# Latest

**URL:** https://discourse.julialang.org/latest.md?page=748

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

**Page:** 749

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## [AbstractTrees - iterating without a tree](https://discourse.julialang.org/t/abstracttrees-iterating-without-a-tree/96339)

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**Author:** [@freeman](https://discourse.julialang.org/u/freeman)\
**Replies:** 0\
**Last updated:** [March 20, 2023, 2:06pm UTC](https://discourse.julialang.org/t/abstracttrees-iterating-without-a-tree/96339 "2023-03-20T14:06:11Z")

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If I have a tree, I can use AbstractTrees.jl to iterate it. All I needed was to define import AbstractTrees as AT AT.children(n::MyNode) = ... Great! But often times I don’t have a tree and I don’t want to build it in…

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## [Is there a way to have a Variable Explorer in Julia?](https://discourse.julialang.org/t/is-there-a-way-to-have-a-variable-explorer-in-julia/76891)

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**Author:** [@Atlas](https://discourse.julialang.org/u/Atlas)\
**Replies:** 18\
**Last updated:** [March 20, 2023, 1:01pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-have-a-variable-explorer-in-julia/76891 "2023-03-20T13:01:15Z")

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Hi there! I come from Python and more specifically, Spyder. Spyder has a wonderful variable explorer which has really optimized my workflow. Is there something similar for Julia? I had a quick look around here and in V…

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## [AssertionError when deleting and updating constraint in JuMP using Mosek solver](https://discourse.julialang.org/t/assertionerror-when-deleting-and-updating-constraint-in-jump-using-mosek-solver/96238)

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**Author:** [@bobo](https://discourse.julialang.org/u/bobo)\
**Replies:** 2\
**Last updated:** [March 20, 2023, 12:53pm UTC](https://discourse.julialang.org/t/assertionerror-when-deleting-and-updating-constraint-in-jump-using-mosek-solver/96238 "2023-03-20T12:53:45Z")

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Dear team, I would like to sequentially solve a problem by updating a constraint, the way I do it is to delete and restate the constraint inside a loop. Once the problem is solved and I try to delete the constraint I ge…

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## [Dierckx to perform a derivative over a 2d spline](https://discourse.julialang.org/t/dierckx-to-perform-a-derivative-over-a-2d-spline/96101)

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**Author:** [@roi.holtzman](https://discourse.julialang.org/u/roi.holtzman)\
**Replies:** 8\
**Last updated:** [March 20, 2023, 11:24am UTC](https://discourse.julialang.org/t/dierckx-to-perform-a-derivative-over-a-2d-spline/96101 "2023-03-20T11:24:08Z")

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I cannot use Dierckx.jl to perform a derivative over a 2d spline even though from the documentation it seems like it should work. The help of the function derivative gives: Dierckx.derivative is a Function. # 10 metho…

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## [Breakpoints fail in code called from compiled code?](https://discourse.julialang.org/t/breakpoints-fail-in-code-called-from-compiled-code/96328)

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**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 3\
**Last updated:** [March 20, 2023, 10:35am UTC](https://discourse.julialang.org/t/breakpoints-fail-in-code-called-from-compiled-code/96328 "2023-03-20T10:35:19Z")

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Using VSCode and the following test code, with a breakpoint set where indicated: function test5(x) a=10 #set breakpoint here return a+x end print(sum(test5(x) for x in \[3, 5\])) When I run this with F5 the cod…

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## [How to get backtrace of \`@async\` Task](https://discourse.julialang.org/t/how-to-get-backtrace-of-async-task/18170)

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**Author:** [@standarddeviant](https://discourse.julialang.org/u/standarddeviant)\
**Replies:** 6\
**Last updated:** [February 2, 2023, 9:43am UTC](https://discourse.julialang.org/t/how-to-get-backtrace-of-async-task/18170 "2023-02-02T09:43:41Z")

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I’m unsure how to get the thrown error or backtrace of an asynchronous Task. Here’s an example script: # silent\_test\_all\_in\_one.jl function do\_some\_work(increase::Real) a = 0.0 start\_time = time() while ti…

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## [Release notes of Julia 1.8 misses multidimensional array initialisation of any object](https://discourse.julialang.org/t/release-notes-of-julia-1-8-misses-multidimensional-array-initialisation-of-any-object/96332)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [March 20, 2023, 10:00am UTC](https://discourse.julialang.org/t/release-notes-of-julia-1-8-misses-multidimensional-array-initialisation-of-any-object/96332 "2023-03-20T10:00:21Z")

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Julia 1.7 added the capacity to use the multiple semicolon syntax to initialise hard-coded arrays: " Repeated semicolons can now be used inside array concatenation expressions to separate dimensions of an array, with th…

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## [How to optimize Jacobian ForwardDiff.jl](https://discourse.julialang.org/t/how-to-optimize-jacobian-forwarddiff-jl/96177)

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**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 2\
**Last updated:** [March 20, 2023, 8:20am UTC](https://discourse.julialang.org/t/how-to-optimize-jacobian-forwarddiff-jl/96177 "2023-03-20T08:20:41Z")

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Hello, I manual calculate Jacobian for the system function TM(u, p, t) U(y) = p\[8\] + p\[9\] / ( 1.0 + exp( -50.0 \* (y - p\[7\]) ) ) σ(x) = 1.0 / ( 1.0 + exp( -20.0 \* (x-p\[6\]) ) ) du1 = (-u\[1\] + p\[1\] \* log( 1.0 +…

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## [Displaying Rationals](https://discourse.julialang.org/t/displaying-rationals/9475)

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**Author:** [@Jean\_Michel](https://discourse.julialang.org/u/Jean_Michel)\
**Replies:** 32\
**Last updated:** [March 20, 2023, 9:44am UTC](https://discourse.julialang.org/t/displaying-rationals/9475 "2023-03-20T09:44:10Z")

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I have a small complaint about julia. I use all the time matrices of Rationals, like \> 10×10 Array{Rational{Int64},2}: \> 2//1 0//1 0//1 0//1 0//1 0//1 0//1 0//1 0//1 0//1 \> 0//1 2//1 0//1 0//1 0/…

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## [Threads question](https://discourse.julialang.org/t/threads-question/96326)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 4\
**Last updated:** [March 20, 2023, 9:19am UTC](https://discourse.julialang.org/t/threads-question/96326 "2023-03-20T09:19:23Z")

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Running Julia on 1 thread on a 4 Core Windows 10 PC, the line rand(10\_000,10\_000)^2 Uses 100% of the CPUs. From this, I assume that unless you are very advanced, there’s no benefit to writing multi-threaded code as…

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## [Can you use Gurobi's \`ObjNRelTol\` and \`ObjNAbsTol\`?](https://discourse.julialang.org/t/can-you-use-gurobis-objnreltol-and-objnabstol/96327)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 3\
**Last updated:** [March 20, 2023, 7:38am UTC](https://discourse.julialang.org/t/can-you-use-gurobis-objnreltol-and-objnabstol/96327 "2023-03-20T07:38:59Z")

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Hi, As for the subject. We’ve tried MOI.set(grb, Gurobi.MultiObjectiveAttribute("ObjNRelTol", 0.001)) But we got ERROR: LoadError: UndefVarError: MultiObjectiveAttribute not defined We’re on Gurobi 0.11.5, which se…

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## [ObjectiveC.jl - Bridge package for using Objective-C in Julia](https://discourse.julialang.org/t/objectivec-jl-bridge-package-for-using-objective-c-in-julia/95862)

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**Author:** [@maleadt](https://discourse.julialang.org/u/maleadt)\
**Replies:** 7\
**Last updated:** [March 20, 2023, 7:25am UTC](https://discourse.julialang.org/t/objectivec-jl-bridge-package-for-using-objective-c-in-julia/95862 "2023-03-20T07:25:16Z")

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I just released ObjectiveC.jl 0.1, a package for working with Objective-C in Julia. The package was created by @MikeInnes back in 2014, but wasn’t registered, or functional anymore on recent versions of Julia. That has b…

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## [Pmap() data inputs](https://discourse.julialang.org/t/pmap-data-inputs/96306)

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**Author:** [@ditfurth](https://discourse.julialang.org/u/ditfurth)\
**Replies:** 4\
**Last updated:** [March 20, 2023, 6:57am UTC](https://discourse.julialang.org/t/pmap-data-inputs/96306 "2023-03-20T06:57:59Z")

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Hi all, I am confused about pmap. I do export all packages to all cores using @everywhere, I also export all functions using @everywhere. But then, I try to use pmap where some of the inputs is a dataset. Do I need to …

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## [Specifying output container type based on input container](https://discourse.julialang.org/t/specifying-output-container-type-based-on-input-container/96197)

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**Author:** [@MilesCranmer](https://discourse.julialang.org/u/MilesCranmer)\
**Replies:** 14\
**Last updated:** [March 20, 2023, 5:44am UTC](https://discourse.julialang.org/t/specifying-output-container-type-based-on-input-container/96197 "2023-03-20T05:44:46Z")

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I have a question about generic functions which is probably something simple I am missing. Let’s say I have a function f defined as follows: function f(x::A)::AbstractArray{T, N-1} where {T\<:Real, N, A\<:AbstractArray{T,…

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## [Check equality of two NamedTuples with order of the fields ignored](https://discourse.julialang.org/t/check-equality-of-two-namedtuples-with-order-of-the-fields-ignored/53177)

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**Author:** [@Norman](https://discourse.julialang.org/u/Norman)\
**Replies:** 6\
**Last updated:** [March 20, 2023, 5:34am UTC](https://discourse.julialang.org/t/check-equality-of-two-namedtuples-with-order-of-the-fields-ignored/53177 "2023-03-20T05:34:53Z")

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Suppose I have the following two instances of NamedTuple. julia\> a = (x=1, y=2) (x = 1, y = 2) julia\> b = (y=2, x=1) (y = 2, x = 1) julia\> a == b false What would be the best approach to test whether a and b contain …

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## [Vscode breakpoint not working in callback](https://discourse.julialang.org/t/vscode-breakpoint-not-working-in-callback/78830)

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**Author:** [@anon69491625](https://discourse.julialang.org/u/anon69491625)\
**Replies:** 1\
**Last updated:** [March 20, 2023, 4:18am UTC](https://discourse.julialang.org/t/vscode-breakpoint-not-working-in-callback/78830 "2023-03-20T04:18:42Z")

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I’m a noob and learning how to set up vscode so bear with me please. So I have an asynchronous process that completes a callback successfully. I picked the line where it prints out the message telling me that it’s in t…

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## [Defining variables in JuMP](https://discourse.julialang.org/t/defining-variables-in-jump/95843)

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**Author:** [@kevinqiao](https://discourse.julialang.org/u/kevinqiao)\
**Replies:** 4\
**Last updated:** [March 20, 2023, 2:46am UTC](https://discourse.julialang.org/t/defining-variables-in-jump/95843 "2023-03-20T02:46:46Z")

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Hello, I have a question about defining variables in JuMP, normally, the variables are defined as @variable(model, testContinusVar) @variable(model, testIntegerVar, Int) @variable(model, testBinaryVar, Bin) And what i…

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## [BasicBSpline.jl - Basic mathematical operations for B-spline](https://discourse.julialang.org/t/basicbspline-jl-basic-mathematical-operations-for-b-spline/96323)

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**Author:** [@hyrodium](https://discourse.julialang.org/u/hyrodium)\
**Replies:** 0\
**Last updated:** [March 20, 2023, 12:56am UTC](https://discourse.julialang.org/t/basicbspline-jl-basic-mathematical-operations-for-b-spline/96323 "2023-03-20T00:56:11Z")

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Hi all, I’m pleased to announce my package BasicBSpline.jl v0.9.4 (repo, docs). Introduction This package provides basic mathematical operations for B-spline. B-spline basis function Some operations for knot vector S…

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## [Unstable Julia Language Server? (was Quarto VSCode and unicode characters?)](https://discourse.julialang.org/t/unstable-julia-language-server-was-quarto-vscode-and-unicode-characters/90317)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 2\
**Last updated:** [March 20, 2023, 12:10am UTC](https://discourse.julialang.org/t/unstable-julia-language-server-was-quarto-vscode-and-unicode-characters/90317 "2023-03-20T00:10:07Z")

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I’m writing a Quarto document as part of a series of tutorials I’m writing, and will announce in a few weeks. My Quarto document explains the basic ideas of differential calculus using nonstandard analysis. I’ve got a c…

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## [Indexin takes a collection](https://discourse.julialang.org/t/indexin-takes-a-collection/96315)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 1\
**Last updated:** [March 19, 2023, 7:48pm UTC](https://discourse.julialang.org/t/indexin-takes-a-collection/96315 "2023-03-19T19:48:57Z")

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indexin takes a collection for both arguments, but since broadcasting is available most functions take a scalar. Why does this one take a collection for a?

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## [Use MPI with iJulia](https://discourse.julialang.org/t/use-mpi-with-ijulia/96319)

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**Author:** [@smartalecH](https://discourse.julialang.org/u/smartalecH)\
**Replies:** 1\
**Last updated:** [March 19, 2023, 8:43pm UTC](https://discourse.julialang.org/t/use-mpi-with-ijulia/96319 "2023-03-19T20:43:01Z")

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Is there an easy/recommended way to use iJulia with MPI? I see this has (somewhat) been asked in the past. But I’m wondering if anything has changed in the last few years (which is quite a bit of time for Julia…)

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## [Warm starting Xpress with a full basis using JuMP](https://discourse.julialang.org/t/warm-starting-xpress-with-a-full-basis-using-jump/96216)

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**Author:** [@Diego](https://discourse.julialang.org/u/Diego)\
**Replies:** 6\
**Last updated:** [March 19, 2023, 8:40pm UTC](https://discourse.julialang.org/t/warm-starting-xpress-with-a-full-basis-using-jump/96216 "2023-03-19T20:40:53Z")

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Dear all, I have tried setting initial values/duals of similar problems in JuMP/Xpress for LP problems but we have not been very successful for LP, for MIP we have been though. I was wondering whether Xpress.writebasis…

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## [Generate vector of binary digits from int](https://discourse.julialang.org/t/generate-vector-of-binary-digits-from-int/96291)

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**Author:** [@smartalecH](https://discourse.julialang.org/u/smartalecH)\
**Replies:** 7\
**Last updated:** [March 19, 2023, 7:01pm UTC](https://discourse.julialang.org/t/generate-vector-of-binary-digits-from-int/96291 "2023-03-19T19:01:37Z")

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Is there an easy way to generate a vector of binary digits from an int? For example, suppose I want a 4-bit representation of the integer 3 (0b0011). Something like: julia\> bin\_to\_vec(3,4) \[0, 0, 1, 1\] where I can opt…

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## [PlotlyJS doesn't implement orthographic projection option](https://discourse.julialang.org/t/plotlyjs-doesnt-implement-orthographic-projection-option/96203)

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**Author:** [@bhalpin](https://discourse.julialang.org/u/bhalpin)\
**Replies:** 6\
**Last updated:** [March 19, 2023, 2:20pm UTC](https://discourse.julialang.org/t/plotlyjs-doesnt-implement-orthographic-projection-option/96203 "2023-03-19T14:20:03Z")

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PlotlyJS has an option for orthographic projection rather than the default “perspective” projection. It is described in the docs here: https://docs.juliaplots.org/stable/gallery/plotlyjs/generated/plotlyjs-ref060/ The …

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## [How exactly "in" and "not in" works in tuples?](https://discourse.julialang.org/t/how-exactly-in-and-not-in-works-in-tuples/96305)

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**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 2\
**Last updated:** [March 19, 2023, 4:38pm UTC](https://discourse.julialang.org/t/how-exactly-in-and-not-in-works-in-tuples/96305 "2023-03-19T16:38:28Z")

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Hi all, I’m trying to check some belonging conditions over some tuples. One set of tuples are numeric like (2,8) and the others are combined with text (2,8,'e','f'). I want to check for every numeric pair their existan…

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## [TransformerBlocks.jl - Simple, blazing fast, transformer components](https://discourse.julialang.org/t/transformerblocks-jl-simple-blazing-fast-transformer-components/96266)

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**Author:** [@JuliaMLTools](https://discourse.julialang.org/u/JuliaMLTools)\
**Replies:** 5\
**Last updated:** [March 19, 2023, 3:32pm UTC](https://discourse.julialang.org/t/transformerblocks-jl-simple-blazing-fast-transformer-components/96266 "2023-03-19T15:32:34Z")

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Hello everyone! I’m very happy to publish my first package: In attempting to create the most performant implementation of Andrej Karpathy’s excellent ShakespeareGPT example (as seen on YouTube), I decided to publish m…

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## [Julia Precompile error](https://discourse.julialang.org/t/julia-precompile-error/96308)

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**Author:** [@Amritesh\_Soni](https://discourse.julialang.org/u/Amritesh_Soni)\
**Replies:** 1\
**Last updated:** [March 19, 2023, 3:01pm UTC](https://discourse.julialang.org/t/julia-precompile-error/96308 "2023-03-19T15:01:25Z")

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Trying to run a set of commands but getting this error for DifferentialEquations package. What do I do? Thanks in advance Failed to precompile DifferentialEquations \[0c46a032-eb83-5123-abaf-570d42b7fbaa\] to C:\\Users\\amr…

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## [PlotlyJS confidence band bug?](https://discourse.julialang.org/t/plotlyjs-confidence-band-bug/96287)

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**Author:** [@Igor\_Douven](https://discourse.julialang.org/u/Igor_Douven)\
**Replies:** 6\
**Last updated:** [March 19, 2023, 12:14pm UTC](https://discourse.julialang.org/t/plotlyjs-confidence-band-bug/96287 "2023-03-19T12:14:57Z")

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Hi all, I’m trying to plot confidence bands using PlotlyJS.jl. It’s almost working, except that while the lines all start at x = 50, the confidence bands, for some reason, start at x = 0. This is for instance how I defi…

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## [High allocations count for TwoPointBVProblem in DifferentialEquations.jl](https://discourse.julialang.org/t/high-allocations-count-for-twopointbvproblem-in-differentialequations-jl/96296)

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**Author:** [@Hawkes](https://discourse.julialang.org/u/Hawkes)\
**Replies:** 4\
**Last updated:** [March 19, 2023, 11:22am UTC](https://discourse.julialang.org/t/high-allocations-count-for-twopointbvproblem-in-differentialequations-jl/96296 "2023-03-19T11:22:52Z")

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Hi, I’m currently trying to port some simulation code from Python to Julia. The Python version uses scipy’s solve\_bvp function to solve a two point boundary value problem. I am using DifferentialEquations.jl to accompl…

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## [MethodError: objects of type String are not callable](https://discourse.julialang.org/t/methoderror-objects-of-type-string-are-not-callable/96302)

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**Author:** [@Amit\_pratap\_singh](https://discourse.julialang.org/u/Amit_pratap_singh)\
**Replies:** 0\
**Last updated:** [March 19, 2023, 10:32am UTC](https://discourse.julialang.org/t/methoderror-objects-of-type-string-are-not-callable/96302 "2023-03-19T10:32:28Z")

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\#first plot the data plot(numpirates, globaltemperatures, legend=false) scatter!(numpirates, globaltemperatures, legend=false) #this reverses x axis we can see how the temperature changes xflip!() title!(“Global tem…

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