# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=279

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**Page:** 280

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## [Implementation of householder/reflection matrices with efficient multiplication?](https://discourse.julialang.org/t/implementation-of-householder-reflection-matrices-with-efficient-multiplication/81257)

<div class="topic-metadata">

**Author:** [@ptonner](https://discourse.julialang.org/u/ptonner)\
**Replies:** 5\
**Last updated:** [May 18, 2022, 3:09pm UTC](https://discourse.julialang.org/t/implementation-of-householder-reflection-matrices-with-efficient-multiplication/81257 "2022-05-18T15:09:02Z")

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Is there a standard implementation of reflector/householder matrices and their efficient multiplication with vectors (e.g. O(n) cost)? I don’t think this would be hard to implement for my specific purposes, but for that…

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## [HTTP: Login to MediaWiki API with post fails (works with python)](https://discourse.julialang.org/t/http-login-to-mediawiki-api-with-post-fails-works-with-python/41657)

<div class="topic-metadata">

**Author:** [@zweiglimmergneis](https://discourse.julialang.org/u/zweiglimmergneis)\
**Replies:** 5\
**Last updated:** [May 18, 2022, 10:48am UTC](https://discourse.julialang.org/t/http-login-to-mediawiki-api-with-post-fails-works-with-python/41657 "2022-05-18T10:48:49Z")

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Why can I login with python (module requests), but not with HTTP.jl? The MediaWiki API requires a login token, a bot user name and password. See python-code example. Bot user name looks like “user@juliahttp”. The passwo…

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## [How to extract weights from SimpleWeightedEdge (from kruskal\_mst)](https://discourse.julialang.org/t/how-to-extract-weights-from-simpleweightededge-from-kruskal-mst/81192)

<div class="topic-metadata">

**Author:** [@JedPhillips](https://discourse.julialang.org/u/JedPhillips)\
**Replies:** 5\
**Last updated:** [May 18, 2022, 7:19am UTC](https://discourse.julialang.org/t/how-to-extract-weights-from-simpleweightededge-from-kruskal-mst/81192 "2022-05-18T07:19:34Z")

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I’m trying to figure out how to interact with a minimal spanning tree object returned by Graphs.kruskal\_mst(). I just can’t figure out how to extract the resulting edge wights (or the edges). Here’s a minimal code to sh…

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## [How to set different linestyles in Makie Series plot](https://discourse.julialang.org/t/how-to-set-different-linestyles-in-makie-series-plot/75818)

<div class="topic-metadata">

**Author:** [@bgctw](https://discourse.julialang.org/u/bgctw)\
**Replies:** 1\
**Last updated:** [May 18, 2022, 6:04am UTC](https://discourse.julialang.org/t/how-to-set-different-linestyles-in-makie-series-plot/75818 "2022-05-18T06:04:11Z")

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The Makie series command can be used to plot several lines of a matrix. I found an documentation example that shows how to set different labels and colors for the different lines. Could someone hint me to documentatio…

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## [Fixing the value of some variables when defining it, not in the constraints](https://discourse.julialang.org/t/fixing-the-value-of-some-variables-when-defining-it-not-in-the-constraints/81218)

<div class="topic-metadata">

**Author:** [@CactusHamster](https://discourse.julialang.org/u/CactusHamster)\
**Replies:** 2\
**Last updated:** [May 17, 2022, 11:07pm UTC](https://discourse.julialang.org/t/fixing-the-value-of-some-variables-when-defining-it-not-in-the-constraints/81218 "2022-05-17T23:07:22Z")

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I’m very new to JuMP so this might be a trivial question. We have a binary variable x\_{ij}. We would like to set x\_{ij} to be zero for some i and some j. So for example, nodes 1:10 cannot be assigned to nodes 1:5. So he…

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## [ParallelStencil works with Threads but not with CUDA](https://discourse.julialang.org/t/parallelstencil-works-with-threads-but-not-with-cuda/78927)

<div class="topic-metadata">

**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 6\
**Last updated:** [May 17, 2022, 5:40pm UTC](https://discourse.julialang.org/t/parallelstencil-works-with-threads-but-not-with-cuda/78927 "2022-05-17T17:40:30Z")

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Hellos I have a code of Edge Detection using ParallelStencil. The algorithm is basic, it just compares one pixel to its left and bottom neighbors, if their values are above one threshold, I fill the image(matrix) with …

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## [How to know the long time behaviour of system of differential equations?](https://discourse.julialang.org/t/how-to-know-the-long-time-behaviour-of-system-of-differential-equations/81148)

<div class="topic-metadata">

**Author:** [@Gerardo\_Suarez](https://discourse.julialang.org/u/Gerardo_Suarez)\
**Replies:** 4\
**Last updated:** [May 17, 2022, 4:24pm UTC](https://discourse.julialang.org/t/how-to-know-the-long-time-behaviour-of-system-of-differential-equations/81148 "2022-05-17T16:24:21Z")

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Hi, I’ve been working with this system of differential equations function JJ!(du,u,p,t) I,g=p du\[1\] = - gu\[1\] - 2u\[3\] + I du\[2\] = -g\*u\[2\] + u\[1\]u\[3\] du\[3\] = -gu\[3\] +(1 -u\[2\])\*u\[1\] end I solve it using the Differen…

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## [How to add significance stars to a Plotly boxplot](https://discourse.julialang.org/t/how-to-add-significance-stars-to-a-plotly-boxplot/81170)

<div class="topic-metadata">

**Author:** [@Juan\_Mac\_Donagh](https://discourse.julialang.org/u/Juan_Mac_Donagh)\
**Replies:** 3\
**Last updated:** [May 17, 2022, 3:30pm UTC](https://discourse.julialang.org/t/how-to-add-significance-stars-to-a-plotly-boxplot/81170 "2022-05-17T15:30:15Z")

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Hi all, I have the following boxplot that I made with Plotly, and I was wondering if there was a general way of adding the significance asterisks above them? I have already done the statistic test, so I only have to add …

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## [Coupling PDEs to Agents.jl](https://discourse.julialang.org/t/coupling-pdes-to-agents-jl/80977)

<div class="topic-metadata">

**Author:** [@Sahil\_Kulkarni](https://discourse.julialang.org/u/Sahil_Kulkarni)\
**Replies:** 2\
**Last updated:** [May 17, 2022, 3:09pm UTC](https://discourse.julialang.org/t/coupling-pdes-to-agents-jl/80977 "2022-05-17T15:09:41Z")

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I want to couple PDEs to with ABMs, on the website of Agents.jl, there is a tutorial that explains how to integrate ODEs with Agents, I was wondering if I discretize a PDE with DiffEqOperators.jl and then solve the remai…

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## [Makie: text coordinates relative to the edges of the Axis](https://discourse.julialang.org/t/makie-text-coordinates-relative-to-the-edges-of-the-axis/81102)

<div class="topic-metadata">

**Author:** [@RayleighLord](https://discourse.julialang.org/u/RayleighLord)\
**Replies:** 3\
**Last updated:** [May 17, 2022, 10:25am UTC](https://discourse.julialang.org/t/makie-text-coordinates-relative-to-the-edges-of-the-axis/81102 "2022-05-17T10:25:41Z")

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Hello, In Matplotlib, it is possible to introduce text in the figures relative to the edges of the axis and not depending on the size of the particular plot you have. For example, you could place a text at (0.1, 0.1), w…

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## [Memory issues generating a search space from protein sequences](https://discourse.julialang.org/t/memory-issues-generating-a-search-space-from-protein-sequences/80860)

<div class="topic-metadata">

**Author:** [@candidaorelmex](https://discourse.julialang.org/u/candidaorelmex)\
**Replies:** 20\
**Last updated:** [May 17, 2022, 9:02am UTC](https://discourse.julialang.org/t/memory-issues-generating-a-search-space-from-protein-sequences/80860 "2022-05-17T09:02:25Z")

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Hi, I wrote two functions in order to generate a peptide search space from protein sequences. In the end, I need a dictionary that tells me in which protein I can find a certain peptide in. Now I have two questions ab…

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## [How to minimize space between colorbar and Axis, with aspect=DataAspect()](https://discourse.julialang.org/t/how-to-minimize-space-between-colorbar-and-axis-with-aspect-dataaspect/81167)

<div class="topic-metadata">

**Author:** [@ederag](https://discourse.julialang.org/u/ederag)\
**Replies:** 4\
**Last updated:** [May 17, 2022, 8:31am UTC](https://discourse.julialang.org/t/how-to-minimize-space-between-colorbar-and-axis-with-aspect-dataaspect/81167 "2022-05-17T08:31:33Z")

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let fig = Figure(resolution=(700,300)) ax = Axis(fig\[1, 1\]; aspect=DataAspect()) lines!(ax, Circle(Point2f(0, 0), 1)) lines!(ax, Circle(Point2f(0, 1), 1)) Colorbar(fig\[1, 2\]) resize\_to\_layout!(fig) fig end result…

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## [Slightly weird LaTeX characters in Makie plots](https://discourse.julialang.org/t/slightly-weird-latex-characters-in-makie-plots/81181)

<div class="topic-metadata">

**Author:** [@RayleighLord](https://discourse.julialang.org/u/RayleighLord)\
**Replies:** 0\
**Last updated:** [May 17, 2022, 7:57am UTC](https://discourse.julialang.org/t/slightly-weird-latex-characters-in-makie-plots/81181 "2022-05-17T07:57:27Z")

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Hello, I would like to point out a strange behaviour I started to notice when using LaTeX strings in Makie plots. This issue might seem subtle, and I do not know how easy a solution could be, but I think raising it is w…

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## [DiffEqCallbacks' StepSizeLimiter and Dual numbers](https://discourse.julialang.org/t/diffeqcallbacks-stepsizelimiter-and-dual-numbers/62197)

<div class="topic-metadata">

**Author:** [@vettert](https://discourse.julialang.org/u/vettert)\
**Replies:** 3\
**Last updated:** [May 17, 2022, 7:56am UTC](https://discourse.julialang.org/t/diffeqcallbacks-stepsizelimiter-and-dual-numbers/62197 "2022-05-17T07:56:00Z")

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I am trying to use GalacticOptim to run an optimization and I am using GalacticOptim.AutoForwardDiff() to generate the gradients and the run an optimizer over my objective function. My objective function contains a model…

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## [How to add a linear constraint to optimize() using optim.jl?](https://discourse.julialang.org/t/how-to-add-a-linear-constraint-to-optimize-using-optim-jl/81176)

<div class="topic-metadata">

**Author:** [@jfanecon](https://discourse.julialang.org/u/jfanecon)\
**Replies:** 2\
**Last updated:** [May 17, 2022, 4:44am UTC](https://discourse.julialang.org/t/how-to-add-a-linear-constraint-to-optimize-using-optim-jl/81176 "2022-05-17T04:44:14Z")

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Hi, I wanted to add a linear constraint to a maximization problem using optim.jl. It is a linear constraint and cannot be done by box constrain. As for algorithms, I will use both gradient free and Gradient required met…

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## [Setting start values for only some indicies of a BilevelJuMP variable](https://discourse.julialang.org/t/setting-start-values-for-only-some-indicies-of-a-bileveljump-variable/81160)

<div class="topic-metadata">

**Author:** [@math\_opt](https://discourse.julialang.org/u/math_opt)\
**Replies:** 3\
**Last updated:** [May 17, 2022, 2:17am UTC](https://discourse.julialang.org/t/setting-start-values-for-only-some-indicies-of-a-bileveljump-variable/81160 "2022-05-17T02:17:00Z")

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For the following BilevelJumP model, I want to set the start value for variable x 's even indices: using JuMP, BilevelJuMP, Gurobi a = \[1.0, 0.0, 1.0, 1.0, 0.0, 0.0\] model = BilevelModel(Gurobi.Optimizer, mode = Bilev…

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## [ModelingToolkit systems from the XML file](https://discourse.julialang.org/t/modelingtoolkit-systems-from-the-xml-file/80991)

<div class="topic-metadata">

**Author:** [@mzhenirovskyy](https://discourse.julialang.org/u/mzhenirovskyy)\
**Replies:** 6\
**Last updated:** [May 16, 2022, 7:36pm UTC](https://discourse.julialang.org/t/modelingtoolkit-systems-from-the-xml-file/80991 "2022-05-16T19:36:19Z")

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Hi All, From this link https://help.juliahub.com/JuliaSim/Tutorials/FMUs/ I can see that we can generate FMU and XML from ModelingToolkit. The question is: can we do a vice verse, get ModelingToolkit systems from the…

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## [Help understanding solves with sparse cholesky factors](https://discourse.julialang.org/t/help-understanding-solves-with-sparse-cholesky-factors/81165)

<div class="topic-metadata">

**Author:** [@cgeoga](https://discourse.julialang.org/u/cgeoga)\
**Replies:** 2\
**Last updated:** [May 16, 2022, 7:28pm UTC](https://discourse.julialang.org/t/help-understanding-solves-with-sparse-cholesky-factors/81165 "2022-05-16T19:28:55Z")

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I recognize there are a few threads about this or something similar already, but I would really appreciate some clarification on something. I am aware that cholesky for sparse matrices permutes, and that you can ostensib…

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## [MethodError: Cannot \`convert\` an object of type String7 to an object of type Float32](https://discourse.julialang.org/t/methoderror-cannot-convert-an-object-of-type-string7-to-an-object-of-type-float32/81163)

<div class="topic-metadata">

**Author:** [@Hupdup](https://discourse.julialang.org/u/Hupdup)\
**Replies:** 1\
**Last updated:** [May 16, 2022, 6:46pm UTC](https://discourse.julialang.org/t/methoderror-cannot-convert-an-object-of-type-string7-to-an-object-of-type-float32/81163 "2022-05-16T18:46:22Z")

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Hi, I am writing a custom environment for a Reinforcement learning project. At every Timestep some Data is used to determine a part of the state/next state. I want to put this data in with a CSV file, but when I want to…

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## [Any way to plot non-orthogonal axis in Julia?](https://discourse.julialang.org/t/any-way-to-plot-non-orthogonal-axis-in-julia/81161)

<div class="topic-metadata">

**Author:** [@chunjiw](https://discourse.julialang.org/u/chunjiw)\
**Replies:** 2\
**Last updated:** [May 16, 2022, 6:42pm UTC](https://discourse.julialang.org/t/any-way-to-plot-non-orthogonal-axis-in-julia/81161 "2022-05-16T18:42:32Z")

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Something like this

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## [Benchmarks for our own new differential equation solver](https://discourse.julialang.org/t/benchmarks-for-our-own-new-differential-equation-solver/81109)

<div class="topic-metadata">

**Author:** [@Mikel\_Antonana](https://discourse.julialang.org/u/Mikel_Antonana)\
**Replies:** 2\
**Last updated:** [May 16, 2022, 5:31pm UTC](https://discourse.julialang.org/t/benchmarks-for-our-own-new-differential-equation-solver/81109 "2022-05-16T17:31:11Z")

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Hi everyone, We are developing a new differential equation solver, function DiffEqBase.\_\_solve(prob::DiffEqBase.AbstractODEProblem{uType,tType,isinplace}, alg::IRKAlgorithm, udim::Array{floatType,dim},args...; …

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## [Makie.jl: colormap without coarse graining](https://discourse.julialang.org/t/makie-jl-colormap-without-coarse-graining/81130)

<div class="topic-metadata">

**Author:** [@Kevin\_Kleinbeck](https://discourse.julialang.org/u/Kevin_Kleinbeck)\
**Replies:** 4\
**Last updated:** [May 16, 2022, 3:48pm UTC](https://discourse.julialang.org/t/makie-jl-colormap-without-coarse-graining/81130 "2022-05-16T15:48:51Z")

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Motivation I have a function f on a 2d domain, which approximatively has a minimal negative value -1 and a maximal positive value of \\approx 1/4 (not really important), which I want to visualise in a way, such that f \\ap…

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## [Disable instability checks in OrdinaryDiffEq](https://discourse.julialang.org/t/disable-instability-checks-in-ordinarydiffeq/80799)

<div class="topic-metadata">

**Author:** [@AndreaRH](https://discourse.julialang.org/u/AndreaRH)\
**Replies:** 2\
**Last updated:** [May 16, 2022, 1:58pm UTC](https://discourse.julialang.org/t/disable-instability-checks-in-ordinarydiffeq/80799 "2022-05-16T13:58:56Z")

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Hi, I have a small network of 3 neurons and I’m using OrdinaryDiffEq to solve the ode system describing their interconnected dynamics. Since this problem is stiff, I’m using an adaptive solver that can handle it and thi…

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## [Get results from CBC solver for optimization](https://discourse.julialang.org/t/get-results-from-cbc-solver-for-optimization/81135)

<div class="topic-metadata">

**Author:** [@ayodyas](https://discourse.julialang.org/u/ayodyas)\
**Replies:** 4\
**Last updated:** [May 16, 2022, 11:43am UTC](https://discourse.julialang.org/t/get-results-from-cbc-solver-for-optimization/81135 "2022-05-16T11:43:43Z")

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I would like to know how to access the results (constraints value, variable value) from the model created using Cbc and Jump model in Julia

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## [Jump process with multiple jumps, which jump occurs?](https://discourse.julialang.org/t/jump-process-with-multiple-jumps-which-jump-occurs/81122)

<div class="topic-metadata">

**Author:** [@Max\_Beez](https://discourse.julialang.org/u/Max_Beez)\
**Replies:** 1\
**Last updated:** [May 16, 2022, 9:21am UTC](https://discourse.julialang.org/t/jump-process-with-multiple-jumps-which-jump-occurs/81122 "2022-05-16T09:21:08Z")

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If we construct a jump process, say one with an underlying ODE and 5 jumps are defined with differing affects. We then pass the jumps, say j1,j2, j3, j4 and j5 to the JumpProblem constructor. How is which jump occurs im…

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## [Can't read a CSV file with empty fields into a DataFrame](https://discourse.julialang.org/t/cant-read-a-csv-file-with-empty-fields-into-a-dataframe/80276)

<div class="topic-metadata">

**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 7\
**Last updated:** [May 16, 2022, 12:06am UTC](https://discourse.julialang.org/t/cant-read-a-csv-file-with-empty-fields-into-a-dataframe/80276 "2022-05-16T00:06:08Z")

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I am trying to read a CSV file into a DataFrame. It clearly has some empty fields, and I get an error ERROR: MethodError: Cannot convert an object of type Missing to an object of type String I have tried to redefine …

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## [FFT with variable sampling frequency](https://discourse.julialang.org/t/fft-with-variable-sampling-frequency/46288)

<div class="topic-metadata">

**Author:** [@EmadMasroor](https://discourse.julialang.org/u/EmadMasroor)\
**Replies:** 11\
**Last updated:** [May 15, 2022, 9:51pm UTC](https://discourse.julialang.org/t/fft-with-variable-sampling-frequency/46288 "2022-05-15T21:51:56Z")

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Hello members of the Julia community, Is it possible to use the FFTW package (or any other Julia package) to perform an FFT on non-uniformly-sampled data? It seems that the functions provided in this package all assume …

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## [Flux.destructure a Flux.Chain that takes an argument?](https://discourse.julialang.org/t/flux-destructure-a-flux-chain-that-takes-an-argument/81067)

<div class="topic-metadata">

**Author:** [@linkz](https://discourse.julialang.org/u/linkz)\
**Replies:** 6\
**Last updated:** [May 15, 2022, 9:47pm UTC](https://discourse.julialang.org/t/flux-destructure-a-flux-chain-that-takes-an-argument/81067 "2022-05-15T21:47:48Z")

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Hello all, I have a use case where I need to use some custom layers in a Flux.Chain that depend on the initial vector passed to the chain (which changes). I can construct the chain easily as per below (with some dummy la…

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## [How to use ForwardDiff with NLopt?](https://discourse.julialang.org/t/how-to-use-forwarddiff-with-nlopt/53368)

<div class="topic-metadata">

**Author:** [@Michael\_Barmann](https://discourse.julialang.org/u/Michael_Barmann)\
**Replies:** 9\
**Last updated:** [May 15, 2022, 9:06pm UTC](https://discourse.julialang.org/t/how-to-use-forwarddiff-with-nlopt/53368 "2022-05-15T21:06:14Z")

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I’m working on an optimization problem, and I’m trying to make use of the gradient-based algorithms in the NLopt library (specifically LD\_SLSQP). The objective function which I am trying to minimize does not have an anal…

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## [How do I check my custom Env in Reinforce.jl?](https://discourse.julialang.org/t/how-do-i-check-my-custom-env-in-reinforce-jl/80808)

<div class="topic-metadata">

**Author:** [@Hupdup](https://discourse.julialang.org/u/Hupdup)\
**Replies:** 4\
**Last updated:** [May 15, 2022, 7:23pm UTC](https://discourse.julialang.org/t/how-do-i-check-my-custom-env-in-reinforce-jl/80808 "2022-05-15T19:23:26Z")

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Hello all, I have written a custom enviroment in reinforce.jl and now I want to check if it is correct (i.e. if the actions and the step function work as thought). For this I wanted to call the functions one by one in …

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