# Latest

**URL:** https://discourse.julialang.org/latest.md?page=723

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

**Page:** 724

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## [SDEProblem driven by two different NoiseProcess(es)](https://discourse.julialang.org/t/sdeproblem-driven-by-two-different-noiseprocess-es/97608)

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**Author:** [@tom-plaa](https://discourse.julialang.org/u/tom-plaa)\
**Replies:** 2\
**Last updated:** [April 19, 2023, 10:37am UTC](https://discourse.julialang.org/t/sdeproblem-driven-by-two-different-noiseprocess-es/97608 "2023-04-19T10:37:20Z")

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How can we pass two different driving noise processes for an SDEProblem? The goal is to simulate a simple system of SDE’s: dX(t) = f(X, Y, t)dt + g(X, Y, t)dZ\_1(t) + h(X, Y, t)dZ\_2(t) dY(t) = \\alpha(Y,t)dt + \\beta(Y,t)…

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## [What does vars do in plot?](https://discourse.julialang.org/t/what-does-vars-do-in-plot/97642)

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**Author:** [@Random\_0826](https://discourse.julialang.org/u/Random_0826)\
**Replies:** 4\
**Last updated:** [April 19, 2023, 8:58am UTC](https://discourse.julialang.org/t/what-does-vars-do-in-plot/97642 "2023-04-19T08:58:10Z")

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Hello. I am using Julia for my research, and I have question. What does ‘vars’ do in plot? For example, when I put ‘vars=(0, \[1, 2\])’ in plot function, what does this mean? I know that changing vars affects the plot, …

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## [Type container equivalence](https://discourse.julialang.org/t/type-container-equivalence/97588)

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**Author:** [@Vinothkumar\_Raman](https://discourse.julialang.org/u/Vinothkumar_Raman)\
**Replies:** 9\
**Last updated:** [April 19, 2023, 1:05am UTC](https://discourse.julialang.org/t/type-container-equivalence/97588 "2023-04-19T01:05:12Z")

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I have struct which encapsulates a value with timestamp, like this. struct Timestampped{T} time:: UInt64 data:: T end Julia seem to have trouble with type stability when it has Timestampped{Union{A, Nothing}}.…

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## [Can't figure out why log-likelihood function doesn't work with autodiff?](https://discourse.julialang.org/t/cant-figure-out-why-log-likelihood-function-doesnt-work-with-autodiff/97636)

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**Author:** [@maxdrohde](https://discourse.julialang.org/u/maxdrohde)\
**Replies:** 2\
**Last updated:** [April 19, 2023, 1:05am UTC](https://discourse.julialang.org/t/cant-figure-out-why-log-likelihood-function-doesnt-work-with-autodiff/97636 "2023-04-19T01:05:32Z")

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I’m trying to practice Julia by coding an ordinal regression model. I have defined a log-likelihood function and it works as expected when I used Optim.jl for optimization. To gain additional speed, I want to try using t…

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## [How best to structure a physics (wave optics) simulator?](https://discourse.julialang.org/t/how-best-to-structure-a-physics-wave-optics-simulator/77952)

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**Author:** [@Yly](https://discourse.julialang.org/u/Yly)\
**Replies:** 2\
**Last updated:** [April 18, 2023, 10:25pm UTC](https://discourse.julialang.org/t/how-best-to-structure-a-physics-wave-optics-simulator/77952 "2023-04-18T22:25:20Z")

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I am a physicist working on a project involving wave optics, which I would like to use Julia for. Being relatively new to this language (and not a programmer by trade), I’m not sure of the best way to structure the prob…

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## [Simplifying LP for repeated resolving](https://discourse.julialang.org/t/simplifying-lp-for-repeated-resolving/97528)

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**Author:** [@mikel8](https://discourse.julialang.org/u/mikel8)\
**Replies:** 13\
**Last updated:** [April 18, 2023, 9:00am UTC](https://discourse.julialang.org/t/simplifying-lp-for-repeated-resolving/97528 "2023-04-18T09:00:03Z")

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Hi all, I’m working on a problem that requires repeated resolving of a large LP with different objectives. The methodology I’m working on involves solving a first problem to optimality, then imposing an epsilon constrai…

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## [Traits via set-theoretic types: proof of concept](https://discourse.julialang.org/t/traits-via-set-theoretic-types-proof-of-concept/97571)

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**Author:** [@Jollywatt](https://discourse.julialang.org/u/Jollywatt)\
**Replies:** 2\
**Last updated:** [April 18, 2023, 9:12pm UTC](https://discourse.julialang.org/t/traits-via-set-theoretic-types-proof-of-concept/97571 "2023-04-18T21:12:43Z")

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I was prompted by these discussions: abstract multiple inheritance · Issue #5 · JuliaLang/julia · GitHub RFC: Language Support for Traits — Yay or Nay? … in particular, this comment about intersection types and also t…

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## [Need advice: tracing function calls non-invasively](https://discourse.julialang.org/t/need-advice-tracing-function-calls-non-invasively/97584)

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**Author:** [@sumiya11](https://discourse.julialang.org/u/sumiya11)\
**Replies:** 7\
**Last updated:** [April 18, 2023, 8:52pm UTC](https://discourse.julialang.org/t/need-advice-tracing-function-calls-non-invasively/97584 "2023-04-18T20:52:41Z")

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Hi everyone ! I want to record statistics about calls of some functions – the number of calls, runtime, etc. – without modifying the function code (or the code in the function parent module). I have the following proto…

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## [Not able to define combinatorial and attributed schemas separetly](https://discourse.julialang.org/t/not-able-to-define-combinatorial-and-attributed-schemas-separetly/97630)

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**Author:** [@Nobel\_Chowdary](https://discourse.julialang.org/u/Nobel_Chowdary)\
**Replies:** 0\
**Last updated:** [April 18, 2023, 8:33pm UTC](https://discourse.julialang.org/t/not-able-to-define-combinatorial-and-attributed-schemas-separetly/97630 "2023-04-18T20:33:48Z")

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The following image shows the definition of schema separately. But when the combinatorial schema is inherited from an attributed schema, it is throwing an error. Can someone help me with this?

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## [Interactive boxplot with GLMakie](https://discourse.julialang.org/t/interactive-boxplot-with-glmakie/97623)

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**Author:** [@ilkerarslan](https://discourse.julialang.org/u/ilkerarslan)\
**Replies:** 6\
**Last updated:** [April 18, 2023, 7:49pm UTC](https://discourse.julialang.org/t/interactive-boxplot-with-glmakie/97623 "2023-04-18T19:49:20Z")

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Hi. I am trying to create an interactive boxplot where the use selects the variable and the boxplot is updated accordingly. The code is like below: xs = @lift($dfbox\[: , 1\]) ys = @lift($dfbox\[:, 2\]) ax = Axis(fig\[1,1\]) …

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## [Using stiff solvers for a large system of ode](https://discourse.julialang.org/t/using-stiff-solvers-for-a-large-system-of-ode/97626)

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**Author:** [@UgoMire](https://discourse.julialang.org/u/UgoMire)\
**Replies:** 3\
**Last updated:** [April 18, 2023, 7:25pm UTC](https://discourse.julialang.org/t/using-stiff-solvers-for-a-large-system-of-ode/97626 "2023-04-18T19:25:49Z")

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Hi, I am trying to solve the following set of partial differential equation: \\begin{cases} \\partial\_t u(x, y, t) = \\partial\_x f(x, y, t, u, \\partial\_x u) \\\\ \\partial\_t v(x, y, t) = \\partial\_y f(x, y, t, u, \\partial\_x …

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## [Label with Latex in CairoMakie](https://discourse.julialang.org/t/label-with-latex-in-cairomakie/97619)

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**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 2\
**Last updated:** [April 18, 2023, 7:22pm UTC](https://discourse.julialang.org/t/label-with-latex-in-cairomakie/97619 "2023-04-18T19:22:30Z")

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Hello! I tried place space between E and (Hz), I\_0, and (Hz) in the next code: f = Figure(resolution = (1300, 600)) ax\_bf = Axis(f\[1,1\]; ylabel = L"E (Hz)", xlabelsize = 35, ylabelsize = 35, xticklabelsiz…

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## [How can I benchmark DataFrames.leftjoin!? (Is this some kind of bug?)](https://discourse.julialang.org/t/how-can-i-benchmark-dataframes-leftjoin-is-this-some-kind-of-bug/97620)

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**Author:** [@NiclasMattsson](https://discourse.julialang.org/u/NiclasMattsson)\
**Replies:** 4\
**Last updated:** [April 18, 2023, 7:16pm UTC](https://discourse.julialang.org/t/how-can-i-benchmark-dataframes-leftjoin-is-this-some-kind-of-bug/97620 "2023-04-18T19:16:27Z")

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I can’t get the setup argument of @benchmark to work correctly with DataFrames. I’ll use the example in the docs of DataFrames.leftjoin! as an MWE: julia\> using DataFrames, BenchmarkTools julia\> name = DataFrame(ID=\[1,…

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## [Making 1.9 weak dependency work](https://discourse.julialang.org/t/making-1-9-weak-dependency-work/97600)

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**Author:** [@bgctw](https://discourse.julialang.org/u/bgctw)\
**Replies:** 3\
**Last updated:** [April 18, 2023, 4:37pm UTC](https://discourse.julialang.org/t/making-1-9-weak-dependency-work/97600 "2023-04-18T16:37:13Z")

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I try update from @require to julia 1.9 weak dependency by following the Pkg documentation at a branch of the DistributionFits package. It works with Require in Julia 1.8.4, but I do not get it to work with Julia 1.9.0-…

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## [How does distribute clean up Distributed without shutting down parallel processes](https://discourse.julialang.org/t/how-does-distribute-clean-up-distributed-without-shutting-down-parallel-processes/97615)

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**Author:** [@13299118606](https://discourse.julialang.org/u/13299118606)\
**Replies:** 0\
**Last updated:** [April 18, 2023, 1:29pm UTC](https://discourse.julialang.org/t/how-does-distribute-clean-up-distributed-without-shutting-down-parallel-processes/97615 "2023-04-18T13:29:56Z")

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How does distribute clean up Distributed without shutting down parallel processes Because it takes time to start the loop, and obviously the second run is faster than the first, I cycle through the parallel process and …

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## [Multi-threading for nested loops with inner loop collection depending on outer loop](https://discourse.julialang.org/t/multi-threading-for-nested-loops-with-inner-loop-collection-depending-on-outer-loop/97569)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 7\
**Last updated:** [April 18, 2023, 12:25pm UTC](https://discourse.julialang.org/t/multi-threading-for-nested-loops-with-inner-loop-collection-depending-on-outer-loop/97569 "2023-04-18T12:25:25Z")

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What is the most efficient way to parallelize an embarrassingly parallel problem with nested loops, while the inner loop’s collection depending on outer loop? MWE is using Base.Threads using ThreadsX using FLoops xs = …

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## [Memory Allocation Increases with Iterations](https://discourse.julialang.org/t/memory-allocation-increases-with-iterations/97532)

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**Author:** [@GeoKou](https://discourse.julialang.org/u/GeoKou)\
**Replies:** 15\
**Last updated:** [April 18, 2023, 12:18pm UTC](https://discourse.julialang.org/t/memory-allocation-increases-with-iterations/97532 "2023-04-18T12:18:38Z")

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Hello, I have a function that generates a number of graphs to extract some features from each, in a for loop. Since the graph is created and the features are extracted, its information is not needed in the next iteratio…

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## [\[ANN\] Released GaloisFields v1.0](https://discourse.julialang.org/t/ann-released-galoisfields-v1-0/33071)

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**Author:** [@tkluck](https://discourse.julialang.org/u/tkluck)\
**Replies:** 7\
**Last updated:** [April 18, 2023, 10:29am UTC](https://discourse.julialang.org/t/ann-released-galoisfields-v1-0/33071 "2023-04-18T10:29:28Z")

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I just released v1.0 of GaloisFields.jl. For those people not familiar – a Galois field (or ‘finite field’) is a finite set that supports addition and multiplication, both with their inverses subtraction and division. Th…

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## [Does Zygote differentiate symbolically?](https://discourse.julialang.org/t/does-zygote-differentiate-symbolically/96528)

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**Author:** [@Euhan](https://discourse.julialang.org/u/Euhan)\
**Replies:** 27\
**Last updated:** [April 18, 2023, 8:52am UTC](https://discourse.julialang.org/t/does-zygote-differentiate-symbolically/96528 "2023-04-18T08:52:07Z")

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Sorry for posting this question in maybe-not-exactly-right category! This was my guess at group with biggest overlap with my question. My question is as simple as it says in the title. Does Zygote differentiate symbolic…

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## [How to install pyqt for PythonPlot](https://discourse.julialang.org/t/how-to-install-pyqt-for-pythonplot/97542)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 3\
**Last updated:** [April 18, 2023, 6:30am UTC](https://discourse.julialang.org/t/how-to-install-pyqt-for-pythonplot/97542 "2023-04-18T06:30:27Z")

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I would like to use PythonPlot.jl with the QT backend. But how can I install it? I tried: using CondaPkg # press \] (Climate) pkg\> conda add pyqt5 which doesn’t work, it cannot find the package: error libmamba Could…

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## [Code intermittently not being interruptible](https://discourse.julialang.org/t/code-intermittently-not-being-interruptible/88881)

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**Author:** [@Nathaniel](https://discourse.julialang.org/u/Nathaniel)\
**Replies:** 5\
**Last updated:** [April 18, 2023, 5:53am UTC](https://discourse.julialang.org/t/code-intermittently-not-being-interruptible/88881 "2023-04-18T05:53:38Z")

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I’ve found that I sometimes can’t interrupt my code using ctrl-C or CMD-dot. The following was working for me earlier today as a minimal example: using Plots function main() while true plt = plot(rand(100)…

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## [Replace all NaN's with zeros in DataFrame](https://discourse.julialang.org/t/replace-all-nans-with-zeros-in-dataframe/10001)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 31\
**Last updated:** [April 18, 2023, 3:19am UTC](https://discourse.julialang.org/t/replace-all-nans-with-zeros-in-dataframe/10001 "2023-04-18T03:19:46Z")

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What’s the best way to replace all NaN’s in a DataFrame with zero? I can write a nested for-loop and check every cell but I thought there may be a simpler way to do that…

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## [Arrays of vector variables in definitions of nonlinear programs in JuMP](https://discourse.julialang.org/t/arrays-of-vector-variables-in-definitions-of-nonlinear-programs-in-jump/97593)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 1\
**Last updated:** [April 18, 2023, 12:27am UTC](https://discourse.julialang.org/t/arrays-of-vector-variables-in-definitions-of-nonlinear-programs-in-jump/97593 "2023-04-18T00:27:15Z")

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Is it possible to define arrays of vector variables while building a nonlinear programming problem in JuMP? I know we can define a scalar variable through @variable(model,x) I also know we can define a vector variable…

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## [Compiling large Symbolics.jl expressions using build\_function](https://discourse.julialang.org/t/compiling-large-symbolics-jl-expressions-using-build-function/97563)

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**Author:** [@zornsllama](https://discourse.julialang.org/u/zornsllama)\
**Replies:** 4\
**Last updated:** [April 17, 2023, 11:14pm UTC](https://discourse.julialang.org/t/compiling-large-symbolics-jl-expressions-using-build-function/97563 "2023-04-17T23:14:03Z")

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Hi, I’m using Symbolics.jl to compute derivatives for a nonlinear optimization problem, to be used as part of the Ipopt callback functions. I am ultimately hoping to match the performance of the C++ code generated in th…

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## [Return the minimum size of an array needed for a function to work](https://discourse.julialang.org/t/return-the-minimum-size-of-an-array-needed-for-a-function-to-work/97591)

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**Author:** [@jarroyoe](https://discourse.julialang.org/u/jarroyoe)\
**Replies:** 7\
**Last updated:** [April 17, 2023, 10:44pm UTC](https://discourse.julialang.org/t/return-the-minimum-size-of-an-array-needed-for-a-function-to-work/97591 "2023-04-17T22:44:34Z")

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Hi everyone, I want to create a function that receives another function as an input and returns the size of the array this. As an example, let’s say I have a simple function that takes a vector as an input: f(x::Vector{…

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## [Test for a zero-valued Tuple in where statement](https://discourse.julialang.org/t/test-for-a-zero-valued-tuple-in-where-statement/97579)

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**Author:** [@RainerHeintzmann](https://discourse.julialang.org/u/RainerHeintzmann)\
**Replies:** 15\
**Last updated:** [April 17, 2023, 9:52pm UTC](https://discourse.julialang.org/t/test-for-a-zero-valued-tuple-in-where-statement/97579 "2023-04-17T21:52:14Z")

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I would like to have a special dispatch for the case that a Tuple{} in the type definition is zero (in all entries). For example: foo(a::AbstractArray{T, N}) where {N, T\<:Tuple{zeros(Int,N)...}} but get an error since N…

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## [Spectral method for 1D heat equation OrdinaryDiffEq.jl](https://discourse.julialang.org/t/spectral-method-for-1d-heat-equation-ordinarydiffeq-jl/97586)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 0\
**Last updated:** [April 17, 2023, 7:25pm UTC](https://discourse.julialang.org/t/spectral-method-for-1d-heat-equation-ordinarydiffeq-jl/97586 "2023-04-17T19:25:29Z")

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Hello, I would like to solve the heat equation \\frac{\\partial u(x,t)}{\\partial t} = \\alpha \\frac{\\partial^2 u}{\\partial x^2} on the periodic domain \[0, 1\] with initial condition u(x, t = 0) = u\_0(x) and periodic boundar…

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## [GPU performance issues with an ML-from-scratch tutorial](https://discourse.julialang.org/t/gpu-performance-issues-with-an-ml-from-scratch-tutorial/97400)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 7\
**Last updated:** [April 17, 2023, 7:39pm UTC](https://discourse.julialang.org/t/gpu-performance-issues-with-an-ml-from-scratch-tutorial/97400 "2023-04-17T19:39:59Z")

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I put together (yet another) Julia ML-from-scratch tutorial for a machine learning course we held in Munich recently: GitHub - odsl-team/julia-ml-from-scratch: Machine learning from scratch in Julia It has very minimal …

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## [Simple Rocket.jl example: Error in Timer](https://discourse.julialang.org/t/simple-rocket-jl-example-error-in-timer/97281)

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**Author:** [@Ralf\_Dietrich](https://discourse.julialang.org/u/Ralf_Dietrich)\
**Replies:** 2\
**Last updated:** [April 17, 2023, 6:09pm UTC](https://discourse.julialang.org/t/simple-rocket-jl-example-error-in-timer/97281 "2023-04-17T18:09:23Z")

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Hello people I am currently working with the package Rocket.jl and would like to run the sample code at GitHub - biaslab/Rocket.jl: Functional reactive programming extensions library for Julia but the following code al…

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## [Entry point for contributing to climate modeling projects?](https://discourse.julialang.org/t/entry-point-for-contributing-to-climate-modeling-projects/48856)

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**Author:** [@crbinz](https://discourse.julialang.org/u/crbinz)\
**Replies:** 10\
**Last updated:** [April 17, 2023, 5:40pm UTC](https://discourse.julialang.org/t/entry-point-for-contributing-to-climate-modeling-projects/48856 "2023-04-17T17:40:07Z")

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I’d like to spend some of my free time contributing to projects that help address the issue of climate change. My background is that I have (basically) no domain knowledge at all, but I have julia and modeling/simulation…

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