](https://discourse.julialang.org/t/how-to-compute-density-of-conditional-probability-from-data/68208 "2021-09-15T17:22:41Z")

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I have samples X::Vector{Float64} and S = rand(0:1,1000). I call X\[i\] succesful, if S\[i\] == 1 is satisfied. I would like to estimate the probablility that a sample is succesful, hence p\_x = \\mathbb P ( S = 1 \\mid X …

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## [HTTP.jl + Ajax](https://discourse.julialang.org/t/http-jl-ajax/68206)

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**Author:** [@Iulian.Cioarca](https://discourse.julialang.org/u/Iulian.Cioarca)\
**Replies:** 4\
**Last updated:** [September 15, 2021, 5:00pm UTC](https://discourse.julialang.org/t/http-jl-ajax/68206 "2021-09-15T17:00:17Z")

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Where can I find a simple example of a HTTP.jl backend server and a HTML+Javascript FE? I want to learn to communicate between Javascript and Julia for a simple app. Example: I would like to create a html input which ta…

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## [Graph function using AlgebraOfGraphics](https://discourse.julialang.org/t/graph-function-using-algebraofgraphics/67888)

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**Author:** [@Adam\_Fleischhacker](https://discourse.julialang.org/u/Adam_Fleischhacker)\
**Replies:** 2\
**Last updated:** [September 15, 2021, 3:07pm UTC](https://discourse.julialang.org/t/graph-function-using-algebraofgraphics/67888 "2021-09-15T15:07:04Z")

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I would like to overlay a density function over a histogram and have a strong preference for using the AlgebraOfGraphics to graph this exact function. Currently, to accomplish this I have to translate the function into …

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## [Graph layout algorithm allowing manual adjustments?](https://discourse.julialang.org/t/graph-layout-algorithm-allowing-manual-adjustments/68164)

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**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 4\
**Last updated:** [September 15, 2021, 1:40pm UTC](https://discourse.julialang.org/t/graph-layout-algorithm-allowing-manual-adjustments/68164 "2021-09-15T13:40:05Z")

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Julia packages like GraphPlot and NetworkLayout can automatically choose the positions of graph vertices to make the graph look nice. However, sometimes I want to manually adjust the positions of the vertices to make the…

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## [Stochastic model building: assistance with the DiffEq ecosystem](https://discourse.julialang.org/t/stochastic-model-building-assistance-with-the-diffeq-ecosystem/46611)

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**Author:** [@Libbum](https://discourse.julialang.org/u/Libbum)\
**Replies:** 0\
**Last updated:** [September 14, 2020, 9:37pm UTC](https://discourse.julialang.org/t/stochastic-model-building-assistance-with-the-diffeq-ecosystem/46611 "2020-09-14T21:37:29Z")

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So, it’s time. I need to put some noise in my nice, clean, simple ODEs. Luckily DifferentialEquations.jl has me covered—the documentation is extensive… But perhaps too extensive: I don’t know where to start. I think, ul…

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## [DifferentialEquations.jl SDE, multiple solvers sharing the same noise](https://discourse.julialang.org/t/differentialequations-jl-sde-multiple-solvers-sharing-the-same-noise/18790)

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**Author:** [@nowozin](https://discourse.julialang.org/u/nowozin)\
**Replies:** 0\
**Last updated:** [December 18, 2018, 9:54am UTC](https://discourse.julialang.org/t/differentialequations-jl-sde-multiple-solvers-sharing-the-same-noise/18790 "2018-12-18T09:54:27Z")

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Thanks to the authors of DifferentialEquations.jl, it is quite a nice package. I would like to evaluate the numerical accuracy of multiple solvers for an SDE. For this, I intend to numerically solve for the same path, …

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## [Coding up basic power flow equation](https://discourse.julialang.org/t/coding-up-basic-power-flow-equation/67896)

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**Author:** [@mbah](https://discourse.julialang.org/u/mbah)\
**Replies:** 6\
**Last updated:** [September 15, 2021, 9:55am UTC](https://discourse.julialang.org/t/coding-up-basic-power-flow-equation/67896 "2021-09-15T09:55:58Z")

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Hello, I am relatively new to Julia and power systems optimization. At the moment, I am trying to understand power flows from scratch and this involves coding up/defining branch power flows for a simple three bus netwo…

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## [Solving a Convex Quadratic Program Using Gurobi & Mosek](https://discourse.julialang.org/t/solving-a-convex-quadratic-program-using-gurobi-mosek/67214)

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**Author:** [@RoyiAvital](https://discourse.julialang.org/u/RoyiAvital)\
**Replies:** 12\
**Last updated:** [September 14, 2021, 10:18pm UTC](https://discourse.julialang.org/t/solving-a-convex-quadratic-program-using-gurobi-mosek/67214 "2021-09-14T22:18:25Z")

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I would like to solve the following Quadratic Program / Quadratic Programming: \\begin{aligned} \\arg \\min\_{x} \\quad & \\frac{1}{2} {x}^{T} P x + {x}^{T} q \\\\ \\text{subject to} \\quad & l \\leq A x \\leq u \\end{aligned} The…

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## [WGLMakie.jl in Pluto running on remote machine](https://discourse.julialang.org/t/wglmakie-jl-in-pluto-running-on-remote-machine/68169)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 3\
**Last updated:** [September 14, 2021, 8:47pm UTC](https://discourse.julialang.org/t/wglmakie-jl-in-pluto-running-on-remote-machine/68169 "2021-09-14T20:47:14Z")

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I am used to WGLMakie.jl visualizations in Pluto locally, following the instructions in the docs: using JSServe Page() # create page in one cell and then using WGLMakie scatter(rand(100), rand(100)) Everything works…

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## [Slow lower triangular solves when compared to full Cholesky](https://discourse.julialang.org/t/slow-lower-triangular-solves-when-compared-to-full-cholesky/68122)

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**Author:** [@cgeoga](https://discourse.julialang.org/u/cgeoga)\
**Replies:** 6\
**Last updated:** [September 14, 2021, 8:12pm UTC](https://discourse.julialang.org/t/slow-lower-triangular-solves-when-compared-to-full-cholesky/68122 "2021-09-14T20:12:25Z")

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Can somebody here help me understand why in this code solving with the L in A = LL^T is an order of magnitude slower than just solving using A? Here is a MWE: using BenchmarkTools if !(@isdefined x) # because I lazily …

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## [Long training time using sciml\_train on universal DAE](https://discourse.julialang.org/t/long-training-time-using-sciml-train-on-universal-dae/46352)

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**Author:** [@mbossart](https://discourse.julialang.org/u/mbossart)\
**Replies:** 18\
**Last updated:** [September 14, 2021, 5:49pm UTC](https://discourse.julialang.org/t/long-training-time-using-sciml-train-on-universal-dae/46352 "2021-09-14T17:49:30Z")

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I’m hoping to gather some advice on how to speed up the following example, which attempts to train a NN to learn part of the dynamics of a DAE system. The first part below simply solves the true DAE in order to generate…

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## [Precompile error with DataFrames](https://discourse.julialang.org/t/precompile-error-with-dataframes/68154)

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**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 6\
**Last updated:** [September 14, 2021, 4:52pm UTC](https://discourse.julialang.org/t/precompile-error-with-dataframes/68154 "2021-09-14T16:52:45Z")

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I started this post because of an issue with CSV, but now I have a precompile error with DataFrames. It installs ok, but when I try using it, I get \\u250c Info: Precompiling DataFrames \[a93c6f00-e57d-5684-b7b6-d8193f3…

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## [Finding plotting function attributes, e.g. alpha, for Makie plotting functions](https://discourse.julialang.org/t/finding-plotting-function-attributes-e-g-alpha-for-makie-plotting-functions/68153)

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**Author:** [@Adam\_Fleischhacker](https://discourse.julialang.org/u/Adam_Fleischhacker)\
**Replies:** 4\
**Last updated:** [September 14, 2021, 4:22pm UTC](https://discourse.julialang.org/t/finding-plotting-function-attributes-e-g-alpha-for-makie-plotting-functions/68153 "2021-09-14T16:22:20Z")

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Is there a programmatic way (or better documentation available) to find the available attributes for each plotting function. For example, the arrows function has a nice attribute list in help and at https://makie.juliap…

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## [Given a PostgresSQL.jl connection string, what's the easiest way to create a table in the database by copying a dataframe into it?](https://discourse.julialang.org/t/given-a-postgressql-jl-connection-string-whats-the-easiest-way-to-create-a-table-in-the-database-by-copying-a-dataframe-into-it/68131)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 6\
**Last updated:** [September 14, 2021, 3:43pm UTC](https://discourse.julialang.org/t/given-a-postgressql-jl-connection-string-whats-the-easiest-way-to-create-a-table-in-the-database-by-copying-a-dataframe-into-it/68131 "2021-09-14T15:43:56Z")

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I have tried using ODBC conn = ODBC.Connection("Driver={PostgreSQL Unicode(x64)};Server=db.bit.io;Port=5432;Database=bitdotio;Uid=xxx;Pwd=xxx;") tbl = DataFrame(a=1:3) ODBC.load(tbl, conn, "tbl1"; append=false) But i…

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## [Reading in with WAV yields different result from data exported through Audacity](https://discourse.julialang.org/t/reading-in-with-wav-yields-different-result-from-data-exported-through-audacity/68102)

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**Author:** [@Nenndul](https://discourse.julialang.org/u/Nenndul)\
**Replies:** 7\
**Last updated:** [September 14, 2021, 3:41pm UTC](https://discourse.julialang.org/t/reading-in-with-wav-yields-different-result-from-data-exported-through-audacity/68102 "2021-09-14T15:41:46Z")

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I have a simple program that I want to run on a wav file. To test the algorithm I have used audacity’s export function to generate a CSV file, and everything works exactly as expected. But when I use WAV: data, fs = wa…

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## [Eigenvalues and extended precision](https://discourse.julialang.org/t/eigenvalues-and-extended-precision/68119)

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**Author:** [@zmoitier](https://discourse.julialang.org/u/zmoitier)\
**Replies:** 10\
**Last updated:** [September 14, 2021, 1:31pm UTC](https://discourse.julialang.org/t/eigenvalues-and-extended-precision/68119 "2021-09-14T13:31:15Z")

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I am interested in computing a small proportion (between 3 and 10% of the matrix size) of the eigenvalues of a matrix with extended precision. As a toy example, let’s take the matrix A define by: T = Complex{Float128} N…

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## [Using the solver SDPT3 with PowerModels.jl](https://discourse.julialang.org/t/using-the-solver-sdpt3-with-powermodels-jl/68070)

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**Author:** [@aaldik](https://discourse.julialang.org/u/aaldik)\
**Replies:** 4\
**Last updated:** [September 14, 2021, 2:52pm UTC](https://discourse.julialang.org/t/using-the-solver-sdpt3-with-powermodels-jl/68070 "2021-09-14T14:52:46Z")

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Hello I’m trying to use the solver SDPT3 for solving a SDP problem using the library PowerModels.jl that utilizes JuMP, the error that I get is julia\> test=run\_opf(“case3\_SDP.m”,SDPWRMPowerModel,solver4) ┌ Warning: Ma…

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## [Solving simple electrostatic problem](https://discourse.julialang.org/t/solving-simple-electrostatic-problem/68046)

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**Author:** [@isentropic](https://discourse.julialang.org/u/isentropic)\
**Replies:** 24\
**Last updated:** [September 14, 2021, 7:03am UTC](https://discourse.julialang.org/t/solving-simple-electrostatic-problem/68046 "2021-09-14T07:03:39Z")

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I’m fairly new to PDE solving domain. Being overwhelmed with what julia offers GitHub - JuliaPDE/SurveyofPDEPackages: Survey of the packages of the Julia ecosystem for solving partial differential equations, I could deci…

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## [Nested Task error: Bad window span - what?](https://discourse.julialang.org/t/nested-task-error-bad-window-span-what/67959)

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**Author:** [@SubTer](https://discourse.julialang.org/u/SubTer)\
**Replies:** 6\
**Last updated:** [September 13, 2021, 8:25pm UTC](https://discourse.julialang.org/t/nested-task-error-bad-window-span-what/67959 "2021-09-13T20:25:11Z")

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hi folks, I am trying to add a column to a df i already have populated, and on a smaller batch size it works just fine, example code below: Timeddf = @linq dfData |\> groupby(:ID) |\> transform(Traili…

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## [Issues with recurrent layers in Flux.jl](https://discourse.julialang.org/t/issues-with-recurrent-layers-in-flux-jl/67815)

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**Author:** [@shindler25](https://discourse.julialang.org/u/shindler25)\
**Replies:** 8\
**Last updated:** [September 13, 2021, 4:26pm UTC](https://discourse.julialang.org/t/issues-with-recurrent-layers-in-flux-jl/67815 "2021-09-13T16:26:48Z")

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I am using Julia 1.6 and Flux v0.12.6 I am having issues using the recurrent layers LSTM and RNN in Flux.jl and it does not make sense why this is happening. hopefully someone can see where it is going wrong? I define …

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## [How to compute a "cumulative" in a dataframe (without a for loop)](https://discourse.julialang.org/t/how-to-compute-a-cumulative-in-a-dataframe-without-a-for-loop/2156)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 44\
**Last updated:** [September 11, 2021, 1:39am UTC](https://discourse.julialang.org/t/how-to-compute-a-cumulative-in-a-dataframe-without-a-for-loop/2156 "2021-09-11T01:39:52Z")

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I am trying to add a new column with a cumulative value in regard to an other column., e.g.: In: df = DataFrame(region = \["US","US","US","US","EU","EU","EU","EU"\], year = \[2010,2011,2012,2013,2010,2011…

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## [Using BlueZ\_jll for bluetooth communication](https://discourse.julialang.org/t/using-bluez-jll-for-bluetooth-communication/68082)

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**Author:** [@albheim](https://discourse.julialang.org/u/albheim)\
**Replies:** 0\
**Last updated:** [September 13, 2021, 9:44am UTC](https://discourse.julialang.org/t/using-bluez-jll-for-bluetooth-communication/68082 "2021-09-13T09:44:32Z")

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I wanted to use julia for collecting some data from a bluetooth device, and couldn’t find any package for that. What I did find was the BlueZ\_jll package, which seemed fit for the job. After some figuring out how the jl…

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## [DataFrames reorder columns in place](https://discourse.julialang.org/t/dataframes-reorder-columns-in-place/67993)

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**Author:** [@mjanun](https://discourse.julialang.org/u/mjanun)\
**Replies:** 4\
**Last updated:** [September 13, 2021, 11:05am UTC](https://discourse.julialang.org/t/dataframes-reorder-columns-in-place/67993 "2021-09-13T11:05:26Z")

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If a dataframe is defined as: df\_dummy = DataFrame(A=\[1,2,3\],B=\["A","B","C"\],ID =\[121,321,421\]) How can I change the order of one or more columns and modify the dataframe in place? If I want to make ID the first colum…

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## [Gurobi Error 10005: Unable to retrieve attribute 'Slack'](https://discourse.julialang.org/t/gurobi-error-10005-unable-to-retrieve-attribute-slack/68067)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 3\
**Last updated:** [September 13, 2021, 3:35am UTC](https://discourse.julialang.org/t/gurobi-error-10005-unable-to-retrieve-attribute-slack/68067 "2021-09-13T03:35:24Z")

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Hi, I’m getting the above error when using Gurobi to solve an LP and then querying the value of a constraint. The LP has been solved such that @assert(termination\_status(𝓜) == MOI.OPTIMAL) passes. Unfortunately, I hav…

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## [JuAFEM read meshes created with gmsh](https://discourse.julialang.org/t/juafem-read-meshes-created-with-gmsh/40117)

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**Author:** [@FrootLoops](https://discourse.julialang.org/u/FrootLoops)\
**Replies:** 0\
**Last updated:** [May 25, 2020, 11:06am UTC](https://discourse.julialang.org/t/juafem-read-meshes-created-with-gmsh/40117 "2020-05-25T11:06:29Z")

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Hi everybody, is it possible to read gmsh meshes into JuAFEM? I just found a package for JuliaFEM and now I am wondering if there is a way to load/read meshes created with gmesh into JuaFEM. Edit: I would also be happy…

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## [How to use a Quasar form in StippleUI?](https://discourse.julialang.org/t/how-to-use-a-quasar-form-in-stippleui/62930)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 11\
**Last updated:** [September 12, 2021, 8:55pm UTC](https://discourse.julialang.org/t/how-to-use-a-quasar-form-in-stippleui/62930 "2021-09-12T20:55:12Z")

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Typically, in a Quasar form the client-side validations, defined as rules in each of the child elements (like QInput, QSelect or your QField wrapped components), get checked when a type=submit button gets pressed with th…

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## [Type instability of pdf of MixtureModel](https://discourse.julialang.org/t/type-instability-of-pdf-of-mixturemodel/68058)

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**Author:** [@sgaure](https://discourse.julialang.org/u/sgaure)\
**Replies:** 2\
**Last updated:** [September 12, 2021, 7:12pm UTC](https://discourse.julialang.org/t/type-instability-of-pdf-of-mixturemodel/68058 "2021-09-12T19:12:36Z")

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When I create a Normal one-dimensional mixture as, d = MixtureModel(\[Normal(-1,1), Normal(1, 1)\], \[0.5,0.5\]) it turns out that the pdf is not type stable: julia\> @code\_warntype pdf(d,0.3) MethodInstance for Distrib…

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## [Help understanding an error on Windows](https://discourse.julialang.org/t/help-understanding-an-error-on-windows/68059)

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**Author:** [@contradict](https://discourse.julialang.org/u/contradict)\
**Replies:** 0\
**Last updated:** [September 12, 2021, 6:43pm UTC](https://discourse.julialang.org/t/help-understanding-an-error-on-windows/68059 "2021-09-12T18:43:34Z")

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In this PR I attempted to fix a few things in YAML.jl. I succeeded in fixing them for Linux, but it looks like I broke something for Windows in the process. It looks to me like eof behaves differently on Windows, but I d…

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