# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=417

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**Page:** 418

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## [Two questions on Flux](https://discourse.julialang.org/t/two-questions-on-flux/22307)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 23\
**Last updated:** [October 2, 2020, 3:28pm UTC](https://discourse.julialang.org/t/two-questions-on-flux/22307 "2020-10-02T15:28:35Z")

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I’ve watched videos in JuliaAcademy (I recommend them), and continued playing around with Flux. To test Flux, I’ve tried to re-create simple results from: Bishop, Chris M. (1994). “Neural networks and their application…

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## [Pgfplotsx, plots: non-uniform colormaps only partially implemented](https://discourse.julialang.org/t/pgfplotsx-plots-non-uniform-colormaps-only-partially-implemented/47621)

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**Author:** [@AntoninDellaNoce](https://discourse.julialang.org/u/AntoninDellaNoce)\
**Replies:** 15\
**Last updated:** [October 2, 2020, 2:16pm UTC](https://discourse.julialang.org/t/pgfplotsx-plots-non-uniform-colormaps-only-partially-implemented/47621 "2020-10-02T14:16:40Z")

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Hi, I have an error at the level of pgfplots package when using pgfplotsx() backend to draw surfaces. Here is the working example provided by the Plots documentation surface(range(-3,3, length=30), range(-3,3, length=3…

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## [Random number generators](https://discourse.julialang.org/t/random-number-generators/47613)

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**Author:** [@caetanotc](https://discourse.julialang.org/u/caetanotc)\
**Replies:** 3\
**Last updated:** [October 2, 2020, 1:28pm UTC](https://discourse.julialang.org/t/random-number-generators/47613 "2020-10-02T13:28:41Z")

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Hi, I’m new to julia and have some questions about RNG’s. If I understood well, MersenneTwister is the default method, but MersenneTwister objects are linked with the Random library and rand() function isn’t. When usin…

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## [GeometricFlux: GCNConv but with different graphs](https://discourse.julialang.org/t/geometricflux-gcnconv-but-with-different-graphs/36518)

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**Author:** [@rkurchin](https://discourse.julialang.org/u/rkurchin)\
**Replies:** 12\
**Last updated:** [October 2, 2020, 5:08am UTC](https://discourse.julialang.org/t/geometricflux-gcnconv-but-with-different-graphs/36518 "2020-10-02T05:08:24Z")

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I’m working with GeometricFlux and want to adapt the GCNConv layer to allow for different adjacency matrices corresponding to each piece of training data. Since this now requires two separate “streams” of input data (the…

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## [Exploring a model?](https://discourse.julialang.org/t/exploring-a-model/47472)

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**Author:** [@amca01](https://discourse.julialang.org/u/amca01)\
**Replies:** 5\
**Last updated:** [October 2, 2020, 4:37am UTC](https://discourse.julialang.org/t/exploring-a-model/47472 "2020-10-02T04:37:21Z")

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I have been investigating JuMP (with optimizers CBC, CLP, and GLPK) for linear models. I can obtain the values of the decision variables, the optimum of the objective function, the shadow prices of the binding constrain…

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## [No changes with Flux NN regression training](https://discourse.julialang.org/t/no-changes-with-flux-nn-regression-training/47490)

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**Author:** [@dmoored4](https://discourse.julialang.org/u/dmoored4)\
**Replies:** 2\
**Last updated:** [October 2, 2020, 3:03am UTC](https://discourse.julialang.org/t/no-changes-with-flux-nn-regression-training/47490 "2020-10-02T03:03:40Z")

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Problem Description Hi all, I’m having trouble using Flux to learn a non-linear function of two independent variables, x1 and x2. Everything is running, but I have a feeling that the parameters aren’t actually being upda…

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## [BUG Plots; pgfplotsx using twinx() ofsets the dates](https://discourse.julialang.org/t/bug-plots-pgfplotsx-using-twinx-ofsets-the-dates/47580)

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**Author:** [@JosephPollacco](https://discourse.julialang.org/u/JosephPollacco)\
**Replies:** 2\
**Last updated:** [October 1, 2020, 8:32pm UTC](https://discourse.julialang.org/t/bug-plots-pgfplotsx-using-twinx-ofsets-the-dates/47580 "2020-10-01T20:32:57Z")

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Hi, I am using Plots;pgfplotsx() and the twinx() functionality and I want to report a bug that the dates are offset the dates as it can be seen in the figure. It will be great if this bug can be fixt. DateTick=cl…

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## [WAIC, or LOO etc in Turing?](https://discourse.julialang.org/t/waic-or-loo-etc-in-turing/30873)

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**Author:** [@aammd](https://discourse.julialang.org/u/aammd)\
**Replies:** 11\
**Last updated:** [October 1, 2020, 8:16pm UTC](https://discourse.julialang.org/t/waic-or-loo-etc-in-turing/30873 "2020-10-01T20:16:19Z")

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Hello everyone, I was wondering if any of the popular model selection criteria have been implemented in Turing? for example WAIC or LOO, etc? I am surprised that I can’t find mention of these in this forum or in the doc…

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## [Package for cell (morphological) profiling](https://discourse.julialang.org/t/package-for-cell-morphological-profiling/47500)

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**Author:** [@koalive](https://discourse.julialang.org/u/koalive)\
**Replies:** 3\
**Last updated:** [October 1, 2020, 5:34pm UTC](https://discourse.julialang.org/t/package-for-cell-morphological-profiling/47500 "2020-10-01T17:34:09Z")

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Hi there. I am currently working on a package compiling useful tools and structures for handling morphological profiles: https://github.com/menchelab/RMP.jl Concretely, part of my research work involves High Content S…

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## [Choosing the "best" sampler](https://discourse.julialang.org/t/choosing-the-best-sampler/47605)

<div class="topic-metadata">

**Author:** [@mcql](https://discourse.julialang.org/u/mcql)\
**Replies:** 1\
**Last updated:** [October 1, 2020, 4:50pm UTC](https://discourse.julialang.org/t/choosing-the-best-sampler/47605 "2020-10-01T16:50:01Z")

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Hello, I would like to know how shoud I choose the sampler given a model (using the Turing framework). I haven’t found information in the official guide. Could you suggest me something to read about that related to th…

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## [Help for basic usage of @distributed for](https://discourse.julialang.org/t/help-for-basic-usage-of-distributed-for/31666)

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**Author:** [@Massimiliano\_Comin](https://discourse.julialang.org/u/Massimiliano_Comin)\
**Replies:** 1\
**Last updated:** [October 1, 2020, 9:27am UTC](https://discourse.julialang.org/t/help-for-basic-usage-of-distributed-for/31666 "2020-10-01T09:27:12Z")

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Hello, I have a computation that I want to perform several times for several realizations of disorder. For this I wrote a serial script doing only one computation, and a separate script that calls it and distributes the…

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## [How to get more info on w ∈ workers()](https://discourse.julialang.org/t/how-to-get-more-info-on-w-workers/34290)

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**Author:** [@healyp](https://discourse.julialang.org/u/healyp)\
**Replies:** 1\
**Last updated:** [October 1, 2020, 9:20am UTC](https://discourse.julialang.org/t/how-to-get-more-info-on-w-workers/34290 "2020-10-01T09:20:39Z")

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I’m getting the following error From worker 30: ErrorException("Process(30) - Invalid connection credentials sent by remote.")CapturedException(ErrorException("Process(30) - Invalid connection credentials sent by remote…

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## [Problems copying data on the GPU](https://discourse.julialang.org/t/problems-copying-data-on-the-gpu/47518)

<div class="topic-metadata">

**Author:** [@bmit](https://discourse.julialang.org/u/bmit)\
**Replies:** 8\
**Last updated:** [October 1, 2020, 6:22am UTC](https://discourse.julialang.org/t/problems-copying-data-on-the-gpu/47518 "2020-10-01T06:22:24Z")

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I’m having trouble with a basic copy operation on the GPU. My goal is to copy a chosen subset of data from an N-D array into a vector. My following two attempts have failed. using CUDA CUDA.allowscalar(false) a=CUDA.ran…

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## [Flux model with categorical and continuous covariates/features](https://discourse.julialang.org/t/flux-model-with-categorical-and-continuous-covariates-features/47556)

<div class="topic-metadata">

**Author:** [@johnbb](https://discourse.julialang.org/u/johnbb)\
**Replies:** 0\
**Last updated:** [September 30, 2020, 10:49pm UTC](https://discourse.julialang.org/t/flux-model-with-categorical-and-continuous-covariates-features/47556 "2020-09-30T22:49:53Z")

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Using Flux, I would like to train a regression model with both continuous and categorical features. Since the categorical variable(s) may have a many levels, I would prefer to map these into a few new continuous variable…

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## [Vectorizing observations from multivariate distribution in Turing](https://discourse.julialang.org/t/vectorizing-observations-from-multivariate-distribution-in-turing/47436)

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**Author:** [@ElOceanografo](https://discourse.julialang.org/u/ElOceanografo)\
**Replies:** 1\
**Last updated:** [September 30, 2020, 9:06pm UTC](https://discourse.julialang.org/t/vectorizing-observations-from-multivariate-distribution-in-turing/47436 "2020-09-30T21:06:31Z")

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I have a model where the data are drawn from multinomial distributions. The parameters of those distributions (number of draws and probabilities) are different at each data point. MWE below: ndata = 100 k = 5 n = 10 p…

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## [Ipopt and external function](https://discourse.julialang.org/t/ipopt-and-external-function/47496)

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**Author:** [@danicaratelli](https://discourse.julialang.org/u/danicaratelli)\
**Replies:** 11\
**Last updated:** [September 30, 2020, 6:40pm UTC](https://discourse.julialang.org/t/ipopt-and-external-function/47496 "2020-09-30T18:40:17Z")

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I am trying to solve a non-linear function using JuMP. From what I saw, I have to use Ipopt and, as Nonlinear Modeling · JuMP says, I cannot directly include the function in the NLobjective. To get around this I define a…

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## [Finding a vector which has the sum of the indices which are prime numbers](https://discourse.julialang.org/t/finding-a-vector-which-has-the-sum-of-the-indices-which-are-prime-numbers/47492)

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**Author:** [@julianoob](https://discourse.julialang.org/u/julianoob)\
**Replies:** 7\
**Last updated:** [September 30, 2020, 6:28pm UTC](https://discourse.julialang.org/t/finding-a-vector-which-has-the-sum-of-the-indices-which-are-prime-numbers/47492 "2020-09-30T18:28:56Z")

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For example a=\[1 2 3; 4 5 6; 7 8 9\] indices are ((1,1) ,(1,2) , (1,3); (2,1),(2,2),(2,3); (3,1),(3,2),(3,3)) and the prime number of these sums are 2,3,5 which should be in the vector s. Is there any function in julia wh…

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## [Most efficient way of computing B'\* inv(A)\* B for A large](https://discourse.julialang.org/t/most-efficient-way-of-computing-b-inv-a-b-for-a-large/47513)

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**Author:** [@Joris\_Pinkse](https://discourse.julialang.org/u/Joris_Pinkse)\
**Replies:** 30\
**Last updated:** [September 30, 2020, 4:19pm UTC](https://discourse.julialang.org/t/most-efficient-way-of-computing-b-inv-a-b-for-a-large/47513 "2020-09-30T16:19:04Z")

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I have a positive definite high-dimensional matrix A and wish to compute B’ \* inv(A) \* B where the result is low-dimensional. What is the fastest way of accomplishing this for generic B?

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## [GraphRecipes (or equivalent) for this series of plots](https://discourse.julialang.org/t/graphrecipes-or-equivalent-for-this-series-of-plots/47544)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 0\
**Last updated:** [September 30, 2020, 4:09pm UTC](https://discourse.julialang.org/t/graphrecipes-or-equivalent-for-this-series-of-plots/47544 "2020-09-30T16:09:44Z")

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I have a directed graph in LightGraphs and I want to produce a series of plots each with the same circular layout but highlighting different subsets of edges, with highlighting on the nodes:

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## [Returning a value calculated inside the ODE function](https://discourse.julialang.org/t/returning-a-value-calculated-inside-the-ode-function/47529)

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**Author:** [@fkrauer](https://discourse.julialang.org/u/fkrauer)\
**Replies:** 1\
**Last updated:** [September 30, 2020, 12:52pm UTC](https://discourse.julialang.org/t/returning-a-value-calculated-inside-the-ode-function/47529 "2020-09-30T12:52:20Z")

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Hi I am using julia via R to simulate compartmental epidemic ODE models. Is there a way to return a value that is calculated inside the ODE function for every step of the integration? So far it only returns the states. …

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## [LASSO.jl, GLMNet.jl - hyperparameters](https://discourse.julialang.org/t/lasso-jl-glmnet-jl-hyperparameters/28799)

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**Author:** [@versipellis](https://discourse.julialang.org/u/versipellis)\
**Replies:** 6\
**Last updated:** [September 30, 2020, 9:35am UTC](https://discourse.julialang.org/t/lasso-jl-glmnet-jl-hyperparameters/28799 "2020-09-30T09:35:34Z")

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I’m not seeing any documentation for such, but in LASSO.jl and GLMNet.jl, I’m looking to do the following: Specify a validation set to train hyperparameters on, rather than just using cross-validation. I know CV is bet…

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## [Adding textures to rectangles using Makie](https://discourse.julialang.org/t/adding-textures-to-rectangles-using-makie/11465)

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**Author:** [@fabiangans](https://discourse.julialang.org/u/fabiangans)\
**Replies:** 4\
**Last updated:** [September 30, 2020, 8:57am UTC](https://discourse.julialang.org/t/adding-textures-to-rectangles-using-makie/11465 "2020-09-30T08:57:49Z")

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I want to create a number of textured (rotated) rectangles where the 3D corner coordinates are given in a single plot using Makie.jl or GLVizualize. I want a plot similar to this example where the earth image is plotted …

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## [Cant create dataframe](https://discourse.julialang.org/t/cant-create-dataframe/47502)

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**Author:** [@andresmorago](https://discourse.julialang.org/u/andresmorago)\
**Replies:** 16\
**Last updated:** [September 29, 2020, 10:00pm UTC](https://discourse.julialang.org/t/cant-create-dataframe/47502 "2020-09-29T22:00:16Z")

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Hello guys. Newbie here I have this array getvalue.(W) 1-dimensional DenseAxisArray{Float64,1,…} with index sets: Dimension 1, 0:6 And data, a 7-element Array{Float64,1}: 80.0 65.0 65.0 65.0 65.0 65.0 65.0 …

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## [Implementing Crystal Graph CNN in Julia](https://discourse.julialang.org/t/implementing-crystal-graph-cnn-in-julia/33169)

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**Author:** [@rkurchin](https://discourse.julialang.org/u/rkurchin)\
**Replies:** 4\
**Last updated:** [September 29, 2020, 6:56pm UTC](https://discourse.julialang.org/t/implementing-crystal-graph-cnn-in-julia/33169 "2020-09-29T18:56:11Z")

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Hi everyone! I’d like to implement Crystal Graph Convolutional Neural Networks (CGCNNs) in Julia, in particular using the GeometricFlux package. CGCNN’s are a method in computational materials science for representing cr…

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## [Debugging with CUDA.jl](https://discourse.julialang.org/t/debugging-with-cuda-jl/47493)

<div class="topic-metadata">

**Author:** [@bmit](https://discourse.julialang.org/u/bmit)\
**Replies:** 1\
**Last updated:** [September 29, 2020, 5:50pm UTC](https://discourse.julialang.org/t/debugging-with-cuda-jl/47493 "2020-09-29T17:50:09Z")

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Does Debugger.jl work with CUDA.jl? I haven’t had any luck and wasn’t sure if I was missing something or it’s not supposed to work. Here’s the simplest case I came up with: using CUDA using Debugger function test\_cuda\_d…

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## [What scaling applies to the irfft (inverse fast fourier transform - FFTW.jl package)](https://discourse.julialang.org/t/what-scaling-applies-to-the-irfft-inverse-fast-fourier-transform-fftw-jl-package/47476)

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**Author:** [@jleman](https://discourse.julialang.org/u/jleman)\
**Replies:** 4\
**Last updated:** [September 29, 2020, 5:28pm UTC](https://discourse.julialang.org/t/what-scaling-applies-to-the-irfft-inverse-fast-fourier-transform-fftw-jl-package/47476 "2020-09-29T17:28:37Z")

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I am trying to understand scaling of the irfft function of the FFTW.jl package. I have a function that defines a continuous frequency domain signal (in radians). The complex portion of the signal has odd symmetry and t…

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## [DiffEqFlux Autodifferentiating inside loss function](https://discourse.julialang.org/t/diffeqflux-autodifferentiating-inside-loss-function/47203)

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**Author:** [@Axlrsn](https://discourse.julialang.org/u/Axlrsn)\
**Replies:** 6\
**Last updated:** [September 29, 2020, 3:03pm UTC](https://discourse.julialang.org/t/diffeqflux-autodifferentiating-inside-loss-function/47203 "2020-09-29T15:03:25Z")

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Hello, I am new to Julia and especially the way Zygote works. For a project in physics informed machine learning I have a neural network NN(x) approximating a function f(x). I want to take the gradient of the neural net…

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## [GPLK vs Gurobi speed on simple MIPs](https://discourse.julialang.org/t/gplk-vs-gurobi-speed-on-simple-mips/47383)

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**Author:** [@adow031](https://discourse.julialang.org/u/adow031)\
**Replies:** 11\
**Last updated:** [September 29, 2020, 1:07pm UTC](https://discourse.julialang.org/t/gplk-vs-gurobi-speed-on-simple-mips/47383 "2020-09-29T13:07:21Z")

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I’m needing to solve a large number of simple MIPs in succession, and I’m finding that GPLK is 2.5 times faster than Gurobi (with presolve disabled; presolve slows Gurobi further). Is this normal? I know that for large/…

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## [Complex-valued functions with real arguments - ForwardDiff, JuliaDiff](https://discourse.julialang.org/t/complex-valued-functions-with-real-arguments-forwarddiff-juliadiff/27386)

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**Author:** [@marcvb97](https://discourse.julialang.org/u/marcvb97)\
**Replies:** 6\
**Last updated:** [September 28, 2020, 10:41pm UTC](https://discourse.julialang.org/t/complex-valued-functions-with-real-arguments-forwarddiff-juliadiff/27386 "2020-09-28T22:41:30Z")

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When executing the following code to apply ForwardDiff to a complex-valued function with real argument: using ForwardDiff f2(t::Real) = real( (cos(t) + 1im\*sin(t))^(1/2) ) t = pi/2 ForwardDiff.derivative(f2,t) I get th…

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## [Contour plot of separate, intersecting levels](https://discourse.julialang.org/t/contour-plot-of-separate-intersecting-levels/47400)

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**Author:** [@ric.cioffi](https://discourse.julialang.org/u/ric.cioffi)\
**Replies:** 6\
**Last updated:** [September 28, 2020, 7:47pm UTC](https://discourse.julialang.org/t/contour-plot-of-separate-intersecting-levels/47400 "2020-09-28T19:47:35Z")

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Problem Hi, I’m having a hard time figuring out how to do the following, though I’m sure there must be some “easy” solution that I just cannot find. I have a 3-dimensional array of booleans and I’d like to see the “cont…

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