# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=516

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**Page:** 517

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## [\[Ann\] julia in parallel batch mode: job schedulers, etc](https://discourse.julialang.org/t/ann-julia-in-parallel-batch-mode-job-schedulers-etc/17855)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 2\
**Last updated:** [November 26, 2018, 6:20am UTC](https://discourse.julialang.org/t/ann-julia-in-parallel-batch-mode-job-schedulers-etc/17855 "2018-11-26T06:20:03Z")

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This may be completely obvious and trivial to most people, but I constantly encounter problems with ClusterManagers.jl package on hpc systems. This is related to this discussion. The main reason is that the model of that…

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## [IdentityMatrix.jl: efficient methods](https://discourse.julialang.org/t/identitymatrix-jl-efficient-methods/17999)

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**Author:** [@jlapeyre](https://discourse.julialang.org/u/jlapeyre)\
**Replies:** 0\
**Last updated:** [November 26, 2018, 2:55am UTC](https://discourse.julialang.org/t/identitymatrix-jl-efficient-methods/17999 "2018-11-26T02:55:17Z")

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There are a lot of possible efficiency improvements for operations involving identity matrices. This package is intended to get several improved (or specialized) methods into circulation. This is not intended to be their…

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## [ANN: ILog2.jl](https://discourse.julialang.org/t/ann-ilog2-jl/17997)

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**Author:** [@jlapeyre](https://discourse.julialang.org/u/jlapeyre)\
**Replies:** 0\
**Last updated:** [November 26, 2018, 2:28am UTC](https://discourse.julialang.org/t/ann-ilog2-jl/17997 "2018-11-26T02:28:46Z")

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Efficient integer valued base 2 logarithm. ilog2(n::Real) Compute the largest m such that 2^m \<= n. https://github.com/jlapeyre/ILog2.jl

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## [De-Serialization Performance](https://discourse.julialang.org/t/de-serialization-performance/17949)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 12\
**Last updated:** [November 25, 2018, 7:59pm UTC](https://discourse.julialang.org/t/de-serialization-performance/17949 "2018-11-25T19:59:10Z")

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Specific Topic Related to Reading Data Is Still Too Slow . I spent the morning figuring out how serialization/deserialization perform. (I was writing more complex programs, but ultimately it whittled down to the follow…

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## [Using SharedArray with structs](https://discourse.julialang.org/t/using-sharedarray-with-structs/17983)

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**Author:** [@HildingElmqvist](https://discourse.julialang.org/u/HildingElmqvist)\
**Replies:** 1\
**Last updated:** [November 25, 2018, 6:30pm UTC](https://discourse.julialang.org/t/using-sharedarray-with-structs/17983 "2018-11-25T18:30:25Z")

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I wanted to use @distributed for and SharedArray{MyStruct,1}. However, I get the error: ArgumentError("type of SharedArray elements must be bits types, got Modia.Instantiation.Instance") Is there any other way of retur…

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## [Failure-resilient parallel computing](https://discourse.julialang.org/t/failure-resilient-parallel-computing/17929)

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**Author:** [@belab](https://discourse.julialang.org/u/belab)\
**Replies:** 6\
**Last updated:** [November 25, 2018, 5:09am UTC](https://discourse.julialang.org/t/failure-resilient-parallel-computing/17929 "2018-11-25T05:09:56Z")

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Hi, I’ve been using Julia’s parallel computing capabilities for some embarrassingly parallel computations (i.e., synchronization between workers is rare) with some success. However, given the HPC environment that I’m wo…

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## [Any fast database working with Julia?](https://discourse.julialang.org/t/any-fast-database-working-with-julia/17960)

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**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 3\
**Last updated:** [November 25, 2018, 12:43am UTC](https://discourse.julialang.org/t/any-fast-database-working-with-julia/17960 "2018-11-25T00:43:44Z")

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What fast on-disk database (such as SciDB, MonetDB…) would you suggest to use to work with Julia. I mean something Julia can easily connect to and able to deal with large datasets. Being able to work distributed and on…

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## [How much faster is GPU compare to CPU](https://discourse.julialang.org/t/how-much-faster-is-gpu-compare-to-cpu/17533)

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**Author:** [@fantapeach](https://discourse.julialang.org/u/fantapeach)\
**Replies:** 16\
**Last updated:** [November 24, 2018, 11:37pm UTC](https://discourse.julialang.org/t/how-much-faster-is-gpu-compare-to-cpu/17533 "2018-11-24T23:37:51Z")

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Hi, I heard the amazing things about GPU and how much faster it can beat CPU. But I don’t know what kind of speed up is expected. So I ran a matrix multiplication to do the comparison. I ran my experiment on a server th…

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## [Time to first plot with Makie too long](https://discourse.julialang.org/t/time-to-first-plot-with-makie-too-long/17947)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 2\
**Last updated:** [November 24, 2018, 7:48pm UTC](https://discourse.julialang.org/t/time-to-first-plot-with-makie-too-long/17947 "2018-11-24T19:48:15Z")

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I am running the following example using Julia 1.0.2 on a fast Ubuntu quad-core: using Makie using GeometryTypes x = Vec3f0(0); baselen = 0.2f0; dirlen = 1f0 # create an array of differently colored boxes in the direct…

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## [What JuMP algorithm to use for this optimization problem?](https://discourse.julialang.org/t/what-jump-algorithm-to-use-for-this-optimization-problem/17936)

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**Author:** [@tyleransom](https://discourse.julialang.org/u/tyleransom)\
**Replies:** 5\
**Last updated:** [November 24, 2018, 7:16pm UTC](https://discourse.julialang.org/t/what-jump-algorithm-to-use-for-this-optimization-problem/17936 "2018-11-24T19:16:16Z")

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I have a question about what type of algorithm I should be using for a fairly straightforward optimization problem. I have the following data id,val,score,id1 1,9,0,64 2,4,0,7 3,11,12,53 4,7,0,8 5,4,35,11 6,14,0,31 7,1…

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## [Transform vector of parameters with TransformVariables.jl](https://discourse.julialang.org/t/transform-vector-of-parameters-with-transformvariables-jl/17923)

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**Author:** [@jkbest2](https://discourse.julialang.org/u/jkbest2)\
**Replies:** 3\
**Last updated:** [November 24, 2018, 11:01am UTC](https://discourse.julialang.org/t/transform-vector-of-parameters-with-transformvariables-jl/17923 "2018-11-24T11:01:04Z")

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I am trying to set up a log-posterior for MCMC sampling using DynamicHMC.jl. I have two unconstrained parameters, and then a vector of parameters that must be negative. Using TransformVariables.jl, I declare problem\_tra…

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## [ANN: Markowitz.jl (mean-variance optimization using the critical line algorithm)](https://discourse.julialang.org/t/ann-markowitz-jl-mean-variance-optimization-using-the-critical-line-algorithm/6624)

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**Author:** [@ungil](https://discourse.julialang.org/u/ungil)\
**Replies:** 1\
**Last updated:** [November 23, 2018, 10:54pm UTC](https://discourse.julialang.org/t/ann-markowitz-jl-mean-variance-optimization-using-the-critical-line-algorithm/6624 "2018-11-23T22:54:22Z")

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https://github.com/ungil/Markowitz.jl

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## [MatrixDepot](https://discourse.julialang.org/t/matrixdepot/17921)

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**Author:** [@klacru](https://discourse.julialang.org/u/klacru)\
**Replies:** 0\
**Last updated:** [November 23, 2018, 6:36pm UTC](https://discourse.julialang.org/t/matrixdepot/17921 "2018-11-23T18:36:33Z")

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A new version of MatrixDepot is available. It has a refreshed API and essential improvements accessing the remote SuiteSparse and NIST MatrixMarket matrix collections. MatrixDepot

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## [Taking abstract domains seriously](https://discourse.julialang.org/t/taking-abstract-domains-seriously/17890)

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**Author:** [@HarrisonGrodin](https://discourse.julialang.org/u/HarrisonGrodin)\
**Replies:** 7\
**Last updated:** [November 23, 2018, 5:20pm UTC](https://discourse.julialang.org/t/taking-abstract-domains-seriously/17890 "2018-11-23T17:20:21Z")

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Hi, everyone! I’ve been planning a redesign for SpecialSets.jl to target use cases needed by Rewrite.jl, but figured that using representations of abstract/infinite sets shouldn’t require reinventing the wheel. I found …

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## [Trying to use quadprog function from MathProgBase, has error "no method matching"](https://discourse.julialang.org/t/trying-to-use-quadprog-function-from-mathprogbase-has-error-no-method-matching/17831)

<div class="topic-metadata">

**Author:** [@Balance37](https://discourse.julialang.org/u/Balance37)\
**Replies:** 2\
**Last updated:** [November 23, 2018, 4:28pm UTC](https://discourse.julialang.org/t/trying-to-use-quadprog-function-from-mathprogbase-has-error-no-method-matching/17831 "2018-11-23T16:28:28Z")

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Hi, I was trying to use JuMP.MathProgBase and Ipopt solver to solve a problem, but it seems my parameters are wrong. The third option in the error message seems to be the closest one to my problem. Does it mean, for exa…

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## [Multivariate Linear Regression in the Julia](https://discourse.julialang.org/t/multivariate-linear-regression-in-the-julia/17909)

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**Author:** [@YonghyunRyu](https://discourse.julialang.org/u/YonghyunRyu)\
**Replies:** 1\
**Last updated:** [November 23, 2018, 3:25pm UTC](https://discourse.julialang.org/t/multivariate-linear-regression-in-the-julia/17909 "2018-11-23T15:25:41Z")

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Hi, there! I am looking for a multivariate linear regression library in the Julia. Could anyone recommend a library for me?

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## [Package for tabular data](https://discourse.julialang.org/t/package-for-tabular-data/17849)

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**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 12\
**Last updated:** [November 23, 2018, 1:50pm UTC](https://discourse.julialang.org/t/package-for-tabular-data/17849 "2018-11-23T13:50:35Z")

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Then for somebody starting to use Julia… which of that many options should we use for our new projects if we want to work with tabular data with real numbers, categorical variables and missing data as fast as possible?

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## [Implementations of Spatial Indices](https://discourse.julialang.org/t/implementations-of-spatial-indices/7638)

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**Author:** [@yeesian](https://discourse.julialang.org/u/yeesian)\
**Replies:** 7\
**Last updated:** [November 22, 2018, 3:43pm UTC](https://discourse.julialang.org/t/implementations-of-spatial-indices/7638 "2018-11-22T15:43:20Z")

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Is there anything along the lines of https://github.com/libspatialindex/libspatialindex in julia?

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## [Plot graphs](https://discourse.julialang.org/t/plot-graphs/17805)

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**Author:** [@kirtsar](https://discourse.julialang.org/u/kirtsar)\
**Replies:** 1\
**Last updated:** [November 22, 2018, 2:28pm UTC](https://discourse.julialang.org/t/plot-graphs/17805 "2018-11-22T14:28:06Z")

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Is it possible to plot graphs with VScode? I was trying TikzGraphs and GraphPlot, but none of it works (it actually gives a lot of text in the REPL, but no pictures).

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## [Dev release: plotty](https://discourse.julialang.org/t/dev-release-plotty/17858)

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**Author:** [@y4lu](https://discourse.julialang.org/u/y4lu)\
**Replies:** 0\
**Last updated:** [November 22, 2018, 12:33pm UTC](https://discourse.julialang.org/t/dev-release-plotty/17858 "2018-11-22T12:33:52Z")

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This has been a bit of a toy project of mine for a little while now, and with a few additions and a new version of julia, a dev release couldn’t hurt Plotty\_dev is basically a static html template with a julia data sect…

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## [Global Inner functions used with remote call julia v0.6 vs v1.0](https://discourse.julialang.org/t/global-inner-functions-used-with-remote-call-julia-v0-6-vs-v1-0/17822)

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**Author:** [@johanter](https://discourse.julialang.org/u/johanter)\
**Replies:** 0\
**Last updated:** [November 21, 2018, 3:33pm UTC](https://discourse.julialang.org/t/global-inner-functions-used-with-remote-call-julia-v0-6-vs-v1-0/17822 "2018-11-21T15:33:20Z")

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Hello, I’m trying to update some code that was working on julia v0.6 with a global inner function. Below is the basic idea of what worked in julia 0.6. In my case (I read image data and process it in the remote) its a …

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## [Dealing with large numbers of points](https://discourse.julialang.org/t/dealing-with-large-numbers-of-points/17826)

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**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 13\
**Last updated:** [November 22, 2018, 9:16am UTC](https://discourse.julialang.org/t/dealing-with-large-numbers-of-points/17826 "2018-11-22T09:16:35Z")

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I’m trying to use Plots.jl with GR backend to generate a scatter plot with a large number of points. However, 10,000 points fails to generate a plot in the Plots window and Juno generally crashes soon after. Am I doing …

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## [Reshaping outputs between layers in Flux.jl](https://discourse.julialang.org/t/reshaping-outputs-between-layers-in-flux-jl/17838)

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**Author:** [@Rademcaher](https://discourse.julialang.org/u/Rademcaher)\
**Replies:** 1\
**Last updated:** [November 22, 2018, 1:02am UTC](https://discourse.julialang.org/t/reshaping-outputs-between-layers-in-flux-jl/17838 "2018-11-22T01:02:41Z")

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The input to my network are N x 2 arrays and I’d like to implement a Dense layer, followed by a convolution. This requires reshaping the output of the dense layer. The forward pass seems to work fine, but I think there’s…

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## [Pmap vs RemoteChannel performance?](https://discourse.julialang.org/t/pmap-vs-remotechannel-performance/17524)

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**Author:** [@aaowens](https://discourse.julialang.org/u/aaowens)\
**Replies:** 2\
**Last updated:** [November 22, 2018, 1:28am UTC](https://discourse.julialang.org/t/pmap-vs-remotechannel-performance/17524 "2018-11-22T01:28:35Z")

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I’m working on a notebook here https://gist.github.com/aaowens/0f4ddc74a180bc726d5d9d2290c29b72 to demonstrate parallel value function iteration. I’ve tried it as serial, with threads, pmap, and remote channels. With th…

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## [Tables.jl vs TableTraits.jl (was TextParse.jl is fast again)](https://discourse.julialang.org/t/tables-jl-vs-tabletraits-jl-was-textparse-jl-is-fast-again/16982)

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**Author:** [@datnamer](https://discourse.julialang.org/u/datnamer)\
**Replies:** 21\
**Last updated:** [November 12, 2018, 10:45am UTC](https://discourse.julialang.org/t/tables-jl-vs-tabletraits-jl-was-textparse-jl-is-fast-again/16982 "2018-11-12T10:45:58Z")

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@davidanthoff what’s the relationship between tabletraits.jl and tables.jl? Edit: and interabletables.jl

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## [Common error: providing an Integer when a Float is expected](https://discourse.julialang.org/t/common-error-providing-an-integer-when-a-float-is-expected/17786)

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**Author:** [@anodos](https://discourse.julialang.org/u/anodos)\
**Replies:** 6\
**Last updated:** [November 21, 2018, 8:19am UTC](https://discourse.julialang.org/t/common-error-providing-an-integer-when-a-float-is-expected/17786 "2018-11-21T08:19:09Z")

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Hi all, Perhaps this should be taken as a comment, but I wanted to raise it nonetheless, as it is an issue I have run into time and time again, and I am beginning to suspect I am missing something. The following code, …

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## [ControlSystems - MIMO inverse / MIMO feedback loops](https://discourse.julialang.org/t/controlsystems-mimo-inverse-mimo-feedback-loops/17784)

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**Author:** [@silch12](https://discourse.julialang.org/u/silch12)\
**Replies:** 3\
**Last updated:** [November 21, 2018, 4:58pm UTC](https://discourse.julialang.org/t/controlsystems-mimo-inverse-mimo-feedback-loops/17784 "2018-11-21T16:58:26Z")

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Hi there. I’m currently studying Electrical Engineering and we have now a lecture Control Systems. Since we (should) use Matlab at school, but I can’t come to terms with proprietary software, I came across Julia as an …

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## [Debugging optimization problem in jump](https://discourse.julialang.org/t/debugging-optimization-problem-in-jump/17798)

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**Author:** [@Rasoul](https://discourse.julialang.org/u/Rasoul)\
**Replies:** 2\
**Last updated:** [November 21, 2018, 1:35pm UTC](https://discourse.julialang.org/t/debugging-optimization-problem-in-jump/17798 "2018-11-21T13:35:32Z")

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Hi everybody, I want to debug my code in julia that solves an optimization problem. I used to debug optimization problem in Matlab by assigning, the corresponding solution obtained by another approach, to variables. “a…

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## [Error with defining customer gradients in Flux.jl](https://discourse.julialang.org/t/error-with-defining-customer-gradients-in-flux-jl/17769)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 9\
**Last updated:** [November 21, 2018, 7:21am UTC](https://discourse.julialang.org/t/error-with-defining-customer-gradients-in-flux-jl/17769 "2018-11-21T07:21:12Z")

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I am trying to define some simple custom graidents in Flux.jl but am running into issues. Here is an MWE # start random parameters W = param(rand(12)) model(x) = begin x\*W end loss(x, y) = sum((model(x) .- y).^2) …

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## [Set the solver tolerance in Optimization Based Bound Tightening (OBBT)](https://discourse.julialang.org/t/set-the-solver-tolerance-in-optimization-based-bound-tightening-obbt/17797)

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**Author:** [@Rasoul](https://discourse.julialang.org/u/Rasoul)\
**Replies:** 2\
**Last updated:** [November 21, 2018, 1:21am UTC](https://discourse.julialang.org/t/set-the-solver-tolerance-in-optimization-based-bound-tightening-obbt/17797 "2018-11-21T01:21:05Z")

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Hi all, I have been working with optimization based bound tightening code in PowerModels for a while. I have a question about setting solver tolerance in which the OBBT code can work for different test cases without an…

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