# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=505

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**Page:** 506

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## [Makie and colours](https://discourse.julialang.org/t/makie-and-colours/21937)

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**Author:** [@fa-bien](https://discourse.julialang.org/u/fa-bien)\
**Replies:** 6\
**Last updated:** [March 16, 2019, 1:46pm UTC](https://discourse.julialang.org/t/makie-and-colours/21937 "2019-03-16T13:46:47Z")

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I am visualising polyhedra with Makie. However I find that colours are all way too dark, see MWE that displays a cube that should be the brightest shade of yellow, but is not very bright. Moreover, I find that it gets br…

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## [Key error in JuMP on domain tuples](https://discourse.julialang.org/t/key-error-in-jump-on-domain-tuples/21872)

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**Author:** [@Di11on](https://discourse.julialang.org/u/Di11on)\
**Replies:** 6\
**Last updated:** [March 15, 2019, 2:18pm UTC](https://discourse.julialang.org/t/key-error-in-jump-on-domain-tuples/21872 "2019-03-15T14:18:02Z")

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Hi folks, I’m having a strange problem with JuMP that I hope someone can identify… The first formulation below results in a key error but the second doesn’t but both should, in theory involve evaluations on the same se…

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## [JuMP/CPLEX: adding objective function expression in loop is very resource-consuming](https://discourse.julialang.org/t/jump-cplex-adding-objective-function-expression-in-loop-is-very-resource-consuming/21859)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 3\
**Last updated:** [March 15, 2019, 11:40am UTC](https://discourse.julialang.org/t/jump-cplex-adding-objective-function-expression-in-loop-is-very-resource-consuming/21859 "2019-03-15T11:40:49Z")

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Dear community, I use JuMP 0.18.5, CPLEX 0.4.3, Julia 1.1, and observe a strange behaviour when adding an objective function expression with a loop. Here is a stupid minimal example: using TimerOutputs using JuMP using…

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## [Plotting a transparent planes/boxes with Makie](https://discourse.julialang.org/t/plotting-a-transparent-planes-boxes-with-makie/21875)

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**Author:** [@cserteGT3](https://discourse.julialang.org/u/cserteGT3)\
**Replies:** 2\
**Last updated:** [March 14, 2019, 4:37pm UTC](https://discourse.julialang.org/t/plotting-a-transparent-planes-boxes-with-makie/21875 "2019-03-14T16:37:59Z")

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I’m looking for a way to plot simple planes with Makie. The only solution I found so far is this: using Makie p1 = Point3(0.0, 0.0, 0.0) p2 = Point3(0.0, 1.0, 0.0) p3 = Point3(0.0, 1.0, 1.0) p4 = Point3(0.0, 0.0, 1.0)…

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## [FFTW Plans for multiple threads](https://discourse.julialang.org/t/fftw-plans-for-multiple-threads/21861)

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**Author:** [@M\_Kaj](https://discourse.julialang.org/u/M_Kaj)\
**Replies:** 1\
**Last updated:** [March 14, 2019, 1:13pm UTC](https://discourse.julialang.org/t/fftw-plans-for-multiple-threads/21861 "2019-03-14T13:13:49Z")

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I need to compute many convolutions of arrays with the same length and I want to use multiple threads for that. So i want each thread to compute a convolution with fft’s. As I understand it right now the creating of the…

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## [PyPlot warning?](https://discourse.julialang.org/t/pyplot-warning/21819)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 4\
**Last updated:** [March 13, 2019, 4:52pm UTC](https://discourse.julialang.org/t/pyplot-warning/21819 "2019-03-13T16:52:16Z")

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I’m not sure whether this is a problem related to my laptop set-up, or a change in Julia… Running IJulia, I want to use the pyplot() back-end to Plots – because it has better LaTeX support than gr(). I get the following…

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## [Handle escaped quotes in CSVFiles/TextParse.jl](https://discourse.julialang.org/t/handle-escaped-quotes-in-csvfiles-textparse-jl/21824)

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**Author:** [@chaydont](https://discourse.julialang.org/u/chaydont)\
**Replies:** 1\
**Last updated:** [March 13, 2019, 4:48pm UTC](https://discourse.julialang.org/t/handle-escaped-quotes-in-csvfiles-textparse-jl/21824 "2019-03-13T16:48:30Z")

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Is it possible to read a csv that has quote-escaped quotes with CSVFiles, without keeping the 2 quotes in the string? I’m trying to do something like this : data = """ 1980-01-01T00:00:00.000Z\\t5\\tC\\t"str…

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## [Gurobi local cuts](https://discourse.julialang.org/t/gurobi-local-cuts/21814)

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**Author:** [@Lefteris\_Manousakis](https://discourse.julialang.org/u/Lefteris_Manousakis)\
**Replies:** 4\
**Last updated:** [March 13, 2019, 1:42pm UTC](https://discourse.julialang.org/t/gurobi-local-cuts/21814 "2019-03-13T13:42:04Z")

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HI everyone! I am tryin to add local cut with Gurobi (Julia v0.6). Although it works with CPLEX is seems that Gurobi wrapper does not support local cuts. \> LoadError: e\[91mMethodError: no method matching cbaddcutlocal!…

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## [Towards new solutions for scientific computing: the case of Julia](https://discourse.julialang.org/t/towards-new-solutions-for-scientific-computing-the-case-of-julia/18302)

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**Author:** [@Maurizio\_Tomasi](https://discourse.julialang.org/u/Maurizio_Tomasi)\
**Replies:** 8\
**Last updated:** [March 13, 2019, 10:19am UTC](https://discourse.julialang.org/t/towards-new-solutions-for-scientific-computing-the-case-of-julia/18302 "2019-03-13T10:19:03Z")

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Hi to everybody, @giordano and I have submitted a paper for the Proceedings of ADASS 2018. It is available here: \[1812.01219\] Towards new solutions for scientific computing: the case of Julia. Slides of the talk I gave …

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## [Variable not defined when working with 2 loops](https://discourse.julialang.org/t/variable-not-defined-when-working-with-2-loops/21772)

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**Author:** [@WangQuanmeng](https://discourse.julialang.org/u/WangQuanmeng)\
**Replies:** 5\
**Last updated:** [March 13, 2019, 6:15am UTC](https://discourse.julialang.org/t/variable-not-defined-when-working-with-2-loops/21772 "2019-03-13T06:15:02Z")

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Hi all, I am working on lagrangian relaxation of a particular problem, and I meet the following error. The original problem consists of 10 almost independent subproblems, where 10 subproblems are only linked by 1 simpl…

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## [Optimization and arbitrary precision](https://discourse.julialang.org/t/optimization-and-arbitrary-precision/21801)

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**Author:** [@Andre\_Mello](https://discourse.julialang.org/u/Andre_Mello)\
**Replies:** 2\
**Last updated:** [March 13, 2019, 12:52am UTC](https://discourse.julialang.org/t/optimization-and-arbitrary-precision/21801 "2019-03-13T00:52:40Z")

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Hi all, I’ve been exploring some packages for solving nonlinear least squares problems. LsqFit.jl, LeastSquaresOptim.jl and Optim.jl are the ones I’ve come across so far and all of them give me great results. However, …

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## [Function in Flux to estimate learning rate](https://discourse.julialang.org/t/function-in-flux-to-estimate-learning-rate/21734)

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**Author:** [@samq](https://discourse.julialang.org/u/samq)\
**Replies:** 7\
**Last updated:** [March 12, 2019, 9:36pm UTC](https://discourse.julialang.org/t/function-in-flux-to-estimate-learning-rate/21734 "2019-03-12T21:36:39Z")

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Is there a function in Flux to estimate the best learning rate for a good gradient descent before training a neural network?

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## [How can we extract the individual random slopes from a MixedModel.jl fit?](https://discourse.julialang.org/t/how-can-we-extract-the-individual-random-slopes-from-a-mixedmodel-jl-fit/21780)

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**Author:** [@arnaudmgh](https://discourse.julialang.org/u/arnaudmgh)\
**Replies:** 2\
**Last updated:** [March 12, 2019, 5:36pm UTC](https://discourse.julialang.org/t/how-can-we-extract-the-individual-random-slopes-from-a-mixedmodel-jl-fit/21780 "2019-03-12T17:36:46Z")

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In R package lme4, the function coef seems to return slopes for each level of the factor, but in Julia coef returns only fixed effects. (see r - Extracting slopes for cases from a mixed effects model (lme4) - Cross Valid…

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## [wrangling large json files](https://discourse.julialang.org/t/wrangling-large-json-files/18505)

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**Author:** [@gvdr](https://discourse.julialang.org/u/gvdr)\
**Replies:** 5\
**Last updated:** [March 12, 2019, 2:48pm UTC](https://discourse.julialang.org/t/wrangling-large-json-files/18505 "2019-03-12T14:48:10Z")

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Dear All, I’m handling a large JSON file (in my case, a 100GB of ndjson). I would need to query it in various and still TBD ways. In my lucky case we can rely on a fixed schema, which is nested (although not deep, we go…

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## [DataFrame transformation question](https://discourse.julialang.org/t/dataframe-transformation-question/21742)

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**Author:** [@johann.spies](https://discourse.julialang.org/u/johann.spies)\
**Replies:** 2\
**Last updated:** [March 11, 2019, 4:30pm UTC](https://discourse.julialang.org/t/dataframe-transformation-question/21742 "2019-03-11T16:30:35Z")

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What I want to do is something like “unstack” but I do not know how to do it. A simple example: l = DataFrame(a = \["a", "a", "b", "b"\], c = \["ZA", "ZM", "BW", "ZA"\]) 4×2 DataFrame │ Row │ a │ c │ │ │ Str…

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## [Flux results not similar to Tensorflow](https://discourse.julialang.org/t/flux-results-not-similar-to-tensorflow/21677)

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**Author:** [@GJBoth](https://discourse.julialang.org/u/GJBoth)\
**Replies:** 3\
**Last updated:** [March 11, 2019, 9:26am UTC](https://discourse.julialang.org/t/flux-results-not-similar-to-tensorflow/21677 "2019-03-11T09:26:15Z")

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Hi everyone, I currently do a lot of ML in Python using Tensorflow, which is working fine but Julia seems to be a bit more then fine, so I’m experimenting with Flux as an alternative. My first step is just to train a si…

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## [Value Function Iteration on GPU](https://discourse.julialang.org/t/value-function-iteration-on-gpu/13774)

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**Author:** [@myroslav](https://discourse.julialang.org/u/myroslav)\
**Replies:** 6\
**Last updated:** [March 9, 2019, 7:12pm UTC](https://discourse.julialang.org/t/value-function-iteration-on-gpu/13774 "2019-03-09T19:12:13Z")

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Hi, I am trying to understand how to do the very basic Value Function Iteration in an Overlapping Generations Model using the GPU. So far it works well on the CPU, but I am starting to run into trouble once I increase t…

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## [How to call this "SortedDict 2D" data structure?](https://discourse.julialang.org/t/how-to-call-this-sorteddict-2d-data-structure/21664)

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**Author:** [@congvan](https://discourse.julialang.org/u/congvan)\
**Replies:** 0\
**Last updated:** [March 9, 2019, 7:54am UTC](https://discourse.julialang.org/t/how-to-call-this-sorteddict-2d-data-structure/21664 "2019-03-09T07:54:15Z")

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Recently I come across a need for a 2D data structure like this, but I am not sure how to call it. Any advice how to call it? For example I have a data structure (called SortedDict2D) containing this table: 1 …

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## [Accumulating error in for loop generated by tensor macro vs sum](https://discourse.julialang.org/t/accumulating-error-in-for-loop-generated-by-tensor-macro-vs-sum/21647)

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**Author:** [@grahamas](https://discourse.julialang.org/u/grahamas)\
**Replies:** 1\
**Last updated:** [March 8, 2019, 11:52pm UTC](https://discourse.julialang.org/t/accumulating-error-in-for-loop-generated-by-tensor-macro-vs-sum/21647 "2019-03-08T23:52:08Z")

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Could anyone give me a pointer on a numerical inaccuracy that’s causing my simulation to explode? Here’s a toy example of the operation I’m running, though in practice it accumulates as b += S(C), where S is a nonlinear…

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## [error building CuArrays in Julia 1.0](https://discourse.julialang.org/t/error-building-cuarrays-in-julia-1-0/21556)

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**Author:** [@wenquan](https://discourse.julialang.org/u/wenquan)\
**Replies:** 4\
**Last updated:** [March 8, 2019, 8:06pm UTC](https://discourse.julialang.org/t/error-building-cuarrays-in-julia-1-0/21556 "2019-03-08T20:06:23Z")

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Error: Error building CUDAdrv: Building against CUDA driver stubs, which is not supported. I built CUDAdrv successfully in Julia 0.6.4, and I don’t know what’s the problem here. Any suggestions? Below is version inf…

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## [using "max" in nonlinear constraints](https://discourse.julialang.org/t/using-max-in-nonlinear-constraints/21606)

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**Author:** [@zhangxz1123](https://discourse.julialang.org/u/zhangxz1123)\
**Replies:** 11\
**Last updated:** [March 8, 2019, 7:22pm UTC](https://discourse.julialang.org/t/using-max-in-nonlinear-constraints/21606 "2019-03-08T19:22:27Z")

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Hi there, I’m trying to use the max function in one of my NLconstraint. Following @ odow’s advice, I use auto-differentiation to allow max into the constraint. The problem is that the length of the array that I want to …

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## [LsqFit.jl error on ODE data fitting](https://discourse.julialang.org/t/lsqfit-jl-error-on-ode-data-fitting/21587)

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**Author:** [@Andre\_Mello](https://discourse.julialang.org/u/Andre_Mello)\
**Replies:** 2\
**Last updated:** [March 8, 2019, 7:06pm UTC](https://discourse.julialang.org/t/lsqfit-jl-error-on-ode-data-fitting/21587 "2019-03-08T19:06:03Z")

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Hi all, my first post here so bare with me please. I’m also new to the Julia language and enjoying it very much so far. Now to the point. I’ve been trying LsqFit and wanted to implement a simple curve fitting model us…

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## [Simulating a Mars Rover - How can I account for random horizontal wind speeds?](https://discourse.julialang.org/t/simulating-a-mars-rover-how-can-i-account-for-random-horizontal-wind-speeds/21642)

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**Author:** [@Rilind\_Berisha](https://discourse.julialang.org/u/Rilind_Berisha)\
**Replies:** 0\
**Last updated:** [March 8, 2019, 5:46pm UTC](https://discourse.julialang.org/t/simulating-a-mars-rover-how-can-i-account-for-random-horizontal-wind-speeds/21642 "2019-03-08T17:46:23Z")

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Hi, This is my first post on here. I’m currently working on a small project to generate and plot a Mars Rover landing. I’ve figured out how code an autopilot that allows me to land on a flat surface at a safe vertical s…

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## [How to write a constraint in JuMP where the index has if-else structure](https://discourse.julialang.org/t/how-to-write-a-constraint-in-jump-where-the-index-has-if-else-structure/21635)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 4\
**Last updated:** [March 8, 2019, 3:42pm UTC](https://discourse.julialang.org/t/how-to-write-a-constraint-in-jump-where-the-index-has-if-else-structure/21635 "2019-03-08T15:42:20Z")

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I have a little question in how to write a constraint in Jump language. The constraint is: sum\_{i} sum\_{r=0}^{9} x\[i,j,t-r\] \<= 1, for all t=1,…,12 and j=1,…,9 if t - r \< 0, change by t - r + 9. How can I use a if-else…

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## [Get in touch with gsoc mentors](https://discourse.julialang.org/t/get-in-touch-with-gsoc-mentors/21428)

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**Author:** [@yash](https://discourse.julialang.org/u/yash)\
**Replies:** 7\
**Last updated:** [March 8, 2019, 2:20pm UTC](https://discourse.julialang.org/t/get-in-touch-with-gsoc-mentors/21428 "2019-03-08T14:20:42Z")

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I am trying for gsoc this year in Julia projects in machine learning side. How can I get in touch with mentors?? And please guide me for my future steps.

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## [Julia TextAnalysis](https://discourse.julialang.org/t/julia-textanalysis/21619)

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**Author:** [@yash](https://discourse.julialang.org/u/yash)\
**Replies:** 2\
**Last updated:** [March 8, 2019, 8:42am UTC](https://discourse.julialang.org/t/julia-textanalysis/21619 "2019-03-08T08:42:01Z")

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What does “rwi” parameter represents in get\_sentiment function in sentiment.jl file in TextAnalysis package?? Text Analysis : GitHub - JuliaText/TextAnalysis.jl: Julia package for text analysis

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## [Special case handling - alternatives to if/else?](https://discourse.julialang.org/t/special-case-handling-alternatives-to-if-else/21608)

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**Author:** [@kevbonham](https://discourse.julialang.org/u/kevbonham)\
**Replies:** 5\
**Last updated:** [March 7, 2019, 11:49pm UTC](https://discourse.julialang.org/t/special-case-handling-alternatives-to-if-else/21608 "2019-03-07T23:49:20Z")

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I have an unruly and monster data table from collaborators, and I’m writing a script to clean it up. The table is updated on a semi-regular basis, and there’s no option to get it in a better form, so I’m stuck trying to …

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## [Automatic Differentiation over Vectors](https://discourse.julialang.org/t/automatic-differentiation-over-vectors/21603)

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**Author:** [@benkj](https://discourse.julialang.org/u/benkj)\
**Replies:** 1\
**Last updated:** [March 7, 2019, 11:30pm UTC](https://discourse.julialang.org/t/automatic-differentiation-over-vectors/21603 "2019-03-07T23:30:01Z")

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Consider the following expression c=exp(A\*t)\*b where A is a matrix, b and c are vectors and t is a scalar. I’m trying to teach ForwardDiff to calculate the derivative of c with respect to t, which is nothing but A\*c. Thi…

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## [Set a function on master and send it to all workers](https://discourse.julialang.org/t/set-a-function-on-master-and-send-it-to-all-workers/21586)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 1\
**Last updated:** [March 7, 2019, 6:21pm UTC](https://discourse.julialang.org/t/set-a-function-on-master-and-send-it-to-all-workers/21586 "2019-03-07T18:21:30Z")

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Hello, I would like to construct an interpolation function from a very large dataset in a serialized way(master worker) and then send it to all workers for parallel computing. I tried sendto(workers(),interp\_function…

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## [How to update a Julia plot without the window grabbing the focus?](https://discourse.julialang.org/t/how-to-update-a-julia-plot-without-the-window-grabbing-the-focus/21558)

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**Author:** [@HenrikM](https://discourse.julialang.org/u/HenrikM)\
**Replies:** 3\
**Last updated:** [March 7, 2019, 8:53am UTC](https://discourse.julialang.org/t/how-to-update-a-julia-plot-without-the-window-grabbing-the-focus/21558 "2019-03-07T08:53:10Z")

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When updating a figure in Julia, how to do it without the plot window grabbing the focus? Let’s say I have the following code: using Plots pyplot() n = 100 x = collect(range(0, pi, length = n)) for i = 1:30 y = …

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