# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=442

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**Page:** 443

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## [Replacing values in a data frame](https://discourse.julialang.org/t/replacing-values-in-a-data-frame/40937)

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**Author:** [@Chris\_Anderson](https://discourse.julialang.org/u/Chris_Anderson)\
**Replies:** 7\
**Last updated:** [June 7, 2020, 7:11pm UTC](https://discourse.julialang.org/t/replacing-values-in-a-data-frame/40937 "2020-06-07T19:11:13Z")

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Don’t know if this is the right category for this… I have a dataframe with a column containing averages calculated with the mean function. These values go out several decimal places, but I want to use round() to set it…

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## [Zygote AD Jacobian-vector product](https://discourse.julialang.org/t/zygote-ad-jacobian-vector-product/40857)

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**Author:** [@pavanakumar](https://discourse.julialang.org/u/pavanakumar)\
**Replies:** 5\
**Last updated:** [June 7, 2020, 7:08pm UTC](https://discourse.julialang.org/t/zygote-ad-jacobian-vector-product/40857 "2020-06-07T19:08:04Z")

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Hi I come from the Tapenade source transformation community and use Fortran as my primary language. I recently moved to Julia and slowly adapting to the language. I have problems understanding the algorithmic differenti…

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## [Absolute value in JuMP](https://discourse.julialang.org/t/absolute-value-in-jump/40911)

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**Author:** [@sobhan](https://discourse.julialang.org/u/sobhan)\
**Replies:** 2\
**Last updated:** [June 7, 2020, 1:52pm UTC](https://discourse.julialang.org/t/absolute-value-in-jump/40911 "2020-06-07T13:52:08Z")

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I’m trying to optimize the absolute value of an affine function, for example, something like: using JuMP model = Model() @variable(model, x) @objective(model, Min, abs(x)) but i get Closest candidates are: abs(::Boo…

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## [Displaying video on a rotating cube](https://discourse.julialang.org/t/displaying-video-on-a-rotating-cube/40920)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 1\
**Last updated:** [June 7, 2020, 10:57am UTC](https://discourse.julialang.org/t/displaying-video-on-a-rotating-cube/40920 "2020-06-07T10:57:09Z")

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When the SGI O2 workstation was introduced (ahem) years ago one of the impressive for the time demos was to display moving video on the faces of a wireframe cube which was being rotated on the screen. My memory may be fa…

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## [Unexpected behavior DifferentialEquations (parabolic ODE) -- large # of steps](https://discourse.julialang.org/t/unexpected-behavior-differentialequations-parabolic-ode-large-of-steps/40886)

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**Author:** [@egcjm](https://discourse.julialang.org/u/egcjm)\
**Replies:** 3\
**Last updated:** [June 6, 2020, 10:32pm UTC](https://discourse.julialang.org/t/unexpected-behavior-differentialequations-parabolic-ode-large-of-steps/40886 "2020-06-06T22:32:31Z")

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\*\* This question is as much about numerics as about use of DifferentialEquations.jl \*\* \*\* This is a toy problem with an analytical solution – I’d like to understand the behavior of DifferentialEquations.jl, not interest…

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## [Using the groupby function](https://discourse.julialang.org/t/using-the-groupby-function/40839)

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**Author:** [@Chris\_Anderson](https://discourse.julialang.org/u/Chris_Anderson)\
**Replies:** 12\
**Last updated:** [June 6, 2020, 4:12pm UTC](https://discourse.julialang.org/t/using-the-groupby-function/40839 "2020-06-06T16:12:33Z")

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I have a dataframe that I would like to group by a categorical variable (4 values, let’s say a, b, c and d) and then by a continuous variable (values between 0 and 40). I’d like the continuous variable to be in groups t…

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## [RMSprop and Early stopping in Flux.jl](https://discourse.julialang.org/t/rmsprop-and-early-stopping-in-flux-jl/21065)

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**Author:** [@charlesll](https://discourse.julialang.org/u/charlesll)\
**Replies:** 8\
**Last updated:** [June 6, 2020, 2:57pm UTC](https://discourse.julialang.org/t/rmsprop-and-early-stopping-in-flux-jl/21065 "2020-06-06T14:57:19Z")

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Hi, I’m playing with Flux.jl and results are really nice. At the moment, I would like to use the RMSprop solver with Early Stopping. Anyone have experience with implementing those in Flux? Thanks!

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## [JuMP 0.21: how to efficiently delete non-binding constraints in an LP?](https://discourse.julialang.org/t/jump-0-21-how-to-efficiently-delete-non-binding-constraints-in-an-lp/40650)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 5\
**Last updated:** [June 5, 2020, 9:58pm UTC](https://discourse.julialang.org/t/jump-0-21-how-to-efficiently-delete-non-binding-constraints-in-an-lp/40650 "2020-06-05T21:58:46Z")

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Dear folks, I like to delete non-binding constraints in an LP, i.e., constraints with zero shadow price, and then re-optimize. I tried: optimize!( model ) if has\_duals( model ) num\_cons = num\_constraints(model, Gen…

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## [Writing complex Flux Models](https://discourse.julialang.org/t/writing-complex-flux-models/40439)

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**Author:** [@irhum](https://discourse.julialang.org/u/irhum)\
**Replies:** 4\
**Last updated:** [June 5, 2020, 7:14pm UTC](https://discourse.julialang.org/t/writing-complex-flux-models/40439 "2020-06-05T19:14:05Z")

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Flux’s typical go to when writing models is Chains, and for most feedforward models (with the occasional skip connection), with one input, it works quite beautifully. Problem is, when defining models as functions, we lo…

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## [Problem LightGraphs creating graphs and accessing vertices LightGraphs](https://discourse.julialang.org/t/problem-lightgraphs-creating-graphs-and-accessing-vertices-lightgraphs/40804)

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**Author:** [@Florent\_Poux](https://discourse.julialang.org/u/Florent_Poux)\
**Replies:** 1\
**Last updated:** [June 5, 2020, 11:25am UTC](https://discourse.julialang.org/t/problem-lightgraphs-creating-graphs-and-accessing-vertices-lightgraphs/40804 "2020-06-05T11:25:49Z")

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Hi, I struggle to have a reliable behavior using Lightgraphs. Yesterday, I could plot some graphs based on some arrays I had, but impossible to use the command “vertices(G)” for example (returned: UndefVarError: vertice…

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## [Need help with Variational Inference](https://discourse.julialang.org/t/need-help-with-variational-inference/40789)

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**Author:** [@Farlein](https://discourse.julialang.org/u/Farlein)\
**Replies:** 0\
**Last updated:** [June 5, 2020, 3:08am UTC](https://discourse.julialang.org/t/need-help-with-variational-inference/40789 "2020-06-05T03:08:28Z")

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Hi there, I have been recently attracted to variational inference. I like the idea to link Bayesian modeling with optimization. I like its uni modal approximation to the parameters in a model (by assuming the variationa…

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## [Relation between Makie.jl and Plots.jl](https://discourse.julialang.org/t/relation-between-makie-jl-and-plots-jl/40731)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 2\
**Last updated:** [June 4, 2020, 11:51pm UTC](https://discourse.julialang.org/t/relation-between-makie-jl-and-plots-jl/40731 "2020-06-04T23:51:42Z")

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There was a similar question asked a year ago, here Current state of the relationship between Plots and Makie. I am just curious of what is the relation between the two plotting libraries at the moment. I know that Plot…

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## [AMD support is understated?](https://discourse.julialang.org/t/amd-support-is-understated/40152)

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**Author:** [@Matt\_Davis](https://discourse.julialang.org/u/Matt_Davis)\
**Replies:** 14\
**Last updated:** [June 4, 2020, 7:52pm UTC](https://discourse.julialang.org/t/amd-support-is-understated/40152 "2020-06-04T19:52:04Z")

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I’ve seen a lot of posts being a little down on support for AMD gpus in Julia. There’s no doubt that the CUDA stack is more mature, but the OpenCL stack seems pretty good. Between OpenCL.jl, CLBlast.jl, and ArrayFire.jl,…

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## [Filtering a DataFrame column using Regex](https://discourse.julialang.org/t/filtering-a-dataframe-column-using-regex/40753)

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**Author:** [@alejandromerchan](https://discourse.julialang.org/u/alejandromerchan)\
**Replies:** 2\
**Last updated:** [June 4, 2020, 6:43pm UTC](https://discourse.julialang.org/t/filtering-a-dataframe-column-using-regex/40753 "2020-06-04T18:43:18Z")

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I have a DataFrame that has this general structure using DataFrames df = DataFrame(Sites = \["N-1", "N-1", "A", "B", "N-2"\], Other = \[randn(5)\]) How can I filter out the rows that are named “N-” on the column :Sites? I…

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## [Dispatch on DataFrame columns](https://discourse.julialang.org/t/dispatch-on-dataframe-columns/40689)

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**Author:** [@lungben](https://discourse.julialang.org/u/lungben)\
**Replies:** 6\
**Last updated:** [June 4, 2020, 5:26pm UTC](https://discourse.julialang.org/t/dispatch-on-dataframe-columns/40689 "2020-06-04T17:26:23Z")

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Hi, I have a function on a DataFrame which should behave differently depending on the names / eltypes of the DataFrame columns. Is this possible using a multiple-dispatch like pattern? Example: using DataFrames functi…

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## [Using ANTIGONE from Julia](https://discourse.julialang.org/t/using-antigone-from-julia/10917)

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**Author:** [@rdeits](https://discourse.julialang.org/u/rdeits)\
**Replies:** 6\
**Last updated:** [June 4, 2020, 2:10pm UTC](https://discourse.julialang.org/t/using-antigone-from-julia/10917 "2020-06-04T14:10:29Z")

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I’ve been investigating the various options for (globally optimal) MINLP in Julia, and ANTIGONE looks like a nice option. I’m curious if anyone has any experience using it from Julia. At first glance, it looks like this…

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## [PATHSolver.jl error using map](https://discourse.julialang.org/t/pathsolver-jl-error-using-map/40724)

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**Author:** [@juliauser](https://discourse.julialang.org/u/juliauser)\
**Replies:** 3\
**Last updated:** [June 4, 2020, 1:36pm UTC](https://discourse.julialang.org/t/pathsolver-jl-error-using-map/40724 "2020-06-04T13:36:08Z")

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I am using PATHSolver to solve linear complementarity problems. I have no problem when using it “normally”, but I get this error when I use parallel computing, as below. What seems to be problematic is the presence of t…

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## [Bell Curve Overlay (Gadfly)](https://discourse.julialang.org/t/bell-curve-overlay-gadfly/40640)

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**Author:** [@Chris\_Anderson](https://discourse.julialang.org/u/Chris_Anderson)\
**Replies:** 4\
**Last updated:** [June 3, 2020, 11:37pm UTC](https://discourse.julialang.org/t/bell-curve-overlay-gadfly/40640 "2020-06-03T23:37:49Z")

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I have data that I’ve plotted using Geom.histogram. I’m trying to determine, visually, how closely it fits a normal distribution. I realize there are other more quantitative methods to test fit to a distribution, but f…

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## [Accelerate solving many matrix problems](https://discourse.julialang.org/t/accelerate-solving-many-matrix-problems/40500)

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**Author:** [@clinton](https://discourse.julialang.org/u/clinton)\
**Replies:** 8\
**Last updated:** [June 3, 2020, 7:17pm UTC](https://discourse.julialang.org/t/accelerate-solving-many-matrix-problems/40500 "2020-06-03T19:17:01Z")

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Say I have a whole lot of independent small matrix problems (posed as regression problems below). Each individual problem is too small for effective CUDA deployment, yet I am wondering if there is an opportunity for subs…

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## [Can a PlotlyJS plot be exported in a form that includes pan/zoom interactivity?](https://discourse.julialang.org/t/can-a-plotlyjs-plot-be-exported-in-a-form-that-includes-pan-zoom-interactivity/40685)

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**Author:** [@klaff](https://discourse.julialang.org/u/klaff)\
**Replies:** 5\
**Last updated:** [June 3, 2020, 6:47pm UTC](https://discourse.julialang.org/t/can-a-plotlyjs-plot-be-exported-in-a-form-that-includes-pan-zoom-interactivity/40685 "2020-06-03T18:47:04Z")

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Hi, I’m using PlotlyJS to explore some lengthy time series data, and it would be great if I could export a plot with the zoom/pan interactivity. I would like to give it to someone who doesn’t have Julia, as a web page t…

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## [Taking gradients when propagating through an ODE solver](https://discourse.julialang.org/t/taking-gradients-when-propagating-through-an-ode-solver/40652)

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**Author:** [@MikeKlocCZ](https://discourse.julialang.org/u/MikeKlocCZ)\
**Replies:** 6\
**Last updated:** [June 3, 2020, 6:45pm UTC](https://discourse.julialang.org/t/taking-gradients-when-propagating-through-an-ode-solver/40652 "2020-06-03T18:45:35Z")

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I need to differentiate parameters of my model (neural network) through an ODE solver. Apparently, DiffEqFlux allows me to do that but it seems that the gradients are computed only if the network parameters enter direct…

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## [PlotlyJS example failure](https://discourse.julialang.org/t/plotlyjs-example-failure/40479)

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**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 9\
**Last updated:** [June 3, 2020, 5:19pm UTC](https://discourse.julialang.org/t/plotlyjs-example-failure/40479 "2020-06-03T17:19:03Z")

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Dear All, I would like to ask for help/advice with following problem. Previously, I used PlotlyJS on Julia 1.1.1 for plotting 3D objects. Unfortunately, after upgrading to Julia 1.4.2 (I deleted Atom + Julia and re-inst…

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## [Custom Sampler in Turing.jl](https://discourse.julialang.org/t/custom-sampler-in-turing-jl/40629)

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**Author:** [@bdeonovic](https://discourse.julialang.org/u/bdeonovic)\
**Replies:** 2\
**Last updated:** [June 3, 2020, 4:04pm UTC](https://discourse.julialang.org/t/custom-sampler-in-turing-jl/40629 "2020-06-03T16:04:12Z")

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Lets say I have some Bayesian model for which the full conditional distributions of some of the variables are known in closed form. How can I write the appropriate Gibbs sampler for these variables in Turing.jl? Lets sa…

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## [Animation from data points (arrays)](https://discourse.julialang.org/t/animation-from-data-points-arrays/40642)

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**Author:** [@Joey](https://discourse.julialang.org/u/Joey)\
**Replies:** 4\
**Last updated:** [June 3, 2020, 12:24pm UTC](https://discourse.julialang.org/t/animation-from-data-points-arrays/40642 "2020-06-03T12:24:48Z")

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Hello, everyone. I recently switched from MATLAB to Julia, and I do not know a lot of stuff about plotting in Julia. It is a really simple problem yet unclear to me: I need to build a 3d animation out of a set of data p…

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## [Contours with equal area changing system](https://discourse.julialang.org/t/contours-with-equal-area-changing-system/40644)

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**Author:** [@Tamuzd](https://discourse.julialang.org/u/Tamuzd)\
**Replies:** 3\
**Last updated:** [June 3, 2020, 9:03am UTC](https://discourse.julialang.org/t/contours-with-equal-area-changing-system/40644 "2020-06-03T09:03:39Z")

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Let’s say I have a system with 3 particles in 2d system a,b,c with the following positions a = \[0.1,0.0\] b = \[-0.1,0.0\] c = \[0.0,0.1\] each particle is described by Gaussian function, therefore the system function is as…

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## [Free GPU resources?](https://discourse.julialang.org/t/free-gpu-resources/40653)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 1\
**Last updated:** [June 3, 2020, 8:54am UTC](https://discourse.julialang.org/t/free-gpu-resources/40653 "2020-06-03T08:54:07Z")

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Hi, I’m running the same Julia code using CuArrays etc in two machines, one at home and one at work. At home my code works well, this is a 16Gb RAM, Ubuntu 18.04 linux box with a Geoforce 1050Ti, 4Gb RAM. On the compute…

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## [Parsing Column values of different types](https://discourse.julialang.org/t/parsing-column-values-of-different-types/40589)

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**Author:** [@Chris\_Anderson](https://discourse.julialang.org/u/Chris_Anderson)\
**Replies:** 2\
**Last updated:** [June 2, 2020, 11:47pm UTC](https://discourse.julialang.org/t/parsing-column-values-of-different-types/40589 "2020-06-02T23:47:40Z")

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I have a side job/project that involves analyzing a large data set. I am leveraging this project to gain competence with programming generally and Julia specifically, meaning the learning curve is steep as I work throug…

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## [Generating equations in ModellingToolkit from infinite series](https://discourse.julialang.org/t/generating-equations-in-modellingtoolkit-from-infinite-series/40244)

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**Author:** [@Bogo](https://discourse.julialang.org/u/Bogo)\
**Replies:** 5\
**Last updated:** [June 2, 2020, 7:28pm UTC](https://discourse.julialang.org/t/generating-equations-in-modellingtoolkit-from-infinite-series/40244 "2020-06-02T19:28:44Z")

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Hi all! I was advised to open this issue as a follow-up of this thread: https://discourse.julialang.org/t/speeding-up-solution-to-the-large-system-of-non-linear-complex-valued-odes/39075 My issue: I am generating nonli…

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## [Sigmoid function](https://discourse.julialang.org/t/sigmoid-function/40614)

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**Author:** [@Shirin](https://discourse.julialang.org/u/Shirin)\
**Replies:** 8\
**Last updated:** [June 2, 2020, 6:25pm UTC](https://discourse.julialang.org/t/sigmoid-function/40614 "2020-06-02T18:25:18Z")

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Hello, I have difficulty with getting the derivate (Gradient ) of sigmoid! using Flux sigmoid(x)=1 ./(1 .+exp(.-x)) sigmoid(x)=s d(s)=x .\* (1 .- x) d(\[1 2 3\]) it causes error or not outputting correct number! I w…

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## [Makie: How to hide axes while plotting text](https://discourse.julialang.org/t/makie-how-to-hide-axes-while-plotting-text/40604)

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**Author:** [@themadprogramer](https://discourse.julialang.org/u/themadprogramer)\
**Replies:** 7\
**Last updated:** [June 2, 2020, 3:25pm UTC](https://discourse.julialang.org/t/makie-how-to-hide-axes-while-plotting-text/40604 "2020-06-02T15:25:13Z")

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As I was starting to lose hope in the future of Julia in terms of applicability, I happened to discover Makie.jl and I am loving it so far. A small question I’d like to ask is how one might hide axes, if only plotting t…

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