# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=384

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**Page:** 385

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## [How to use Fourier Filter on Complex Data](https://discourse.julialang.org/t/how-to-use-fourier-filter-on-complex-data/54967)

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**Author:** [@mdsa3d](https://discourse.julialang.org/u/mdsa3d)\
**Replies:** 8\
**Last updated:** [March 4, 2021, 2:16am UTC](https://discourse.julialang.org/t/how-to-use-fourier-filter-on-complex-data/54967 "2021-03-04T02:16:06Z")

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I would like to know, how may I filter or separate this complex function into its simpler sub-functions (something like fourier filter). Example I have a noisy dataset: x = 1:1:10 y = \[-1,5,0,2,-7,1,6,9,-2,3\] If I wou…

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## [Gradient of NN not changing with different inputs](https://discourse.julialang.org/t/gradient-of-nn-not-changing-with-different-inputs/56435)

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**Author:** [@edwinb-ai](https://discourse.julialang.org/u/edwinb-ai)\
**Replies:** 2\
**Last updated:** [March 3, 2021, 8:12pm UTC](https://discourse.julialang.org/t/gradient-of-nn-not-changing-with-different-inputs/56435 "2021-03-03T20:12:28Z")

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While playing around with some neural networks (NN) I found out this using Flux using Random using Zygote using ForwardDiff Random.seed!(9120) n = 1 m = 5 hidden = 10 x, y = rand(m), rand(n) # some data model = Flux.…

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## [Lilith.jl is now called Avalon.jl](https://discourse.julialang.org/t/lilith-jl-is-now-called-avalon-jl/51621)

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**Author:** [@dfdx](https://discourse.julialang.org/u/dfdx)\
**Replies:** 31\
**Last updated:** [March 3, 2021, 7:08pm UTC](https://discourse.julialang.org/t/lilith-jl-is-now-called-avalon-jl/51621 "2021-03-03T19:08:47Z")

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You know this moment when you realize you made a mistake. When registration to a flight ends in 5 minutes and you find yourself in a wrong terminal. Or its the first day at a new job and you understand they don’t have fr…

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## [Non-linear latency of sparse-dense matrix multiplication](https://discourse.julialang.org/t/non-linear-latency-of-sparse-dense-matrix-multiplication/56424)

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**Author:** [@albin](https://discourse.julialang.org/u/albin)\
**Replies:** 11\
**Last updated:** [March 3, 2021, 5:37pm UTC](https://discourse.julialang.org/t/non-linear-latency-of-sparse-dense-matrix-multiplication/56424 "2021-03-03T17:37:52Z")

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Hello, I’m measuring the latency of mul!(C, A, B), where C and B are dense and A is sparse, and I’m seeing something surprising: the latency isn’t linear in the number of operations required. Does anyone know why this i…

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## [ForwardDiff.dual TypeError while Solving ODE with 3 by 3 Matrix Input and ProximalOperators Package which Keep the Output Positive Definite](https://discourse.julialang.org/t/forwarddiff-dual-typeerror-while-solving-ode-with-3-by-3-matrix-input-and-proximaloperators-package-which-keep-the-output-positive-definite/56039)

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**Author:** [@yushang-lai](https://discourse.julialang.org/u/yushang-lai)\
**Replies:** 1\
**Last updated:** [March 3, 2021, 5:01pm UTC](https://discourse.julialang.org/t/forwarddiff-dual-typeerror-while-solving-ode-with-3-by-3-matrix-input-and-proximaloperators-package-which-keep-the-output-positive-definite/56039 "2021-03-03T17:01:39Z")

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Hi! I write a Turing ODE code as follows: The data is u\_account = \[953.0; 1075.0; 1223.0\] which represents three states \[A,B,C\] being observed. The parameter p consists of variables \[v1,v2,v4,u1,u3,w1\] Vector u\_mean d…

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## [How to plot a graph using the "for"?](https://discourse.julialang.org/t/how-to-plot-a-graph-using-the-for/56115)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 9\
**Last updated:** [March 3, 2021, 4:38pm UTC](https://discourse.julialang.org/t/how-to-plot-a-graph-using-the-for/56115 "2021-03-03T16:38:45Z")

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Hello everybody In this example I put only the results of the variable r and managed to plot the graph using JuMP, Plots r = \[69.60, 17.39, 0, 0\],\[0, 8.8, 2.1, 0\],\[0, 0, 8.8, 1.9\], \[16, 3.9, 0,0\] j = sum(r) x = T y = …

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## [How to convert all columns of type Int8 to Int64](https://discourse.julialang.org/t/how-to-convert-all-columns-of-type-int8-to-int64/56413)

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**Author:** [@kobusherbst](https://discourse.julialang.org/u/kobusherbst)\
**Replies:** 3\
**Last updated:** [March 3, 2021, 3:43pm UTC](https://discourse.julialang.org/t/how-to-convert-all-columns-of-type-int8-to-int64/56413 "2021-03-03T15:43:39Z")

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I have a dataframe with quite a few columns of type Int8 that I need to convert to Int64 to satisfy XLSX.jl non-support for integer sizes other than Int64. Currently I do it column by column: sf\[!,:Enumeration\] = conv…

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## [Read JLD files in MATLAB](https://discourse.julialang.org/t/read-jld-files-in-matlab/5492)

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**Author:** [@grero](https://discourse.julialang.org/u/grero)\
**Replies:** 3\
**Last updated:** [March 3, 2021, 3:40pm UTC](https://discourse.julialang.org/t/read-jld-files-in-matlab/5492 "2021-03-03T15:40:31Z")

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Dear all, I was wondering if anyone has implementing something to read JLD files in MATLAB? Since these files are basically HDF5 files, this should be easy using the built-in HDF5 tools in MATLAB, but I’m having some tr…

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## [Reaction rate laws of chemical reaction networks](https://discourse.julialang.org/t/reaction-rate-laws-of-chemical-reaction-networks/56049)

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**Author:** [@Nino-42](https://discourse.julialang.org/u/Nino-42)\
**Replies:** 7\
**Last updated:** [March 3, 2021, 10:12am UTC](https://discourse.julialang.org/t/reaction-rate-laws-of-chemical-reaction-networks/56049 "2021-03-03T10:12:28Z")

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Hi everyone, I am new in this forum and rather new to coding with julia (I have been using it for a while but more on a surface level). My question concerns the modeling of chemical reaction networks, specifically with …

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## [LoadError: MethodError: no method matching record although another package with "record" works](https://discourse.julialang.org/t/loaderror-methoderror-no-method-matching-record-although-another-package-with-record-works/56394)

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**Author:** [@meck](https://discourse.julialang.org/u/meck)\
**Replies:** 0\
**Last updated:** [March 3, 2021, 9:55am UTC](https://discourse.julialang.org/t/loaderror-methoderror-no-method-matching-record-although-another-package-with-record-works/56394 "2021-03-03T09:55:03Z")

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First package using WaterLily using LinearAlgebra: norm2 using Makie function donut\_sim(p=6,Re=1e3) # Define simulation size, velocity, viscosity n,U = 2^p, \[1, 0, 0\] center,R,r = \[n/2,n/2,n/2\], n/4, n/16 …

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## [Setting Time Limits for JuMP (with CBC solver)](https://discourse.julialang.org/t/setting-time-limits-for-jump-with-cbc-solver/56303)

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**Author:** [@acwkim](https://discourse.julialang.org/u/acwkim)\
**Replies:** 6\
**Last updated:** [March 3, 2021, 3:05am UTC](https://discourse.julialang.org/t/setting-time-limits-for-jump-with-cbc-solver/56303 "2021-03-03T03:05:19Z")

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Hi all. Is there a way to set time limit for JuMP models using CBC solver? The “seconds” parameter only limits CPU seconds, which is different from Wallclock seconds. I need to set a limit for Wallclock second! Thanks …

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## [Update QR factorization by adding a column for orthogonal matching pursuit](https://discourse.julialang.org/t/update-qr-factorization-by-adding-a-column-for-orthogonal-matching-pursuit/56368)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 0\
**Last updated:** [March 2, 2021, 9:44pm UTC](https://discourse.julialang.org/t/update-qr-factorization-by-adding-a-column-for-orthogonal-matching-pursuit/56368 "2021-03-02T21:44:36Z")

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Hello, I am working on the orthogonal matching pursuit algorithm to select a sparse set of features to solve Ax = b. In this algorithm, we add in a greedy fashion a new column (i.e. feature) at each step. The residual …

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## [Link function Bijectors.jl](https://discourse.julialang.org/t/link-function-bijectors-jl/56362)

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**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 3\
**Last updated:** [March 3, 2021, 12:10am UTC](https://discourse.julialang.org/t/link-function-bijectors-jl/56362 "2021-03-03T00:10:17Z")

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Dear All, I would like to ask probably a stupid question. What exactly does link() function? Documentation: link: maps a sample of a random distribution dist from its support to a value in R^n. Example: \` How how exac…

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## [MarkerElement allowable shapes](https://discourse.julialang.org/t/markerelement-allowable-shapes/56356)

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**Author:** [@kevbonham](https://discourse.julialang.org/u/kevbonham)\
**Replies:** 3\
**Last updated:** [March 2, 2021, 8:27pm UTC](https://discourse.julialang.org/t/markerelement-allowable-shapes/56356 "2021-03-02T20:27:01Z")

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I was searching for which shape symbols are allowable in MarkerElements for the marker kwarg. I identified :circle was what I needed, but wasn’t able to find where the possibilities are documented. Using characters like o…

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## [How to access CPLEX.CplexError in JuMP 0.18?](https://discourse.julialang.org/t/how-to-access-cplex-cplexerror-in-jump-0-18/22598)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 5\
**Last updated:** [March 2, 2021, 8:18pm UTC](https://discourse.julialang.org/t/how-to-access-cplex-cplexerror-in-jump-0-18/22598 "2021-03-02T20:18:27Z")

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Dear community, I always start cplex like for instance: try status = solve(model) println("status: ", status) println("obj\_val: ", getobjectivevalue(model)) catch msg println("ERROR SOLVING MODEL: ", ms…

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## [Flux unroll](https://discourse.julialang.org/t/flux-unroll/56355)

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**Author:** [@Ul44rich](https://discourse.julialang.org/u/Ul44rich)\
**Replies:** 1\
**Last updated:** [March 2, 2021, 7:01pm UTC](https://discourse.julialang.org/t/flux-unroll/56355 "2021-03-02T19:01:17Z")

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Need hints: Flux “unroll not defined” Thanks

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## [ANN: New interactive Plots.jl backend for large datasets](https://discourse.julialang.org/t/ann-new-interactive-plots-jl-backend-for-large-datasets/1442)

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**Author:** [@MA\_Laforge](https://discourse.julialang.org/u/MA_Laforge)\
**Replies:** 7\
**Last updated:** [March 2, 2021, 1:22pm UTC](https://discourse.julialang.org/t/ann-new-interactive-plots-jl-backend-for-large-datasets/1442 "2021-03-02T13:22:42Z")

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About InspectDR.jl Fast plotting with a responsive GUI (optional). Target: Quickly identify design/simulation issues & glitches in order to shorten design iterations. Pros Relatively short load times / time to first …

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## [Tell Flux not to differentiate something](https://discourse.julialang.org/t/tell-flux-not-to-differentiate-something/56253)

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**Author:** [@Michaela\_Maskova](https://discourse.julialang.org/u/Michaela_Maskova)\
**Replies:** 8\
**Last updated:** [March 2, 2021, 8:41am UTC](https://discourse.julialang.org/t/tell-flux-not-to-differentiate-something/56253 "2021-03-02T08:41:42Z")

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Hi, I’m trying to create a model using Flux. The model is quite complicated (it builds on Normalizing Flows, RealNVP) and uses many layers on top of each other. There are two inputs - vector Z and matrix X. X is transfo…

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## [Implementation for accessing Cholesky factors](https://discourse.julialang.org/t/implementation-for-accessing-cholesky-factors/56219)

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**Author:** [@ksil](https://discourse.julialang.org/u/ksil)\
**Replies:** 2\
**Last updated:** [March 2, 2021, 3:53am UTC](https://discourse.julialang.org/t/implementation-for-accessing-cholesky-factors/56219 "2021-03-02T03:53:42Z")

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Hi everyone! I’ve been a Julia user for several years, but this is my first time posting here, so apologies if this has been asked somewhere before. I was curious about Julia’s implementation of Cholesky factorization —…

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## [Losses for parameter estimation of Neural SDE](https://discourse.julialang.org/t/losses-for-parameter-estimation-of-neural-sde/50771)

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**Author:** [@jlmaccal](https://discourse.julialang.org/u/jlmaccal)\
**Replies:** 15\
**Last updated:** [March 1, 2021, 10:30pm UTC](https://discourse.julialang.org/t/losses-for-parameter-estimation-of-neural-sde/50771 "2021-03-01T22:30:07Z")

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I’m trying to understand the various options for doing parameter estimation on a USDE. I’m completely new to parameter estimation in SDEs, so ELI-dumb-chemist would be appreciated. Background I’m trying to model a physi…

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## [How to write a sum constraint in JuMP with condition](https://discourse.julialang.org/t/how-to-write-a-sum-constraint-in-jump-with-condition/56269)

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**Author:** [@GraceMabele](https://discourse.julialang.org/u/GraceMabele)\
**Replies:** 4\
**Last updated:** [March 1, 2021, 8:30pm UTC](https://discourse.julialang.org/t/how-to-write-a-sum-constraint-in-jump-with-condition/56269 "2021-03-01T20:30:11Z")

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Hi, I am having trouble writing the following constraint in JuMP I currently have it written as below but it is not returning the desired output. @constraints model begin constraint\_1\[n in n\], sum(w\[i,n,n…

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## [Add a column in dataframe based on another column](https://discourse.julialang.org/t/add-a-column-in-dataframe-based-on-another-column/56275)

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**Author:** [@Shazman](https://discourse.julialang.org/u/Shazman)\
**Replies:** 4\
**Last updated:** [March 1, 2021, 7:35pm UTC](https://discourse.julialang.org/t/add-a-column-in-dataframe-based-on-another-column/56275 "2021-03-01T19:35:21Z")

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Hi I have two dataframe and the " IID " in A and " X " in B are same but order is not. I want to add column " phenotype " of B into A according to column IID. how can I do it? dataframe A Herd.when.genotyped X…

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## [SOCP constraint](https://discourse.julialang.org/t/socp-constraint/56234)

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**Author:** [@SonLe](https://discourse.julialang.org/u/SonLe)\
**Replies:** 3\
**Last updated:** [March 1, 2021, 6:25pm UTC](https://discourse.julialang.org/t/socp-constraint/56234 "2021-03-01T18:25:14Z")

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Hi, I have a question about verifying the SOCP constraint in JuMP. So far, my SOCP constraint is \\epsilon t \\geq \\theta\\|\\mathbf{x}\\|\_{2}+\\frac{1}{N} \\sum\_{i \\in\[N\]} r^{i} and my code is @constraint(model, \[ϵ \* t \* (1…

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## [MethodError: no method matching getindex(::VariableRef, ::Int64)](https://discourse.julialang.org/t/methoderror-no-method-matching-getindex-variableref-int64/56252)

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**Author:** [@Kavitha](https://discourse.julialang.org/u/Kavitha)\
**Replies:** 4\
**Last updated:** [March 1, 2021, 5:55pm UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-getindex-variableref-int64/56252 "2021-03-01T17:55:33Z")

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Hi, I’m using JuMP to solve my optimization problem. Following is a part of the formulation and its causing the methoderror. for t in 1:tp for j in 1:nt c10= @constraint(p, LT\[j\]\[t\] - (l\[j\] \* Z\[j\]\[t\]) == 0) set\_nam…

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## [Subset a dataframe by column of another dataframe](https://discourse.julialang.org/t/subset-a-dataframe-by-column-of-another-dataframe/56263)

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**Author:** [@Shazman](https://discourse.julialang.org/u/Shazman)\
**Replies:** 4\
**Last updated:** [March 1, 2021, 5:17pm UTC](https://discourse.julialang.org/t/subset-a-dataframe-by-column-of-another-dataframe/56263 "2021-03-01T17:17:26Z")

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I have two dataframes (A) with 6 columns and (B) with 1 column. and B is subset of second column of A, now I want subset the dataframe (A) based on the values of B. how can I do it ? here is my dataframes. Blockqu…

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## [Does sciml\_train require ensemble to collect MSE of monte carlo solves when connected to a neural network or can I do it with a for loop?](https://discourse.julialang.org/t/does-sciml-train-require-ensemble-to-collect-mse-of-monte-carlo-solves-when-connected-to-a-neural-network-or-can-i-do-it-with-a-for-loop/56171)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 5\
**Last updated:** [March 1, 2021, 3:19pm UTC](https://discourse.julialang.org/t/does-sciml-train-require-ensemble-to-collect-mse-of-monte-carlo-solves-when-connected-to-a-neural-network-or-can-i-do-it-with-a-for-loop/56171 "2021-03-01T15:19:32Z")

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General diffeqflux question. I have a diffeq simulation using DifferentialEquations.jl and solve that works fine by itself. I want to prepend the outputs of a neural network to the solution setup so when trained, it wo…

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## [Save and Load Random Forest trained with MLJ/ScikitLearn.jl](https://discourse.julialang.org/t/save-and-load-random-forest-trained-with-mlj-scikitlearn-jl/55798)

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**Author:** [@rio](https://discourse.julialang.org/u/rio)\
**Replies:** 4\
**Last updated:** [March 1, 2021, 2:08pm UTC](https://discourse.julialang.org/t/save-and-load-random-forest-trained-with-mlj-scikitlearn-jl/55798 "2021-03-01T14:08:25Z")

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I would like to train a Random Forest model (RandomForestRegressor pkg=ScikitLearn) and save the trained model to disk. Then, I would like to load the model and apply it to new data. After training with success, I tried…

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## [How to plot distinct plots in grid layout](https://discourse.julialang.org/t/how-to-plot-distinct-plots-in-grid-layout/56242)

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**Author:** [@xyz1](https://discourse.julialang.org/u/xyz1)\
**Replies:** 3\
**Last updated:** [March 1, 2021, 12:59pm UTC](https://discourse.julialang.org/t/how-to-plot-distinct-plots-in-grid-layout/56242 "2021-03-01T12:59:04Z")

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Hi, I’m trying to visualize some data with Plots.jl and even with the amazing Plots documentation i am unable to plot a grid (2,2) of plots. Specifically I would like to create something like using Plots plot(rand(100,…

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## [ROS, ROS2 or PX4 packages in Julia](https://discourse.julialang.org/t/ros-ros2-or-px4-packages-in-julia/56245)

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**Author:** [@iHany](https://discourse.julialang.org/u/iHany)\
**Replies:** 0\
**Last updated:** [March 1, 2021, 11:57am UTC](https://discourse.julialang.org/t/ros-ros2-or-px4-packages-in-julia/56245 "2021-03-01T11:57:51Z")

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I’ve seen several packages of ROS, ROS2, and PX4 in Julia but they seem to be not maintained anymore. Is there any package or plan for this? Especially about multicopter simulation and experiments.

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## [How do you store your data before and after processing with Julia?](https://discourse.julialang.org/t/how-do-you-store-your-data-before-and-after-processing-with-julia/41205)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 35\
**Last updated:** [March 1, 2021, 7:42am UTC](https://discourse.julialang.org/t/how-do-you-store-your-data-before-and-after-processing-with-julia/41205 "2021-03-01T07:42:47Z")

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Overview I intend to process simulation data generated externally with Julia and would like some opinions on storage solutions for 1) the raw data, 2) the processed data, and 3) the processing inputs. Data Description …

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