# Latest

**URL:** https://discourse.julialang.org/latest.md?page=710

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

**Page:** 711

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## [Dot syntax](https://discourse.julialang.org/t/dot-syntax/96789)

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**Author:** [@lancejnelson](https://discourse.julialang.org/u/lancejnelson)\
**Replies:** 6\
**Last updated:** [May 4, 2023, 5:53pm UTC](https://discourse.julialang.org/t/dot-syntax/96789 "2023-05-04T17:53:33Z")

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I can’t see why these three statements do different things: data = \[4;3;2;1;5\] x = data .- findmin(data)\[1\] # Subtract the min from each value. Does what I want. x = @. data - findmin(data)\[1\] # Error, can't broadcast …

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## [No result from nlsolve](https://discourse.julialang.org/t/no-result-from-nlsolve/98325)

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**Author:** [@cdestael](https://discourse.julialang.org/u/cdestael)\
**Replies:** 2\
**Last updated:** [May 4, 2023, 4:53pm UTC](https://discourse.julialang.org/t/no-result-from-nlsolve/98325 "2023-05-04T16:53:09Z")

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Below is a MWE of a problem I am working with. First, a function is defined with a system of 4 equations. Second, matrices are initialized. Third, I try to solve the system using nlsolve. After running this MWE, the c…

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## [\[ANN\] SnoopPrecompile -\> PrecompileTools](https://discourse.julialang.org/t/ann-snoopprecompile-precompiletools/97882)

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**Author:** [@tim.holy](https://discourse.julialang.org/u/tim.holy)\
**Replies:** 22\
**Last updated:** [May 4, 2023, 4:26pm UTC](https://discourse.julialang.org/t/ann-snoopprecompile-precompiletools/97882 "2023-05-04T16:26:09Z")

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SnoopPrecompile is being deprecated in favor of PrecompileTools. If you maintain a General-registry package that uses SnoopPrecompile, you should soon receive a pull request that will migrate you to PrecompileTools. Othe…

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## [Vector Equations with ModelingToolkit and MethodOfLines (Updated Syntax)](https://discourse.julialang.org/t/vector-equations-with-modelingtoolkit-and-methodoflines-updated-syntax/98254)

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**Author:** [@johnb](https://discourse.julialang.org/u/johnb)\
**Replies:** 3\
**Last updated:** [May 4, 2023, 3:40pm UTC](https://discourse.julialang.org/t/vector-equations-with-modelingtoolkit-and-methodoflines-updated-syntax/98254 "2023-05-04T15:40:51Z")

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I have attempted to update some code to the preferred updated syntax u(..)\[1:n\] since u\[1:n\](..) is slated for deprecation. When I modify this in the code, I get a new error. I have attached an example problem from adap…

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## [How to best parallelize custom decision tree / forest?](https://discourse.julialang.org/t/how-to-best-parallelize-custom-decision-tree-forest/98328)

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**Author:** [@MiquellaXMalenia](https://discourse.julialang.org/u/MiquellaXMalenia)\
**Replies:** 0\
**Last updated:** [May 4, 2023, 3:39pm UTC](https://discourse.julialang.org/t/how-to-best-parallelize-custom-decision-tree-forest/98328 "2023-05-04T15:39:45Z")

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Hello, Could anyone give me advice on the best way to parallelize a custom decision tree or forest algorithm on CPU / GPU? I am currently building my own from scratch to experiment with some of my ideas for multi-class…

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## [Fast \`diag(A' \* B \* A)\`](https://discourse.julialang.org/t/fast-diag-a-b-a/98216)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 22\
**Last updated:** [May 4, 2023, 3:32pm UTC](https://discourse.julialang.org/t/fast-diag-a-b-a/98216 "2023-05-04T15:32:22Z")

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Let A be a k \\times n matrix and B a k\\times k matrix, with k \\ll n. I want to compute the diagonal diag(A' \* B \* A) in a faster way. Here A' \* B \* A is a large n \\times n matrix, which I would like to avoid instantia…

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## [Oblique slices in Makie](https://discourse.julialang.org/t/oblique-slices-in-makie/83879)

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**Author:** [@fedoroff](https://discourse.julialang.org/u/fedoroff)\
**Replies:** 14\
**Last updated:** [May 4, 2023, 3:03pm UTC](https://discourse.julialang.org/t/oblique-slices-in-makie/83879 "2023-05-04T15:03:18Z")

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Are there any way to plot an oblique slice in Makie? Something similar to Matlab’s obliqueslice function.

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## [Visualization of Jason agent-based system using InteractiveDyamics](https://discourse.julialang.org/t/visualization-of-jason-agent-based-system-using-interactivedyamics/98321)

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**Author:** [@aidbar](https://discourse.julialang.org/u/aidbar)\
**Replies:** 1\
**Last updated:** [May 4, 2023, 2:51pm UTC](https://discourse.julialang.org/t/visualization-of-jason-agent-based-system-using-interactivedyamics/98321 "2023-05-04T14:51:44Z")

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Hello everyone, I’m new here! :slight\_smile: Is there a way to visualize an agent-based system written in Jason (Jason | a Java-based interpreter for an extended version of AgentSpeak) using InteractiveDynamics? …

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## [Efficient matrix multiplication over 4-dimensional arrays](https://discourse.julialang.org/t/efficient-matrix-multiplication-over-4-dimensional-arrays/98319)

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**Author:** [@thbake](https://discourse.julialang.org/u/thbake)\
**Replies:** 7\
**Last updated:** [May 4, 2023, 2:41pm UTC](https://discourse.julialang.org/t/efficient-matrix-multiplication-over-4-dimensional-arrays/98319 "2023-05-04T14:41:11Z")

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I have two 4-dimensional arrays of sizes (r1, m, n, r2) and (s1, n, p, s2), respectively, and these have to be multiplied such that the resulting 4-dimensional array has shape (r1 \* s1, m, p, r2 \* s2). My naive implement…

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## [Loess.jl version 0.6](https://discourse.julialang.org/t/loess-jl-version-0-6/98324)

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**Author:** [@andreasnoack](https://discourse.julialang.org/u/andreasnoack)\
**Replies:** 0\
**Last updated:** [May 4, 2023, 2:32pm UTC](https://discourse.julialang.org/t/loess-jl-version-0-6/98324 "2023-05-04T14:32:52Z")

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Loess version 0.6 has just been released with a few breaking changes. Most importantly, the interpolation method for predictions has changed and predictions can be very different from predictions in prior versions. The n…

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## [Is there a way to display a CairoMakie plot in a Gtk/Qt window in remote X11 session](https://discourse.julialang.org/t/is-there-a-way-to-display-a-cairomakie-plot-in-a-gtk-qt-window-in-remote-x11-session/98222)

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**Author:** [@yvikhlya](https://discourse.julialang.org/u/yvikhlya)\
**Replies:** 8\
**Last updated:** [May 4, 2023, 12:57pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-display-a-cairomakie-plot-in-a-gtk-qt-window-in-remote-x11-session/98222 "2023-05-04T12:57:49Z")

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I am doing data analysis on a remote server and trying to utilize Makie to produce interactive quick plots. I can’t use GLMakie and using something like Jupyter notebooks remotely is complicated on my cluster. Pretty muc…

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## [Finding Smooth Roots of a Function with log-term in the Upper Half-plane by Julia NLSolve](https://discourse.julialang.org/t/finding-smooth-roots-of-a-function-with-log-term-in-the-upper-half-plane-by-julia-nlsolve/98299)

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**Author:** [@Nek](https://discourse.julialang.org/u/Nek)\
**Replies:** 4\
**Last updated:** [May 4, 2023, 2:02pm UTC](https://discourse.julialang.org/t/finding-smooth-roots-of-a-function-with-log-term-in-the-upper-half-plane-by-julia-nlsolve/98299 "2023-05-04T14:02:54Z")

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I am currently dealing with a complex function F(z) on the upper half-plane that has a log-term. I am trying to obtain its inverse function, but I can’t obtain its explicit form. I used Julia package NLSolve and got F^{…

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## [How to set the font size for labels in a legend using GMT.jl](https://discourse.julialang.org/t/how-to-set-the-font-size-for-labels-in-a-legend-using-gmt-jl/97778)

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**Author:** [@MJulia](https://discourse.julialang.org/u/MJulia)\
**Replies:** 7\
**Last updated:** [May 4, 2023, 12:35pm UTC](https://discourse.julialang.org/t/how-to-set-the-font-size-for-labels-in-a-legend-using-gmt-jl/97778 "2023-05-04T12:35:23Z")

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I’m new to GMT.jl, I hope to adjust the font size of label (“data”) in the legend as in the following code: using GMT lines(1:12, 1:12, figsize=(6,4), legend=(label=“data”,pos=:LT,box=:none,), show=true) None of FONT\_…

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## [Average of Zygote gradients](https://discourse.julialang.org/t/average-of-zygote-gradients/98303)

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**Author:** [@RoBertimus](https://discourse.julialang.org/u/RoBertimus)\
**Replies:** 2\
**Last updated:** [May 4, 2023, 12:11pm UTC](https://discourse.julialang.org/t/average-of-zygote-gradients/98303 "2023-05-04T12:11:42Z")

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Hi Everyone, I would like to know how I can manually calculate for example the mean over an array of gradients of a neural network. I have the following setup : In the training loop I calculate the gradient of the los…

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## [Absolute value of a matrix](https://discourse.julialang.org/t/absolute-value-of-a-matrix/98301)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 3\
**Last updated:** [May 4, 2023, 11:59am UTC](https://discourse.julialang.org/t/absolute-value-of-a-matrix/98301 "2023-05-04T11:59:27Z")

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Let A be a symmetric (or Hermitian) matrix. I want to compute abs(A). By this I mean taking the absolute value of the eigenvalues. See for instance linear algebra - Understanding the absolute value of a matrix. - Mathema…

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## [Should slices of Adjoint/Transpose be StridedVectors?](https://discourse.julialang.org/t/should-slices-of-adjoint-transpose-be-stridedvectors/98297)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 4\
**Last updated:** [May 4, 2023, 11:55am UTC](https://discourse.julialang.org/t/should-slices-of-adjoint-transpose-be-stridedvectors/98297 "2023-05-04T11:55:06Z")

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julia\> X = rand(2,2); julia\> view(X', :, 1) == view(X, 1, :) true julia\> view(X,1,:) isa StridedVector true julia\> view(X',:,1) isa StridedVector false Ideally, view(X',:,1) would also be a StridedVector and access t…

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## [Only show significand as tick label](https://discourse.julialang.org/t/only-show-significand-as-tick-label/98308)

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**Author:** [@alistair.white](https://discourse.julialang.org/u/alistair.white)\
**Replies:** 2\
**Last updated:** [May 4, 2023, 10:05am UTC](https://discourse.julialang.org/t/only-show-significand-as-tick-label/98308 "2023-05-04T10:05:31Z")

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Hi there, If I have tick labels like those in the picture, is there a nice way to express them in scientific notation and display the exponent e.g. at the top of the y-axis, with only the significands as tick labels? Th…

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## [Changing transparency of individual bars in a barplot using CairoMakie](https://discourse.julialang.org/t/changing-transparency-of-individual-bars-in-a-barplot-using-cairomakie/98250)

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**Author:** [@bhache](https://discourse.julialang.org/u/bhache)\
**Replies:** 1\
**Last updated:** [May 4, 2023, 9:39am UTC](https://discourse.julialang.org/t/changing-transparency-of-individual-bars-in-a-barplot-using-cairomakie/98250 "2023-05-04T09:39:20Z")

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Hi, I am trying to generate a barplot using CairoMakie which would consist two sets of bars each with a different transparency. So far I am not sure how to achieve that. MWE below depicts the barplot I am generating so …

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## [Eulerian number or Euler triangle](https://discourse.julialang.org/t/eulerian-number-or-euler-triangle/98304)

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**Author:** [@stephans3](https://discourse.julialang.org/u/stephans3)\
**Replies:** 0\
**Last updated:** [May 4, 2023, 8:29am UTC](https://discourse.julialang.org/t/eulerian-number-or-euler-triangle/98304 "2023-05-04T08:29:33Z")

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Hi all, as I could not find an implementation for the Eulerian number / Eulerian triangle I developed it briefly. There exists an recursive algorithm and an explicit formula. More infos could be found on Wikipedia: ht…

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## [Mutate a Dates.Date](https://discourse.julialang.org/t/mutate-a-dates-date/97936)

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**Author:** [@nsslh](https://discourse.julialang.org/u/nsslh)\
**Replies:** 7\
**Last updated:** [May 4, 2023, 5:42am UTC](https://discourse.julialang.org/t/mutate-a-dates-date/97936 "2023-05-04T05:42:56Z")

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Is there a way to mutate a Dates.Date without allocation, such that I don’t put pressure on the garbage collector? I am reusing an array of structs to reduce GC pressure in an RPC service. I would like to mutate the dat…

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## [\[ANN\] MoYe.jl: Layout Algebra on GPU](https://discourse.julialang.org/t/ann-moye-jl-layout-algebra-on-gpu/98226)

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**Author:** [@MilkshakeForReal](https://discourse.julialang.org/u/MilkshakeForReal)\
**Replies:** 0\
**Last updated:** [May 3, 2023, 1:26am UTC](https://discourse.julialang.org/t/ann-moye-jl-layout-algebra-on-gpu/98226 "2023-05-03T01:26:17Z")

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Hi people, I’m excited to announce the release of my new package, MoYe.jl, a powerful package for performing Layout Algebra for gpu kernel programming. Why this package? Index bookkeeping on GPU can be challenging. M…

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## [Vector{Vector} indices](https://discourse.julialang.org/t/vector-vector-indices/87418)

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**Author:** [@unhandyandy](https://discourse.julialang.org/u/unhandyandy)\
**Replies:** 22\
**Last updated:** [September 19, 2022, 5:36am UTC](https://discourse.julialang.org/t/vector-vector-indices/87418 "2022-09-19T05:36:00Z")

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This is a trivial issue, but it puzzles me, and makes me think I don’t understand Julia arrays. With julia\> test = \[\[1,2\],\[3,4\]\] 2-element Vector{Vector{Int64}}: \[1, 2\] \[3, 4\] then julia\> test\[1\] 2-element Vector{I…

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## [Can't register a function to JuMP](https://discourse.julialang.org/t/cant-register-a-function-to-jump/98276)

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**Author:** [@bdas123](https://discourse.julialang.org/u/bdas123)\
**Replies:** 1\
**Last updated:** [May 3, 2023, 9:33pm UTC](https://discourse.julialang.org/t/cant-register-a-function-to-jump/98276 "2023-05-03T21:33:25Z")

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Hello, here is a reduced version of my actual code which replicates my problem. using JuMP using Ipopt; a0 = rand(81); b = 10 c = 11 d = zeros(b,c) function calculation\_2(a) for i in 1:b for j in 1:c …

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## [Automatic differentiation in different cases](https://discourse.julialang.org/t/automatic-differentiation-in-different-cases/98268)

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**Author:** [@Djamil\_Lakhdar-Hamin](https://discourse.julialang.org/u/Djamil_Lakhdar-Hamin)\
**Replies:** 2\
**Last updated:** [May 3, 2023, 8:10pm UTC](https://discourse.julialang.org/t/automatic-differentiation-in-different-cases/98268 "2023-05-03T20:10:57Z")

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I am trying to figure out : how to automatically differentiate some function f(x1,x2,x3…) for vector of numbers. I want to use one package preferably , but if I have to mix, I want to mix zygote with ForwardDiff. I th…

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## [Help optimizing a non-linear objective with JuMP](https://discourse.julialang.org/t/help-optimizing-a-non-linear-objective-with-jump/98270)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 2\
**Last updated:** [May 3, 2023, 9:16pm UTC](https://discourse.julialang.org/t/help-optimizing-a-non-linear-objective-with-jump/98270 "2023-05-03T21:16:05Z")

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Here is a very stripped down toy example that is roughly equivalent to my real problem (without any constraints): using JuMP using Ipopt N = 54 r = rand(N) R = rand() model = Model(Ipopt.Optimizer) @variable(mod…

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## [Tell us which talks you're interested in at JuliaCon 2023!](https://discourse.julialang.org/t/tell-us-which-talks-youre-interested-in-at-juliacon-2023/98277)

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**Author:** [@ranjan](https://discourse.julialang.org/u/ranjan)\
**Replies:** 0\
**Last updated:** [May 3, 2023, 8:51pm UTC](https://discourse.julialang.org/t/tell-us-which-talks-youre-interested-in-at-juliacon-2023/98277 "2023-05-03T20:51:10Z")

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Hi all, We would love for you to let us know which talks you’re interested in seeing at JuliaCon 2023: https://forms.gle/D5zEB4gzF8NMcm5S7. This primarily helps us decide which talks go into which rooms. Please note t…

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## [Error precompiling CSV and SentinelArrays](https://discourse.julialang.org/t/error-precompiling-csv-and-sentinelarrays/98274)

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**Author:** [@burtmonroe](https://discourse.julialang.org/u/burtmonroe)\
**Replies:** 2\
**Last updated:** [May 3, 2023, 8:31pm UTC](https://discourse.julialang.org/t/error-precompiling-csv-and-sentinelarrays/98274 "2023-05-03T20:31:04Z")

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Hi: Trying to run the first notebook (Data) in the Julia Academy Data Science course and it fails immediately on the using CSV command, failing to precompile SentinelArrays. I’ve seen there were problems people had last…

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## [Zygote gradient slow for TriMAP](https://discourse.julialang.org/t/zygote-gradient-slow-for-trimap/98235)

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**Author:** [@somethrowawaynamegoo](https://discourse.julialang.org/u/somethrowawaynamegoo)\
**Replies:** 0\
**Last updated:** [May 3, 2023, 7:06am UTC](https://discourse.julialang.org/t/zygote-gradient-slow-for-trimap/98235 "2023-05-03T07:06:38Z")

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Hello, I was trying to implement TriMAP using Zygote’s gradient function, but it is very slow and the data is very high dimensional, is there any tip to improve the performance of the gradient function? The following fu…

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## [Custom Flux layer looking weird upon profiling](https://discourse.julialang.org/t/custom-flux-layer-looking-weird-upon-profiling/98273)

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**Author:** [@AMart](https://discourse.julialang.org/u/AMart)\
**Replies:** 1\
**Last updated:** [May 3, 2023, 8:11pm UTC](https://discourse.julialang.org/t/custom-flux-layer-looking-weird-upon-profiling/98273 "2023-05-03T20:11:21Z")

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I’m developing some custom Conv and Dense layers to use with Flux for my research and I’m having trouble understanding the profiler output. I’m using LeNet from Flux examples to study my implementation. The following co…

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## [AbidesMarkets.jl](https://discourse.julialang.org/t/abidesmarkets-jl/98269)

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**Author:** [@fipelle](https://discourse.julialang.org/u/fipelle)\
**Replies:** 0\
**Last updated:** [May 3, 2023, 6:33pm UTC](https://discourse.julialang.org/t/abidesmarkets-jl/98269 "2023-05-03T18:33:27Z")

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Hi, I am pleased to announce that I have released a wrapper for ABIDES-Markets: a J.P. Morgan Chase’s multi-agent discrete event simulator specialised for financial markets. This is part of a project I am working on wit…

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