# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=191

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**Page:** 192

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## [Reject requests in HTTP.jl server based on memory usage](https://discourse.julialang.org/t/reject-requests-in-http-jl-server-based-on-memory-usage/99216)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 6\
**Last updated:** [May 23, 2023, 7:59am UTC](https://discourse.julialang.org/t/reject-requests-in-http-jl-server-based-on-memory-usage/99216 "2023-05-23T07:59:16Z")

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The idea is to prevent a web service to suffer memory exhaustion by rejecting requests, or react to other similar resource allocation issues based on the machine state. I suppose it can be done using the HTTP.Middleware …

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## [Dual vs shadow price: Which one to use?](https://discourse.julialang.org/t/dual-vs-shadow-price-which-one-to-use/99260)

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**Author:** [@math\_opt](https://discourse.julialang.org/u/math_opt)\
**Replies:** 8\
**Last updated:** [May 23, 2023, 7:54am UTC](https://discourse.julialang.org/t/dual-vs-shadow-price-which-one-to-use/99260 "2023-05-23T07:54:29Z")

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I want to make sure I understand correctly the difference between the dual/shadow\_price returned by JuMP. Let’s consider the following primal problem: using JuMP, Gurobi begin model = Model(Gurobi.Optimizer) @va…

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## [Why do I have to install PGFPlotsX manually?](https://discourse.julialang.org/t/why-do-i-have-to-install-pgfplotsx-manually/99140)

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**Author:** [@LeePhillips](https://discourse.julialang.org/u/LeePhillips)\
**Replies:** 7\
**Last updated:** [May 23, 2023, 7:32am UTC](https://discourse.julialang.org/t/why-do-i-have-to-install-pgfplotsx-manually/99140 "2023-05-23T07:32:20Z")

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After adding and importing a package that has PGFPlotsX as a dependency, and checking that the dependency has been added to my environment’s Manifest (confirmed by entering st -m in package mode), I get an error when cal…

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## [Metalog Distributions](https://discourse.julialang.org/t/metalog-distributions/99259)

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**Author:** [@vshesh](https://discourse.julialang.org/u/vshesh)\
**Replies:** 0\
**Last updated:** [May 23, 2023, 5:16am UTC](https://discourse.julialang.org/t/metalog-distributions/99259 "2023-05-23T05:16:55Z")

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Hi, I am looking to use Metalog Distributions (1 1 The Three Types of Probability Distributions - YouTube) in a project I’m working on. Are there any packages that have implemented them (including fitting to data, and …

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## [Incorporating SVD factorization into GPUs with CUDA](https://discourse.julialang.org/t/incorporating-svd-factorization-into-gpus-with-cuda/99252)

<div class="topic-metadata">

**Author:** [@jarroyoe](https://discourse.julialang.org/u/jarroyoe)\
**Replies:** 7\
**Last updated:** [May 23, 2023, 2:31am UTC](https://discourse.julialang.org/t/incorporating-svd-factorization-into-gpus-with-cuda/99252 "2023-05-23T02:31:21Z")

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I’m trying to run the following code to optimize the spectral radius of the weight matrices of a neural network: using CUDA, Random, Lux, ComponentArrays, Optimization, OptimizationOptimisers, OptimizationOptimJL, Linea…

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## [ReverseDiff over ForwardDiff behaves strangely with Lux networks (Issue)](https://discourse.julialang.org/t/reversediff-over-forwarddiff-behaves-strangely-with-lux-networks-issue/99175)

<div class="topic-metadata">

**Author:** [@Bizzi](https://discourse.julialang.org/u/Bizzi)\
**Replies:** 3\
**Last updated:** [May 23, 2023, 2:06am UTC](https://discourse.julialang.org/t/reversediff-over-forwarddiff-behaves-strangely-with-lux-networks-issue/99175 "2023-05-23T02:06:13Z")

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Hello everyone. For my work with PINNs, I am trying to use ReverseDiff to calculate the gradient of a loss function that itself contains a ForwardDiff gradient. It is easy enough to do so with explicitly-parametrized dec…

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## [Nested parallel loops with @spawn](https://discourse.julialang.org/t/nested-parallel-loops-with-spawn/32364)

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**Author:** [@mzilhao](https://discourse.julialang.org/u/mzilhao)\
**Replies:** 13\
**Last updated:** [May 22, 2023, 11:30pm UTC](https://discourse.julialang.org/t/nested-parallel-loops-with-spawn/32364 "2023-05-22T23:30:15Z")

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Hi all, I’m trying to choose the best way of parallelizing my code given the the current options of @spawn and @threads. A toy model for what I’m trying to do is the following: function solve\_model\_serial!(A, Nu, Nx, N…

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## [ABM performance tips](https://discourse.julialang.org/t/abm-performance-tips/99146)

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**Author:** [@sea\_slug](https://discourse.julialang.org/u/sea_slug)\
**Replies:** 5\
**Last updated:** [May 22, 2023, 11:07pm UTC](https://discourse.julialang.org/t/abm-performance-tips/99146 "2023-05-22T23:07:17Z")

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I have a mainly complete ABM built using Agents.jl (awesome package!) which functions as I want (albeit with placeholder parameters) now I am at the point I want to improve the performance of the model, but I am struggli…

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## [Please, how do I remove the key from a colored bar chart? Deadline immenient, help greatly appreciated](https://discourse.julialang.org/t/please-how-do-i-remove-the-key-from-a-colored-bar-chart-deadline-immenient-help-greatly-appreciated/99248)

<div class="topic-metadata">

**Author:** [@johnabs](https://discourse.julialang.org/u/johnabs)\
**Replies:** 2\
**Last updated:** [May 22, 2023, 10:08pm UTC](https://discourse.julialang.org/t/please-how-do-i-remove-the-key-from-a-colored-bar-chart-deadline-immenient-help-greatly-appreciated/99248 "2023-05-22T22:08:07Z")

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I currently have some separate data frames that aren’t particularly amenable to being combined; but I need to plot them on the same plot but with a single legend/color key. I have done so with the following code, but whe…

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## [Multi-thread Variable Creation](https://discourse.julialang.org/t/multi-thread-variable-creation/93300)

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**Author:** [@A\_M](https://discourse.julialang.org/u/A_M)\
**Replies:** 8\
**Last updated:** [May 22, 2023, 7:27pm UTC](https://discourse.julialang.org/t/multi-thread-variable-creation/93300 "2023-05-22T19:27:43Z")

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I have a large problem; even model creation will take a long time, and I was thinking of using a thread-safe approach to speed up the process. Here is the code: using Random using JuMP using HiGHS using ThreadSafeDicts …

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## [DiffEqFlux throws a CUDA error on installation](https://discourse.julialang.org/t/diffeqflux-throws-a-cuda-error-on-installation/99212)

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**Author:** [@Vidianos](https://discourse.julialang.org/u/Vidianos)\
**Replies:** 6\
**Last updated:** [May 22, 2023, 6:52pm UTC](https://discourse.julialang.org/t/diffeqflux-throws-a-cuda-error-on-installation/99212 "2023-05-22T18:52:18Z")

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Hello, I am trying to get into the SciML ecosystem and as such I installed DiffEqFlux. During installation, I get this error Blockquote DiffEqFlux \[aae7a2af-3d4f-5e19-a356-7da93b79d9d0\] │ ┌ Error: Failed to initial…

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## [Is CUDA.jl and FFTW threadsafe?](https://discourse.julialang.org/t/is-cuda-jl-and-fftw-threadsafe/99219)

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**Author:** [@jpdoane](https://discourse.julialang.org/u/jpdoane)\
**Replies:** 4\
**Last updated:** [May 22, 2023, 2:44pm UTC](https://discourse.julialang.org/t/is-cuda-jl-and-fftw-threadsafe/99219 "2023-05-22T14:44:21Z")

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I am getting the following error when using CUDA.jl FFTW plans in multiple threads. Is this interface not threadsafe? If not, do I just need a mutex around plan\_fft!(), or might the actual fft be not threadsafe as well? …

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## [Normalizing Values and Floating Point Error](https://discourse.julialang.org/t/normalizing-values-and-floating-point-error/99213)

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**Author:** [@ianroddis](https://discourse.julialang.org/u/ianroddis)\
**Replies:** 6\
**Last updated:** [May 22, 2023, 12:04pm UTC](https://discourse.julialang.org/t/normalizing-values-and-floating-point-error/99213 "2023-05-22T12:04:46Z")

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Sorry if this isn’t the right place to post this question, but it was as close as I could think for the intersection of concerns. Most sources I’ve read on data modelling suggest that, when required, values be normalize…

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## [Numeric value substitution into SymPy Symbolic array or matrix](https://discourse.julialang.org/t/numeric-value-substitution-into-sympy-symbolic-array-or-matrix/99204)

<div class="topic-metadata">

**Author:** [@johannesnauta](https://discourse.julialang.org/u/johannesnauta)\
**Replies:** 5\
**Last updated:** [May 22, 2023, 10:42am UTC](https://discourse.julialang.org/t/numeric-value-substitution-into-sympy-symbolic-array-or-matrix/99204 "2023-05-22T10:42:10Z")

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I am having trouble substituting numerical values into symbolic arrays and matrices. I have read about lambdify, but I still fail to provide numerical values for the arguments in a consistent way. As an example, consid…

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## [Designing a band pass filter with modeling toolkit](https://discourse.julialang.org/t/designing-a-band-pass-filter-with-modeling-toolkit/99118)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [May 22, 2023, 6:51am UTC](https://discourse.julialang.org/t/designing-a-band-pass-filter-with-modeling-toolkit/99118 "2023-05-22T06:51:49Z")

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What is the best way to design a band pass filter in the continues domain using modelling toolkit? Some hints how to do it in Python: Butterworth Bandpass — SciPy Cookbook documentation Update: OK, I can design a filte…

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## [Stackoverflow Error in plot of 3D data point](https://discourse.julialang.org/t/stackoverflow-error-in-plot-of-3d-data-point/99093)

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**Author:** [@Movicmatics](https://discourse.julialang.org/u/Movicmatics)\
**Replies:** 8\
**Last updated:** [May 22, 2023, 12:25am UTC](https://discourse.julialang.org/t/stackoverflow-error-in-plot-of-3d-data-point/99093 "2023-05-22T00:25:30Z")

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Hello everyone, I am trying to run my code but I am encountering an error, I would be glad if help can be render. The Error mesage is: ERROR: StackOverflowError: Stacktrace: \[1\] RecipesPipeline.Volume(v::Array{Floa…

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## [Radial basis functions in surrogates.jl?](https://discourse.julialang.org/t/radial-basis-functions-in-surrogates-jl/99144)

<div class="topic-metadata">

**Author:** [@rkube](https://discourse.julialang.org/u/rkube)\
**Replies:** 4\
**Last updated:** [May 21, 2023, 9:47pm UTC](https://discourse.julialang.org/t/radial-basis-functions-in-surrogates-jl/99144 "2023-05-21T21:47:54Z")

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Hi, I’m trying to understand what RBFs Surrogates.jl is using. For example, the documentation only specifies that it uses RadialBasis . The \[code\] specifies that there is a linearRadial and cubicRadial. What equation is…

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## [Chains vs iterations behavior in Turing sampler (conditional priors)](https://discourse.julialang.org/t/chains-vs-iterations-behavior-in-turing-sampler-conditional-priors/99165)

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**Author:** [@PeX](https://discourse.julialang.org/u/PeX)\
**Replies:** 8\
**Last updated:** [May 21, 2023, 9:02pm UTC](https://discourse.julialang.org/t/chains-vs-iterations-behavior-in-turing-sampler-conditional-priors/99165 "2023-05-21T21:02:51Z")

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I wrote a simple model that looks like this: @model function stam() # Prior distributions op = \[1.0, 2.0, 3.0, 4.0\] α ~ DiscreteUniform(1, length(op)) β ~ truncated(Normal(op\[α\] , 0.1); lower=0.01, upper=10.0)…

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## [Eigenvalue ordering unexpectedly different in two cases](https://discourse.julialang.org/t/eigenvalue-ordering-unexpectedly-different-in-two-cases/99189)

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**Author:** [@Nikos\_Gianniotis](https://discourse.julialang.org/u/Nikos_Gianniotis)\
**Replies:** 2\
**Last updated:** [May 21, 2023, 8:52pm UTC](https://discourse.julialang.org/t/eigenvalue-ordering-unexpectedly-different-in-two-cases/99189 "2023-05-21T20:52:23Z")

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Hello everyone, I am probably making a subtle mistake or assumption somewhere as I cannot understand why the following two eigendecompositions do not return the eigenvalues in the same order. Could somebody please expla…

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## [How to create ASCII equations](https://discourse.julialang.org/t/how-to-create-ascii-equations/99180)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 4\
**Last updated:** [May 21, 2023, 8:33pm UTC](https://discourse.julialang.org/t/how-to-create-ascii-equations/99180 "2023-05-21T20:33:06Z")

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In the documentation of ModelingToolkit I find a lot of ASCII equations, e.g. k ─────── sT + 1 Is there a way to generate this ascii art automatically? I looked at latexify, but I did not find an option to generate …

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## [Solving unbounded problem by NeuralPDE](https://discourse.julialang.org/t/solving-unbounded-problem-by-neuralpde/99169)

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**Author:** [@Ethan\_Tran](https://discourse.julialang.org/u/Ethan_Tran)\
**Replies:** 6\
**Last updated:** [May 21, 2023, 6:36pm UTC](https://discourse.julialang.org/t/solving-unbounded-problem-by-neuralpde/99169 "2023-05-21T18:36:45Z")

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I would like to solve an unbounded problem in PDE format by NeuralPDE. The domains of the problem is x belong \[0;inf) and y belong real number (R) please help me on how could I implement these domains in Julia and whet…

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## [Help to plot a surface plot with infinite roots?](https://discourse.julialang.org/t/help-to-plot-a-surface-plot-with-infinite-roots/98291)

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**Author:** [@Moslem\_Uddin](https://discourse.julialang.org/u/Moslem_Uddin)\
**Replies:** 10\
**Last updated:** [May 21, 2023, 6:18pm UTC](https://discourse.julialang.org/t/help-to-plot-a-surface-plot-with-infinite-roots/98291 "2023-05-21T18:18:02Z")

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I am trying to generate a surface plot of the following in Julia. As I’m new, I’m struggling where \\alpha\_k are I’m being able to generate a line plot at a fixed time using the following code: using Roots,Plots plot…

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## [Julia supported by LangChain?](https://discourse.julialang.org/t/julia-supported-by-langchain/98509)

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**Author:** [@Alex\_Tantos](https://discourse.julialang.org/u/Alex_Tantos)\
**Replies:** 14\
**Last updated:** [May 21, 2023, 5:27pm UTC](https://discourse.julialang.org/t/julia-supported-by-langchain/98509 "2023-05-21T17:27:21Z")

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Hi there! Is anyone aware of any attempts/plans by LangChain to support julia? Any answer will be greatly appreciated! Best! Alex

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## [Histogram with Y-axis in log-scale](https://discourse.julialang.org/t/histogram-with-y-axis-in-log-scale/99183)

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**Author:** [@parf](https://discourse.julialang.org/u/parf)\
**Replies:** 1\
**Last updated:** [May 21, 2023, 2:10pm UTC](https://discourse.julialang.org/t/histogram-with-y-axis-in-log-scale/99183 "2023-05-21T14:10:22Z")

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Hi all, I want to plot histogram with Y-axis in log-scale. So, I do the following: using Plots gr() histogram(r\_pos\*L/n, normed=:pdf, bins=0.0:0.012:0.8, yaxis=:log10, ylim=(1e-3,10)) How to make the bins filling …

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## [Probablistic modeling of multiagent systems?](https://discourse.julialang.org/t/probablistic-modeling-of-multiagent-systems/95689)

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**Author:** [@DanielV](https://discourse.julialang.org/u/DanielV)\
**Replies:** 5\
**Last updated:** [May 21, 2023, 12:44pm UTC](https://discourse.julialang.org/t/probablistic-modeling-of-multiagent-systems/95689 "2023-05-21T12:44:14Z")

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I have a simple agents.jl sim where at each step with some probability agents are added or change state or are removed. Agents are not independent, e.g., there is a finite “capacity” resource which might prevent an agent…

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## [Solving Ax = b s.t. x contains all positive values](https://discourse.julialang.org/t/solving-ax-b-s-t-x-contains-all-positive-values/99138)

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**Author:** [@dleather](https://discourse.julialang.org/u/dleather)\
**Replies:** 4\
**Last updated:** [May 20, 2023, 8:00am UTC](https://discourse.julialang.org/t/solving-ax-b-s-t-x-contains-all-positive-values/99138 "2023-05-20T08:00:11Z")

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I am solving an asset pricing equations via discretizing an underlying Markov process, X \\in R^d, resulting in \\tilde{X} \\sim \\Pi, where \\Pi is a transition matrix whose rows sum to unity, and all entries in \[0,1\]. Let \\…

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## [Implementing Gibbs sampler for ODE parameter estimation](https://discourse.julialang.org/t/implementing-gibbs-sampler-for-ode-parameter-estimation/99132)

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**Author:** [@PeX](https://discourse.julialang.org/u/PeX)\
**Replies:** 2\
**Last updated:** [May 20, 2023, 8:58pm UTC](https://discourse.julialang.org/t/implementing-gibbs-sampler-for-ode-parameter-estimation/99132 "2023-05-20T20:58:14Z")

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I would like to use a Gibbs sampler for a model that looks like this (in Turing.jl): @model function fit\_burger2(data::AbstractVector, prob) # Prior distributions σᵣ = 1.5e6 Aₘ ~ truncated(Normal(0.1, 0.05); lo…

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## [Implementation of graphical lasso with Cholesky factor](https://discourse.julialang.org/t/implementation-of-graphical-lasso-with-cholesky-factor/99016)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 2\
**Last updated:** [May 20, 2023, 3:47pm UTC](https://discourse.julialang.org/t/implementation-of-graphical-lasso-with-cholesky-factor/99016 "2023-05-20T15:47:02Z")

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Hello, I am working on an implementation of the graphical Lasso (Glasso) (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3019769/pdf/kxm045.pdf) in pure Julia. In the algorithm, we have to use a square root of sample cova…

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## [Strange results when using seed kwarg in solve function](https://discourse.julialang.org/t/strange-results-when-using-seed-kwarg-in-solve-function/99128)

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**Author:** [@stochasticguy](https://discourse.julialang.org/u/stochasticguy)\
**Replies:** 2\
**Last updated:** [May 20, 2023, 12:58pm UTC](https://discourse.julialang.org/t/strange-results-when-using-seed-kwarg-in-solve-function/99128 "2023-05-20T12:58:13Z")

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Hi everyone, First of all I wanted to congratulate you all for this amazing community. I’m having issues with the solution of a Stochastic Differential Equation (SDE) when passing the seed kwarg to the solve method. W…

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## [Zerocrossing detection with ModelingToolkit](https://discourse.julialang.org/t/zerocrossing-detection-with-modelingtoolkit/99150)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 1\
**Last updated:** [May 20, 2023, 8:22am UTC](https://discourse.julialang.org/t/zerocrossing-detection-with-modelingtoolkit/99150 "2023-05-20T08:22:19Z")

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I Simulink many components have the option to turn “zero crossing detection” on or off, which has a large influence on the simulation time, stability and accuracy. How is this issue handled in ModelingToolkit?

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