# Latest

**URL:** https://discourse.julialang.org/latest.md?page=814

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

**Page:** 815

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## [NLP is not solving in ubuntu OS whereas It is solving in Windows OS with all versions of package and Julia is same (Juniper optimzer with Ipopt and HiGHS)](https://discourse.julialang.org/t/nlp-is-not-solving-in-ubuntu-os-whereas-it-is-solving-in-windows-os-with-all-versions-of-package-and-julia-is-same-juniper-optimzer-with-ipopt-and-highs/92866)

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**Author:** [@Balakumar\_A](https://discourse.julialang.org/u/Balakumar_A)\
**Replies:** 3\
**Last updated:** [January 12, 2023, 2:56pm UTC](https://discourse.julialang.org/t/nlp-is-not-solving-in-ubuntu-os-whereas-it-is-solving-in-windows-os-with-all-versions-of-package-and-julia-is-same-juniper-optimzer-with-ipopt-and-highs/92866 "2023-01-12T14:56:30Z")

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I am trying to Solve a Non Linear model using Juniper with Ipopt and GiGHS. I am getting solution in my windows operating system, whereas Ubuntu OS is not giving any results immediately as it is saying NLP couldn’t solve…

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## [Is it possible to get coefficients from interpolation function?](https://discourse.julialang.org/t/is-it-possible-to-get-coefficients-from-interpolation-function/92862)

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**Author:** [@Tatiana\_P](https://discourse.julialang.org/u/Tatiana_P)\
**Replies:** 3\
**Last updated:** [January 12, 2023, 2:46pm UTC](https://discourse.julialang.org/t/is-it-possible-to-get-coefficients-from-interpolation-function/92862 "2023-01-12T14:46:40Z")

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I use method ‘interpolate’ from Interpolation.jl library with interpmode=FritschCarlsonMonotonicInterpolation, for example, y\_spline = interpolate(x, y\_initial\_curve.(x), FritschCarlsonMonotonicInterpolation()) How to …

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## [Understanding push!](https://discourse.julialang.org/t/understanding-push/92872)

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**Author:** [@ditfurth](https://discourse.julialang.org/u/ditfurth)\
**Replies:** 1\
**Last updated:** [January 12, 2023, 12:09pm UTC](https://discourse.julialang.org/t/understanding-push/92872 "2023-01-12T12:09:32Z")

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If I want to create a vector with 15 names, where each one is pushed into the vector individually, this code just replaces the former iteration with the new iteration instead of appending to it. Right?

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## [Call For Proposals: WAW2023 18th Workshop on Algorithms and Models for the Web Graph](https://discourse.julialang.org/t/call-for-proposals-waw2023-18th-workshop-on-algorithms-and-models-for-the-web-graph/90366)

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**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 3\
**Last updated:** [January 3, 2023, 3:12pm UTC](https://discourse.julialang.org/t/call-for-proposals-waw2023-18th-workshop-on-algorithms-and-models-for-the-web-graph/90366 "2023-01-03T15:12:07Z")

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I would like to invite everyone interested in graphs to send a talk proposal to WAW2023 conference (we are flexible with what we accept as long as it is graph related and interesting). You can find a link to Call For Pr…

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## [ForwardDiff.derivative pointwise](https://discourse.julialang.org/t/forwarddiff-derivative-pointwise/92867)

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**Author:** [@c\_sell](https://discourse.julialang.org/u/c_sell)\
**Replies:** 2\
**Last updated:** [January 12, 2023, 1:15pm UTC](https://discourse.julialang.org/t/forwarddiff-derivative-pointwise/92867 "2023-01-12T13:15:48Z")

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Hello, is it possible to use ForwardDiff in the following way. I have a function (a forward diff through a neural network). I want to take the second derivative of the output with respect to the input. If I use n input…

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## [How to get a stacktrace](https://discourse.julialang.org/t/how-to-get-a-stacktrace/9960)

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**Author:** [@leoll2](https://discourse.julialang.org/u/leoll2)\
**Replies:** 5\
**Last updated:** [January 12, 2023, 1:15pm UTC](https://discourse.julialang.org/t/how-to-get-a-stacktrace/9960 "2023-01-12T13:15:18Z")

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My question is simple: When I perform an operation, I need to get a list of all the functions that get called during its execution. For example: function foo() ... rand(Int32) end function bar() foo() end …

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## [How do I initialize an empty array / vector of strings, and then push strings into](https://discourse.julialang.org/t/how-do-i-initialize-an-empty-array-vector-of-strings-and-then-push-strings-into/56980)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [March 11, 2021, 11:32pm UTC](https://discourse.julialang.org/t/how-do-i-initialize-an-empty-array-vector-of-strings-and-then-push-strings-into/56980 "2021-03-11T23:32:43Z")

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How do I initialize an empty array / vector of strings, and then push strings into it? When I do t = Vector{String} , I get this error when I then push into it: push!(t, "a") ERROR: MethodError: no method matching push!…

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## [Symbolics.jl, ModelingToolkit.jl, DifferentialEquations.jl and the Lagrangian approach](https://discourse.julialang.org/t/symbolics-jl-modelingtoolkit-jl-differentialequations-jl-and-the-lagrangian-approach/89629)

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**Author:** [@Sh\_166](https://discourse.julialang.org/u/Sh_166)\
**Replies:** 6\
**Last updated:** [January 12, 2023, 10:36am UTC](https://discourse.julialang.org/t/symbolics-jl-modelingtoolkit-jl-differentialequations-jl-and-the-lagrangian-approach/89629 "2023-01-12T10:36:57Z")

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So, as I mentioned in this topic, I was trying to implement the Lagrangian approach from scratch in Julia, and inquired for existing ways to do that. As the comments on that discussion point out, nothing of the sort exis…

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## [PageBreak when exporting a Pluto notebook to PDF](https://discourse.julialang.org/t/pagebreak-when-exporting-a-pluto-notebook-to-pdf/92281)

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**Author:** [@lgmendes](https://discourse.julialang.org/u/lgmendes)\
**Replies:** 2\
**Last updated:** [January 12, 2023, 9:56am UTC](https://discourse.julialang.org/t/pagebreak-when-exporting-a-pluto-notebook-to-pdf/92281 "2023-01-12T09:56:22Z")

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Is it possible to add a page break in a particular position of a Pluto notebook when exporting to PDF?

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## [How can I use \`get\` with a subtype of a Dict key?](https://discourse.julialang.org/t/how-can-i-use-get-with-a-subtype-of-a-dict-key/92857)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 4\
**Last updated:** [January 12, 2023, 9:48am UTC](https://discourse.julialang.org/t/how-can-i-use-get-with-a-subtype-of-a-dict-key/92857 "2023-01-12T09:48:12Z")

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I would like to define a Dict{A, Bool} and then put entries with keys of type B (a subtype of A) into it. Adding B entries to the Dict works, as does indexing the Dict with \[\], but get doesn’t seem to work: julia\> VERS…

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## [Calling cublas within a kernel?](https://discourse.julialang.org/t/calling-cublas-within-a-kernel/92852)

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**Author:** [@bcsj](https://discourse.julialang.org/u/bcsj)\
**Replies:** 0\
**Last updated:** [January 12, 2023, 8:39am UTC](https://discourse.julialang.org/t/calling-cublas-within-a-kernel/92852 "2023-01-12T08:39:24Z")

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Hi, I’m working on speeding up an iterative algorithm by running it on the gpu. Being iterative, depending on the problem structure it may at times take on the other of 10^6 iterations to reach a good solution, and I’d l…

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## [How to solve these equations?](https://discourse.julialang.org/t/how-to-solve-these-equations/92788)

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**Author:** [@Raymond](https://discourse.julialang.org/u/Raymond)\
**Replies:** 33\
**Last updated:** [January 12, 2023, 7:37am UTC](https://discourse.julialang.org/t/how-to-solve-these-equations/92788 "2023-01-12T07:37:53Z")

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using SymPy @syms x y z e₁ e₂ c₁ c₂ c₃ c₅ s₁ s₂ s₃ g₁ g₂ fx = x\*(x - 1)\*(c₁ + c₂\*y\*z - c₂\*y - c₂\*z - e₁ - e₂\*y\*z + e₂\*y + e₂\*z - g₁\*y - g₂\*z - s₁\*y) fy = y\*(y - 1)\*(c₃ + g₁\*x - g₁ + s₁\*x) fz = -z\*(z - 1)\*(-c₅ + s₂ + s…

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## [How to remove ASCII definition of a single character in Pluto Notebook?](https://discourse.julialang.org/t/how-to-remove-ascii-definition-of-a-single-character-in-pluto-notebook/92835)

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**Author:** [@Allan\_Olave](https://discourse.julialang.org/u/Allan_Olave)\
**Replies:** 3\
**Last updated:** [January 12, 2023, 6:26am UTC](https://discourse.julialang.org/t/how-to-remove-ascii-definition-of-a-single-character-in-pluto-notebook/92835 "2023-01-12T06:26:53Z")

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The following is the code I’ve written in Pluto Notebook: md""" Problem 4: Given with the following x and y data, what is the lagrange polynomial correspond to data at x = $(x₂\[1\]) and y = $(y₂\[1\]). """ The output of t…

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## [Minimizing the distance between centers of multiple circles](https://discourse.julialang.org/t/minimizing-the-distance-between-centers-of-multiple-circles/92843)

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**Author:** [@MadJoe](https://discourse.julialang.org/u/MadJoe)\
**Replies:** 5\
**Last updated:** [January 12, 2023, 5:47am UTC](https://discourse.julialang.org/t/minimizing-the-distance-between-centers-of-multiple-circles/92843 "2023-01-12T05:47:14Z")

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Hello, I am new to optimization and Julia, and I need to minimize the distance between some circles that encircle multiple points in a 2-D plane by moving the centers of the circles. We know where all of the blue spots a…

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## [Maintain backwards compatibility when using \`const\` on a mutable struct field](https://discourse.julialang.org/t/maintain-backwards-compatibility-when-using-const-on-a-mutable-struct-field/85965)

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**Author:** [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Replies:** 12\
**Last updated:** [January 12, 2023, 5:43am UTC](https://discourse.julialang.org/t/maintain-backwards-compatibility-when-using-const-on-a-mutable-struct-field/85965 "2023-01-12T05:43:42Z")

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I searched, and it doesn’t look like anyone has asked this before, but I would be surprised if I am the first, so I apologize if this question is a dupe and I missed it. In the newly released Julia v1.8.0, you can annot…

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## [Reading sockets asynchronously](https://discourse.julialang.org/t/reading-sockets-asynchronously/92096)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 6\
**Last updated:** [January 12, 2023, 5:05am UTC](https://discourse.julialang.org/t/reading-sockets-asynchronously/92096 "2023-01-12T05:05:24Z")

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I’m using readavailable() within a loop to read messages from a tcp socket as they come in. Is there a version that doesn’t require a loop ? i.e. something that will call a function asynchronously with the incoming mes…

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## [Surprising type widening when constructing Tuple{...}](https://discourse.julialang.org/t/surprising-type-widening-when-constructing-tuple/92840)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 2\
**Last updated:** [January 12, 2023, 3:18am UTC](https://discourse.julialang.org/t/surprising-type-widening-when-constructing-tuple/92840 "2023-01-12T03:18:58Z")

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Dear Julia type inference masters, I am facing some inference/performance problems which look like they could be circumvented, but I don’t know enough about what is going on here. struct ValType{T, V} end ValTypeof(v::…

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## [Nested optimizations, vars traverse nesting](https://discourse.julialang.org/t/nested-optimizations-vars-traverse-nesting/91960)

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**Author:** [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)\
**Replies:** 7\
**Last updated:** [January 12, 2023, 2:53am UTC](https://discourse.julialang.org/t/nested-optimizations-vars-traverse-nesting/91960 "2023-01-12T02:53:18Z")

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Someone asked for my help with this, however it is outside my experience. I am told the outer maximization is a quadratic in αi and βi and the inner minimization is solvable by e.g gradient descent maximize( m…

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## [Much worse import time for \`Statistics\` and \`SparseArrays\` on julia 1.9.0 nightly?](https://discourse.julialang.org/t/much-worse-import-time-for-statistics-and-sparsearrays-on-julia-1-9-0-nightly/83679)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 3\
**Last updated:** [January 12, 2023, 12:43am UTC](https://discourse.julialang.org/t/much-worse-import-time-for-statistics-and-sparsearrays-on-julia-1-9-0-nightly/83679 "2023-01-12T00:43:30Z")

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I am confused by this. Why would Statistics (or its dependency SparseArrays), a package in the standard library, have such a bad time to import? Anything I can do about this in my package that depends on Statistics? I ha…

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## [Why is the name of the language "Julia"?](https://discourse.julialang.org/t/why-is-the-name-of-the-language-julia/4382)

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**Author:** [@Evey](https://discourse.julialang.org/u/Evey)\
**Replies:** 22\
**Last updated:** [January 11, 2023, 3:29pm UTC](https://discourse.julialang.org/t/why-is-the-name-of-the-language-julia/4382 "2023-01-11T15:29:05Z")

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Python comes from Monty Python. C++ is the successor of C. C is the letter after B (another programming language). Haskell is named after Haskell Curry. Ada is inspired by Ada Lovelace. Java is coffee. Lisp is a contrive…

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## [When to use promote on parametric constructors](https://discourse.julialang.org/t/when-to-use-promote-on-parametric-constructors/92828)

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**Author:** [@graphitical](https://discourse.julialang.org/u/graphitical)\
**Replies:** 5\
**Last updated:** [January 11, 2023, 11:27pm UTC](https://discourse.julialang.org/t/when-to-use-promote-on-parametric-constructors/92828 "2023-01-11T23:27:47Z")

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I’m #newtojulia and working on converting a C++ project (hence my habit to type everything). I’m trying to be flexible and using parametric composite types (see below) and bumped into the common error of “no method match…

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## [Matrix-Free Eigensolver in BifurcationKit.jl](https://discourse.julialang.org/t/matrix-free-eigensolver-in-bifurcationkit-jl/92780)

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**Author:** [@TKBlarg](https://discourse.julialang.org/u/TKBlarg)\
**Replies:** 11\
**Last updated:** [January 11, 2023, 7:56pm UTC](https://discourse.julialang.org/t/matrix-free-eigensolver-in-bifurcationkit-jl/92780 "2023-01-11T19:56:11Z")

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I have a large-scale continuation problem for which I’m considering using matrix-free methods in Bifurcationkit.jl. To evaluate stability and detect bifurcations, I implemented a matrix-free, shift-inverting eigensolver …

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## [How can I fix my code to run using JuMP](https://discourse.julialang.org/t/how-can-i-fix-my-code-to-run-using-jump/92573)

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**Author:** [@lara](https://discourse.julialang.org/u/lara)\
**Replies:** 3\
**Last updated:** [January 11, 2023, 8:34pm UTC](https://discourse.julialang.org/t/how-can-i-fix-my-code-to-run-using-jump/92573 "2023-01-11T20:34:44Z")

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Hey, guys. This is my first time working with both Julia and JuMP. I’m making lot of mistakes, but I finally got my code running fine. Using JuMP in my code would be a plus, so I’m trying to do that, but I am having pro…

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## [Solve JuMP model with COSMO arbitrary precision](https://discourse.julialang.org/t/solve-jump-model-with-cosmo-arbitrary-precision/92807)

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**Author:** [@Thomas](https://discourse.julialang.org/u/Thomas)\
**Replies:** 1\
**Last updated:** [January 11, 2023, 8:30pm UTC](https://discourse.julialang.org/t/solve-jump-model-with-cosmo-arbitrary-precision/92807 "2023-01-11T20:30:02Z")

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Afaik there is no support for arbitrary precision in JuMP, but is there a quick hack for COSMO?

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## [In which shell Julia is running?](https://discourse.julialang.org/t/in-which-shell-julia-is-running/92814)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 8\
**Last updated:** [January 11, 2023, 8:10pm UTC](https://discourse.julialang.org/t/in-which-shell-julia-is-running/92814 "2023-01-11T20:10:03Z")

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I have Julia code that executes external commands with parameters. The parameters are file or folder names. I thought if I check if the code is executed on Windows and use a backslash as path delimiter on Windows and a s…

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## [Arbitrary Precision Optimization](https://discourse.julialang.org/t/arbitrary-precision-optimization/92803)

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**Author:** [@csmarra](https://discourse.julialang.org/u/csmarra)\
**Replies:** 2\
**Last updated:** [January 11, 2023, 7:21pm UTC](https://discourse.julialang.org/t/arbitrary-precision-optimization/92803 "2023-01-11T19:21:19Z")

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Hi, I am trying to perform a function minimization with BigFloat numbers. However, it seems that I cannot get it to work. I am using the BlackBoxOptim.jl package. Is there a way to do that? As an example, I tried to do…

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## [Automatic Differentiation with ReservoirComputing.jl Echo State Networks](https://discourse.julialang.org/t/automatic-differentiation-with-reservoircomputing-jl-echo-state-networks/92818)

<div class="topic-metadata">

**Author:** [@jClugstor](https://discourse.julialang.org/u/jClugstor)\
**Replies:** 0\
**Last updated:** [January 11, 2023, 6:28pm UTC](https://discourse.julialang.org/t/automatic-differentiation-with-reservoircomputing-jl-echo-state-networks/92818 "2023-01-11T18:28:03Z")

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I’m trying to use auto diff to find the jacobian of an echo state network from ReservoirComputing.jl. So far, I just would like to get the jacobian from the Lorenz forecast tutorial along the trajectory working. #loren…

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## [Various equalities of NaN?](https://discourse.julialang.org/t/various-equalities-of-nan/42649)

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**Author:** [@tomohiro\_soejima](https://discourse.julialang.org/u/tomohiro_soejima)\
**Replies:** 13\
**Last updated:** [January 11, 2023, 5:48pm UTC](https://discourse.julialang.org/t/various-equalities-of-nan/42649 "2023-01-11T17:48:13Z")

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I know of three functions for checking for equality: ==, ===, and isequal. The documentation comments on subtlety regarding floating point numbers, and there is indeed a difference: julia\> NaN == NaN false julia\> isequ…

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## [Overlay values as text in a PlotlyJS heatmap annotations](https://discourse.julialang.org/t/overlay-values-as-text-in-a-plotlyjs-heatmap-annotations/92733)

<div class="topic-metadata">

**Author:** [@sob](https://discourse.julialang.org/u/sob)\
**Replies:** 5\
**Last updated:** [January 11, 2023, 5:18pm UTC](https://discourse.julialang.org/t/overlay-values-as-text-in-a-plotlyjs-heatmap-annotations/92733 "2023-01-11T17:18:07Z")

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Hi, My code is rather simple: using PlotlyJS plot(heatmap(x=\["a","b"\],y=\["c","d"\],z=rand(2,2),colorscale="Reds",showscale=false)) I’m trying to have the values as an overlay (say black text) on each of the 4 squares. …

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## [Can not add Pkgs tag: buildbot ; worker ; workdir](https://discourse.julialang.org/t/can-not-add-pkgs-tag-buildbot-worker-workdir/92633)

<div class="topic-metadata">

**Author:** [@ajsagit](https://discourse.julialang.org/u/ajsagit)\
**Replies:** 2\
**Last updated:** [January 11, 2023, 4:04pm UTC](https://discourse.julialang.org/t/can-not-add-pkgs-tag-buildbot-worker-workdir/92633 "2023-01-11T16:04:58Z")

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Alway works fine but recently when \] and up or add CSV / other add \[pkgs\] returns errs and the process of Julia.exe crashed. Windows 10 x64, Windows11 x64 Julia 1.7~1.84 TIA.

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