# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=413

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**Page:** 414

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## [Numerical error when optimising expression with JuMP](https://discourse.julialang.org/t/numerical-error-when-optimising-expression-with-jump/48847)

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**Author:** [@f6v](https://discourse.julialang.org/u/f6v)\
**Replies:** 1\
**Last updated:** [October 22, 2020, 9:58pm UTC](https://discourse.julialang.org/t/numerical-error-when-optimising-expression-with-jump/48847 "2020-10-22T21:58:40Z")

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I’m completely new to mathematical optimisation and would appreciate if you could give a hint here. I have a function of three vectors x, y and z(each of size 15). Now I want to maximise a function of the vectors with c…

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## [Is it possible to use variables in Pluto sliders?](https://discourse.julialang.org/t/is-it-possible-to-use-variables-in-pluto-sliders/48828)

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**Author:** [@mihalybaci](https://discourse.julialang.org/u/mihalybaci)\
**Replies:** 2\
**Last updated:** [October 22, 2020, 4:21pm UTC](https://discourse.julialang.org/t/is-it-possible-to-use-variables-in-pluto-sliders/48828 "2020-10-22T16:21:52Z")

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So far I am loving the interactivity in Pluto notebooks, but I am frequently hitting a roadblock in setting up sliders. I find I have to manually set the slider range like this begin number\_slider = @bind number html"\<i…

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## [Techniques to improve resolution of a system of nonlinear equations](https://discourse.julialang.org/t/techniques-to-improve-resolution-of-a-system-of-nonlinear-equations/48712)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 13\
**Last updated:** [October 22, 2020, 10:28am UTC](https://discourse.julialang.org/t/techniques-to-improve-resolution-of-a-system-of-nonlinear-equations/48712 "2020-10-22T10:28:36Z")

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Hello, I would like to solve a set of N = 300 independent 1D nonlinear equations of the type f\_i(x\_i) = a\_i where the a\_i are given and each function f\_i is a univariate strictly increasing bijection. There is a unique…

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## [Couenne with JuMP: can't evaluate pow"(0,1.5)](https://discourse.julialang.org/t/couenne-with-jump-cant-evaluate-pow-0-1-5/48734)

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**Author:** [@Shuhua](https://discourse.julialang.org/u/Shuhua)\
**Replies:** 3\
**Last updated:** [October 22, 2020, 9:15am UTC](https://discourse.julialang.org/t/couenne-with-jump-cant-evaluate-pow-0-1-5/48734 "2020-10-22T09:15:52Z")

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I am playing with Couenne for NLP optimization problems with JuMP and AmplNLWriter. After setting up these packages, I tried the toy example in Couenne’s documentation (section 5). For convenience, the problem is posted …

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## [How to change colormap in histogram2d (Plots.jl)](https://discourse.julialang.org/t/how-to-change-colormap-in-histogram2d-plots-jl/48784)

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**Author:** [@klaff](https://discourse.julialang.org/u/klaff)\
**Replies:** 1\
**Last updated:** [October 22, 2020, 12:59am UTC](https://discourse.julialang.org/t/how-to-change-colormap-in-histogram2d-plots-jl/48784 "2020-10-22T00:59:54Z")

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How do I change the colormap of histogram2d? Thanks!

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## [Celltracker updates](https://discourse.julialang.org/t/celltracker-updates/48781)

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**Author:** [@ervern](https://discourse.julialang.org/u/ervern)\
**Replies:** 1\
**Last updated:** [October 22, 2020, 12:10am UTC](https://discourse.julialang.org/t/celltracker-updates/48781 "2020-10-22T00:10:13Z")

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Hi so I recently posted and found some useful information on how to make code that would track cells. However I’m running into an issue where I think the cells are too close to the background to use most of the detection…

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## [Clp: problem to build the package](https://discourse.julialang.org/t/clp-problem-to-build-the-package/48763)

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**Author:** [@Luca](https://discourse.julialang.org/u/Luca)\
**Replies:** 1\
**Last updated:** [October 21, 2020, 6:07pm UTC](https://discourse.julialang.org/t/clp-problem-to-build-the-package/48763 "2020-10-21T18:07:09Z")

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Dear all, I have installed Clp, but when I try to build it, julia reports: julia\> Pkg.build(“Clp”) Building CodecZlib ─→ ~/.julia/packages/CodecZlib/5t9zO/deps/build.log Building MbedTLS ───→ ~/.julia/packages/MbedTL…

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## [Help speed up SimpleGraph creation](https://discourse.julialang.org/t/help-speed-up-simplegraph-creation/48754)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 4\
**Last updated:** [October 21, 2020, 5:58pm UTC](https://discourse.julialang.org/t/help-speed-up-simplegraph-creation/48754 "2020-10-21T17:58:56Z")

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Here’s a MWE of what I’m attempting to do: using DataFrames using LightGraphs using ProgressMeter df = DataFrame(a = rand(1:50\_000, 150\_000), b = rand(1:25\_000, 150\_000)) |\> unique! vs = unique(vcat(df.a, df.b)) n = le…

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## [Help with debugging some code for the MKLSparse package](https://discourse.julialang.org/t/help-with-debugging-some-code-for-the-mklsparse-package/48764)

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**Author:** [@dmbates](https://discourse.julialang.org/u/dmbates)\
**Replies:** 0\
**Last updated:** [October 21, 2020, 5:51pm UTC](https://discourse.julialang.org/t/help-with-debugging-some-code-for-the-mklsparse-package/48764 "2020-10-21T17:51:41Z")

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On the principle that “given enough eyeballs, all bugs are shallow” I am asking for help in debugging a problem in the dmb/matrix\_sparse branch of the MKLSparse package. The purpose of this package is to use Intel’s Mat…

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## [Call backend functions on Plots.jl (PyPlot backend)](https://discourse.julialang.org/t/call-backend-functions-on-plots-jl-pyplot-backend/45789)

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**Author:** [@teored90](https://discourse.julialang.org/u/teored90)\
**Replies:** 1\
**Last updated:** [October 21, 2020, 12:39pm UTC](https://discourse.julialang.org/t/call-backend-functions-on-plots-jl-pyplot-backend/45789 "2020-10-21T12:39:23Z")

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Is there a way to modify a Plots.jl plot by directly calling the backend’s functions on that plot? In my case, the backend would be PyPlot. I need to have a multi-column legend, which doesn’t seem to be supported.

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## [How to properly set log axis scale with a 2d color plot?](https://discourse.julialang.org/t/how-to-properly-set-log-axis-scale-with-a-2d-color-plot/46481)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 1\
**Last updated:** [October 21, 2020, 12:33pm UTC](https://discourse.julialang.org/t/how-to-properly-set-log-axis-scale-with-a-2d-color-plot/46481 "2020-10-21T12:33:41Z")

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I have a program which scans a 2d parameter space. For each point in the parameter space, it generates a colour (corresponding to system behaviours). The grid points are log10-log10 distributed. I wish to plot this, but …

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## [How to set :juno as the default Plots theme during startup](https://discourse.julialang.org/t/how-to-set-juno-as-the-default-plots-theme-during-startup/14971)

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**Author:** [@zekeriya.sari](https://discourse.julialang.org/u/zekeriya.sari)\
**Replies:** 6\
**Last updated:** [October 21, 2020, 11:28am UTC](https://discourse.julialang.org/t/how-to-set-juno-as-the-default-plots-theme-during-startup/14971 "2020-10-21T11:28:29Z")

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Hi all, I want to set the :juno theme as the default theme of the Plots during startup of a new julia session. For this purpose, I wrote the following lines in the startup.jl file. using Plots using PlotThemes theme(:j…

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## [PyPlot doesn't release mem after close()](https://discourse.julialang.org/t/pyplot-doesnt-release-mem-after-close/47953)

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**Author:** [@JesperMartinsson](https://discourse.julialang.org/u/JesperMartinsson)\
**Replies:** 10\
**Last updated:** [October 21, 2020, 8:19am UTC](https://discourse.julialang.org/t/pyplot-doesnt-release-mem-after-close/47953 "2020-10-21T08:19:01Z")

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I’m creating and saving a series of images using PyPlot and savefig. However, despite using ioff() and closing all the figures, the memory increases linearly with number of figures that are created, saved and closed. I u…

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## [Plotting images on GPU with ArrayFire](https://discourse.julialang.org/t/plotting-images-on-gpu-with-arrayfire/48676)

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**Author:** [@libensvivit](https://discourse.julialang.org/u/libensvivit)\
**Replies:** 7\
**Last updated:** [October 21, 2020, 4:30am UTC](https://discourse.julialang.org/t/plotting-images-on-gpu-with-arrayfire/48676 "2020-10-21T04:30:09Z")

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I’m combining lots of images into a single one and then add custom ticks and labels to the final image using Plots.jl library, then save it on the disk. However, we have millions of images to be processed, and it becomes…

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## [\[ANN\] Upcoming breaking changes to CPLEX.jl and Gurobi.jl](https://discourse.julialang.org/t/ann-upcoming-breaking-changes-to-cplex-jl-and-gurobi-jl/47814)

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**Author:** [@odow](https://discourse.julialang.org/u/odow)\
**Replies:** 6\
**Last updated:** [October 21, 2020, 1:04am UTC](https://discourse.julialang.org/t/ann-upcoming-breaking-changes-to-cplex-jl-and-gurobi-jl/47814 "2020-10-21T01:04:47Z")

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Update: 20 October 2020: New versions of CPLEX.jl and Gurobi.jl are tagged. tl;dr: CPLEX.jl and Gurobi.jl will have major breaking changes in the next latest release. If you just use CPLEX.Optimizer() or Gurobi.Optimize…

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## [Help with the implementation of Deutsch Algorithm using Yao.jl](https://discourse.julialang.org/t/help-with-the-implementation-of-deutsch-algorithm-using-yao-jl/45384)

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**Author:** [@ChetanVardhan](https://discourse.julialang.org/u/ChetanVardhan)\
**Replies:** 3\
**Last updated:** [October 20, 2020, 8:43pm UTC](https://discourse.julialang.org/t/help-with-the-implementation-of-deutsch-algorithm-using-yao-jl/45384 "2020-10-20T20:43:17Z")

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Need help implementing the oracle from Deutsch’s Algorithm in Yao.jl Anyone has any ideas on how to do this? Any type of help will be appreciated

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## [Array multiplication](https://discourse.julialang.org/t/array-multiplication/48610)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 4\
**Last updated:** [October 20, 2020, 7:57pm UTC](https://discourse.julialang.org/t/array-multiplication/48610 "2020-10-20T19:57:03Z")

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Why does this generate DimensionMismatch? The dimensions seem to be the same size when I break them out into individual vectors u,v,w. ### A Pluto.jl notebook ### # v0.12.4 using Markdown using InteractiveUtils # ╔…

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## [GUI to edit matrix in Julia?](https://discourse.julialang.org/t/gui-to-edit-matrix-in-julia/48663)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 7\
**Last updated:** [October 20, 2020, 1:22pm UTC](https://discourse.julialang.org/t/gui-to-edit-matrix-in-julia/48663 "2020-10-20T13:22:16Z")

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I would like to ask a similar question to Stack Overflow’s GUI to Create Table in Julia. Is there any Pkg in Julia that has a GUI like uitable in Matlab or similar that allows editing interactively a matrix/table? And on…

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## [Easiest way to load a DataFrame from a compressed, newline delimited json file on the cloud?](https://discourse.julialang.org/t/easiest-way-to-load-a-dataframe-from-a-compressed-newline-delimited-json-file-on-the-cloud/48678)

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**Author:** [@s-kap](https://discourse.julialang.org/u/s-kap)\
**Replies:** 2\
**Last updated:** [October 20, 2020, 1:08pm UTC](https://discourse.julialang.org/t/easiest-way-to-load-a-dataframe-from-a-compressed-newline-delimited-json-file-on-the-cloud/48678 "2020-10-20T13:08:38Z")

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I’m trying to convert a python notebook into Julia. In python we have pd.read\_json("gs://bucket/file.json.gz", lines=True, compression="gzip") I don’t think there’s a way to do this. The approach I’ve taken is to fir…

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## [Can I Change Font Sizes in Julia Markdown?](https://discourse.julialang.org/t/can-i-change-font-sizes-in-julia-markdown/48599)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 4\
**Last updated:** [October 20, 2020, 8:06am UTC](https://discourse.julialang.org/t/can-i-change-font-sizes-in-julia-markdown/48599 "2020-10-20T08:06:27Z")

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Is there a way in julia Markdown, to have the font size of an output changed? I have a representation of a cantor set. const width = 81 const height = 5 function cantor!(lines, start, len, idx) seg = div(len, 3) …

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## [Rotate a subplot in MakieLayout?](https://discourse.julialang.org/t/rotate-a-subplot-in-makielayout/48573)

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**Author:** [@wherrera](https://discourse.julialang.org/u/wherrera)\
**Replies:** 3\
**Last updated:** [October 20, 2020, 6:46am UTC](https://discourse.julialang.org/t/rotate-a-subplot-in-makielayout/48573 "2020-10-20T06:46:01Z")

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I am trying to make the individual cubes in the grid of graphs rotate below, but get: "ERROR: MethodError: no method matching transformation(::LAxis) I am not sure how to refer to a specific axis or subscene’s mesh to r…

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## [Graph Piecewise Function in Julia](https://discourse.julialang.org/t/graph-piecewise-function-in-julia/48662)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 6\
**Last updated:** [October 20, 2020, 7:41am UTC](https://discourse.julialang.org/t/graph-piecewise-function-in-julia/48662 "2020-10-20T07:41:35Z")

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How do graph a piecewise function?

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## [Need help plotting using Blink and Interact](https://discourse.julialang.org/t/need-help-plotting-using-blink-and-interact/48644)

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**Author:** [@groovyda](https://discourse.julialang.org/u/groovyda)\
**Replies:** 1\
**Last updated:** [October 20, 2020, 6:56am UTC](https://discourse.julialang.org/t/need-help-plotting-using-blink-and-interact/48644 "2020-10-20T06:56:26Z")

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Hi there I have a simple interactive plot (in Pluto) that is slow - and should benefit from using Blink instead. I have spent the last day trying to make it work, but I just can’t figure out how to. Could someone pleas…

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## [Identify important subspaces of a function without squaring the conditioning number](https://discourse.julialang.org/t/identify-important-subspaces-of-a-function-without-squaring-the-conditioning-number/48664)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 2\
**Last updated:** [October 20, 2020, 4:06am UTC](https://discourse.julialang.org/t/identify-important-subspaces-of-a-function-without-squaring-the-conditioning-number/48664 "2020-10-20T04:06:19Z")

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Hello, I would like to find the important directions in the input and output spaces for a \\mu-measurable function f: \\mathbb{R}^n \\xrightarrow{} \\mathbb{R}^d. One way to identify these directions is to look at the eige…

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## [CUDA Error in constant CuArray with conditional usage](https://discourse.julialang.org/t/cuda-error-in-constant-cuarray-with-conditional-usage/48581)

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**Author:** [@ozmaden](https://discourse.julialang.org/u/ozmaden)\
**Replies:** 3\
**Last updated:** [October 19, 2020, 10:37pm UTC](https://discourse.julialang.org/t/cuda-error-in-constant-cuarray-with-conditional-usage/48581 "2020-10-19T22:37:12Z")

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Hi everyone, I am confronted with an error concerning a constant CuArray. Any help would be greatly appreciated. Quick context: I’m one of the developers of the GNSSSignals package, adapting it to do signal processing …

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## [Is there a Julia Pkg for user data dir (appdirs)?](https://discourse.julialang.org/t/is-there-a-julia-pkg-for-user-data-dir-appdirs/48632)

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**Author:** [@zkamvar](https://discourse.julialang.org/u/zkamvar)\
**Replies:** 5\
**Last updated:** [October 19, 2020, 9:28pm UTC](https://discourse.julialang.org/t/is-there-a-julia-pkg-for-user-data-dir-appdirs/48632 "2020-10-19T21:28:35Z")

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I’m curious if there are any Julia Pkgs that port python’s appdirs.

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## [QP returns NUMERICAL\_ERROR status](https://discourse.julialang.org/t/qp-returns-numerical-error-status/48630)

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**Author:** [@arkanver](https://discourse.julialang.org/u/arkanver)\
**Replies:** 3\
**Last updated:** [October 19, 2020, 5:38pm UTC](https://discourse.julialang.org/t/qp-returns-numerical-error-status/48630 "2020-10-19T17:38:37Z")

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Hello all, I have been trying to solve a quadratic problem with linear and box constraints. My objective function is convex. In most cases the problem gets solved fine (OPTIMAL status), but sometimes on larger examples …

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## [Locally connected layer in Flux](https://discourse.julialang.org/t/locally-connected-layer-in-flux/48624)

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**Author:** [@johnbb](https://discourse.julialang.org/u/johnbb)\
**Replies:** 0\
**Last updated:** [October 19, 2020, 12:00pm UTC](https://discourse.julialang.org/t/locally-connected-layer-in-flux/48624 "2020-10-19T12:00:12Z")

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Has anyone made an implementation of a locally connected layer in Flux similar to the one(s) in Keras?

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## [Optimal with IPOPTH, Infeasible with Gurobi](https://discourse.julialang.org/t/optimal-with-ipopth-infeasible-with-gurobi/48523)

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**Author:** [@SingingKim](https://discourse.julialang.org/u/SingingKim)\
**Replies:** 4\
**Last updated:** [October 19, 2020, 12:34am UTC](https://discourse.julialang.org/t/optimal-with-ipopth-infeasible-with-gurobi/48523 "2020-10-19T00:34:37Z")

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Hi, I’m working on a bilevel problem that is converted into an equivalent non-convex QCQP by applying strong duality to the lower-level problem (LP). My code returns a (local) optimal solution with Ipopt solver (w/ ma86…

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## [Upload of DataFrame data to databases](https://discourse.julialang.org/t/upload-of-dataframe-data-to-databases/36950)

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**Author:** [@lungben](https://discourse.julialang.org/u/lungben)\
**Replies:** 6\
**Last updated:** [October 19, 2020, 12:18am UTC](https://discourse.julialang.org/t/upload-of-dataframe-data-to-databases/36950 "2020-10-19T00:18:07Z")

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Hi, for evaluation of a possible projet usage I did a comparison of DataFrames.jl to Pandas, with side-by-side examples and timings: Overall, DataFrames.jl performs very well in my experiments, great work! One funct…

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