# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=114

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

**Page:** 115

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## [Database backed for DataFrames](https://discourse.julialang.org/t/database-backed-for-dataframes/94768)

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**Author:** [@ayushpatnaikgit](https://discourse.julialang.org/u/ayushpatnaikgit)\
**Replies:** 6\
**Last updated:** [May 4, 2024, 3:05am UTC](https://discourse.julialang.org/t/database-backed-for-dataframes/94768 "2024-05-04T03:05:54Z")

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Any package in Julia like R’s dbplyr? dbplyr allows you to use remote database tables as if they are in-memory data frames by automatically converting dplyr code into SQL. I want to do the same with DataFrames and SQL.

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## [How to extract the Std. Error of a linear regression model by GLM?](https://discourse.julialang.org/t/how-to-extract-the-std-error-of-a-linear-regression-model-by-glm/113793)

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**Author:** [@Shayan](https://discourse.julialang.org/u/Shayan)\
**Replies:** 3\
**Last updated:** [May 3, 2024, 3:10pm UTC](https://discourse.julialang.org/t/how-to-extract-the-std-error-of-a-linear-regression-model-by-glm/113793 "2024-05-03T15:10:39Z")

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How to extract the Std. Error of a linear regression model by GLM.jl? julia\> using GLM julia\> x = rand(10); y = rand(10); julia\> lr = lm(@formula(y~x), (;x, y)) StatsModels.TableRegressionModel{LinearModel{GLM.LmResp{…

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## [Convergence of RK4 solver](https://discourse.julialang.org/t/convergence-of-rk4-solver/113770)

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**Author:** [@Pranav\_Vinod](https://discourse.julialang.org/u/Pranav_Vinod)\
**Replies:** 5\
**Last updated:** [May 3, 2024, 2:40pm UTC](https://discourse.julialang.org/t/convergence-of-rk4-solver/113770 "2024-05-03T14:40:32Z")

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Hi, I am working on solving some differential equations and noticed some discrepancies in the convergence of the RK4 solver. I tested the error by finding the difference between the solver solution and analytical result…

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## [Non-linear optimization with Ipopt](https://discourse.julialang.org/t/non-linear-optimization-with-ipopt/113772)

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**Author:** [@bada5150](https://discourse.julialang.org/u/bada5150)\
**Replies:** 1\
**Last updated:** [May 3, 2024, 2:44am UTC](https://discourse.julialang.org/t/non-linear-optimization-with-ipopt/113772 "2024-05-03T02:44:38Z")

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Hi everyone I am new to Juila and working on non-linear optimization problem with Ipopt solver. Here are my code and my third constraint is 0.0653 \* (2 \* x\[2\])^-2 \<= 30. However, I am getting \[0, 0\] and it seems like I…

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## [JuMP constraint coefficients](https://discourse.julialang.org/t/jump-constraint-coefficients/113754)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 4\
**Last updated:** [May 2, 2024, 11:09pm UTC](https://discourse.julialang.org/t/jump-constraint-coefficients/113754 "2024-05-02T23:09:36Z")

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What am I doing wrong here? model = JuMP.Model() JuMP.@variable(model, x\[1:length(s)\]) JuMP.@constraint(model, c, s .\* x ∈ JuMP.MOI.Nonnegatives(10)) JuMP.normalized\_coefficient(c, x\[1\]) ERROR: MethodError: no method ma…

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## [Visualize FEM results in julia](https://discourse.julialang.org/t/visualize-fem-results-in-julia/113759)

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**Author:** [@trasor](https://discourse.julialang.org/u/trasor)\
**Replies:** 1\
**Last updated:** [May 2, 2024, 7:50pm UTC](https://discourse.julialang.org/t/visualize-fem-results-in-julia/113759 "2024-05-02T19:50:06Z")

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Hello everyone. I wrote a spectral element solver in julia, but cant visualize my results for unstructured domains. I have x,y coordinates from a classical finite element mesh with corresponding values. I would like to …

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## [Turing: Non informative improper prior](https://discourse.julialang.org/t/turing-non-informative-improper-prior/88069)

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**Author:** [@Sourish](https://discourse.julialang.org/u/Sourish)\
**Replies:** 14\
**Last updated:** [May 2, 2024, 5:10pm UTC](https://discourse.julialang.org/t/turing-non-informative-improper-prior/88069 "2024-05-02T17:10:15Z")

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Hi I am looking for an example of how to assign non-informative improper prior using Turing.jl? So far all example that I have seen uses proper prior. Thanks and regards, Sourish

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## [Find out which state(s) cause convergence problems](https://discourse.julialang.org/t/find-out-which-state-s-cause-convergence-problems/113738)

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**Author:** [@BdeKoning](https://discourse.julialang.org/u/BdeKoning)\
**Replies:** 3\
**Last updated:** [May 2, 2024, 3:55pm UTC](https://discourse.julialang.org/t/find-out-which-state-s-cause-convergence-problems/113738 "2024-05-02T15:55:19Z")

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I am solving various non-linear graph flow problems with OrdinaryDiffEq, with the states representing storages on the nodes. As the number of states can be quite large, it would be nice to have tooling to find out which …

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## [Spectrum of open hamiltonian in Quantica](https://discourse.julialang.org/t/spectrum-of-open-hamiltonian-in-quantica/113731)

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**Author:** [@Milt](https://discourse.julialang.org/u/Milt)\
**Replies:** 1\
**Last updated:** [May 2, 2024, 3:51pm UTC](https://discourse.julialang.org/t/spectrum-of-open-hamiltonian-in-quantica/113731 "2024-05-02T15:51:42Z")

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Hi @pablosanjose , I am trying to evaluate the spectrum for a graphene ribbon of varying widths. I am trying to do this by attaching leads to graphene resulting in an open hamiltonian but this is not compatible with the…

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## [ReinforcementLearning.jl](https://discourse.julialang.org/t/reinforcementlearning-jl/113745)

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**Author:** [@ttidrick](https://discourse.julialang.org/u/ttidrick)\
**Replies:** 0\
**Last updated:** [May 2, 2024, 2:27pm UTC](https://discourse.julialang.org/t/reinforcementlearning-jl/113745 "2024-05-02T14:27:56Z")

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Hi All, I’m considering using RL.jl for a project. I would like to know this discussion group’s opinion about the safety and the usefulness of this tool. Thanks, Ty Tidrick

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## [InfiniteOpt: Unable to put expressions with divide operation into objective](https://discourse.julialang.org/t/infiniteopt-unable-to-put-expressions-with-divide-operation-into-objective/113661)

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**Author:** [@aruna-ram](https://discourse.julialang.org/u/aruna-ram)\
**Replies:** 7\
**Last updated:** [May 2, 2024, 9:31am UTC](https://discourse.julialang.org/t/infiniteopt-unable-to-put-expressions-with-divide-operation-into-objective/113661 "2024-05-02T09:31:25Z")

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Hi there! I am quite new to Julia and JuMP/InfiniteOpt. I’m trying to solve a time optimal control problem. I have an issue when I incorporate an expression using the divide operator into the objective function. The fol…

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## [Convex Semi-definite Problem](https://discourse.julialang.org/t/convex-semi-definite-problem/113656)

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**Author:** [@Julian\_Villaquira](https://discourse.julialang.org/u/Julian_Villaquira)\
**Replies:** 5\
**Last updated:** [May 2, 2024, 1:32am UTC](https://discourse.julialang.org/t/convex-semi-definite-problem/113656 "2024-05-02T01:32:12Z")

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I am trying to solve a convex semi-definite optimization problem, and I don’t know what would be the right approach to implement it in Julia. The problem is the following: min c'x where c and x are vectors in R^n subje…

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## [Gradient-based optimization when gradient is only a function of y = f(x)](https://discourse.julialang.org/t/gradient-based-optimization-when-gradient-is-only-a-function-of-y-f-x/113674)

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**Author:** [@dieg0](https://discourse.julialang.org/u/dieg0)\
**Replies:** 3\
**Last updated:** [May 1, 2024, 8:47pm UTC](https://discourse.julialang.org/t/gradient-based-optimization-when-gradient-is-only-a-function-of-y-f-x/113674 "2024-05-01T20:47:01Z")

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Hi all, I am new to Julia, coming from MATLAB. I am writing some optimization code that tries to find parameters by minimizing the difference between some already computed probabilities (s) and model estimated probabilit…

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## [Align boxplot and scatter points in a rainclouds plot (Makie.jl)](https://discourse.julialang.org/t/align-boxplot-and-scatter-points-in-a-rainclouds-plot-makie-jl/113675)

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**Author:** [@TheHedgehog2000](https://discourse.julialang.org/u/TheHedgehog2000)\
**Replies:** 6\
**Last updated:** [May 1, 2024, 3:44pm UTC](https://discourse.julialang.org/t/align-boxplot-and-scatter-points-in-a-rainclouds-plot-makie-jl/113675 "2024-05-01T15:44:57Z")

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Pretty specific question: is it possible to align the boxplot and scatter components of a rainclouds plot and have them centered on the xticks with Makie.jl? Basically, I am looking to overlay a boxplot and jitter plot a…

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## [Matrix inversion in ODESystem in ModelingToolkit](https://discourse.julialang.org/t/matrix-inversion-in-odesystem-in-modelingtoolkit/113687)

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**Author:** [@rveynde](https://discourse.julialang.org/u/rveynde)\
**Replies:** 1\
**Last updated:** [May 1, 2024, 12:03pm UTC](https://discourse.julialang.org/t/matrix-inversion-in-odesystem-in-modelingtoolkit/113687 "2024-05-01T12:03:00Z")

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Hi all, I’m trying to build an ODESystem in ModelingToolkit, with an equation that uses a matrix inversion. Basically, I initialize a random matrix A of size (industries,industries), and the matrix L of size (industries,…

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## [Looking for Julia implementations of online clustering algorithms](https://discourse.julialang.org/t/looking-for-julia-implementations-of-online-clustering-algorithms/113649)

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**Author:** [@vvbond](https://discourse.julialang.org/u/vvbond)\
**Replies:** 4\
**Last updated:** [May 1, 2024, 10:28am UTC](https://discourse.julialang.org/t/looking-for-julia-implementations-of-online-clustering-algorithms/113649 "2024-05-01T10:28:41Z")

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… to no avail. The use case is quite common: real time clustering of streamed data. I envision a fusion between functionalities of the excellent OnlineStats.jl and Clustering.jl, but so far couldn’t find any ready imp…

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## [Nested AD with Lux etc](https://discourse.julialang.org/t/nested-ad-with-lux-etc/113573)

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**Author:** [@avikpal](https://discourse.julialang.org/u/avikpal)\
**Replies:** 26\
**Last updated:** [May 1, 2024, 6:05am UTC](https://discourse.julialang.org/t/nested-ad-with-lux-etc/113573 "2024-05-01T06:05:44Z")

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Nested AD (Starting v0.5.38) Starting v0.5.38, Lux automatically captures some common possibilities of AD calls inside loss functions on lux layers and converts them into a faster version to do a JVP over gradient (inste…

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## [How to merge two \`JuMP\` models?](https://discourse.julialang.org/t/how-to-merge-two-jump-models/113646)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 7\
**Last updated:** [May 1, 2024, 3:14am UTC](https://discourse.julialang.org/t/how-to-merge-two-jump-models/113646 "2024-05-01T03:14:59Z")

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For example, there are two JuMP models named M1 and M2: using JuMP M1 = Model() @variable(M1, x \<= 3) @variable(M1, y \<= 3) @objective(M1, Max, x + y) M2 = Model() @variable(M2, x \>= 1) @variable(M2, y \>= 1) @constrai…

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## [Baron installation issue](https://discourse.julialang.org/t/baron-installation-issue/113603)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 3\
**Last updated:** [May 1, 2024, 2:09am UTC](https://discourse.julialang.org/t/baron-installation-issue/113603 "2024-05-01T02:09:41Z")

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hi All, i am facing running the issue in BARON. m = Model(BARON.Optimizer) ub = \[2, 2, 1\] @variable(m, 0 ≤ x\[i = 1:3\] ≤ ub\[i\]) @variable(m, y\[1:3\], Bin) @NLconstraints( m, begin 0.8log(x\[2\] + 1) + 0.9…

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## [Multi variables in lsqfit](https://discourse.julialang.org/t/multi-variables-in-lsqfit/112210)

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**Author:** [@Stephen](https://discourse.julialang.org/u/Stephen)\
**Replies:** 6\
**Last updated:** [May 1, 2024, 2:08am UTC](https://discourse.julialang.org/t/multi-variables-in-lsqfit/112210 "2024-05-01T02:08:27Z")

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using XLSX, DataFrames, LsqFit df = DataFrame(XLSX.readtable("SMB.xlsx","平衡吸附量", infer\_eltypes = true)) function Com\_Langmuir(p, x) Ha, bA, bC, Hc = p CA = @view x\[:, 1\] CC = @view x\[:, 2\] @. qA = Ha\*CA…

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## [How to set the title of a Makie window?](https://discourse.julialang.org/t/how-to-set-the-title-of-a-makie-window/113228)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 3\
**Last updated:** [April 30, 2024, 3:52pm UTC](https://discourse.julialang.org/t/how-to-set-the-title-of-a-makie-window/113228 "2024-04-30T15:52:35Z")

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How can I change the title of a a GLMakie window?

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## [MTK: computing solutions of vectors of unknowns?](https://discourse.julialang.org/t/mtk-computing-solutions-of-vectors-of-unknowns/113614)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 11\
**Last updated:** [April 30, 2024, 3:29pm UTC](https://discourse.julialang.org/t/mtk-computing-solutions-of-vectors-of-unknowns/113614 "2024-04-30T15:29:08Z")

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With ModelingToolkit, I have a number of variables of.w\_1.m, of.w\_2.m, …, of\_w\_5.m and I want to check the solution of these variables, e.g., at time = 0.5. With solution structure sol, I can do this as follows: sol(0.…

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## [Same color sequence with marker and line when using addtraces!](https://discourse.julialang.org/t/same-color-sequence-with-marker-and-line-when-using-addtraces/113641)

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**Author:** [@Stephen](https://discourse.julialang.org/u/Stephen)\
**Replies:** 2\
**Last updated:** [April 30, 2024, 12:21pm UTC](https://discourse.julialang.org/t/same-color-sequence-with-marker-and-line-when-using-addtraces/113641 "2024-04-30T12:21:41Z")

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\# 实验数据散点图 using PlotlyJS EA\_293K = scatter(df, x = :C\_EA, y = :q\_EA\_293K, mode="markers", name = "293K") EA\_303K = scatter(df, x = :C\_EA, y = :q\_EA\_303K, mode="markers", name = "303K") EA\_313K = scatter(df, x = :C\_EA, y …

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## [Flux data parallelism](https://discourse.julialang.org/t/flux-data-parallelism/113627)

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**Author:** [@jafagervik](https://discourse.julialang.org/u/jafagervik)\
**Replies:** 2\
**Last updated:** [April 30, 2024, 8:29am UTC](https://discourse.julialang.org/t/flux-data-parallelism/113627 "2024-04-30T08:29:46Z")

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Hi, I’ve tried finding resources regarding Flux/Lux data parallelism. Im still unsure what the current SOTA solution for data parallel training would be. Im creating a different kinds of autoencoders, with the main one …

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## [Parquet2.jl: type Nothing has no field meta\_data](https://discourse.julialang.org/t/parquet2-jl-type-nothing-has-no-field-meta-data/113613)

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**Author:** [@rongcuid](https://discourse.julialang.org/u/rongcuid)\
**Replies:** 6\
**Last updated:** [April 29, 2024, 5:09pm UTC](https://discourse.julialang.org/t/parquet2-jl-type-nothing-has-no-field-meta-data/113613 "2024-04-29T17:09:59Z")

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I am trying to read some data using Parquet2.jl. The data was generated by pyarrow.parquet around 1MB in size, so very small. Compression is Snappy, as by default in pyarrow. I am getting a very long stack trace about t…

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## [How to sort a GPU StructArray vector by a subfield and update location of other elements in place?](https://discourse.julialang.org/t/how-to-sort-a-gpu-structarray-vector-by-a-subfield-and-update-location-of-other-elements-in-place/113617)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 0\
**Last updated:** [April 29, 2024, 4:18pm UTC](https://discourse.julialang.org/t/how-to-sort-a-gpu-structarray-vector-by-a-subfield-and-update-location-of-other-elements-in-place/113617 "2024-04-29T16:18:26Z")

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Hi! I have the following code: using Random using StaticArrays using StructArrays using CUDA # Function to generate a simplified SimParticles with random values function generate\_simplified\_particles(num\_particles::Int…

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## [Anyone has a starter guide on finite element analysis?](https://discourse.julialang.org/t/anyone-has-a-starter-guide-on-finite-element-analysis/112894)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 5\
**Last updated:** [April 29, 2024, 12:22pm UTC](https://discourse.julialang.org/t/anyone-has-a-starter-guide-on-finite-element-analysis/112894 "2024-04-29T12:22:45Z")

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After exploring several ideas, I think the idea I’m going to implement would be to simulate air pressure in a musical instrument or vocal tract to synthesize voice. I found finite-element method to be suitable for this a…

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## [Can we accelerate functions from other packages using juliaGPU package?](https://discourse.julialang.org/t/can-we-accelerate-functions-from-other-packages-using-juliagpu-package/113587)

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**Author:** [@tjk](https://discourse.julialang.org/u/tjk)\
**Replies:** 2\
**Last updated:** [April 29, 2024, 11:03am UTC](https://discourse.julialang.org/t/can-we-accelerate-functions-from-other-packages-using-juliagpu-package/113587 "2024-04-29T11:03:15Z")

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Hello, I want to accelerate functions imported from other julia packages. In the past, I always use using Distributed addprocs(Num) To accelerate computation, and what I need to do is just write the functions and exec…

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## [Efficient approach to modifying existing JuMP constraints](https://discourse.julialang.org/t/efficient-approach-to-modifying-existing-jump-constraints/113492)

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**Author:** [@aartinian](https://discourse.julialang.org/u/aartinian)\
**Replies:** 8\
**Last updated:** [April 29, 2024, 7:21am UTC](https://discourse.julialang.org/t/efficient-approach-to-modifying-existing-jump-constraints/113492 "2024-04-29T07:21:49Z")

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Hello everyone, Long time lurker, first time poster. :smiley: I’m trying to add a new expression to an existing JuMP constraint, but my approach seems pretty slow. Am I approaching this wrong? Thank you in advance. # @…

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## [Why are Neural SDEs trained with TrackerAdjoint()?](https://discourse.julialang.org/t/why-are-neural-sdes-trained-with-trackeradjoint/113514)

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**Author:** [@agelgazzar](https://discourse.julialang.org/u/agelgazzar)\
**Replies:** 1\
**Last updated:** [April 29, 2024, 5:39am UTC](https://discourse.julialang.org/t/why-are-neural-sdes-trained-with-trackeradjoint/113514 "2024-04-29T05:39:31Z")

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I thought that Tracker was mostly replaced by Zygote and Enzyme for Reverse-mode Autodiff in the sciml ecosystem. Why is it still being used for computing the sensitivities in DiffeqFlux?

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