# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=543

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**Page:** 544

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## [KeyedTuple and inference](https://discourse.julialang.org/t/keyedtuple-and-inference/9059)

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**Author:** [@bramtayl](https://discourse.julialang.org/u/bramtayl)\
**Replies:** 12\
**Last updated:** [March 3, 2018, 6:17pm UTC](https://discourse.julialang.org/t/keyedtuple-and-inference/9059 "2018-03-03T18:17:36Z")

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I wonder if you’ve tried with the named tuple implementation in Keys.jl (v0.0.1, not master). That’s built on tuples.

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## [Packages & organisation for the Biometrics domain](https://discourse.julialang.org/t/packages-organisation-for-the-biometrics-domain/9454)

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**Author:** [@tibaes](https://discourse.julialang.org/u/tibaes)\
**Replies:** 2\
**Last updated:** [March 2, 2018, 2:39pm UTC](https://discourse.julialang.org/t/packages-organisation-for-the-biometrics-domain/9454 "2018-03-02T14:39:52Z")

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Hi there, I am developing a new organisation and a set of packages for Biometrics algorithms: https://github.com/JuliaBiometrics I would really appreciate the help of the community for: documentation, code review, uni…

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## [Online/out-of-core machine learning (ML) algorithms needs to compete with H20 & Spark](https://discourse.julialang.org/t/online-out-of-core-machine-learning-ml-algorithms-needs-to-compete-with-h20-spark/9382)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 13\
**Last updated:** [March 1, 2018, 7:05pm UTC](https://discourse.julialang.org/t/online-out-of-core-machine-learning-ml-algorithms-needs-to-compete-with-h20-spark/9382 "2018-03-01T19:05:53Z")

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I was just thinking about what is needed in Julia in order for it to compete with H20 and Spark and be a serious contender in enterprise ML. I think JuliaDB.jl can handle the data manipulation aspects and OnlineStats.jl…

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## [Field as Variable in Query.jl](https://discourse.julialang.org/t/field-as-variable-in-query-jl/9365)

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**Author:** [@RobertR](https://discourse.julialang.org/u/RobertR)\
**Replies:** 5\
**Last updated:** [March 1, 2018, 9:28am UTC](https://discourse.julialang.org/t/field-as-variable-in-query-jl/9365 "2018-03-01T09:28:54Z")

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I’m a bit confused about why something (admittedly stupid) I was trying to do didn’t work. Using Query.jl you can write something like: x = @from i in df begin @where i.age\>50 @select {i.name, i.children} @…

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## [Saving Differential Equations Solutions to disk](https://discourse.julialang.org/t/saving-differential-equations-solutions-to-disk/9387)

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**Author:** [@FHell](https://discourse.julialang.org/u/FHell)\
**Replies:** 3\
**Last updated:** [February 28, 2018, 2:05pm UTC](https://discourse.julialang.org/t/saving-differential-equations-solutions-to-disk/9387 "2018-02-28T14:05:55Z")

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Hi everyone, I want to generate an ensemble of Solutions to a differential equation to later study more in depth, so I want to save it to disk (keeping it simple: one file per simulation. Each solution is about 100Mb). …

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## [Browser side memory leaks using InteractNext.jl](https://discourse.julialang.org/t/browser-side-memory-leaks-using-interactnext-jl/9170)

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**Author:** [@jwikmark](https://discourse.julialang.org/u/jwikmark)\
**Replies:** 3\
**Last updated:** [February 27, 2018, 7:32pm UTC](https://discourse.julialang.org/t/browser-side-memory-leaks-using-interactnext-jl/9170 "2018-02-27T19:32:09Z")

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Hello, I’m having an issue with browser side memory leaks when using the InteractNext.jl (https://github.com/JuliaGizmos/InteractNext.jl) package. Running the svg example (the first example in the readme) and serving it …

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## [Lufact SparseMatrixCSC Int32](https://discourse.julialang.org/t/lufact-sparsematrixcsc-int32/6784)

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**Author:** [@lkskstlr](https://discourse.julialang.org/u/lkskstlr)\
**Replies:** 9\
**Last updated:** [February 27, 2018, 6:03pm UTC](https://discourse.julialang.org/t/lufact-sparsematrixcsc-int32/6784 "2018-02-27T18:03:28Z")

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Hi everyone, I am very new to Julia, so please let me know if there is info in the documentation that would have avoided the issue. I use the following version: Julia Version 0.6.1 Commit 0d7248e (2017-10-24 22:15 UTC)…

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## [Can't create animations](https://discourse.julialang.org/t/cant-create-animations/9363)

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**Author:** [@Robert\_Toth](https://discourse.julialang.org/u/Robert_Toth)\
**Replies:** 3\
**Last updated:** [February 27, 2018, 11:43am UTC](https://discourse.julialang.org/t/cant-create-animations/9363 "2018-02-27T11:43:25Z")

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Hi guys, when I try the code from home page of plots: initialize the attractor n = 1500 dt = 0.02 σ, ρ, β = 10., 28., 8/3 x, y, z = 1., 1., 1. initialize a 3D plot with 1 empty series plt = path3d(1, xlim=(-25,25), …

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## [Data Frames for non null data](https://discourse.julialang.org/t/data-frames-for-non-null-data/9266)

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**Author:** [@Jupiterjosh](https://discourse.julialang.org/u/Jupiterjosh)\
**Replies:** 4\
**Last updated:** [February 23, 2018, 8:13pm UTC](https://discourse.julialang.org/t/data-frames-for-non-null-data/9266 "2018-02-23T20:13:36Z")

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Is there a “dataframes” for data that you know will not be null? I have used both datatables and dataframes and like their syntactic sugar, but I find myself fussing with nullable arrays or missing.missing issues too mu…

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## [Parallel starting from array of JuMP models](https://discourse.julialang.org/t/parallel-starting-from-array-of-jump-models/9297)

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**Author:** [@bbrunaud](https://discourse.julialang.org/u/bbrunaud)\
**Replies:** 1\
**Last updated:** [February 24, 2018, 7:01pm UTC](https://discourse.julialang.org/t/parallel-starting-from-array-of-jump-models/9297 "2018-02-24T19:01:19Z")

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Hello, I am writing an algorithm that receives an array of JuMP models that need to be solved in parallel. I’ve read the recommendations on this forum to just send the data to the worker to build and solve the model. Ho…

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## [Use Ipopt with custom version](https://discourse.julialang.org/t/use-ipopt-with-custom-version/9176)

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**Author:** [@TPDS1993](https://discourse.julialang.org/u/TPDS1993)\
**Replies:** 3\
**Last updated:** [February 24, 2018, 5:01pm UTC](https://discourse.julialang.org/t/use-ipopt-with-custom-version/9176 "2018-02-24T17:01:04Z")

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Hi, I wanted to point Ipopt to a custom version that I installed with other linear solvers, can someone help me achieve that? Thanks in advance.

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## [CSDP.jl in Linux](https://discourse.julialang.org/t/csdp-jl-in-linux/9205)

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**Author:** [@MarioSouto](https://discourse.julialang.org/u/MarioSouto)\
**Replies:** 2\
**Last updated:** [February 23, 2018, 4:58pm UTC](https://discourse.julialang.org/t/csdp-jl-in-linux/9205 "2018-02-23T16:58:55Z")

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Dear all, I’m having some trouble to install the CSDP.jl package in a Linux machine. I already have the CSDP solver installed but I want to use it within the JuMP framework. When I try to build the package I’m getting t…

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## [Package for deseasonalizing](https://discourse.julialang.org/t/package-for-deseasonalizing/9275)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [February 23, 2018, 12:49pm UTC](https://discourse.julialang.org/t/package-for-deseasonalizing/9275 "2018-02-23T12:49:19Z")

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Is there a Julia package that has some functionality for deseasonalizing time series data (eg monthly)? I can implement a naive approach (regress, remove) very quickly, looking for something more sophisticated. If there…

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## [Buglet in PDF installation deletion request notice](https://discourse.julialang.org/t/buglet-in-pdf-installation-deletion-request-notice/9243)

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**Author:** [@ivo\_welch](https://discourse.julialang.org/u/ivo_welch)\
**Replies:** 2\
**Last updated:** [February 22, 2018, 7:50am UTC](https://discourse.julialang.org/t/buglet-in-pdf-installation-deletion-request-notice/9243 "2018-02-22T07:50:50Z")

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JuliaPro 0.6.2.1 julia\> draw(PDF("loess.pdf", 3inch, 1.5inch), p) ERROR: Cairo and Fontconfig are necessary for the PDF backend. Run: Pkg.add("Cairo") Pkg.add("Fontconfig") You also have to delete /Applications/Jul…

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## [\[JuMP\] Defining Ordinal Parameters](https://discourse.julialang.org/t/jump-defining-ordinal-parameters/9207)

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**Author:** [@shoshievass](https://discourse.julialang.org/u/shoshievass)\
**Replies:** 2\
**Last updated:** [February 21, 2018, 3:47pm UTC](https://discourse.julialang.org/t/jump-defining-ordinal-parameters/9207 "2018-02-21T15:47:12Z")

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I would like to define a JuMP optimization program with a vector of variables x that is ordered, i.e. x\[1\] \< x\[2\] \< x\[3\] .... Is there any elegant way to do this in lieu of manually adding constraints for every pair of e…

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## [\`isposdef\` inconsistent results, numerically unstable?](https://discourse.julialang.org/t/isposdef-inconsistent-results-numerically-unstable/9013)

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**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 54\
**Last updated:** [February 21, 2018, 9:34am UTC](https://discourse.julialang.org/t/isposdef-inconsistent-results-numerically-unstable/9013 "2018-02-21T09:34:06Z")

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I am checking here before opening an issue. https://www.dropbox.com/s/qgefu7t85rcr7xe/posdef\_symm\_sparse\_matrix.jld?dl=0 Using the above jld file holding a symmetric matrix A, the following results are very weird: jul…

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## [How to permute the rows of a DataFrame in-place efficiently?](https://discourse.julialang.org/t/how-to-permute-the-rows-of-a-dataframe-in-place-efficiently/8825)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 11\
**Last updated:** [February 20, 2018, 11:29pm UTC](https://discourse.julialang.org/t/how-to-permute-the-rows-of-a-dataframe-in-place-efficiently/8825 "2018-02-20T23:29:27Z")

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I have a vector of row numbers and I want to use it to permute a DataFrame’s rows. Here is an MVE using StatsBase df = DataFrame(a = rand(1\_000\_000)) r=sample(1:size(df,1), size(df,1), replace=false) @time df = df\[r,:\]…

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## [Controlsystem.jl : how to mix continuous and discrete time transfer functions](https://discourse.julialang.org/t/controlsystem-jl-how-to-mix-continuous-and-discrete-time-transfer-functions/8894)

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**Author:** [@bo-lo](https://discourse.julialang.org/u/bo-lo)\
**Replies:** 4\
**Last updated:** [February 20, 2018, 11:28pm UTC](https://discourse.julialang.org/t/controlsystem-jl-how-to-mix-continuous-and-discrete-time-transfer-functions/8894 "2018-02-20T23:28:33Z")

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I am using Julia 0.5.2 I am modeling a continuous time RLC circuit in the s domain. I am modeling a digital controller in the z domain. I tried multiplying the 2 transfer functions together to get the open loop transfe…

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## [How to read a table with missing values using CSV?](https://discourse.julialang.org/t/how-to-read-a-table-with-missing-values-using-csv/7556)

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**Author:** [@Fred](https://discourse.julialang.org/u/Fred)\
**Replies:** 9\
**Last updated:** [February 20, 2018, 4:16pm UTC](https://discourse.julialang.org/t/how-to-read-a-table-with-missing-values-using-csv/7556 "2018-02-20T16:16:35Z")

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Hi, I read a table where some values are missing using : f = CSV.read(“data/$file”) When the missing values is ‘NA’ in the table, I obtain : ERROR: CSV.ParsingException(“error parsing a Float64 value on column 27, ro…

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## [Fill!() vs for loop](https://discourse.julialang.org/t/fill-vs-for-loop/9194)

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**Author:** [@abshej](https://discourse.julialang.org/u/abshej)\
**Replies:** 15\
**Last updated:** [February 20, 2018, 10:56am UTC](https://discourse.julialang.org/t/fill-vs-for-loop/9194 "2018-02-20T10:56:58Z")

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Technically there shouldnt be a difference between using fill! to make every element of a matrix a SMCSC and using a for loop to do so. But using fill!() messes up code. As in it seems like two copies are being made som…

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## [Running JuMP using Ipopt in Parallel](https://discourse.julialang.org/t/running-jump-using-ipopt-in-parallel/9167)

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**Author:** [@huckl3b3rry87](https://discourse.julialang.org/u/huckl3b3rry87)\
**Replies:** 13\
**Last updated:** [February 19, 2018, 10:28pm UTC](https://discourse.julialang.org/t/running-jump-using-ipopt-in-parallel/9167 "2018-02-19T22:28:27Z")

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I am trying to run several different JuMP models at once in parallel and I have a MWE, and was curious if anyone has any suggestions or thoughts on what I am doing. A serial approach (where only a single type of model is…

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## [Weird bug when plotting step function](https://discourse.julialang.org/t/weird-bug-when-plotting-step-function/9172)

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**Author:** [@j2b2](https://discourse.julialang.org/u/j2b2)\
**Replies:** 7\
**Last updated:** [February 19, 2018, 5:40pm UTC](https://discourse.julialang.org/t/weird-bug-when-plotting-step-function/9172 "2018-02-19T17:40:09Z")

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First I define two step functions: julia\> f(x)=floor(5x)-floor(2x)-floor(3x) f (generic function with 1 method) julia\> g(x)=f(2x)-f(x) g (generic function with 1 method) and then I plot g: julia\> using Plots julia\> gr…

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## [Loess -- Gadfly -- SVG/PDF "False" Error](https://discourse.julialang.org/t/loess-gadfly-svg-pdf-false-error/9151)

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**Author:** [@ivo\_welch](https://discourse.julialang.org/u/ivo_welch)\
**Replies:** 0\
**Last updated:** [February 18, 2018, 11:46pm UTC](https://discourse.julialang.org/t/loess-gadfly-svg-pdf-false-error/9151 "2018-02-18T23:46:29Z")

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Dear Julia Experts— on macOS, julia 0.6.2, Feb 2018: using Loess xs = 10 .\* rand(100); ys = sin(xs) .+ 0.5 \* rand(100); model = loess(xs, ys); us = collect(minimum(xs):0.1:maximum(xs)) vs = predict(model, us) using Gad…

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## [0.6.2 Histograms and Finding Good Packages For Plotting](https://discourse.julialang.org/t/0-6-2-histograms-and-finding-good-packages-for-plotting/9099)

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**Author:** [@ivo\_welch](https://discourse.julialang.org/u/ivo_welch)\
**Replies:** 13\
**Last updated:** [February 18, 2018, 9:43pm UTC](https://discourse.julialang.org/t/0-6-2-histograms-and-finding-good-packages-for-plotting/9099 "2018-02-18T21:43:05Z")

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dear julia experts—I am running into some issues with plotting simple histograms, as of mid-Feb 2018, julia 0.6.2, macOS. Yes, I did RTFMs. For example, I added Pkg.add("PyPlot"). Then I did 'using PyPlot, which led t…

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## [Product of univariate distributions](https://discourse.julialang.org/t/product-of-univariate-distributions/1350)

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**Author:** [@nbren12](https://discourse.julialang.org/u/nbren12)\
**Replies:** 13\
**Last updated:** [February 18, 2018, 6:27pm UTC](https://discourse.julialang.org/t/product-of-univariate-distributions/1350 "2018-02-18T18:27:27Z")

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In Distributions.jl is it possible to create a cartesian product distribution, given two univariate random variables? I want to do this to make a multivariate uniform distribution supported over \[0,1\]\\times\[0,1\]

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## [Jg-plot\_v0.1 / simple julia - webGl passthrough](https://discourse.julialang.org/t/jg-plot-v0-1-simple-julia-webgl-passthrough/8768)

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**Author:** [@y4lu](https://discourse.julialang.org/u/y4lu)\
**Replies:** 8\
**Last updated:** [February 17, 2018, 10:35am UTC](https://discourse.julialang.org/t/jg-plot-v0-1-simple-julia-webgl-passthrough/8768 "2018-02-17T10:35:44Z")

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It’s pretty basic currently, just does 2d plots, but the potential is there for 3d animation etc size is 8Kb, most of which is the html / js / glsl getup https://nofile.io/f/Fzs8RKOa5Rx/jg\_plot.jl basic usage: jg\_plot…

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## [Performing multiple melt/stack operations on a dataset simultaneously](https://discourse.julialang.org/t/performing-multiple-melt-stack-operations-on-a-dataset-simultaneously/8947)

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**Author:** [@Raf](https://discourse.julialang.org/u/Raf)\
**Replies:** 5\
**Last updated:** [February 16, 2018, 9:18am UTC](https://discourse.julialang.org/t/performing-multiple-melt-stack-operations-on-a-dataset-simultaneously/8947 "2018-02-16T09:18:54Z")

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I’m importing some R data so decided to learn DataFrames manipulation in julia instead of doing it in R. I have a wide dataframe with some initial columns followed by four variables that span 12 columns, one for each mon…

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## [JuMP interface access to automatic differentiation (ReverseDiffSparse)](https://discourse.julialang.org/t/jump-interface-access-to-automatic-differentiation-reversediffsparse/8354)

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**Author:** [@jacob-roth](https://discourse.julialang.org/u/jacob-roth)\
**Replies:** 5\
**Last updated:** [February 15, 2018, 2:18am UTC](https://discourse.julialang.org/t/jump-interface-access-to-automatic-differentiation-reversediffsparse/8354 "2018-02-15T02:18:53Z")

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I’m trying to use ReverseDiffSparse to return the gradient and Hessian of a scalar valued function f. I only need to evaluate the gradient and Hessian (i.e., I don’t need to set up a whole model). I saw from the JuMP Doc…

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## [JuMP, excessive memory usage?](https://discourse.julialang.org/t/jump-excessive-memory-usage/1057)

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**Author:** [@mauro](https://discourse.julialang.org/u/mauro)\
**Replies:** 16\
**Last updated:** [February 14, 2018, 9:12pm UTC](https://discourse.julialang.org/t/jump-excessive-memory-usage/1057 "2018-02-14T21:12:02Z")

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Hi all, I have a question about the memory requirements of the following toy example, which is a simplified versions of my real problem: using JuMP using Ipopt N = 29 p1 = rand(N+1,N+1,N+1) p2 = rand(N+1,N+1,N+1) p…

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## [\[ANN\] JuMP now supports OSQP](https://discourse.julialang.org/t/ann-jump-now-supports-osqp/9068)

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**Author:** [@bstellato](https://discourse.julialang.org/u/bstellato)\
**Replies:** 0\
**Last updated:** [February 14, 2018, 8:11pm UTC](https://discourse.julialang.org/t/ann-jump-now-supports-osqp/9068 "2018-02-14T20:11:27Z")

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Hi Julia optimizers! We have just added JuMP support to the latest OSQP.jl Julia interface. For those who do not know it, OSQP is a new efficient first-order QP solver based on ADMM. You can find some benchmarks agains…

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