# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=504

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**Page:** 505

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## [Insufficient orthogonality of eigenvectors](https://discourse.julialang.org/t/insufficient-orthogonality-of-eigenvectors/22193)

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**Author:** [@ivanslapnicar](https://discourse.julialang.org/u/ivanslapnicar)\
**Replies:** 1\
**Last updated:** [March 22, 2019, 1:12pm UTC](https://discourse.julialang.org/t/insufficient-orthogonality-of-eigenvectors/22193 "2019-03-22T13:12:28Z")

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In eigen.jl function eigen() calls eigen!() which appears to call LAPACK.geevx!() for all types of matrices (symmetric and non-symmetric). For symmetric matrices this results in insufficiently orthogonal eigenvectors …

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## [OpenAL GPT](https://discourse.julialang.org/t/openal-gpt/22197)

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**Author:** [@yash](https://discourse.julialang.org/u/yash)\
**Replies:** 0\
**Last updated:** [March 22, 2019, 1:07pm UTC](https://discourse.julialang.org/t/openal-gpt/22197 "2019-03-22T13:07:27Z")

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Is there any implementation of OpenAL GPT model in julia?

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## [How to use a color gradient when plotting different functions in the same plot?](https://discourse.julialang.org/t/how-to-use-a-color-gradient-when-plotting-different-functions-in-the-same-plot/22117)

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**Author:** [@drarnau](https://discourse.julialang.org/u/drarnau)\
**Replies:** 2\
**Last updated:** [March 22, 2019, 1:01pm UTC](https://discourse.julialang.org/t/how-to-use-a-color-gradient-when-plotting-different-functions-in-the-same-plot/22117 "2019-03-22T13:01:59Z")

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I have tried something like plot() for a = 1:5 f(x) = x^a plot!(f, -5, 5, palette = cgrad(:viridis)) end plot!() What I am looking for is that the colours of each plot reflect the idea that a increases. For ex…

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## [Raincloud Plots](https://discourse.julialang.org/t/raincloud-plots/22146)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 2\
**Last updated:** [March 22, 2019, 11:31am UTC](https://discourse.julialang.org/t/raincloud-plots/22146 "2019-03-22T11:31:14Z")

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Looks interesting! I guess it will be easy enough to use the Python code.

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## [Find normal vector of the triangle faces on the mesh](https://discourse.julialang.org/t/find-normal-vector-of-the-triangle-faces-on-the-mesh/22178)

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**Author:** [@yusri-dh](https://discourse.julialang.org/u/yusri-dh)\
**Replies:** 0\
**Last updated:** [March 22, 2019, 3:08am UTC](https://discourse.julialang.org/t/find-normal-vector-of-the-triangle-faces-on-the-mesh/22178 "2019-03-22T03:08:34Z")

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Hello all, I have some question about finding the normal vector of the faces in the mesh using GeometryTypes.jl In GeometryTypes.jl, I can calculate the normal of the vertices using normals(mesh), is there any function…

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## [SOS1 variables are not supported](https://discourse.julialang.org/t/sos1-variables-are-not-supported/22012)

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**Author:** [@SingingKim](https://discourse.julialang.org/u/SingingKim)\
**Replies:** 5\
**Last updated:** [March 21, 2019, 9:40pm UTC](https://discourse.julialang.org/t/sos1-variables-are-not-supported/22012 "2019-03-21T21:40:06Z")

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I’m trying to build a SOS1 constraint using JuMP MOI (with Gurobi, CPLEX, Mosek). m = Model(with\_optimizer(Mosek.Optimizer)) @variable(m, x\[1:3\]) @constraint(m, x in MOI.SOS1(\[1, 2, 3\])) But it gives me an error saying…

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## [Plot Neural Network Layout](https://discourse.julialang.org/t/plot-neural-network-layout/22007)

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**Author:** [@Zach\_Christensen](https://discourse.julialang.org/u/Zach_Christensen)\
**Replies:** 13\
**Last updated:** [March 21, 2019, 9:24pm UTC](https://discourse.julialang.org/t/plot-neural-network-layout/22007 "2019-03-21T21:24:48Z")

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I need to make a plot/graphic of my neural network. I know there’s stuff out there for plotting graphs but I can’t seem to find anything that has the typical structure with the vertices lined up and connected by edges to…

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## [Interactive plot with Vegalite](https://discourse.julialang.org/t/interactive-plot-with-vegalite/22129)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 8\
**Last updated:** [March 21, 2019, 5:15pm UTC](https://discourse.julialang.org/t/interactive-plot-with-vegalite/22129 "2019-03-21T17:15:07Z")

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Is anyone familiar with using Vegalite from the REPL to produce interactive plots (to zoom in/out at a minimum)? I understand this works in Jupyter notebooks, but I want to avoid notebooks and work directly in the termi…

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## [How to distribute the definitions of preexisting functions to workers?](https://discourse.julialang.org/t/how-to-distribute-the-definitions-of-preexisting-functions-to-workers/22072)

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**Author:** [@Babber](https://discourse.julialang.org/u/Babber)\
**Replies:** 12\
**Last updated:** [March 21, 2019, 3:43pm UTC](https://discourse.julialang.org/t/how-to-distribute-the-definitions-of-preexisting-functions-to-workers/22072 "2019-03-21T15:43:21Z")

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I think, more or less, I defined my problem in the title. After extensive search, I couldn’t find a solution to it, maybe someone can help me here. So in a nutshell: I have some functions already defined well before I wo…

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## [Having problems with creating animations with Plots.jl - GRBackend - Juno](https://discourse.julialang.org/t/having-problems-with-creating-animations-with-plots-jl-grbackend-juno/21876)

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**Author:** [@tiago](https://discourse.julialang.org/u/tiago)\
**Replies:** 6\
**Last updated:** [March 21, 2019, 3:41pm UTC](https://discourse.julialang.org/t/having-problems-with-creating-animations-with-plots-jl-grbackend-juno/21876 "2019-03-21T15:41:19Z")

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Hello! I am trying to create a simple animation in 1D, using the Plots.jl with GR as a backend. Basically, I have a matrix where the rows are the solution u at a time instant. What I was trying to do was to plot the ev…

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## [Generate nonlinear expressions in an explicit loop](https://discourse.julialang.org/t/generate-nonlinear-expressions-in-an-explicit-loop/20447)

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**Author:** [@ncostilla](https://discourse.julialang.org/u/ncostilla)\
**Replies:** 1\
**Last updated:** [March 21, 2019, 3:09pm UTC](https://discourse.julialang.org/t/generate-nonlinear-expressions-in-an-explicit-loop/20447 "2019-03-21T15:09:06Z")

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I want to generate nonlinear expressions in an explicit loop. I know You can iterate over constraints and store references like in the next example: @variable(m, x\[1:5\] \>= 0) @constraintref myCons\[1:5\] for i = 1:5 myC…

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## [User-defined distribution function example](https://discourse.julialang.org/t/user-defined-distribution-function-example/22035)

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**Author:** [@roi.holtzman](https://discourse.julialang.org/u/roi.holtzman)\
**Replies:** 14\
**Last updated:** [March 21, 2019, 12:28pm UTC](https://discourse.julialang.org/t/user-defined-distribution-function-example/22035 "2019-03-21T12:28:30Z")

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I am new to Julia, and I want to define my own distribution function. I found this post and followed the documentation, but I did not understand where do I put in the actual function (namely f(x)) of the distribution. Ca…

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## [Help with function sum{}](https://discourse.julialang.org/t/help-with-function-sum/22128)

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**Author:** [@danielcas](https://discourse.julialang.org/u/danielcas)\
**Replies:** 3\
**Last updated:** [March 21, 2019, 2:05am UTC](https://discourse.julialang.org/t/help-with-function-sum/22128 "2019-03-21T02:05:30Z")

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H, on my file there’s a constraint written like this @NLconstraint(m,-sum{log(x\[i\])/gamma\[i\], i=1:n}\<=mm), when I run the program I get an error saying that this type of syntax is no longer supported. so…¿What is the new…

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## [Vector affine function with SOC not supported in JuMP (.18 -\> .19 breaking change?)](https://discourse.julialang.org/t/vector-affine-function-with-soc-not-supported-in-jump-18-19-breaking-change/22076)

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**Author:** [@guille](https://discourse.julialang.org/u/guille)\
**Replies:** 6\
**Last updated:** [March 20, 2019, 4:47pm UTC](https://discourse.julialang.org/t/vector-affine-function-with-soc-not-supported-in-jump-18-19-breaking-change/22076 "2019-03-20T16:47:34Z")

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Hey all! Quick question (it is quite likely this question has a simple solution), but I’m working on doing a quick overhaul of some code for a paper. The original code was written on JuMP .17/.18, but with some of the b…

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## [CUDA fft against CPU fft](https://discourse.julialang.org/t/cuda-fft-against-cpu-fft/22029)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 4\
**Last updated:** [March 19, 2019, 6:50pm UTC](https://discourse.julialang.org/t/cuda-fft-against-cpu-fft/22029 "2019-03-19T18:50:38Z")

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Dear all, in my attempts to play with CUDA in Julia, I’ve come accross something I can’t really understand -hopefully because I’m doing something wrong. The fact is that in my calculations I need to perform Fourier tran…

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## [UnicodePlots multiple plots?](https://discourse.julialang.org/t/unicodeplots-multiple-plots/22063)

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**Author:** [@natemcintosh](https://discourse.julialang.org/u/natemcintosh)\
**Replies:** 1\
**Last updated:** [March 19, 2019, 5:17pm UTC](https://discourse.julialang.org/t/unicodeplots-multiple-plots/22063 "2019-03-19T17:17:20Z")

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I been having TONS of fun with UnicodePlots recently. However, when I want to make two plots, one after the other, in a script, only the last is displayed in my REPL. For example, with this code in a .jl file, I call i…

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## [Error while using DifferentialEquations.jl stiff methods](https://discourse.julialang.org/t/error-while-using-differentialequations-jl-stiff-methods/22004)

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**Author:** [@Andre\_Mello](https://discourse.julialang.org/u/Andre_Mello)\
**Replies:** 3\
**Last updated:** [March 19, 2019, 4:42pm UTC](https://discourse.julialang.org/t/error-while-using-differentialequations-jl-stiff-methods/22004 "2019-03-19T16:42:41Z")

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Hi all, The DifferentialEquations’ suggested integration methods when trying to solve this stiff problem all yield the same error. The native Julia ones, that is. Sundial’s CVODE\_BDF as well as lsoda are able to solve t…

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## [If condition in constraint set](https://discourse.julialang.org/t/if-condition-in-constraint-set/22057)

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**Author:** [@ilias](https://discourse.julialang.org/u/ilias)\
**Replies:** 1\
**Last updated:** [March 19, 2019, 3:37pm UTC](https://discourse.julialang.org/t/if-condition-in-constraint-set/22057 "2019-03-19T15:37:33Z")

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Is there a way to rewrite the following constraint set in one row? for i in set\_i for ii in set\_i if parameter\[ii\] \>= parameter\[i\] @constraint( model, x\[i\] - y\[ii\] \<= 0 ); end end end…

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## [help converting JuMPArray to regular array](https://discourse.julialang.org/t/help-converting-jumparray-to-regular-array/21924)

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**Author:** [@levip](https://discourse.julialang.org/u/levip)\
**Replies:** 2\
**Last updated:** [March 19, 2019, 2:56pm UTC](https://discourse.julialang.org/t/help-converting-jumparray-to-regular-array/21924 "2019-03-19T14:56:23Z")

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I’m trying to inspect the dual values of one of my constraints, but I cannot figure out how to convert the returned variable to a regular Array (so that I can ultimately save it to a CSV). I get a 3-dimensional JuMPArray…

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## [Recommended way of solving multiple similar problems with JuMP](https://discourse.julialang.org/t/recommended-way-of-solving-multiple-similar-problems-with-jump/22055)

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**Author:** [@Sebastian\_Rollen](https://discourse.julialang.org/u/Sebastian_Rollen)\
**Replies:** 1\
**Last updated:** [March 19, 2019, 2:20pm UTC](https://discourse.julialang.org/t/recommended-way-of-solving-multiple-similar-problems-with-jump/22055 "2019-03-19T14:20:32Z")

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Hi, I have an application where I have to solve a quadratic problem multiple times, with the only thing changing between problems being the RHS of a constraint. Currently I do this by setting up the problem with the RHS…

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## [FluxML Basic Custom Layer with Custom Loss Function](https://discourse.julialang.org/t/fluxml-basic-custom-layer-with-custom-loss-function/22036)

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**Author:** [@LudiWin](https://discourse.julialang.org/u/LudiWin)\
**Replies:** 3\
**Last updated:** [March 19, 2019, 2:01pm UTC](https://discourse.julialang.org/t/fluxml-basic-custom-layer-with-custom-loss-function/22036 "2019-03-19T14:01:45Z")

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Hi, I want to write a custom layer and a custom loss function and thought I’d start out with the basic linear regression problem from the tutorial of Flux and do the SGD from scratch for a custom layer in a Chain. For …

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## [Tutorial on GPU programming on julia](https://discourse.julialang.org/t/tutorial-on-gpu-programming-on-julia/21957)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 5\
**Last updated:** [March 19, 2019, 10:01am UTC](https://discourse.julialang.org/t/tutorial-on-gpu-programming-on-julia/21957 "2019-03-19T10:01:34Z")

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Hi, I’m starting to appreciate CUDA programming in Julia, but find hard to learn how to do that properly since I can not find any tutorial or book on that. I’ve read the documentation about CuArrays.jl and CUDAnative.jl…

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## [Any synthetic control libraries in julia?](https://discourse.julialang.org/t/any-synthetic-control-libraries-in-julia/21272)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 4\
**Last updated:** [March 18, 2019, 10:57pm UTC](https://discourse.julialang.org/t/any-synthetic-control-libraries-in-julia/21272 "2019-03-18T22:57:03Z")

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Is anyone doing anything related to synthetic controls in julia? Like the Synth package for R and Stata? It would be great to see some of the implementations and work done in that space.

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## [Moving camera then saving picture in Makie](https://discourse.julialang.org/t/moving-camera-then-saving-picture-in-makie/21938)

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**Author:** [@fa-bien](https://discourse.julialang.org/u/fa-bien)\
**Replies:** 2\
**Last updated:** [March 16, 2019, 6:24pm UTC](https://discourse.julialang.org/t/moving-camera-then-saving-picture-in-makie/21938 "2019-03-16T18:24:49Z")

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I visualise 3d scenes with Makie. Moving the camera (either with rotate\_cam! or with update\_cam!) only seems to works from the REPL or when saving an animation: as soon as the scene is evaluated, it returns to the origin…

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## [Optimize slow constraint generation](https://discourse.julialang.org/t/optimize-slow-constraint-generation/21996)

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**Author:** [@Di11on](https://discourse.julialang.org/u/Di11on)\
**Replies:** 1\
**Last updated:** [March 18, 2019, 12:55pm UTC](https://discourse.julialang.org/t/optimize-slow-constraint-generation/21996 "2019-03-18T12:55:25Z")

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This is somewhat related to my other post (Deleting containerized constraints) but here, I want to see if there is a way to formulate my constraint differently. Following advice in this thread, I put all my variable and…

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## [Basics steps to build an ANN?](https://discourse.julialang.org/t/basics-steps-to-build-an-ann/21366)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 24\
**Last updated:** [March 18, 2019, 10:04am UTC](https://discourse.julialang.org/t/basics-steps-to-build-an-ann/21366 "2019-03-18T10:04:38Z")

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Is there a simple example on how to build a first ANN? I have a basic understanding of ANNs. I’m not looking for impressive examples. So, I’m not interested in hand writing recognition, image recognition, etc. Instead: …

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## [RigidBodyDynamics, Munthe-Kaas integrator, step(integrator, t, Δt)](https://discourse.julialang.org/t/rigidbodydynamics-munthe-kaas-integrator-step-integrator-t-t/21906)

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**Author:** [@RogerP](https://discourse.julialang.org/u/RogerP)\
**Replies:** 4\
**Last updated:** [March 18, 2019, 8:49am UTC](https://discourse.julialang.org/t/rigidbodydynamics-munthe-kaas-integrator-step-integrator-t-t/21906 "2019-03-18T08:49:00Z")

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I want to set up a stepwise Munthe-Kass integrator for use in a real-time control system. I do: t = 0.0; Δt = 1e-4 ringBuff2 = RigidBodyDynamics.OdeIntegrators.RingBufferStorage{Float64}(state, 10000) butcherTableau = R…

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## [calculate p(D|M) for Turing tutorial model?](https://discourse.julialang.org/t/calculate-p-d-m-for-turing-tutorial-model/21985)

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**Author:** [@subunit](https://discourse.julialang.org/u/subunit)\
**Replies:** 0\
**Last updated:** [March 18, 2019, 2:31am UTC](https://discourse.julialang.org/t/calculate-p-d-m-for-turing-tutorial-model/21985 "2019-03-18T02:31:13Z")

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Hi folks, I am new to Julia, Turing, and Bayes, so I’m a bit out of my depth here. I think I have a rough handle on what Turing is doing in the third tutorial (http://turing.ml/tutorials/3-bayesnn/), which is close to m…

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## [How to obtain the number of rows in each group using DataFramesMeta?](https://discourse.julialang.org/t/how-to-obtain-the-number-of-rows-in-each-group-using-dataframesmeta/21955)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 2\
**Last updated:** [March 17, 2019, 6:50am UTC](https://discourse.julialang.org/t/how-to-obtain-the-number-of-rows-in-each-group-using-dataframesmeta/21955 "2019-03-17T06:50:16Z")

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using DataFrames, DataFramesMeta a = DataFrame(a = rand(1:10, 100)) @\> begin a @by(:a, count = length(:a)) end is there a more convenient function like R’s dplyr::n() which returns the number of rows? Or even, R…

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## [Ways to order a \`DataFrame\` by mixed order?](https://discourse.julialang.org/t/ways-to-order-a-dataframe-by-mixed-order/21952)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 2\
**Last updated:** [March 17, 2019, 4:26am UTC](https://discourse.julialang.org/t/ways-to-order-a-dataframe-by-mixed-order/21952 "2019-03-17T04:26:52Z")

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I wanted to order a DataFrame by certain mixed order, e.g. i want to order a DataFrame by a\_str in descending order followed by b\_str in ascending order Setting up data using DataFrames, Query a\_str = string.(rand(UI…

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