# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=490

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**Page:** 491

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## [Error "isjulia\_display not defined" while trying compile\_incremental PyPlot package](https://discourse.julialang.org/t/error-isjulia-display-not-defined-while-trying-compile-incremental-pyplot-package/26056)

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**Author:** [@KestutisMa](https://discourse.julialang.org/u/KestutisMa)\
**Replies:** 2\
**Last updated:** [July 10, 2019, 4:39pm UTC](https://discourse.julialang.org/t/error-isjulia-display-not-defined-while-trying-compile-incremental-pyplot-package/26056 "2019-07-10T16:39:56Z")

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HI, I am trying using PackageCompiler to compile\_incremental PyPlot package, using predefined snoopfile (runtests.jl), but got following error: Project.toml: name = "helloPkg" uuid = "04847676-9f50-11e9-38a1-b1b365cc1e…

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## [Issue with ODE solver for solving Burgers equation using spectral method](https://discourse.julialang.org/t/issue-with-ode-solver-for-solving-burgers-equation-using-spectral-method/26224)

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**Author:** [@henry2004y](https://discourse.julialang.org/u/henry2004y)\
**Replies:** 1\
**Last updated:** [July 10, 2019, 3:26pm UTC](https://discourse.julialang.org/t/issue-with-ode-solver-for-solving-burgers-equation-using-spectral-method/26224 "2019-07-10T15:26:04Z")

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Hi all, I am trying to solve the 1D Burgers equation Burgers equation wiki using Fourier transform and the ODE package. Things works smoothly in Matlab, but not in Julia. I’m just wondering where I went wrong. Matlab …

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## [How do you apply ceil/round function inside JuMP constraints, or can you force constraints to evaluate to Ints?](https://discourse.julialang.org/t/how-do-you-apply-ceil-round-function-inside-jump-constraints-or-can-you-force-constraints-to-evaluate-to-ints/26197)

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**Author:** [@clausherther](https://discourse.julialang.org/u/clausherther)\
**Replies:** 4\
**Last updated:** [July 10, 2019, 2:29pm UTC](https://discourse.julialang.org/t/how-do-you-apply-ceil-round-function-inside-jump-constraints-or-can-you-force-constraints-to-evaluate-to-ints/26197 "2019-07-10T14:29:15Z")

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Hi, I have this simple model that tries to maximize theoretical demand for a product given some SKU level inventory constraints and a probability distribution for SKU demand. In the first constraint I’d like to compare t…

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## [Declaring state-dependent delay with DDEProblem; simulation gets slower?](https://discourse.julialang.org/t/declaring-state-dependent-delay-with-ddeproblem-simulation-gets-slower/26048)

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**Author:** [@ANasc](https://discourse.julialang.org/u/ANasc)\
**Replies:** 7\
**Last updated:** [July 10, 2019, 1:15pm UTC](https://discourse.julialang.org/t/declaring-state-dependent-delay-with-ddeproblem-simulation-gets-slower/26048 "2019-07-10T13:15:33Z")

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Dear All, I am having a hard time figuring out how to declare dependent\_lags that depend on one of the state variables in my DDE model (using DelayDiffEq.jl). It seems like it should be easy since the state variable i…

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## [For loop error](https://discourse.julialang.org/t/for-loop-error/26210)

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**Author:** [@MuadhF](https://discourse.julialang.org/u/MuadhF)\
**Replies:** 7\
**Last updated:** [July 10, 2019, 9:46am UTC](https://discourse.julialang.org/t/for-loop-error/26210 "2019-07-10T09:46:56Z")

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Hi, I’m still new to Julia, and am having problems with a for loop. I’m trying to create an array where each value is the former value minus another value. This is the code: for i = 1:T bal\[i\] = bal\[i-1\] - A\[i\] e…

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## [Using vectors of vectors with CuArrays](https://discourse.julialang.org/t/using-vectors-of-vectors-with-cuarrays/25042)

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**Author:** [@tanhevg](https://discourse.julialang.org/u/tanhevg)\
**Replies:** 2\
**Last updated:** [July 9, 2019, 8:43am UTC](https://discourse.julialang.org/t/using-vectors-of-vectors-with-cuarrays/25042 "2019-07-09T08:43:34Z")

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Hello, I am trying to get the blstm example from Flux model zoo to work on GPU. The latest hurdle that I ran into is trying to convert the training data to GPU arrays. The example uses arrays of arrays to store the data…

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## [How to close InspectDR plot window or update it?](https://discourse.julialang.org/t/how-to-close-inspectdr-plot-window-or-update-it/25787)

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**Author:** [@Iulian.Cioarca](https://discourse.julialang.org/u/Iulian.Cioarca)\
**Replies:** 8\
**Last updated:** [July 9, 2019, 3:55pm UTC](https://discourse.julialang.org/t/how-to-close-inspectdr-plot-window-or-update-it/25787 "2019-07-09T15:55:56Z")

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Hi, Sorry for the noob question, but I searched through some documentation and examples of InspectDR and could not figure out how to close a plot window. Can someone point me in the right direction, please? I’m sure I m…

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## [Rootfinding on manifold](https://discourse.julialang.org/t/rootfinding-on-manifold/26113)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 8\
**Last updated:** [July 9, 2019, 2:20pm UTC](https://discourse.julialang.org/t/rootfinding-on-manifold/26113 "2019-07-09T14:20:40Z")

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I have an f: \\mathbb{R}^n \\to \\mathbb{R}^m function with m \> n. I am looking for a root f(x) \\approx 0. f is continuous, differentiable, generally rather nice, if somewhat nonlinear. I managed to make this work with NLs…

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## [Dynamic @select with Query.jl](https://discourse.julialang.org/t/dynamic-select-with-query-jl/25242)

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**Author:** [@tencnivel](https://discourse.julialang.org/u/tencnivel)\
**Replies:** 2\
**Last updated:** [July 9, 2019, 10:12am UTC](https://discourse.julialang.org/t/dynamic-select-with-query-jl/25242 "2019-07-09T10:12:54Z")

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Hello, I’m using Query,jl with LINQ style query command. I try to pass a dynamic selection of variables to @select For example, instead of writing this: data\_table = @from i in data begin @select {i.id, i.la…

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## [Assigning strictly integer values](https://discourse.julialang.org/t/assigning-strictly-integer-values/26178)

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**Author:** [@MuadhF](https://discourse.julialang.org/u/MuadhF)\
**Replies:** 4\
**Last updated:** [July 9, 2019, 9:23am UTC](https://discourse.julialang.org/t/assigning-strictly-integer-values/26178 "2019-07-09T09:23:16Z")

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Hi, I am having trouble with assigning values from a CSV file into a variable. So I have a value of 300 in a cell (\[4,2\]) in the CSV file, and in the code I created a dataframe (df1) and tried to assign the value of 300…

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## [Interlacing frames from videos](https://discourse.julialang.org/t/interlacing-frames-from-videos/26152)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 1\
**Last updated:** [July 8, 2019, 9:02pm UTC](https://discourse.julialang.org/t/interlacing-frames-from-videos/26152 "2019-07-08T21:02:29Z")

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TL,DR: This is a call for help to improve de-interlacing in VideoIO. Thanks to @ianshmean, VideoIO has received a large number of significant improvements lately. These changes make VideoIO a viable tool for reading and…

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## [Naming multiple constraints](https://discourse.julialang.org/t/naming-multiple-constraints/26134)

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**Author:** [@MuadhF](https://discourse.julialang.org/u/MuadhF)\
**Replies:** 2\
**Last updated:** [July 8, 2019, 3:41pm UTC](https://discourse.julialang.org/t/naming-multiple-constraints/26134 "2019-07-08T15:41:07Z")

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Hi, In JuMP, how do I get the name of a constraint by which I can refer to, if I haven’t named it already? Also, for multiple constraints, how do you name them? For example: for i = 1:5 @constraint(m, con\[i=1:5\],…

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## [AmplNLWriter, NLexpression, can't evaluate pow('(0,0.45),](https://discourse.julialang.org/t/amplnlwriter-nlexpression-cant-evaluate-pow-0-0-45/26006)

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**Author:** [@Raminel](https://discourse.julialang.org/u/Raminel)\
**Replies:** 2\
**Last updated:** [July 8, 2019, 3:35pm UTC](https://discourse.julialang.org/t/amplnlwriter-nlexpression-cant-evaluate-pow-0-0-45/26006 "2019-07-08T15:35:04Z")

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Hi all, I am trying include a power expression in my objective function. and I get an error “can’t evaluate pow’(0,0.45)”, even though I forced my variables to start from 1e-20. Has anyone an idea why? using JuMP usin…

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## [How to add/edit values in an NDSparse?](https://discourse.julialang.org/t/how-to-add-edit-values-in-an-ndsparse/26135)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 9\
**Last updated:** [July 8, 2019, 3:07pm UTC](https://discourse.julialang.org/t/how-to-add-edit-values-in-an-ndsparse/26135 "2019-07-08T15:07:55Z")

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(crosposting from this so question) How to add or edit values in an sparse indexed table ? From the documentation I understood that the NDSparse object itself is immutable but not the underlying data, so I “understand” …

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## [Chaostools reinit! function](https://discourse.julialang.org/t/chaostools-reinit-function/26046)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 11\
**Last updated:** [July 7, 2019, 10:50pm UTC](https://discourse.julialang.org/t/chaostools-reinit-function/26046 "2019-07-07T22:50:38Z")

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Hi, so I am calculating Lyapunov exponents for a lot of initial values, parameters for specific systems. I want to make heavy use of the reinit! function for integrator objects, especially the tangent\_integrator from th…

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## [Nested optimization](https://discourse.julialang.org/t/nested-optimization/26061)

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**Author:** [@Farnazmdi](https://discourse.julialang.org/u/Farnazmdi)\
**Replies:** 2\
**Last updated:** [July 6, 2019, 6:16pm UTC](https://discourse.julialang.org/t/nested-optimization/26061 "2019-07-06T18:16:19Z")

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Hi, I have a model from which I estimate some parameters, and the parameters are “data” to my second model. I want to be able to optimize the parameters of the first model in a way that the second model fits well. Since…

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## [Highly Asymmetric Hessian after optimization](https://discourse.julialang.org/t/highly-asymmetric-hessian-after-optimization/26027)

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**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 26\
**Last updated:** [July 6, 2019, 9:05pm UTC](https://discourse.julialang.org/t/highly-asymmetric-hessian-after-optimization/26027 "2019-07-06T21:05:18Z")

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The Hessian after optimization is not even close to symmetric; for example the 1, 2 element is 16.7 while the 2, 1 element is 1.4. The 12, 13 element is -3945 and 13, 12 is -16 (I’m rounding the numbers). I’m using aut…

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## [Google Summer of Code Proposal: Econometrics.jl](https://discourse.julialang.org/t/google-summer-of-code-proposal-econometrics-jl/2811)

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**Author:** [@Nosferican](https://discourse.julialang.org/u/Nosferican)\
**Replies:** 20\
**Last updated:** [July 6, 2019, 8:29pm UTC](https://discourse.julialang.org/t/google-summer-of-code-proposal-econometrics-jl/2811 "2019-07-06T20:29:38Z")

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Greetings y’all. I am applying for the Google Summer of Code with Julia. My proposal draft is here: Proposal. Any comments or suggestions are welcomed. Thanks! Bayoán PS: Latest Draft Version can be accessed here.

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## [Error "unexpected token G.." while running PackageCompiler on Blink.jl](https://discourse.julialang.org/t/error-unexpected-token-g-while-running-packagecompiler-on-blink-jl/26063)

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**Author:** [@KestutisMa](https://discourse.julialang.org/u/KestutisMa)\
**Replies:** 2\
**Last updated:** [July 6, 2019, 9:19am UTC](https://discourse.julialang.org/t/error-unexpected-token-g-while-running-packagecompiler-on-blink-jl/26063 "2019-07-06T09:19:06Z")

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Hi, I want to compile Blink to increase it’s performance. During Blink.jl package compilation JS error is shown. I use PackageCompiler#sd-notomls (using official branch also throws that error). julia\> compile\_increment…

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## [Optim and differential equations?](https://discourse.julialang.org/t/optim-and-differential-equations/25861)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 45\
**Last updated:** [July 5, 2019, 2:22pm UTC](https://discourse.julialang.org/t/optim-and-differential-equations/25861 "2019-07-05T14:22:23Z")

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I’m using Optim with the Fminbox() algorithm to tune some model parameters in a model simulated by DifferentialEquations. In total, the model has 14 scaled parameters. The model fit with initial parameter guesses is: …

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## [Odd result from Distributions quantile](https://discourse.julialang.org/t/odd-result-from-distributions-quantile/25820)

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**Author:** [@abx](https://discourse.julialang.org/u/abx)\
**Replies:** 3\
**Last updated:** [July 4, 2019, 6:56pm UTC](https://discourse.julialang.org/t/odd-result-from-distributions-quantile/25820 "2019-07-04T18:56:34Z")

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I am experiencing inconsistent results using the Distributions package. When I run the following code, I get two different results on different machines Distributions.quantile(Distributions.Normal(), 0.3631592166130919…

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## [Flux: MethodError: no method matching Float32(::Tracker.TrackedReal{Float32})](https://discourse.julialang.org/t/flux-methoderror-no-method-matching-float32-tracker-trackedreal-float32/26018)

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**Author:** [@rlrs](https://discourse.julialang.org/u/rlrs)\
**Replies:** 2\
**Last updated:** [July 4, 2019, 6:08pm UTC](https://discourse.julialang.org/t/flux-methoderror-no-method-matching-float32-tracker-trackedreal-float32/26018 "2019-07-04T18:08:11Z")

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I’m trying to calculate gradients through a chain of NN applications where I have some other differentiable operations in between, but Flux fails with the error in the title. I have made a minimal example to show the pro…

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## [How could I define my own division operation with QR decomposition?](https://discourse.julialang.org/t/how-could-i-define-my-own-division-operation-with-qr-decomposition/26015)

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**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 0\
**Last updated:** [July 4, 2019, 4:28pm UTC](https://discourse.julialang.org/t/how-could-i-define-my-own-division-operation-with-qr-decomposition/26015 "2019-07-04T16:28:05Z")

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(Feel free to skip this part and look at the minimal example below) After a long time, I had to continue again with some old code, that stillyslalom already posted here, and because is a different question, I created a …

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## [Gaussian Mixture Model estimation in Julia 1.0](https://discourse.julialang.org/t/gaussian-mixture-model-estimation-in-julia-1-0/17339)

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**Author:** [@tanhevg](https://discourse.julialang.org/u/tanhevg)\
**Replies:** 8\
**Last updated:** [July 3, 2019, 12:16pm UTC](https://discourse.julialang.org/t/gaussian-mixture-model-estimation-in-julia-1-0/17339 "2019-07-03T12:16:53Z")

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Hello, I wonder, if there are any up-to-date Julia packages for GMM estimation? I googled around, and came across https://github.com/davidavdav/GaussianMixtures.jl and https://github.com/lindahua/MixtureModels.jl. Both …

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## [Parameters in IPOPT](https://discourse.julialang.org/t/parameters-in-ipopt/25908)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 5\
**Last updated:** [July 3, 2019, 12:05pm UTC](https://discourse.julialang.org/t/parameters-in-ipopt/25908 "2019-07-03T12:05:38Z")

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Dear all, I am with code: using Ipopt model = Model(with\_optimizer(Ipopt.Optimizer)) @variable(model, x, start = 500) @variable(model, y, start = 500) @NLobjective(model, Min, (1 - x)^2 + 100 \* (y - x^2)^2) optimi…

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## [Shared library errors when using optirun](https://discourse.julialang.org/t/shared-library-errors-when-using-optirun/17309)

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**Author:** [@galenlynch](https://discourse.julialang.org/u/galenlynch)\
**Replies:** 4\
**Last updated:** [July 2, 2019, 8:40pm UTC](https://discourse.julialang.org/t/shared-library-errors-when-using-optirun/17309 "2019-07-02T20:40:08Z")

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I’m just trying Julia’s CUDA packages for the first time, and am having problems launching Julia with optirun. I’m hoping that there are other people out there trying to run Julia with optirun, and that they may have fig…

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## [Maintaining Julia native GPU codegen vs relying on MLIR](https://discourse.julialang.org/t/maintaining-julia-native-gpu-codegen-vs-relying-on-mlir/25615)

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**Author:** [@datnamer](https://discourse.julialang.org/u/datnamer)\
**Replies:** 5\
**Last updated:** [July 2, 2019, 7:38pm UTC](https://discourse.julialang.org/t/maintaining-julia-native-gpu-codegen-vs-relying-on-mlir/25615 "2019-07-02T19:38:29Z")

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Apparently swift will be getting GPU kernel generation capability through MLIR. As far as I understand it, Julia relies already on LLVM to generate Cuda code. What are the costs and benefits of maintaining an extra laye…

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## [Multivariable numerical integration with changing limits](https://discourse.julialang.org/t/multivariable-numerical-integration-with-changing-limits/25862)

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**Author:** [@sevimora](https://discourse.julialang.org/u/sevimora)\
**Replies:** 4\
**Last updated:** [July 2, 2019, 5:02pm UTC](https://discourse.julialang.org/t/multivariable-numerical-integration-with-changing-limits/25862 "2019-07-02T17:02:34Z")

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Hi! I am not very proficient in Julia (or in numerical methods, for that matter), so please be forgiving with my ignorance… I am trying to numerically integrate a function of the form: \\int\_a^b \\int\_{\\underline x(w)}…

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## [PSA: breaking changes in StatsModels v0.6.0 (Terms 2.0: Son of Terms)](https://discourse.julialang.org/t/psa-breaking-changes-in-statsmodels-v0-6-0-terms-2-0-son-of-terms/25626)

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**Author:** [@dave.f.kleinschmidt](https://discourse.julialang.org/u/dave.f.kleinschmidt)\
**Replies:** 6\
**Last updated:** [July 2, 2019, 2:53pm UTC](https://discourse.julialang.org/t/psa-breaking-changes-in-statsmodels-v0-6-0-terms-2-0-son-of-terms/25626 "2019-07-02T14:53:28Z")

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It’s finally time to release version 0.6.0 of StatsModels.jl, which includes the radically re-designed internals introduced in Terms 2.0: Son of Terms (announcement here). Most of these changes should not affect end use…

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## [Data stream library comparable to Python streamz or tributary](https://discourse.julialang.org/t/data-stream-library-comparable-to-python-streamz-or-tributary/25925)

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**Author:** [@FemtoTrader](https://discourse.julialang.org/u/FemtoTrader)\
**Replies:** 0\
**Last updated:** [July 2, 2019, 1:32pm UTC](https://discourse.julialang.org/t/data-stream-library-comparable-to-python-streamz-or-tributary/25925 "2019-07-02T13:32:27Z")

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Hello, I wonder if Julia currently have libraries to deal with data stream / real-time stream processing comparable to Python streamz or tributary. https://github.com/python-streamz/streamz https://github.com/timkpain…

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