# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=227

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**Page:** 228

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## [GPU kernel?](https://discourse.julialang.org/t/gpu-kernel/92010)

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**Author:** [@sim](https://discourse.julialang.org/u/sim)\
**Replies:** 9\
**Last updated:** [December 22, 2022, 11:31pm UTC](https://discourse.julialang.org/t/gpu-kernel/92010 "2022-12-22T23:31:31Z")

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Hi everyone, I need help for understanding well how to take the most out of my GPU. I have a large Hermitian matrix A, but very sparse (zeroes everywhere except exactly 3 entries equal to 1 on each row, so total number …

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## [How to make graphplot do the same layout every invocation](https://discourse.julialang.org/t/how-to-make-graphplot-do-the-same-layout-every-invocation/92024)

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**Author:** [@brianguenter](https://discourse.julialang.org/u/brianguenter)\
**Replies:** 0\
**Last updated:** [December 22, 2022, 11:01pm UTC](https://discourse.julialang.org/t/how-to-make-graphplot-do-the-same-layout-every-invocation/92024 "2022-12-22T23:01:57Z")

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I am using graphplot from GraphRecipes.jl to draw expression trees. The best layout option is :tree but unfortunately the layout changes every time graphplot is called, even if the arguments are exactly the same. Below…

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## [Use of save\_idxs solver option with MethodOfLines/ModelingToolkit](https://discourse.julialang.org/t/use-of-save-idxs-solver-option-with-methodoflines-modelingtoolkit/92023)

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**Author:** [@johnb](https://discourse.julialang.org/u/johnb)\
**Replies:** 2\
**Last updated:** [December 22, 2022, 10:54pm UTC](https://discourse.julialang.org/t/use-of-save-idxs-solver-option-with-methodoflines-modelingtoolkit/92023 "2022-12-22T22:54:08Z")

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I’m trying to use save\_idxs to facilitate parameter fitting and while I’ve figured out that my solution needs to be accessed after solving as: sol.u\[var1(x,t)\]\[idx1,idx2\] I’m having trouble figuring out how to use the …

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## [Where is the input column name information in a dataframe transformation?](https://discourse.julialang.org/t/where-is-the-input-column-name-information-in-a-dataframe-transformation/91973)

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**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 9\
**Last updated:** [December 22, 2022, 9:01pm UTC](https://discourse.julialang.org/t/where-is-the-input-column-name-information-in-a-dataframe-transformation/91973 "2022-12-22T21:01:45Z")

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suppose I want to use some specific columns of a dataframe to do some operations and output another number of columns. In dynamically defining the name of these columns I want to use the name of the source columns. In …

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## [How to @opt\_out rules defined with RuleConfig in Zygote](https://discourse.julialang.org/t/how-to-opt-out-rules-defined-with-ruleconfig-in-zygote/92014)

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**Author:** [@tansongchen](https://discourse.julialang.org/u/tansongchen)\
**Replies:** 0\
**Last updated:** [December 22, 2022, 6:29pm UTC](https://discourse.julialang.org/t/how-to-opt-out-rules-defined-with-ruleconfig-in-zygote/92014 "2022-12-22T18:29:16Z")

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Let’s say I have a type WeirdNumber \<: Number is so weird that I don’t want its derivative of power function (^) be calculated by rrule of ^ and literal\_pow, and should instead go through and differentiate its definition…

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## [Use or not functions in JuMP](https://discourse.julialang.org/t/use-or-not-functions-in-jump/92003)

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**Author:** [@lara](https://discourse.julialang.org/u/lara)\
**Replies:** 1\
**Last updated:** [December 22, 2022, 4:45pm UTC](https://discourse.julialang.org/t/use-or-not-functions-in-jump/92003 "2022-12-22T16:45:13Z")

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Hey, guys. This is my first time working with both Julia and JuMP. It has been an adventure (and a lot of mistakes). Right now I accomplished to do the base code to work as I need and I am trying to put it inside the J…

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## [Create plot layout with no separation between plots](https://discourse.julialang.org/t/create-plot-layout-with-no-separation-between-plots/91976)

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**Author:** [@Pablo\_Marchant](https://discourse.julialang.org/u/Pablo_Marchant)\
**Replies:** 3\
**Last updated:** [December 22, 2022, 1:32pm UTC](https://discourse.julialang.org/t/create-plot-layout-with-no-separation-between-plots/91976 "2022-12-22T13:32:12Z")

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Hi all, I’m currently trying to use Plots to produce a figure with two panels and no distance between panels. Essentially in the following example: using Plots p1 = plot(rand(10),rand(10),xformatter=Returns("")) p2 = …

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## [BSplineKit Spline Derivative](https://discourse.julialang.org/t/bsplinekit-spline-derivative/91961)

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**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 5\
**Last updated:** [December 22, 2022, 1:08pm UTC](https://discourse.julialang.org/t/bsplinekit-spline-derivative/91961 "2022-12-22T13:08:34Z")

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BSplineKit has in Library =\> Data Interpolation =\> Functions, the example xs = -1:0.1:1; ys = cospi.(xs); S = interpolate(xs, ys, BSplineOrder(4)) (Derivative(1) \* S)(-1) For me, this example fails with no method ma…

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## [How to Approach Parameter Estimation with Non-Linear Optimizers](https://discourse.julialang.org/t/how-to-approach-parameter-estimation-with-non-linear-optimizers/91985)

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**Author:** [@ejmeitz](https://discourse.julialang.org/u/ejmeitz)\
**Replies:** 3\
**Last updated:** [December 21, 2022, 11:25pm UTC](https://discourse.julialang.org/t/how-to-approach-parameter-estimation-with-non-linear-optimizers/91985 "2022-12-21T23:25:12Z")

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Hello, I am trying to estimate the parameters of an ODE given discrete data x(t) that is the solution to that ODE. The ODE is: m\\ddot{x}=f(x,\\theta) where \\theta is some vector of parameters. I can estimate the paramete…

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## [How to get non-trivial solution with SDP in SCS?](https://discourse.julialang.org/t/how-to-get-non-trivial-solution-with-sdp-in-scs/91896)

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**Author:** [@ivzktch99](https://discourse.julialang.org/u/ivzktch99)\
**Replies:** 9\
**Last updated:** [December 21, 2022, 9:53pm UTC](https://discourse.julialang.org/t/how-to-get-non-trivial-solution-with-sdp-in-scs/91896 "2022-12-21T21:53:29Z")

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I am trying to solve the following, but I want to find the nonzero solution (right now it returns only trivial solutions). Is there anyway to do that? Basically I want to find matrix G (symmetric and PSD) and matrix D (…

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## [Construct a JuMP model from smaller models](https://discourse.julialang.org/t/construct-a-jump-model-from-smaller-models/91929)

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**Author:** [@Betristor](https://discourse.julialang.org/u/Betristor)\
**Replies:** 4\
**Last updated:** [December 21, 2022, 8:18pm UTC](https://discourse.julialang.org/t/construct-a-jump-model-from-smaller-models/91929 "2022-12-21T20:18:52Z")

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Hey guys, I’m quite curious about the JuMP model object. Once I construct a JuMP model where all variables and expressions are organized into one model instance which goes through many scripts and it worked. It could be …

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## [HypothesisTests, rand and very low pvalue](https://discourse.julialang.org/t/hypothesistests-rand-and-very-low-pvalue/91939)

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**Author:** [@fpoling](https://discourse.julialang.org/u/fpoling)\
**Replies:** 1\
**Last updated:** [December 21, 2022, 9:53am UTC](https://discourse.julialang.org/t/hypothesistests-rand-and-very-low-pvalue/91939 "2022-12-21T09:53:56Z")

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Consider the following code: using Distributions import HypothesisTests as HT HT.pvalue(HT.ApproximateOneSampleKSTest(rand(Normal(), 1\_000\_000), Normal())) I expected that the answer will be very close to one, but depe…

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## [Mini batching with ensemble problem diffeq and neural ode's sciml](https://discourse.julialang.org/t/mini-batching-with-ensemble-problem-diffeq-and-neural-odes-sciml/91665)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 11\
**Last updated:** [December 20, 2022, 11:26pm UTC](https://discourse.julialang.org/t/mini-batching-with-ensemble-problem-diffeq-and-neural-odes-sciml/91665 "2022-12-20T23:26:19Z")

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Following this excellent example: https://docs.sciml.ai/SciMLSensitivity/stable/ode\_fitting/data\_parallel/#Minibatching-Across-GPUs-with-DiffEqGPU The title seems to tempt me with the syntax for micro-batching to make …

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## [Parsing of mysql timestamps](https://discourse.julialang.org/t/parsing-of-mysql-timestamps/77587)

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**Author:** [@linusheinz](https://discourse.julialang.org/u/linusheinz)\
**Replies:** 8\
**Last updated:** [December 20, 2022, 9:42pm UTC](https://discourse.julialang.org/t/parsing-of-mysql-timestamps/77587 "2022-12-20T21:42:50Z")

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I am querying a table with a timestamp: data = DBInterface.execute(database, sql) df = DataFrame(data) But I get : ERROR: LoadError: error parsing DateTime from "2022-01-04 15:08:44.171540" Stacktrace: How can I tell…

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## [Best way to use Cgl within JuMP?](https://discourse.julialang.org/t/best-way-to-use-cgl-within-jump/91900)

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**Author:** [@Maxime](https://discourse.julialang.org/u/Maxime)\
**Replies:** 2\
**Last updated:** [December 20, 2022, 8:24pm UTC](https://discourse.julialang.org/t/best-way-to-use-cgl-within-jump/91900 "2022-12-20T20:24:38Z")

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Hi, I need to use the Cgl cut generation library GitHub - coin-or/Cgl: Cut Generator Library from within JuMP. In particular I want to generate KnapsackCover cuts. I managed to install Cgl, however I’m struggling beca…

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## [ControlSystems + PlotlyJS](https://discourse.julialang.org/t/controlsystems-plotlyjs/91898)

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**Author:** [@stephans3](https://discourse.julialang.org/u/stephans3)\
**Replies:** 1\
**Last updated:** [December 20, 2022, 4:44pm UTC](https://discourse.julialang.org/t/controlsystems-plotlyjs/91898 "2022-12-20T16:44:42Z")

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I just read in this post Implementation of matlab function in julia (Root locus plot) that it is possible to use ControlSystems together with PlotlyJS. To use plotlyjs() the package PlotlyJShas to be installed. using…

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## [K-Medoids clustering in BetaML.jl](https://discourse.julialang.org/t/k-medoids-clustering-in-betaml-jl/91865)

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**Author:** [@math\_opt](https://discourse.julialang.org/u/math_opt)\
**Replies:** 10\
**Last updated:** [December 20, 2022, 3:11pm UTC](https://discourse.julialang.org/t/k-medoids-clustering-in-betaml-jl/91865 "2022-12-20T15:11:31Z")

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I am trying to use BetaML.jl package to cluster a set of data using K-Medoids algorithm; however, it seems to not classify the data into all classes. For example: using Random, BetaML X = rand(MersenneTwister(1234), 10…

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## [Accessing backend of Model](https://discourse.julialang.org/t/accessing-backend-of-model/91689)

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**Author:** [@Maxime](https://discourse.julialang.org/u/Maxime)\
**Replies:** 3\
**Last updated:** [December 20, 2022, 3:08pm UTC](https://discourse.julialang.org/t/accessing-backend-of-model/91689 "2022-12-20T15:08:44Z")

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Hi, I have a usecase where I have to copy models. I also need to access the solver backend. However it seems that I can either use direct\_model(), so I have access to the backend, but can’t copy the model, or i can use …

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## [Confused about how Zygote pullback handles tuple-valued loss functions](https://discourse.julialang.org/t/confused-about-how-zygote-pullback-handles-tuple-valued-loss-functions/91899)

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**Author:** [@bgroenks](https://discourse.julialang.org/u/bgroenks)\
**Replies:** 2\
**Last updated:** [December 20, 2022, 3:05pm UTC](https://discourse.julialang.org/t/confused-about-how-zygote-pullback-handles-tuple-valued-loss-functions/91899 "2022-12-20T15:05:07Z")

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I noticed something odd (or at least that I don’t understand) with the Zygote.pullback method. Let’s consider a very simple test case: using Zygote losses, back = Zygote.pullback(x -\> (sum(x), sum(x)), \[1.0,1.0\]) Her…

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## [Comparison between Julia and Python Random Forest Regression](https://discourse.julialang.org/t/comparison-between-julia-and-python-random-forest-regression/28033)

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**Author:** [@richie96](https://discourse.julialang.org/u/richie96)\
**Replies:** 6\
**Last updated:** [December 20, 2022, 12:55pm UTC](https://discourse.julialang.org/t/comparison-between-julia-and-python-random-forest-regression/28033 "2022-12-20T12:55:34Z")

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Hi, I am doing a comparison between Julia and Python by converting a python ML code into Julia and the documenting the time taken by both the codes for different sections. I am using Random Forest algorithm. In Julia, I…

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## [Best way to define lat, lon -or- projected x,y points that play nicely with GeoInterface.jl](https://discourse.julialang.org/t/best-way-to-define-lat-lon-or-projected-x-y-points-that-play-nicely-with-geointerface-jl/89795)

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**Author:** [@alex-s-gardner](https://discourse.julialang.org/u/alex-s-gardner)\
**Replies:** 4\
**Last updated:** [December 20, 2022, 10:04am UTC](https://discourse.julialang.org/t/best-way-to-define-lat-lon-or-projected-x-y-points-that-play-nicely-with-geointerface-jl/89795 "2022-12-20T10:04:52Z")

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Is there a general standard for defining lat lon and projected points in the GeoJulia community such that they play nicely across packages? I looked through the GeoInterface.jl documentation but wasn’t able to locate tha…

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## [\[ANN\] BosonSampling.jl - A package for multiphoton interference](https://discourse.julialang.org/t/ann-bosonsampling-jl-a-package-for-multiphoton-interference/91891)

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**Author:** [@benoitseron](https://discourse.julialang.org/u/benoitseron)\
**Replies:** 0\
**Last updated:** [December 20, 2022, 9:45am UTC](https://discourse.julialang.org/t/ann-bosonsampling-jl-a-package-for-multiphoton-interference/91891 "2022-12-20T09:45:38Z")

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I am pleased to announce BosonSampling.jl, a free open source package for high performance simulation and numerical investigation of boson samplers and, more generally, multi-photon interferometry. Underlying building b…

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## [Training Neural SDEs with Mutating Arrays](https://discourse.julialang.org/t/training-neural-sdes-with-mutating-arrays/91877)

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**Author:** [@ChrisVL1](https://discourse.julialang.org/u/ChrisVL1)\
**Replies:** 2\
**Last updated:** [December 20, 2022, 7:46am UTC](https://discourse.julialang.org/t/training-neural-sdes-with-mutating-arrays/91877 "2022-12-20T07:46:51Z")

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I am writing a training function that requires a loop as my loss is the difference between call prices which I need to calculate for various strikes using a loop. However, this results in a mutating array, how do I get a…

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## [New package to map GRIB files to the Unidata's Common Data Model v4 following the CF Conventions](https://discourse.julialang.org/t/new-package-to-map-grib-files-to-the-unidatas-common-data-model-v4-following-the-cf-conventions/32375)

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**Author:** [@cvitolo](https://discourse.julialang.org/u/cvitolo)\
**Replies:** 18\
**Last updated:** [December 20, 2022, 7:23am UTC](https://discourse.julialang.org/t/new-package-to-map-grib-files-to-the-unidatas-common-data-model-v4-following-the-cf-conventions/32375 "2022-12-20T07:23:46Z")

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Hi all! At ECMWF we are starting a new project/Julia package to map GRIB files (typically used in meteorology and climate science) to the Unidata’s Common Data Model v4 following the CF Conventions. We have already a P…

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## [How to save a file with the log of Gurobi solver in JuMP](https://discourse.julialang.org/t/how-to-save-a-file-with-the-log-of-gurobi-solver-in-jump/91874)

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**Author:** [@Luiz\_Monteiro](https://discourse.julialang.org/u/Luiz_Monteiro)\
**Replies:** 2\
**Last updated:** [December 20, 2022, 12:55am UTC](https://discourse.julialang.org/t/how-to-save-a-file-with-the-log-of-gurobi-solver-in-jump/91874 "2022-12-20T00:55:20Z")

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Hi, I’m running a MIP model using JuMP with solver Gurobi and need to save the solution log as a file. I tryed to read Gurobi documentation bur couldnt find how to do this in Julia. Is there a way to do it? Thanks in …

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## [Question about garbage collection, AD, and CUDA](https://discourse.julialang.org/t/question-about-garbage-collection-ad-and-cuda/91718)

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**Author:** [@kcqpo](https://discourse.julialang.org/u/kcqpo)\
**Replies:** 1\
**Last updated:** [December 19, 2022, 9:05pm UTC](https://discourse.julialang.org/t/question-about-garbage-collection-ad-and-cuda/91718 "2022-12-19T21:05:40Z")

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I encountered an issue that is in this thread Allocator very slow to reclaim memory after running for sufficiently long · Issue #137 · JuliaGPU/CUDA.jl · GitHub. For a machine learning workload, I noticed that if I don’t…

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## [Dirac delta in boundary conditions for MethodOfLines.jl](https://discourse.julialang.org/t/dirac-delta-in-boundary-conditions-for-methodoflines-jl/80567)

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**Author:** [@sdwfrost](https://discourse.julialang.org/u/sdwfrost)\
**Replies:** 15\
**Last updated:** [December 19, 2022, 8:28pm UTC](https://discourse.julialang.org/t/dirac-delta-in-boundary-conditions-for-methodoflines-jl/80567 "2022-12-19T20:28:49Z")

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As a basis for more complex models, I’m trying to get a simplified version of the Von Foerster equation - Wikipedia discretized and running in MethodOfLines.jl. Here’s my model: using ModelingToolkit using MethodOfLine…

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## [Numerically stable "cumulative variance" function in O(n)](https://discourse.julialang.org/t/numerically-stable-cumulative-variance-function-in-o-n/91872)

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**Author:** [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Replies:** 5\
**Last updated:** [December 19, 2022, 8:12pm UTC](https://discourse.julialang.org/t/numerically-stable-cumulative-variance-function-in-o-n/91872 "2022-12-19T20:12:43Z")

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I’m posting this in off-topic because my question is about algorithmic complexity and not about Julia performance. I’m trying to write a function that computes the cumulative variance of a vector x–that is, the vector y …

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## [Makie recipe for creating a scatter plot with points colored by value](https://discourse.julialang.org/t/makie-recipe-for-creating-a-scatter-plot-with-points-colored-by-value/91754)

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**Author:** [@alex-s-gardner](https://discourse.julialang.org/u/alex-s-gardner)\
**Replies:** 6\
**Last updated:** [December 19, 2022, 6:15pm UTC](https://discourse.julialang.org/t/makie-recipe-for-creating-a-scatter-plot-with-points-colored-by-value/91754 "2022-12-19T18:15:04Z")

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Does anyone have a simple example of how to make a scatter plot using Makie.jl where the points are colored by value? The same questions was posed more generally here: But I’m looking for a Makie specific solution.

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## [Using a (computed) function in DataFrames with multiple arguments](https://discourse.julialang.org/t/using-a-computed-function-in-dataframes-with-multiple-arguments/91833)

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**Author:** [@mreichMPI-BGC](https://discourse.julialang.org/u/mreichMPI-BGC)\
**Replies:** 11\
**Last updated:** [December 19, 2022, 10:26am UTC](https://discourse.julialang.org/t/using-a-computed-function-in-dataframes-with-multiple-arguments/91833 "2022-12-19T10:26:31Z")

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In Julia I can do: meanratio(x,y) = mean(x) / mean(y) function calc(fun, vbl) fun(vbl...) end julia\> x1=rand(10); x2=rand(10);calc(meanratio, (x1, x2)) 0.8271083961061552 I want fun to be flexible in term of how…

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