# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=502

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**Page:** 503

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## [Using RCall](https://discourse.julialang.org/t/using-rcall/22714)

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**Author:** [@Gunter\_Faes](https://discourse.julialang.org/u/Gunter_Faes)\
**Replies:** 7\
**Last updated:** [April 4, 2019, 11:37am UTC](https://discourse.julialang.org/t/using-rcall/22714 "2019-04-04T11:37:58Z")

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Hello, I’m still trying to solve my PCA problem, so I’m trying to use R over RCall. The package can be installed, but after using RCall, R reports up, but gets stuck! That is, nothing happens more…! The behavior applies…

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## [\`back!\` was already used error in Flux](https://discourse.julialang.org/t/back-was-already-used-error-in-flux/22709)

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**Author:** [@Dipak\_Narayan](https://discourse.julialang.org/u/Dipak_Narayan)\
**Replies:** 0\
**Last updated:** [April 3, 2019, 5:45pm UTC](https://discourse.julialang.org/t/back-was-already-used-error-in-flux/22709 "2019-04-03T17:45:18Z")

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What I’m trying to do is pass a linear combination of images (lets say a1img1 + a2img2 + a3\*img3) through a neural network and I want the network to choose the best a1, a2, a3 for classification. To do this I’ve made a …

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## [State of GIS package ecosystem?](https://discourse.julialang.org/t/state-of-gis-package-ecosystem/21864)

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**Author:** [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Replies:** 11\
**Last updated:** [April 3, 2019, 11:39am UTC](https://discourse.julialang.org/t/state-of-gis-package-ecosystem/21864 "2019-04-03T11:39:17Z")

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I’m looking to move as much of my workflow as I can into julia from R/Python, and was hoping to get a sense of what the Julia GIS ecosystem looks like (especially for vector data). Has Julia developed anything like sp i…

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## [Help with hyper-stiff ODE system](https://discourse.julialang.org/t/help-with-hyper-stiff-ode-system/22681)

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**Author:** [@jcook](https://discourse.julialang.org/u/jcook)\
**Replies:** 2\
**Last updated:** [April 3, 2019, 10:22am UTC](https://discourse.julialang.org/t/help-with-hyper-stiff-ode-system/22681 "2019-04-03T10:22:19Z")

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Dear All, I’ve come against a pretty tricky problem that I can’t find an accurate and performant solution to in Julia. There is a closed source FORTRAN code that can solve this problem quickly and accurately. So at leas…

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## [PCA not working](https://discourse.julialang.org/t/pca-not-working/22645)

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**Author:** [@Gunter\_Faes](https://discourse.julialang.org/u/Gunter_Faes)\
**Replies:** 13\
**Last updated:** [April 3, 2019, 8:38am UTC](https://discourse.julialang.org/t/pca-not-working/22645 "2019-04-03T08:38:34Z")

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Hello, I’m working on the PCA from the MultivariateStats package and get the following error message (I’m working with ATOM): julia\> PCA\_Modell = fit(PCA, PCA\_Daten) ERROR: MethodError: no method matching fit(::Type{PC…

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## [Any good OpenCL examples to demonstrate a speedup?](https://discourse.julialang.org/t/any-good-opencl-examples-to-demonstrate-a-speedup/22656)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 4\
**Last updated:** [April 3, 2019, 5:44am UTC](https://discourse.julialang.org/t/any-good-opencl-examples-to-demonstrate-a-speedup/22656 "2019-04-03T05:44:50Z")

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I am taking my first steps trying to use Julia with GPUs, even though all I have available in my machine is a humble integrated Intel chip (UHD Graphics 620). I was pretty stoked to manage to run the CLBlast.jl example, …

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## [Updating lazy kronecker products](https://discourse.julialang.org/t/updating-lazy-kronecker-products/22650)

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**Author:** [@eliassno](https://discourse.julialang.org/u/eliassno)\
**Replies:** 4\
**Last updated:** [April 3, 2019, 1:22am UTC](https://discourse.julialang.org/t/updating-lazy-kronecker-products/22650 "2019-04-03T01:22:27Z")

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I need to calculate something of the form: where are dense matrices, are diagonal, is the identity matrix and is an arbitrary scalar function. The following code creates all the variations of Kronecker product…

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## [Memory blow-up when passing DataFrame to function inside @threads loop](https://discourse.julialang.org/t/memory-blow-up-when-passing-dataframe-to-function-inside-threads-loop/22643)

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**Author:** [@ruthmarx1](https://discourse.julialang.org/u/ruthmarx1)\
**Replies:** 1\
**Last updated:** [April 2, 2019, 5:06pm UTC](https://discourse.julialang.org/t/memory-blow-up-when-passing-dataframe-to-function-inside-threads-loop/22643 "2019-04-02T17:06:15Z")

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When I run the code below, the memory usage blows up: function func(df::DataFrame) X = df\[:time\] indices = findall(X .\> 0) end # read in R data rds = "blablab.rds" objs = load(rds); params = collect(0.5:0.005:…

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## [Problem with an observable array of varying length in Makie.jl](https://discourse.julialang.org/t/problem-with-an-observable-array-of-varying-length-in-makie-jl/22638)

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**Author:** [@skarp](https://discourse.julialang.org/u/skarp)\
**Replies:** 3\
**Last updated:** [April 2, 2019, 4:08pm UTC](https://discourse.julialang.org/t/problem-with-an-observable-array-of-varying-length-in-makie-jl/22638 "2019-04-02T16:08:11Z")

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Hello. I am facing a problem with Observables (of varying length) in Makie.jl. The problem can be summarised to the following minimal example: using Makie #AbstractPlotting.inline!(true) # Uncomment if using Atom and J…

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## [Error with Openpyxl: Pyimport is not in current path](https://discourse.julialang.org/t/error-with-openpyxl-pyimport-is-not-in-current-path/22460)

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**Author:** [@Rajat\_Sanyal](https://discourse.julialang.org/u/Rajat_Sanyal)\
**Replies:** 14\
**Last updated:** [April 2, 2019, 11:01am UTC](https://discourse.julialang.org/t/error-with-openpyxl-pyimport-is-not-in-current-path/22460 "2019-04-02T11:01:27Z")

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I am looking for a package which can read and write an excel file cell by cell. I know openpyxl do the job. Is there any other better package in Julia which does the same job? Now, I am trying to install it, so I used t…

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## [Is it possible to make \`Normal(mu, sigma)\` work for when \`mu\` and \`sigma\` are tracked arrays?](https://discourse.julialang.org/t/is-it-possible-to-make-normal-mu-sigma-work-for-when-mu-and-sigma-are-tracked-arrays/22616)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 0\
**Last updated:** [April 1, 2019, 11:11pm UTC](https://discourse.julialang.org/t/is-it-possible-to-make-normal-mu-sigma-work-for-when-mu-and-sigma-are-tracked-arrays/22616 "2019-04-01T23:11:45Z")

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I am trying to make some code where the parameters defined the distribution. This is done in variational auto-encoders (VAE). But I am doing something simpler, I am just trying to implement a maximum likelihood estimator…

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## [Flux params() not working for composed layers](https://discourse.julialang.org/t/flux-params-not-working-for-composed-layers/22480)

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**Author:** [@aldopareja](https://discourse.julialang.org/u/aldopareja)\
**Replies:** 2\
**Last updated:** [April 1, 2019, 6:08pm UTC](https://discourse.julialang.org/t/flux-params-not-working-for-composed-layers/22480 "2019-04-01T18:08:24Z")

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I’m trying to create a multi-headed attention layer, which is composed several “heads”. Each head has its own parameters (three matrices) and the “wrapper” layer has one output parameter (matrix). This is the code to do …

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## [Does Bio support EMBL and/or IMGT/HLA format ?](https://discourse.julialang.org/t/does-bio-support-embl-and-or-imgt-hla-format/22541)

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**Author:** [@zimoun](https://discourse.julialang.org/u/zimoun)\
**Replies:** 7\
**Last updated:** [April 1, 2019, 5:03pm UTC](https://discourse.julialang.org/t/does-bio-support-embl-and-or-imgt-hla-format/22541 "2019-04-01T17:03:28Z")

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Dear, I am not able to find in the doc if the metapackage Bio supports the format EMBL and/or the specific one about HLA database \[1\] (hla.dat). The wiki \[2\] mentions EMBL but is it accurate ? Thank you in advance for…

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## [Is there a better DSL (domain-specific language) for defining a formula in linear models?](https://discourse.julialang.org/t/is-there-a-better-dsl-domain-specific-language-for-defining-a-formula-in-linear-models/22555)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 5\
**Last updated:** [April 1, 2019, 9:22am UTC](https://discourse.julialang.org/t/is-there-a-better-dsl-domain-specific-language-for-defining-a-formula-in-linear-models/22555 "2019-04-01T09:22:17Z")

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I have been an R user and I can see where StatsModel’s @formula macro came from - R! @formula(x ~ y - 1) where the -1 is to fit without an intercept was unintuitive to me, and also a\*b is the same as a + b + a&b i.e. in…

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## [Getting Gap and #Nodes in JuMP v0.19](https://discourse.julialang.org/t/getting-gap-and-nodes-in-jump-v0-19/22566)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 4\
**Last updated:** [March 31, 2019, 9:12pm UTC](https://discourse.julialang.org/t/getting-gap-and-nodes-in-jump-v0-19/22566 "2019-03-31T21:12:11Z")

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Dear users, I have tried to use the command GAP = MOI.get(model, MOI.RelativeGap()) Nodes = MOI.get(modelo, MOI.NodeCount()) to obtain the relative GAP of my solution. Some colleagues in this group helped me, but thi…

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## [Query Solution Time](https://discourse.julialang.org/t/query-solution-time/22263)

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**Author:** [@octavia9](https://discourse.julialang.org/u/octavia9)\
**Replies:** 9\
**Last updated:** [March 31, 2019, 9:09pm UTC](https://discourse.julialang.org/t/query-solution-time/22263 "2019-03-31T21:09:28Z")

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Hello, I am very new to Julia and JuMP. I am using CPLEX 12.8 together with my optimization problem. Instead of using self-defined time function to capture the total time spent in the optimization process, is there a d…

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## [Optimizing parameters of ODE in DiffEqFlux: Not implemented: convert tracked Tracker.TrackedReal{Float64} to tracked Float64](https://discourse.julialang.org/t/optimizing-parameters-of-ode-in-diffeqflux-not-implemented-convert-tracked-tracker-trackedreal-float64-to-tracked-float64/22560)

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**Author:** [@mzhenirovskyy](https://discourse.julialang.org/u/mzhenirovskyy)\
**Replies:** 4\
**Last updated:** [March 31, 2019, 8:33pm UTC](https://discourse.julialang.org/t/optimizing-parameters-of-ode-in-diffeqflux-not-implemented-convert-tracked-tracker-trackedreal-float64-to-tracked-float64/22560 "2019-03-31T20:33:58Z")

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My model: using Random using Flux, DiffEqFlux, DifferentialEquations function model(dZ, Z, params, t) W0 = reshape(params\[1:12\], (1, 12)) b0 = reshape(params\[13:24\], (1, 12)) W1 = reshape(params\[25:36\], (1…

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## [Plots.jl add colorbar when plotting Shape](https://discourse.julialang.org/t/plots-jl-add-colorbar-when-plotting-shape/22544)

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**Author:** [@andferrari](https://discourse.julialang.org/u/andferrari)\
**Replies:** 4\
**Last updated:** [March 31, 2019, 6:10pm UTC](https://discourse.julialang.org/t/plots-jl-add-colorbar-when-plotting-shape/22544 "2019-03-31T18:10:03Z")

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I am plotting in the same plot multiple Shape(), each with a different fill color. How can I add a colorbar for these colors to the plot ?

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## [GAP and CPUTime in JuMP v0.19](https://discourse.julialang.org/t/gap-and-cputime-in-jump-v0-19/22521)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 5\
**Last updated:** [March 31, 2019, 5:29pm UTC](https://discourse.julialang.org/t/gap-and-cputime-in-jump-v0-19/22521 "2019-03-31T17:29:39Z")

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Dear users, I begin to use the JuMP v0.19 today. Some functions in previous versions were implemented, for example getobjvalue(model) and getsolvetime(model). But, this commands are not working in this version! Pleas…

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## [Flux.jl: Different set of optimisation parameters per layer](https://discourse.julialang.org/t/flux-jl-different-set-of-optimisation-parameters-per-layer/22518)

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**Author:** [@rederekt](https://discourse.julialang.org/u/rederekt)\
**Replies:** 1\
**Last updated:** [March 30, 2019, 8:59pm UTC](https://discourse.julialang.org/t/flux-jl-different-set-of-optimisation-parameters-per-layer/22518 "2019-03-30T20:59:49Z")

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Hi, Just copying over my question from the GitHub issues to hopefully get more visibility here. In Flux.jl, I’d like to use a separate set of optimisation parameters for each hidden layer in a single Chain. For example…

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## [Flux.jl: Changing the value of activations from hidden nodes during backprop](https://discourse.julialang.org/t/flux-jl-changing-the-value-of-activations-from-hidden-nodes-during-backprop/22525)

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**Author:** [@v-i-s-h](https://discourse.julialang.org/u/v-i-s-h)\
**Replies:** 0\
**Last updated:** [March 30, 2019, 3:46am UTC](https://discourse.julialang.org/t/flux-jl-changing-the-value-of-activations-from-hidden-nodes-during-backprop/22525 "2019-03-30T03:46:00Z")

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Hi, I have a research project where I want to change the value of activations during backpropagation. It works like this: First I do the forward pass the traditional way and compute node activations at all layers. Then …

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## [Neural ODE in DiffEqFlux that is not a time series](https://discourse.julialang.org/t/neural-ode-in-diffeqflux-that-is-not-a-time-series/22395)

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**Author:** [@JackDevine](https://discourse.julialang.org/u/JackDevine)\
**Replies:** 6\
**Last updated:** [March 30, 2019, 12:07am UTC](https://discourse.julialang.org/t/neural-ode-in-diffeqflux-that-is-not-a-time-series/22395 "2019-03-30T00:07:16Z")

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I am trying to use DiffEqFlux.jl to make a model that takes in a vector of length 200 and passes it through a neural ODE layer to output a vector of length 200. I tried to do so by tweaking the time series example in th…

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## [Flux.jl Training loop where data sequentially depends on model output](https://discourse.julialang.org/t/flux-jl-training-loop-where-data-sequentially-depends-on-model-output/22510)

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**Author:** [@Ares\_Fisher](https://discourse.julialang.org/u/Ares_Fisher)\
**Replies:** 1\
**Last updated:** [March 29, 2019, 7:22pm UTC](https://discourse.julialang.org/t/flux-jl-training-loop-where-data-sequentially-depends-on-model-output/22510 "2019-03-29T19:22:54Z")

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Hey all! I’m interested in writing some “closed loop” generative models that receive their prediction error for the previous input as their next input. Is there a way to do this in Flux.jl’s Train! loop? Thanks!

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## [Infeasible integer - solution CPLEX](https://discourse.julialang.org/t/infeasible-integer-solution-cplex/22502)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 5\
**Last updated:** [March 29, 2019, 6:57pm UTC](https://discourse.julialang.org/t/infeasible-integer-solution-cplex/22502 "2019-03-29T18:57:34Z")

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Hello Julia’s users, I have a little question. I am solving a complex integer problem using CPLEX. Many times, a long computation time does not provide an integer feasible solution. If I limit the CPU time (for exampl…

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## [Flux parallel execution](https://discourse.julialang.org/t/flux-parallel-execution/12931)

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**Author:** [@kkmann](https://discourse.julialang.org/u/kkmann)\
**Replies:** 3\
**Last updated:** [March 29, 2019, 3:48pm UTC](https://discourse.julialang.org/t/flux-parallel-execution/12931 "2019-03-29T15:48:33Z")

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Hi, so, this might be a very dumb question but how do I train model in flux.jl in parallel on my cpu?

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## [Pardiso linear solver with Ipopt](https://discourse.julialang.org/t/pardiso-linear-solver-with-ipopt/6417)

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**Author:** [@JackDevine](https://discourse.julialang.org/u/JackDevine)\
**Replies:** 6\
**Last updated:** [March 29, 2019, 2:52pm UTC](https://discourse.julialang.org/t/pardiso-linear-solver-with-ipopt/6417 "2019-03-29T14:52:27Z")

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I have installed Pardiso 5.0 and I have gotten it to work with Pardiso.jl by following the instructions in the README. When I try getting Ipopt.jl to work with PARDISO by following the steps in this issue, I run into pro…

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## [\[ANN\] SatelliteToolbox.jl v0.6.0](https://discourse.julialang.org/t/ann-satellitetoolbox-jl-v0-6-0/22287)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 1\
**Last updated:** [March 29, 2019, 1:38pm UTC](https://discourse.julialang.org/t/ann-satellitetoolbox-jl-v0-6-0/22287 "2019-03-29T13:38:21Z")

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Hi guys! We now have a new version of SatelliteToolbox.jl. The most important things are: Support for the entire IAU-2006/2010 theory (CIO approach); Support for state vectors, including conversion between all support…

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## [I succeeded to porting the POC with Julia.](https://discourse.julialang.org/t/i-succeeded-to-porting-the-poc-with-julia/22488)

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**Author:** [@bemorejul](https://discourse.julialang.org/u/bemorejul)\
**Replies:** 0\
**Last updated:** [March 29, 2019, 3:18am UTC](https://discourse.julialang.org/t/i-succeeded-to-porting-the-poc-with-julia/22488 "2019-03-29T03:18:09Z")

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I succeeded to porting the POC(Phase only correlation) with Julia.

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## [DiffEqSensitivity Parameter ranges](https://discourse.julialang.org/t/diffeqsensitivity-parameter-ranges/22435)

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**Author:** [@alewolf](https://discourse.julialang.org/u/alewolf)\
**Replies:** 4\
**Last updated:** [March 28, 2019, 9:23pm UTC](https://discourse.julialang.org/t/diffeqsensitivity-parameter-ranges/22435 "2019-03-28T21:23:17Z")

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Hi, I’ve been working with DifferentialEquations Package - I am ready to run some global sensitivity analysis (GSA) I noticed that the way to input the ranges of evaluation goes something like this Let’s say my param…

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## [DataFrame type instability - Unneccesary memory allocation](https://discourse.julialang.org/t/dataframe-type-instability-unneccesary-memory-allocation/22465)

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**Author:** [@Eric\_Chen](https://discourse.julialang.org/u/Eric_Chen)\
**Replies:** 1\
**Last updated:** [March 28, 2019, 5:27pm UTC](https://discourse.julialang.org/t/dataframe-type-instability-unneccesary-memory-allocation/22465 "2019-03-28T17:27:34Z")

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I am running Julia 1.1, here is my Code using BenchmarkTools using DataFrames df = DataFrame(rand(10\_000\_000, 10)); Threads.nthreads() function singlethread(df) N = nrow(df) M = ncol(df) cumsum = 0.0 …

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