# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1286

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 1287

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## [Setting 'Package Server' for JuliaHub (WSL)](https://discourse.julialang.org/t/setting-package-server-for-juliahub-wsl/67066)

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**Author:** [@banksiaboy](https://discourse.julialang.org/u/banksiaboy)\
**Replies:** 1\
**Last updated:** [August 26, 2021, 9:41pm UTC](https://discourse.julialang.org/t/setting-package-server-for-juliahub-wsl/67066 "2021-08-26T21:41:32Z")

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Because I’m a fool for platform independence I just tried the JuliaHub extension for vscode in WSL. I’m very much looking forward to using it. The documentation says: Also make sure that you’re connected to the right…

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## [Packaging: How to export an imported module?](https://discourse.julialang.org/t/packaging-how-to-export-an-imported-module/67062)

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**Author:** [@thisismygitrepo](https://discourse.julialang.org/u/thisismygitrepo)\
**Replies:** 3\
**Last updated:** [August 26, 2021, 9:08pm UTC](https://discourse.julialang.org/t/packaging-how-to-export-an-imported-module/67062 "2021-08-26T21:08:08Z")

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I’m writing a package, and in one of the modules, I would like e.g, Plots to be available to the user. However, I simply failed to do that. import Plots as P module mylibrary export P end In particular, compilation e…

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## [How to format the type of a column in Julia?](https://discourse.julialang.org/t/how-to-format-the-type-of-a-column-in-julia/67051)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 2\
**Last updated:** [August 26, 2021, 8:15pm UTC](https://discourse.julialang.org/t/how-to-format-the-type-of-a-column-in-julia/67051 "2021-08-26T20:15:22Z")

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Hello, I have a dataframe and I would like to set the type of each column. In my case, all columns are strings. How do I, for instance, format to numeric? I am looking for a Julia version of R’s df$x \<- as.numeric(as.c…

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## [Introduction on Julia for a master course: feedback welcome :-)](https://discourse.julialang.org/t/introduction-on-julia-for-a-master-course-feedback-welcome/66925)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 7\
**Last updated:** [August 26, 2021, 7:55pm UTC](https://discourse.julialang.org/t/introduction-on-julia-for-a-master-course-feedback-welcome/66925 "2021-08-26T19:55:49Z")

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I am preparing a master course on “Introduction to Scientific Programming and Machine Learning with Julia” for non-teach audience and I am preparing a (long) slide where I introduce Julia and I preview its main concepts. …

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## [Get information on state of IOStream](https://discourse.julialang.org/t/get-information-on-state-of-iostream/66910)

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**Author:** [@DorianT](https://discourse.julialang.org/u/DorianT)\
**Replies:** 2\
**Last updated:** [August 26, 2021, 6:46pm UTC](https://discourse.julialang.org/t/get-information-on-state-of-iostream/66910 "2021-08-26T18:46:48Z")

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Hey everyone! I have a function makebatch!(::IOStream, kwargs...) that creates one batch of data to feed to a model (from a file). For this the function takes an IOStream and reads as many lines as it needs to fill the …

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## [SequenceVariation: Brainstorming for new package](https://discourse.julialang.org/t/sequencevariation-brainstorming-for-new-package/66918)

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**Author:** [@jakobnissen](https://discourse.julialang.org/u/jakobnissen)\
**Replies:** 3\
**Last updated:** [August 26, 2021, 6:04pm UTC](https://discourse.julialang.org/t/sequencevariation-brainstorming-for-new-package/66918 "2021-08-26T18:04:29Z")

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I’d like to make a new package for BioJulia. I’ve made a crude prototype, but I’m still unsure about the design and API and would like some feedback, and maybe pushback if my current design has problems. I think I asked …

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## [VS code debugger question: environments](https://discourse.julialang.org/t/vs-code-debugger-question-environments/66173)

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**Author:** [@kumarbalachandran](https://discourse.julialang.org/u/kumarbalachandran)\
**Replies:** 2\
**Last updated:** [August 26, 2021, 6:02pm UTC](https://discourse.julialang.org/t/vs-code-debugger-question-environments/66173 "2021-08-26T18:02:42Z")

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In VS code, when I start a debugger session, how do I set the environment. The ALT-J ALT-O julia REPL is set to the right environment, but when I start the debugger, it throws me to the parent environment and complains a…

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## [How to sum outputs from DifferentialEquations.jl](https://discourse.julialang.org/t/how-to-sum-outputs-from-differentialequations-jl/67034)

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**Author:** [@mgp](https://discourse.julialang.org/u/mgp)\
**Replies:** 7\
**Last updated:** [August 26, 2021, 5:31pm UTC](https://discourse.julialang.org/t/how-to-sum-outputs-from-differentialequations-jl/67034 "2021-08-26T17:31:00Z")

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I am making a series of compartmental ODE infection models using DifferentialEquations. I would like to be able to plot the sum of two or more compartments (e.g. I might have people with undiagnosed infection and diagnos…

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## [Delay Differential Equation problem](https://discourse.julialang.org/t/delay-differential-equation-problem/67044)

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**Author:** [@Liwei17](https://discourse.julialang.org/u/Liwei17)\
**Replies:** 5\
**Last updated:** [August 26, 2021, 5:17pm UTC](https://discourse.julialang.org/t/delay-differential-equation-problem/67044 "2021-08-26T17:17:29Z")

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DifferentialEquation.jl DDE running problem: using DifferentialEquations, Plots function dde(du,u,h,p,t) M\_A, M\_B = u; tau, mu, n, P0, b = p; hist\_A = h(p, t-tau)\[1\]; hist\_B = h(p, t-tau)\[2\]; du\[1\] …

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## [Merging two dictionaries with only keys in “b” that also exist in “a”](https://discourse.julialang.org/t/merging-two-dictionaries-with-only-keys-in-b-that-also-exist-in-a/66985)

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**Author:** [@Jan\_Dolinsky](https://discourse.julialang.org/u/Jan_Dolinsky)\
**Replies:** 5\
**Last updated:** [August 26, 2021, 4:50pm UTC](https://discourse.julialang.org/t/merging-two-dictionaries-with-only-keys-in-b-that-also-exist-in-a/66985 "2021-08-26T16:50:01Z")

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Hello, I would like to merge two dictionaries where I want to merge only keys in “b” that also exists in “a”. Is there a neat way of doing this? Example: a = Dict("foo" =\> 23, "bar" =\> 24) b = Dict("bar" =\> 450, "unwa…

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## [Pluto plot layout for a figure with 4 rows and one column](https://discourse.julialang.org/t/pluto-plot-layout-for-a-figure-with-4-rows-and-one-column/67049)

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**Author:** [@kumarbalachandran](https://discourse.julialang.org/u/kumarbalachandran)\
**Replies:** 0\
**Last updated:** [August 26, 2021, 4:35pm UTC](https://discourse.julialang.org/t/pluto-plot-layout-for-a-figure-with-4-rows-and-one-column/67049 "2021-08-26T16:35:25Z")

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Hi I am using layout=(4,1) to place subplots from Plots.jl, but the y axis gets compressed for a fixed plot height on screen within a Pluto notebook. Is there some way of expanding the height of the plot canvas so that …

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## [Problem in opening dataframe](https://discourse.julialang.org/t/problem-in-opening-dataframe/67043)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 4\
**Last updated:** [August 26, 2021, 3:59pm UTC](https://discourse.julialang.org/t/problem-in-opening-dataframe/67043 "2021-08-26T15:59:54Z")

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Hello, I have been trying to open a tab delimited file as dataframe. My command was: using DataFrames using CSV df = CSV.read(\<file\>, delim='\\t', missingstring="NA", decimal='.', header = false; copycols=true) Now I a…

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## [NeuralODE not taking multiple inputs although neural network is able to do so](https://discourse.julialang.org/t/neuralode-not-taking-multiple-inputs-although-neural-network-is-able-to-do-so/67042)

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**Author:** [@DiracFermion1](https://discourse.julialang.org/u/DiracFermion1)\
**Replies:** 0\
**Last updated:** [August 26, 2021, 2:58pm UTC](https://discourse.julialang.org/t/neuralode-not-taking-multiple-inputs-although-neural-network-is-able-to-do-so/67042 "2021-08-26T14:58:15Z")

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(this question is related to How to use multiple inputs in \`NeuralODE\` object? with a concrete example) Hi, I am trying to define a NeuralODE that takes two inputs (one input is a Float array, another is an Int array). …

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## [Performance drawback with subtyping](https://discourse.julialang.org/t/performance-drawback-with-subtyping/51939)

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**Author:** [@Ronneesley](https://discourse.julialang.org/u/Ronneesley)\
**Replies:** 34\
**Last updated:** [August 26, 2021, 2:37pm UTC](https://discourse.julialang.org/t/performance-drawback-with-subtyping/51939 "2021-08-26T14:37:16Z")

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Hello, I’ve a problem with subtype, see the code: abstract type LineAbstract end mutable struct LineA \<: LineAbstract color::String end mutable struct LineB \<: LineAbstract length::Int end mutable struct…

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## [Generate Struct based on stat distribution](https://discourse.julialang.org/t/generate-struct-based-on-stat-distribution/67040)

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**Author:** [@rodolforbcoutinho](https://discourse.julialang.org/u/rodolforbcoutinho)\
**Replies:** 1\
**Last updated:** [August 26, 2021, 2:23pm UTC](https://discourse.julialang.org/t/generate-struct-based-on-stat-distribution/67040 "2021-08-26T14:23:34Z")

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Hello, I’m trying to generate a random data for a struct based on stat distribution. I think it should be a simple task, but probably i’m not knowing how to search for it. Spend a day and a half searching how to do it a…

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## [Passing Function As Object VS Creating New Function](https://discourse.julialang.org/t/passing-function-as-object-vs-creating-new-function/66933)

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**Author:** [@cmdenis](https://discourse.julialang.org/u/cmdenis)\
**Replies:** 5\
**Last updated:** [August 26, 2021, 1:56pm UTC](https://discourse.julialang.org/t/passing-function-as-object-vs-creating-new-function/66933 "2021-08-26T13:56:48Z")

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Hello! So, I’ve stumbled upon a performance difference between two situations, and I don’t understand the reason behind this difference. The difference in computation time occurs between 1) passing a function to a varia…

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## [Specifying datatype in JuMP expressions and constraints to save memory](https://discourse.julialang.org/t/specifying-datatype-in-jump-expressions-and-constraints-to-save-memory/66515)

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**Author:** [@anon94806364](https://discourse.julialang.org/u/anon94806364)\
**Replies:** 14\
**Last updated:** [August 26, 2021, 1:43pm UTC](https://discourse.julialang.org/t/specifying-datatype-in-jump-expressions-and-constraints-to-save-memory/66515 "2021-08-26T13:43:07Z")

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I am solving for an ILP that, despite my best efforts to downsize (ie. use sparse matrices), is taking ~ 100 GB RAM. In my model, I have expressions that are the sum of binary variables \* integer variables. Perhaps mist…

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## [Load testing of REST APIs](https://discourse.julialang.org/t/load-testing-of-rest-apis/66906)

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**Author:** [@Jan\_Dolinsky](https://discourse.julialang.org/u/Jan_Dolinsky)\
**Replies:** 3\
**Last updated:** [August 26, 2021, 1:39pm UTC](https://discourse.julialang.org/t/load-testing-of-rest-apis/66906 "2021-08-26T13:39:37Z")

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Hello, I would like to ask whether there is some package / effort providing load testing functionalities for REST APIs. We currently consider using jMeter but I wanted to check whether there is something I might not be …

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## [Why isn't a simple map type stable?](https://discourse.julialang.org/t/why-isnt-a-simple-map-type-stable/67028)

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**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 2\
**Last updated:** [August 26, 2021, 12:11pm UTC](https://discourse.julialang.org/t/why-isnt-a-simple-map-type-stable/67028 "2021-08-26T12:11:33Z")

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Shouldn’t Julia be able to infer that the return type is Vector{Float64} in the example below? prevx is initialized to a Float64 value and randn() returns a Float64 value. julia\> function gen1(n) prevx = 0.0 …

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## [Error when calling 'using Cbc'](https://discourse.julialang.org/t/error-when-calling-using-cbc/67014)

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**Author:** [@Kreiton\_Sitorus](https://discourse.julialang.org/u/Kreiton_Sitorus)\
**Replies:** 10\
**Last updated:** [August 26, 2021, 12:43pm UTC](https://discourse.julialang.org/t/error-when-calling-using-cbc/67014 "2021-08-26T12:43:28Z")

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Hello, I think I need help. I’m trying to use Cbc. I’ve called the Pkg.add(“Cbc”) and it installs it as usual. But, when I called using Cbc this error message pops out: julia\> using Cbc \[ Info: Precompiling Cbc \[9961bab…

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## [Can Julia access Memory locations or Registers directly](https://discourse.julialang.org/t/can-julia-access-memory-locations-or-registers-directly/67016)

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**Author:** [@R.T.A.M](https://discourse.julialang.org/u/R.T.A.M)\
**Replies:** 12\
**Last updated:** [August 26, 2021, 12:32pm UTC](https://discourse.julialang.org/t/can-julia-access-memory-locations-or-registers-directly/67016 "2021-08-26T12:32:59Z")

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Hi all, I’m after some advice on low level memory access. What is the best way to access (read or write) to individual registers in an embedded application with Julia? Say I want to read address 0x6000 0000 plus an off…

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## [\[MTK\] Interpolating observed variables](https://discourse.julialang.org/t/mtk-interpolating-observed-variables/66308)

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**Author:** [@doppioandante](https://discourse.julialang.org/u/doppioandante)\
**Replies:** 9\
**Last updated:** [August 26, 2021, 11:55am UTC](https://discourse.julialang.org/t/mtk-interpolating-observed-variables/66308 "2021-08-26T11:55:38Z")

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I am toying around with ModelingToolkit, I have a very simple algebraic model representing the voltage/current relationship in a ideal resistor: using ModelingToolkit, OrdinaryDiffEq @parameters R @variables t v(t) i(t…

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## [DifferentialEquations.jl and Measurements.jl](https://discourse.julialang.org/t/differentialequations-jl-and-measurements-jl/6350)

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**Author:** [@giordano](https://discourse.julialang.org/u/giordano)\
**Replies:** 11\
**Last updated:** [August 26, 2021, 10:54am UTC](https://discourse.julialang.org/t/differentialequations-jl-and-measurements-jl/6350 "2021-08-26T10:54:24Z")

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Today I was asked whether it was possible to solve in Julia differential equations involving numbers with uncertainties. Of course the answer is yes. What I find really amazing about Julia is that the two packages don’…

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## [Reading metadata from files](https://discourse.julialang.org/t/reading-metadata-from-files/67027)

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**Author:** [@reinermartin](https://discourse.julialang.org/u/reinermartin)\
**Replies:** 0\
**Last updated:** [August 26, 2021, 10:13am UTC](https://discourse.julialang.org/t/reading-metadata-from-files/67027 "2021-08-26T10:13:25Z")

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Are there Julia libraries for reading metadata from music and image files (as for example tinytag for Python)?

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## [Best way to group functions?](https://discourse.julialang.org/t/best-way-to-group-functions/67011)

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**Author:** [@DiracFermion1](https://discourse.julialang.org/u/DiracFermion1)\
**Replies:** 7\
**Last updated:** [August 26, 2021, 8:33am UTC](https://discourse.julialang.org/t/best-way-to-group-functions/67011 "2021-08-26T08:33:16Z")

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Since there are no classes in Julia, I wonder what might be a good way to group functions that work for the same type of objects? One way I can think of is to use modules, just want to hear if there are other better app…

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## [How to use functions in jump's target functions](https://discourse.julialang.org/t/how-to-use-functions-in-jumps-target-functions/67019)

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**Author:** [@zhangsanle](https://discourse.julialang.org/u/zhangsanle)\
**Replies:** 1\
**Last updated:** [August 26, 2021, 8:17am UTC](https://discourse.julialang.org/t/how-to-use-functions-in-jumps-target-functions/67019 "2021-08-26T08:17:05Z")

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I want to know why there was an error running the following program. I need to change the parameters wx and wy of tt several times, so I want to use them directly in the target function Incorrect number of arguments for…

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## [Help fitting linear probability model with GLM.jl](https://discourse.julialang.org/t/help-fitting-linear-probability-model-with-glm-jl/67004)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 4\
**Last updated:** [August 26, 2021, 7:25am UTC](https://discourse.julialang.org/t/help-fitting-linear-probability-model-with-glm-jl/67004 "2021-08-26T07:25:57Z")

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I’m looking to fit a linear probability model of the form: y\_i = \\alpha X\_i + PT\_i \\beta + \\phi\_j + \\lambda\_r + \\epsilon\_i Where: y\_i is 1 if worker is independent contractor on main job, else 0 X\_i is a vector of pe…

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## [Approximating sine function using Flux for Solving PINN problem](https://discourse.julialang.org/t/approximating-sine-function-using-flux-for-solving-pinn-problem/66323)

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**Author:** [@Chaitanya](https://discourse.julialang.org/u/Chaitanya)\
**Replies:** 5\
**Last updated:** [August 26, 2021, 6:01am UTC](https://discourse.julialang.org/t/approximating-sine-function-using-flux-for-solving-pinn-problem/66323 "2021-08-26T06:01:06Z")

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In this code I am trying to predict u(x,t)= NN(\\theta) so that after I predict this I can use the neural network to solve PINN problems. However, I’m not able to train the model and reduce the loss function. import Flux…

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## [Joining two ODE solutions](https://discourse.julialang.org/t/joining-two-ode-solutions/63710)

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**Author:** [@Free\_ion](https://discourse.julialang.org/u/Free_ion)\
**Replies:** 5\
**Last updated:** [August 26, 2021, 4:31am UTC](https://discourse.julialang.org/t/joining-two-ode-solutions/63710 "2021-08-26T04:31:07Z")

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Is there any way to join two ODE solutions so that I can use the final product as a function like an usual ODE solution? My problem is that I have a function α(ϕ) defined in two regimes, so I have to solve two ODEs. The…

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## [Product of two stochastic processes in DifferentialEquations.jl](https://discourse.julialang.org/t/product-of-two-stochastic-processes-in-differentialequations-jl/66391)

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**Author:** [@mastrof](https://discourse.julialang.org/u/mastrof)\
**Replies:** 3\
**Last updated:** [August 26, 2021, 4:27am UTC](https://discourse.julialang.org/t/product-of-two-stochastic-processes-in-differentialequations-jl/66391 "2021-08-26T04:27:32Z")

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Hello, I have recently started to play out with DifferentialEquations.jl; I’m gradually reading through the docs but there’s a lot of stuff in there which will keep me busy for a while, so I’m still at a beginner level. …

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