# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=539

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**Page:** 540

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## [Hard-SVM in Julia](https://discourse.julialang.org/t/hard-svm-in-julia/10326)

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**Author:** [@Paul\_McVay](https://discourse.julialang.org/u/Paul_McVay)\
**Replies:** 2\
**Last updated:** [April 16, 2018, 7:47pm UTC](https://discourse.julialang.org/t/hard-svm-in-julia/10326 "2018-04-16T19:47:15Z")

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Is there any library that implements hard-SVM directly instead of soft-SVM? I looked at several libraries and they all seem to implement C-SVM or nu-SVM, something with the slack variables.

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## [Axes attributes (labels, limits) not working in 3d plots](https://discourse.julialang.org/t/axes-attributes-labels-limits-not-working-in-3d-plots/10341)

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**Author:** [@leoll2](https://discourse.julialang.org/u/leoll2)\
**Replies:** 4\
**Last updated:** [April 15, 2018, 5:05pm UTC](https://discourse.julialang.org/t/axes-attributes-labels-limits-not-working-in-3d-plots/10341 "2018-04-15T17:05:20Z")

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I need to modify the labels and the range limits of the axes of my graph. It should be an easy task with Plots, indeed it is for 2d graphs. However, the same code doesn’t work when the dimensions become three (3d). I’m …

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## [How does juliaDB store data on disk? Is it a row store or a column store?](https://discourse.julialang.org/t/how-does-juliadb-store-data-on-disk-is-it-a-row-store-or-a-column-store/10339)

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**Author:** [@Steven\_Sagaert](https://discourse.julialang.org/u/Steven_Sagaert)\
**Replies:** 1\
**Last updated:** [April 15, 2018, 6:32am UTC](https://discourse.julialang.org/t/how-does-juliadb-store-data-on-disk-is-it-a-row-store-or-a-column-store/10339 "2018-04-15T06:32:07Z")

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What is the storage format? By column store I mean Column-oriented DBMS - Wikipedia

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## [How to create a huge set of variables (500k or more) in JUMP](https://discourse.julialang.org/t/how-to-create-a-huge-set-of-variables-500k-or-more-in-jump/10325)

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**Author:** [@jayce\_ram](https://discourse.julialang.org/u/jayce_ram)\
**Replies:** 4\
**Last updated:** [April 15, 2018, 5:26am UTC](https://discourse.julialang.org/t/how-to-create-a-huge-set-of-variables-500k-or-more-in-jump/10325 "2018-04-15T05:26:45Z")

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Hello everybody, I’m completely new in Jump and I have a very large LP to solve. The number of variables depend of the input data. My variables are too nested, for example, for each given installation, there’s an associa…

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## [Is it possible to use "supertype" in function type declaration](https://discourse.julialang.org/t/is-it-possible-to-use-supertype-in-function-type-declaration/10320)

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**Author:** [@Fred](https://discourse.julialang.org/u/Fred)\
**Replies:** 9\
**Last updated:** [April 13, 2018, 12:38pm UTC](https://discourse.julialang.org/t/is-it-possible-to-use-supertype-in-function-type-declaration/10320 "2018-04-13T12:38:30Z")

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Hi, When I process strings in Julia, I have often a problem with the ::String type because sometime my function need a String and sometime a SubString{String} and I have this error no method matching processData(::Sub…

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## [MultiResolutionInterators.jl: Tools for working with data that has macro-scale hierachical structure, where you don't always care about some of the levels](https://discourse.julialang.org/t/multiresolutioninterators-jl-tools-for-working-with-data-that-has-macro-scale-hierachical-structure-where-you-dont-always-care-about-some-of-the-levels/10315)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 1\
**Last updated:** [April 13, 2018, 10:22am UTC](https://discourse.julialang.org/t/multiresolutioninterators-jl-tools-for-working-with-data-that-has-macro-scale-hierachical-structure-where-you-dont-always-care-about-some-of-the-levels/10315 "2018-04-13T10:22:23Z")

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I wanted to share this that I am working on right now. (Not yet registered) https://github.com/oxinabox/MultiResolutionIterators.jl I’m making it as a part in my reengineering of CorpusLoaders.jl. Basically a lot of …

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## [Newton optimization with Optim doing strange things](https://discourse.julialang.org/t/newton-optimization-with-optim-doing-strange-things/10008)

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**Author:** [@bdeonovic](https://discourse.julialang.org/u/bdeonovic)\
**Replies:** 36\
**Last updated:** [April 12, 2018, 7:46am UTC](https://discourse.julialang.org/t/newton-optimization-with-optim-doing-strange-things/10008 "2018-04-12T07:46:18Z")

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I’m having some issues with optimizing an objective with Newton from Optim. I started a brief discussion on slack which has led me to isolate the problem: Okay I am getting closer to the issue. So consider gradient and …

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## [Understanding GPU Kernels](https://discourse.julialang.org/t/understanding-gpu-kernels/10252)

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**Author:** [@jacobcvt12](https://discourse.julialang.org/u/jacobcvt12)\
**Replies:** 4\
**Last updated:** [April 10, 2018, 3:05pm UTC](https://discourse.julialang.org/t/understanding-gpu-kernels/10252 "2018-04-10T15:05:38Z")

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I’m trying understand the basics of GPU kernels for Julia. I’ve followed http://mikeinnes.github.io/2017/08/24/cudanative.html and the basic example for addition makes sense using CuArrays, CUDAnative n = 1024 xs, ys, …

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## [DataFrames & IJulia?](https://discourse.julialang.org/t/dataframes-ijulia/10118)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 9\
**Last updated:** [April 9, 2018, 6:35am UTC](https://discourse.julialang.org/t/dataframes-ijulia/10118 "2018-04-09T06:35:36Z")

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I have used pandas in Python to typeset a table in Jupyter notebook (standard Anaconda installation, nothing fancy). The data consisted in a simple list of dictionaries: using pandas, this resulted in a table with dictio…

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## [Support of \`rand(Complex{T})\`](https://discourse.julialang.org/t/support-of-rand-complex-t/10232)

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**Author:** [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)\
**Replies:** 3\
**Last updated:** [April 8, 2018, 5:37pm UTC](https://discourse.julialang.org/t/support-of-rand-complex-t/10232 "2018-04-08T17:37:40Z")

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I noticed that rand(Complex{Float64}) seems to have support in \\{z ~|~ 0 \\le \\textrm{Re}(z) \\le 1 ~ \\wedge ~ 0 \\le \\textrm{Im}(z) \\le 1\\}. I certainly understand why this happens from a computing perspective (it just ca…

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## [Optim.jl OnceDifferentiable Baby Steps](https://discourse.julialang.org/t/optim-jl-oncedifferentiable-baby-steps/10185)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 19\
**Last updated:** [April 8, 2018, 5:22pm UTC](https://discourse.julialang.org/t/optim-jl-oncedifferentiable-baby-steps/10185 "2018-04-08T17:22:52Z")

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Automatic differentiation seems a little like magic. ?OnceDifferentiable is not very informative. Experimenting with it, I want to see, e.g., what happens if my function uses abs(). As always, I want to start with …

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## [Is BioJulia team maintaining the IntervalTree package regularly?](https://discourse.julialang.org/t/is-biojulia-team-maintaining-the-intervaltree-package-regularly/10173)

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**Author:** [@sambitdash](https://discourse.julialang.org/u/sambitdash)\
**Replies:** 24\
**Last updated:** [April 7, 2018, 6:34pm UTC](https://discourse.julialang.org/t/is-biojulia-team-maintaining-the-intervaltree-package-regularly/10173 "2018-04-07T18:34:14Z")

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Hi BioJulia Team, Just wanted to check if this team is actively maintaining the IntervalTree package. I have raised a few issues and submitted a PR today. Will request quick turnaround or a time line when you can do so.…

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## [How to read a system of equations?](https://discourse.julialang.org/t/how-to-read-a-system-of-equations/10207)

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**Author:** [@tomj](https://discourse.julialang.org/u/tomj)\
**Replies:** 5\
**Last updated:** [April 7, 2018, 1:13pm UTC](https://discourse.julialang.org/t/how-to-read-a-system-of-equations/10207 "2018-04-07T13:13:13Z")

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Hello Julia users! I’m a beginner in Julia, and am currently blocked with the following problem. Imagine a system of equations like x(t) = c1 + c2\*x(t-1) + c3\*y(t-1) y(t) = c4 + c5\*y(t-1) + c6\*x(t-1) I would like t…

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## [GtkReactive: hooking functions to button press](https://discourse.julialang.org/t/gtkreactive-hooking-functions-to-button-press/10186)

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**Author:** [@stillyslalom](https://discourse.julialang.org/u/stillyslalom)\
**Replies:** 2\
**Last updated:** [April 6, 2018, 6:17pm UTC](https://discourse.julialang.org/t/gtkreactive-hooking-functions-to-button-press/10186 "2018-04-06T18:17:34Z")

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I’m trying to add a button to the image series display GUI from ImageView.jl that, when pressed, runs some series of functions. I’ve added the button, but (probably due to some reading comprehension failure) I haven’t ma…

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## [Quasi Maximum Likelihood implementation with Optim.jl](https://discourse.julialang.org/t/quasi-maximum-likelihood-implementation-with-optim-jl/9757)

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**Author:** [@AnttiSim](https://discourse.julialang.org/u/AnttiSim)\
**Replies:** 21\
**Last updated:** [April 6, 2018, 8:45am UTC](https://discourse.julialang.org/t/quasi-maximum-likelihood-implementation-with-optim-jl/9757 "2018-04-06T08:45:14Z")

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Hi, I am trying to implement a QML estimation problem with a system of censored equations. I am trying this with Julia’s Optim library. However, I have not been able to build a working model. I get an error message: Me…

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## [SAMIN Example in Optim.jl not working](https://discourse.julialang.org/t/samin-example-in-optim-jl-not-working/10187)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 6\
**Last updated:** [April 6, 2018, 8:35am UTC](https://discourse.julialang.org/t/samin-example-in-optim-jl-not-working/10187 "2018-04-06T08:35:53Z")

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From Simulated Annealing w/ bounds - Optim.jl julia\> using Optim, OptimTestProblems julia\> prob = OptimTestProblems.UnconstrainedProblems.examples\["Rosenbrock"\]; julia\> res = Optim.optimize(prob.f, prob.initial\_x, …

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## [JuMP NL Baby Steps](https://discourse.julialang.org/t/jump-nl-baby-steps/10168)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 4\
**Last updated:** [April 5, 2018, 4:50pm UTC](https://discourse.julialang.org/t/jump-nl-baby-steps/10168 "2018-04-05T16:50:15Z")

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I am now diving into another interesting Julia 0.6.2 area—non-linear non-quadratic (unconstrained) optimization with JuMP 0.18.1. The documentation is partly nice and easy, partly difficult. This is because the differe…

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## [Optim with occasionally non-finite values](https://discourse.julialang.org/t/optim-with-occasionally-non-finite-values/10174)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [April 5, 2018, 4:44pm UTC](https://discourse.julialang.org/t/optim-with-occasionally-non-finite-values/10174 "2018-04-05T16:44:33Z")

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I am maximizing a somewhat difficult likelihood function, for which the values are occasionally non-finite. I run into stack traces like ERROR: AssertionError: isfinite(phid) && isfinite(gphi) Stacktrace: \[1\] bisect!(:…

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## [Efficient IRLS](https://discourse.julialang.org/t/efficient-irls/9936)

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**Author:** [@Nosferican](https://discourse.julialang.org/u/Nosferican)\
**Replies:** 2\
**Last updated:** [April 4, 2018, 10:58pm UTC](https://discourse.julialang.org/t/efficient-irls/9936 "2018-04-04T22:58:27Z")

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I was inspecting GLM.jl IRLS implementation, but haven’t figured out from the code how many matrix decompositions it performs. For any given, A::AbstractMatrix{\<:Real}, b::AbstractVector{\<:Real}, and wts::AbstractWeight…

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## [Has anyone noticed numerical instability in Base.LinAlg.cholfact or Base.LinAlg.ishermitian?](https://discourse.julialang.org/t/has-anyone-noticed-numerical-instability-in-base-linalg-cholfact-or-base-linalg-ishermitian/10163)

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**Author:** [@krylea](https://discourse.julialang.org/u/krylea)\
**Replies:** 3\
**Last updated:** [April 4, 2018, 10:00pm UTC](https://discourse.julialang.org/t/has-anyone-noticed-numerical-instability-in-base-linalg-cholfact-or-base-linalg-ishermitian/10163 "2018-04-04T22:00:45Z")

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I have been using some stuff from Distributions.jl and ConjugatePriors.jl to (amongst other things) sample from a NormalWishart distribution. I am getting a whole bunch of problems that trace back to Base.LinAlg.ishermit…

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## [JuAFEM + ForwardDiff + NLsolve = Finite elements for nonlinear problems?](https://discourse.julialang.org/t/juafem-forwarddiff-nlsolve-finite-elements-for-nonlinear-problems/10085)

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**Author:** [@louisponet](https://discourse.julialang.org/u/louisponet)\
**Replies:** 53\
**Last updated:** [April 4, 2018, 9:56pm UTC](https://discourse.julialang.org/t/juafem-forwarddiff-nlsolve-finite-elements-for-nonlinear-problems/10085 "2018-04-04T21:56:42Z")

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Hi, I’m in the process of solving a Landau theory model concerning a crystal where strain and electric polarization are coupled. I’m trying to minimize the total free energy given by: F = Fl(P, α) + Fc(ε, C) + Fq(P, ε,…

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## [Get error when solving SDEs after last update](https://discourse.julialang.org/t/get-error-when-solving-sdes-after-last-update/10137)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 3\
**Last updated:** [April 4, 2018, 1:25pm UTC](https://discourse.julialang.org/t/get-error-when-solving-sdes-after-last-update/10137 "2018-04-04T13:25:54Z")

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I tried rerunning my code after the latest 4.2 update to the DifferentialEquations package. I use the reaction\_network DSL from DiffEqBiological package, from these I generate and solve SDEs with non-diagonal noise. Howe…

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## [nonlinear MPC example](https://discourse.julialang.org/t/nonlinear-mpc-example/10134)

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**Author:** [@Jelly](https://discourse.julialang.org/u/Jelly)\
**Replies:** 2\
**Last updated:** [April 4, 2018, 2:48am UTC](https://discourse.julialang.org/t/nonlinear-mpc-example/10134 "2018-04-04T02:48:58Z")

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hello ,every one! i 'm new here ,i am learning model predictive control and i want to know if there are any nonlinear MPC examples written in julia . If there is ,please let me know Thanks very much

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## [How to insert data into a field from a table using JuliaDb](https://discourse.julialang.org/t/how-to-insert-data-into-a-field-from-a-table-using-juliadb/10136)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 1\
**Last updated:** [April 4, 2018, 12:16am UTC](https://discourse.julialang.org/t/how-to-insert-data-into-a-field-from-a-table-using-juliadb/10136 "2018-04-04T00:16:47Z")

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How to insert data into a field from a table using JuliaDb?

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## [Best practice for data-parallel computation using DistributedArrays](https://discourse.julialang.org/t/best-practice-for-data-parallel-computation-using-distributedarrays/10078)

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**Author:** [@jinliangwei](https://discourse.julialang.org/u/jinliangwei)\
**Replies:** 1\
**Last updated:** [April 3, 2018, 7:46pm UTC](https://discourse.julialang.org/t/best-practice-for-data-parallel-computation-using-distributedarrays/10078 "2018-04-03T19:46:44Z")

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There is a popular programming paradigm in distributed ML training called data parallelism, which I will briefly describe below. What is the best way to program it using DistributedArray (or anything else that might be a…

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## [Wire plots](https://discourse.julialang.org/t/wire-plots/10100)

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**Author:** [@Anton\_Hinneck](https://discourse.julialang.org/u/Anton_Hinneck)\
**Replies:** 6\
**Last updated:** [April 2, 2018, 11:47am UTC](https://discourse.julialang.org/t/wire-plots/10100 "2018-04-02T11:47:28Z")

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Hi, I urgently needed a certain type of wire plot to visualize the weights of arcs between the nodes in a network. As I could not find any existing solution, I created an own package using Cairo: Hargreaves.jl. Is anybo…

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## [Data set size in DataFrames with Vector{T, Missing}](https://discourse.julialang.org/t/data-set-size-in-dataframes-with-vector-t-missing/10081)

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**Author:** [@mwsohn](https://discourse.julialang.org/u/mwsohn)\
**Replies:** 3\
**Last updated:** [April 1, 2018, 9:12pm UTC](https://discourse.julialang.org/t/data-set-size-in-dataframes-with-vector-t-missing/10081 "2018-04-01T21:12:34Z")

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I have recently moved to DataFrames 0.11 on Julia 0.6.2 and used StatFiles.jl with FileIO.jl to convert Stata datasets to DataFrames. I was astounded by the memory used by DataFrames. It seems to me that DataFrames requi…

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## [Parametrize JuMP problem for repeat evaluation?](https://discourse.julialang.org/t/parametrize-jump-problem-for-repeat-evaluation/10091)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 5\
**Last updated:** [April 1, 2018, 10:23am UTC](https://discourse.julialang.org/t/parametrize-jump-problem-for-repeat-evaluation/10091 "2018-04-01T10:23:53Z")

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Hi all, I have got at JuMP.jl problem. I have the following discrete optimization problem: using JuMP, Cbc function best\_bundle(;m=10,b=2) srand(1) # m = courses available k = 5 # courses to take price = coll…

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## [Avoiding high plotting densities when plotting Solutions to SDE with small time steps](https://discourse.julialang.org/t/avoiding-high-plotting-densities-when-plotting-solutions-to-sde-with-small-time-steps/9168)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 8\
**Last updated:** [April 1, 2018, 9:04am UTC](https://discourse.julialang.org/t/avoiding-high-plotting-densities-when-plotting-solutions-to-sde-with-small-time-steps/9168 "2018-04-01T09:04:37Z")

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I am looking at a biochemical reaction networks and how it behaves under noise. The code looks something like: gr() ... prob\_sde = SDEProblem(model,u0,(0.,1000.)) sol = solve(prob\_sde,ImplicitEM(),dt=1//2^(7),callback=c…

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## [Julia Bloggers web site - Your connection is not private!](https://discourse.julialang.org/t/julia-bloggers-web-site-your-connection-is-not-private/9982)

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**Author:** [@ArchieCall](https://discourse.julialang.org/u/ArchieCall)\
**Replies:** 7\
**Last updated:** [March 30, 2018, 8:04pm UTC](https://discourse.julialang.org/t/julia-bloggers-web-site-your-connection-is-not-private/9982 "2018-03-30T20:04:28Z")

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I noticed www.juliabloggers.com Leads to the following message: Your connection is not private. Attackers can steal information …

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