# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=400

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**Page:** 401

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## [DifferentialEquations: ┌ Warning: IDAGetDky failed with error code](https://discourse.julialang.org/t/differentialequations-warning-idagetdky-failed-with-error-code/52195)

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**Author:** [@JuhaHeiskala](https://discourse.julialang.org/u/JuhaHeiskala)\
**Replies:** 10\
**Last updated:** [December 22, 2020, 11:30pm UTC](https://discourse.julialang.org/t/differentialequations-warning-idagetdky-failed-with-error-code/52195 "2020-12-22T23:30:40Z")

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I tried a test case from Octave ode15i tests and get the error: \[IDAS ERROR\] IDAGetDky Illegal value for k. ┌ Warning: IDAGetDky failed with error code = │ flag = -25 └ @ Sundials ~/.julia/dev/Sundials/src/simpl…

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## [QuantumClifford.jl for efficient simulation of Clifford circuits](https://discourse.julialang.org/t/quantumclifford-jl-for-efficient-simulation-of-clifford-circuits/52236)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 1\
**Last updated:** [December 22, 2020, 6:52pm UTC](https://discourse.julialang.org/t/quantumclifford-jl-for-efficient-simulation-of-clifford-circuits/52236 "2020-12-22T18:52:40Z")

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This is a crosspost of the announcement of QuantumClifford.jl in the community thread. You can read there for more details of a small package with efficient allocation free algorithms for the simulation of circuits with …

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## [TypeError: non-boolean (Term{Bool}) used in boolean context when trying to modelingtoolkitize a DifferentialEquations.jl SDEProblem](https://discourse.julialang.org/t/typeerror-non-boolean-term-bool-used-in-boolean-context-when-trying-to-modelingtoolkitize-a-differentialequations-jl-sdeproblem/51130)

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**Author:** [@claudio20497](https://discourse.julialang.org/u/claudio20497)\
**Replies:** 3\
**Last updated:** [December 22, 2020, 2:16pm UTC](https://discourse.julialang.org/t/typeerror-non-boolean-term-bool-used-in-boolean-context-when-trying-to-modelingtoolkitize-a-differentialequations-jl-sdeproblem/51130 "2020-12-22T14:16:37Z")

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Hello, This issue is maybe related to this one although the solution could be totally different. If this is the wrong place to post it, please tell me and I’ll be happy to move it. So the goal would be to optimize a Di…

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## [Density Distributions](https://discourse.julialang.org/t/density-distributions/52224)

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**Author:** [@lorrp1](https://discourse.julialang.org/u/lorrp1)\
**Replies:** 6\
**Last updated:** [December 22, 2020, 12:28pm UTC](https://discourse.julialang.org/t/density-distributions/52224 "2020-12-22T12:28:25Z")

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Hello, im trying to get the array of the discrete probability distribution of a normal distribution: i have tried: d = Normal() #standard a = rand(d,1000) x = pdf.(d, a) #even with just pdf(d,a) plot(x) but its not wo…

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## [Surfc equivalent? Plotting contour underneath surfacep plot](https://discourse.julialang.org/t/surfc-equivalent-plotting-contour-underneath-surfacep-plot/52108)

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**Author:** [@jg-854](https://discourse.julialang.org/u/jg-854)\
**Replies:** 2\
**Last updated:** [December 20, 2020, 2:44am UTC](https://discourse.julialang.org/t/surfc-equivalent-plotting-contour-underneath-surfacep-plot/52108 "2020-12-20T02:44:13Z")

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MATLAB has this feature which allows you to plot a contour plot underneath a surface plot of a function. I would like to recreate this in JULIA. If I used contour!() after surface(), this doesn’t seem to work… Thanks! …

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## [How to specify point vs fill for Geom.point in Gadfly?](https://discourse.julialang.org/t/how-to-specify-point-vs-fill-for-geom-point-in-gadfly/52097)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 3\
**Last updated:** [December 19, 2020, 10:12pm UTC](https://discourse.julialang.org/t/how-to-specify-point-vs-fill-for-geom-point-in-gadfly/52097 "2020-12-19T22:12:53Z")

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In the gallery example here we have: using Gadfly, RDatasets set\_default\_plot\_size(21cm, 8cm) p1 = plot(dataset("MASS", "mammals"), x="Body", y="Brain", label=1, Scale.x\_log10, Scale.y\_log10, Geom.point, Geom.label…

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## [Groupby / reshaping dataframe with unique values](https://discourse.julialang.org/t/groupby-reshaping-dataframe-with-unique-values/51149)

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**Author:** [@Smith](https://discourse.julialang.org/u/Smith)\
**Replies:** 17\
**Last updated:** [December 19, 2020, 11:22pm UTC](https://discourse.julialang.org/t/groupby-reshaping-dataframe-with-unique-values/51149 "2020-12-19T23:22:29Z")

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How can I rearrange a dataframe so that values of a particular column that are repeated appear only once and the related data is transposed to columns? Suppose I have a dataframe given by: df1 = DataFrame(NAME = \["A1"…

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## [Unable to optimize using Alpine.jl](https://discourse.julialang.org/t/unable-to-optimize-using-alpine-jl/52088)

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**Author:** [@hassanis](https://discourse.julialang.org/u/hassanis)\
**Replies:** 2\
**Last updated:** [December 19, 2020, 6:48pm UTC](https://discourse.julialang.org/t/unable-to-optimize-using-alpine-jl/52088 "2020-12-19T18:48:15Z")

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I’m havinng trouble using Alpine.jl. I know that it’s compatible with MOI now, and the new version was presented at INFORMS this year. Yet, when I try using it, I get the following error: MethodError: no method matching…

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## [WGLMakie animations?](https://discourse.julialang.org/t/wglmakie-animations/52084)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 5\
**Last updated:** [December 19, 2020, 4:55pm UTC](https://discourse.julialang.org/t/wglmakie-animations/52084 "2020-12-19T16:55:00Z")

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Hi, I use (GL)Makie for animations. When I replace using GLMakie with using WGLMakie its fails: ERROR: type GenericIOBuffer has no field io Is it possible to display animations via WGLMakie ? Is there an example avai…

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## [Method Error: No mathching method when using ContinuousDynamicalSystem](https://discourse.julialang.org/t/method-error-no-mathching-method-when-using-continuousdynamicalsystem/52040)

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**Author:** [@Gary\_McCormack](https://discourse.julialang.org/u/Gary_McCormack)\
**Replies:** 7\
**Last updated:** [December 19, 2020, 4:31pm UTC](https://discourse.julialang.org/t/method-error-no-mathching-method-when-using-continuousdynamicalsystem/52040 "2020-12-19T16:31:56Z")

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Hi everyone, I’m very new to Julia and trying to wrap my head around the following error. This is a stripped-down version of the ODE I am trying to wrap as a Continuous Dynamical System. using DifferentialEquations usi…

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## [Numerical continuation and periodic orbits](https://discourse.julialang.org/t/numerical-continuation-and-periodic-orbits/51580)

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**Author:** [@cadojo](https://discourse.julialang.org/u/cadojo)\
**Replies:** 11\
**Last updated:** [December 19, 2020, 3:08pm UTC](https://discourse.julialang.org/t/numerical-continuation-and-periodic-orbits/51580 "2020-12-19T15:08:07Z")

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Apologies if this question is poorly worded, I’m very new to numerical continuation and nonlinear frequency analysis. I have a nonlinear system of ODEs, and I’d like to numerically find periodic solutions for a changing …

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## [Zygote fails with gradients of destructured/restructured RNNs](https://discourse.julialang.org/t/zygote-fails-with-gradients-of-destructured-restructured-rnns/52065)

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**Author:** [@noumea](https://discourse.julialang.org/u/noumea)\
**Replies:** 0\
**Last updated:** [December 18, 2020, 6:59pm UTC](https://discourse.julialang.org/t/zygote-fails-with-gradients-of-destructured-restructured-rnns/52065 "2020-12-18T18:59:24Z")

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I am trying to optimize a NN with an Optim.jl optimizer by using destructure/restructure on the model, and Zygote to obtain the gradient of the loss function. I noticed that Zygote does not seem to be able to calculate t…

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## [Do I have to implement Flux.testmode! for my own models?](https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038)

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**Author:** [@maxfreu](https://discourse.julialang.org/u/maxfreu)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 6:00pm UTC](https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038 "2020-12-18T18:00:58Z")

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Hi, I implemented a U-Net and would like to switch between train and test mode for the BN layers. struct Unet encoder # tuple of chains decoder # tuple of UpBlocks segmentation\_head # normal conv layer end …

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## [Model Predictive Controller only works for certain values](https://discourse.julialang.org/t/model-predictive-controller-only-works-for-certain-values/51916)

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**Author:** [@LukasLundgren96](https://discourse.julialang.org/u/LukasLundgren96)\
**Replies:** 8\
**Last updated:** [December 18, 2020, 3:43pm UTC](https://discourse.julialang.org/t/model-predictive-controller-only-works-for-certain-values/51916 "2020-12-18T15:43:23Z")

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I am using JuMP and Ipopt to solve an online optimization for a Furuta pendulum. Quite quickly I got it running in simulation but for the real pendulum I had some trouble. The trouble was solved by substituting one of th…

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## [GeoStats.jl Meeting](https://discourse.julialang.org/t/geostats-jl-meeting/51824)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 11:44am UTC](https://discourse.julialang.org/t/geostats-jl-meeting/51824 "2020-12-18T11:44:15Z")

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The GeoStats.jl community has grown a lot this year, and we would like to invite all users and contributors to join an informal conversation to get to know each other =) Tell us how you are using the project and what you…

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## [BatchNorm gradient is inconsistent with PyTorch in training mode](https://discourse.julialang.org/t/batchnorm-gradient-is-inconsistent-with-pytorch-in-training-mode/40389)

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**Author:** [@yiyuezhuo](https://discourse.julialang.org/u/yiyuezhuo)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 11:12am UTC](https://discourse.julialang.org/t/batchnorm-gradient-is-inconsistent-with-pytorch-in-training-mode/40389 "2020-12-18T11:12:29Z")

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I found Flux’s BatchNorm output in training/test mode and gradient in test mode is consistent with PyTorch but gradient in training mode is not. It’s kind of strange since all parameters look the same. Example: using F…

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## [Mapreduce of Softmax-ed array can't be differentiated on GPU](https://discourse.julialang.org/t/mapreduce-of-softmax-ed-array-cant-be-differentiated-on-gpu/52013)

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**Author:** [@kmaile](https://discourse.julialang.org/u/kmaile)\
**Replies:** 0\
**Last updated:** [December 17, 2020, 10:40pm UTC](https://discourse.julialang.org/t/mapreduce-of-softmax-ed-array-cant-be-differentiated-on-gpu/52013 "2020-12-17T22:40:11Z")

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In an MWE of my use case below, I am trying to output a softmax-weighted sum of multiple layers on the same input. The output needs to be differentiable with respect to both the weights within the layers as well as the s…

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## [Efficient and CuArray compatible implementation of \`StatsBase.\_compute\_extrema\`](https://discourse.julialang.org/t/efficient-and-cuarray-compatible-implementation-of-statsbase-compute-extrema/51671)

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**Author:** [@sdewaele](https://discourse.julialang.org/u/sdewaele)\
**Replies:** 5\
**Last updated:** [December 17, 2020, 8:25pm UTC](https://discourse.julialang.org/t/efficient-and-cuarray-compatible-implementation-of-statsbase-compute-extrema/51671 "2020-12-17T20:25:10Z")

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For this PR to StatsBase.jl, I am looking for a way to compute extrema that is both efficient for regular arrays and CuArrays. This implementation is efficient for regular arrays: function \_compute\_extrema\_A(X; dims) …

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## [MLJ and ClusterManagers](https://discourse.julialang.org/t/mlj-and-clustermanagers/51540)

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**Author:** [@pfarndt](https://discourse.julialang.org/u/pfarndt)\
**Replies:** 4\
**Last updated:** [December 17, 2020, 8:16pm UTC](https://discourse.julialang.org/t/mlj-and-clustermanagers/51540 "2020-12-17T20:16:11Z")

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I want do some machine learning using MLJ on a cluster of 200+ nodes. To hook up my workers to the main process I want to use an ElasticManager from the ClusterManagers package (this way I can also utilize workers which …

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## [Filter rows using a filter table](https://discourse.julialang.org/t/filter-rows-using-a-filter-table/51975)

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**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 1\
**Last updated:** [December 17, 2020, 6:04pm UTC](https://discourse.julialang.org/t/filter-rows-using-a-filter-table/51975 "2020-12-17T18:04:09Z")

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I have a table whose rows I want to filter (by choosing or excluding them) on the basis of a series of criteria contained in a table. The criteria table has column fields corresponding by position to those of the data ta…

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## [Impulse response of Butterworth filter](https://discourse.julialang.org/t/impulse-response-of-butterworth-filter/51543)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 4\
**Last updated:** [December 17, 2020, 5:31pm UTC](https://discourse.julialang.org/t/impulse-response-of-butterworth-filter/51543 "2020-12-17T17:31:54Z")

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In the following code example, a 6th-order Butterworth filter is defined over 4-50 Hz and the frequency response plotted. How to use DSP.jl to compute the corresponding zero-phase filter time response? Using filt(fil,ht…

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## [A question on the DiffEqFlux module](https://discourse.julialang.org/t/a-question-on-the-diffeqflux-module/51987)

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**Author:** [@anC](https://discourse.julialang.org/u/anC)\
**Replies:** 0\
**Last updated:** [December 17, 2020, 3:51pm UTC](https://discourse.julialang.org/t/a-question-on-the-diffeqflux-module/51987 "2020-12-17T15:51:56Z")

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First of all, I’d like to say thanks and congratulations to Dr. Rackauckas and the team responsible for the DiffEqFlux module. This is an excellent module and I can see some really useful applications of this work. I hav…

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## [Preventing abuse with interactive Pluto notebooks](https://discourse.julialang.org/t/preventing-abuse-with-interactive-pluto-notebooks/45588)

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**Author:** [@stroebel](https://discourse.julialang.org/u/stroebel)\
**Replies:** 5\
**Last updated:** [December 17, 2020, 1:14pm UTC](https://discourse.julialang.org/t/preventing-abuse-with-interactive-pluto-notebooks/45588 "2020-12-17T13:14:15Z")

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I’ve never been a fan of notebooks but Pluto has converted me, I think. And this has led me to think about ways to share notebooks, especially with interactive elements (my first thought was about using it in a teaching …

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## [Latest wisdom on Python vs. Julia for Economists (Applied Micro)?](https://discourse.julialang.org/t/latest-wisdom-on-python-vs-julia-for-economists-applied-micro/51942)

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**Author:** [@samerb](https://discourse.julialang.org/u/samerb)\
**Replies:** 8\
**Last updated:** [December 17, 2020, 10:28am UTC](https://discourse.julialang.org/t/latest-wisdom-on-python-vs-julia-for-economists-applied-micro/51942 "2020-12-17T10:28:31Z")

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Hi, Early stage econ Phd student here focusing in micro theory but considering a shift/expansion into applied micro IO/health. I’ve previously learned some basic Python from a more traditional software engineering viewp…

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## [BoundsError with SharedArrays in remote node](https://discourse.julialang.org/t/boundserror-with-sharedarrays-in-remote-node/51670)

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**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 1\
**Last updated:** [December 17, 2020, 1:28am UTC](https://discourse.julialang.org/t/boundserror-with-sharedarrays-in-remote-node/51670 "2020-12-17T01:28:34Z")

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I want to broadcast a matrix into some remote nodes to avoid communication. My best guess is to use SharedArrays, but, when I try to copy the data on remote node, I got a error. Here an example: args = (exeflags=\`--thr…

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## [DifferentialEquations error: "Event repeated at the same time"](https://discourse.julialang.org/t/differentialequations-error-event-repeated-at-the-same-time/51830)

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**Author:** [@Bastien](https://discourse.julialang.org/u/Bastien)\
**Replies:** 12\
**Last updated:** [December 16, 2020, 6:38pm UTC](https://discourse.julialang.org/t/differentialequations-error-event-repeated-at-the-same-time/51830 "2020-12-16T18:38:01Z")

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Hi, I’m trying to reproduce results presented in Roup et al. where a verge and foliot mechanism used in clocks is simulated. I tried to use a VectorContinuousCallback to determine the times at which collision events hap…

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## [How to generate n samples from a peculiar (normally distributed) distribution](https://discourse.julialang.org/t/how-to-generate-n-samples-from-a-peculiar-normally-distributed-distribution/51911)

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**Author:** [@Jaidy](https://discourse.julialang.org/u/Jaidy)\
**Replies:** 1\
**Last updated:** [December 16, 2020, 4:12pm UTC](https://discourse.julialang.org/t/how-to-generate-n-samples-from-a-peculiar-normally-distributed-distribution/51911 "2020-12-16T16:12:58Z")

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Hi, I am trying to generate n samples from a distribution as follows: each sample is of size m. Say x is a sample. Then for each of the components {x\_1,x\_2,…x\_m}, x\_i follows a normal distribution with mean 0 and varia…

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## [HTTP.jl doesn't seem to be good at handling over 1k concurrent requests, in comparison to an alternative in Python?](https://discourse.julialang.org/t/http-jl-doesnt-seem-to-be-good-at-handling-over-1k-concurrent-requests-in-comparison-to-an-alternative-in-python/38281)

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**Author:** [@aviatesk](https://discourse.julialang.org/u/aviatesk)\
**Replies:** 30\
**Last updated:** [December 16, 2020, 3:24pm UTC](https://discourse.julialang.org/t/http-jl-doesnt-seem-to-be-good-at-handling-over-1k-concurrent-requests-in-comparison-to-an-alternative-in-python/38281 "2020-12-16T15:24:23Z")

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I’m implementing an simple API server that is supposed to handle over concurrent 1k requests at a time. I have a code like below: using HTTP: @register, Response, handle const HEADERS = \["Content-Type" =\> "application…

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## [KernelDensity.jl vs scipy.stats' gaussian\_kde](https://discourse.julialang.org/t/kerneldensity-jl-vs-scipy-stats-gaussian-kde/51917)

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**Author:** [@danielalfonsetti](https://discourse.julialang.org/u/danielalfonsetti)\
**Replies:** 2\
**Last updated:** [December 16, 2020, 2:15pm UTC](https://discourse.julialang.org/t/kerneldensity-jl-vs-scipy-stats-gaussian-kde/51917 "2020-12-16T14:15:31Z")

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I’m trying to convert some python code to julia code, but there appears to be a discrepancy between the python KDE and the julia KDE. Here is a reproducible example, similar to what is happening in my project: Python: f…

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## [Compose GraphPlot LightGraphs Position](https://discourse.julialang.org/t/compose-graphplot-lightgraphs-position/33177)

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**Author:** [@Simplex](https://discourse.julialang.org/u/Simplex)\
**Replies:** 8\
**Last updated:** [December 16, 2020, 10:41am UTC](https://discourse.julialang.org/t/compose-graphplot-lightgraphs-position/33177 "2020-12-16T10:41:50Z")

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I do a project about infection spreading. I want to have my network immovable but I don’t find a solution. I also tried to have no superposition but I find nothing Thanks a lot for your help ! My code won’t work with …

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