# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=277

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**Page:** 278

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## [To provide Jacobian in non-linear solver, time-stepping or Jacobian](https://discourse.julialang.org/t/to-provide-jacobian-in-non-linear-solver-time-stepping-or-jacobian/81632)

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**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 2\
**Last updated:** [May 26, 2022, 12:52pm UTC](https://discourse.julialang.org/t/to-provide-jacobian-in-non-linear-solver-time-stepping-or-jacobian/81632 "2022-05-26T12:52:20Z")

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Is there a good example showing that the effort of providing the Jacobian to either a non-linear solver, a time-stepping solver or an optimization solver does pay off in reducing the number of (non-linear, right-hand sid…

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## [Can we find a DDe's canstant from a table](https://discourse.julialang.org/t/can-we-find-a-ddes-canstant-from-a-table/81676)

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**Author:** [@Achraf\_el\_fadli](https://discourse.julialang.org/u/Achraf_el_fadli)\
**Replies:** 6\
**Last updated:** [May 26, 2022, 12:35pm UTC](https://discourse.julialang.org/t/can-we-find-a-ddes-canstant-from-a-table/81676 "2022-05-26T12:35:33Z")

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for finding a,b,c the most compatible with the model

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## [Making Plots place its legend in a better spot](https://discourse.julialang.org/t/making-plots-place-its-legend-in-a-better-spot/74986)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 18\
**Last updated:** [May 26, 2022, 10:27am UTC](https://discourse.julialang.org/t/making-plots-place-its-legend-in-a-better-spot/74986 "2022-05-26T10:27:21Z")

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Apparently this is a feature, or not of the backend, and Plots sends legend=:best to them. PyPlot should place the legend in a nice position by default, avoiding the data, but GR apparently does not have this feature. I…

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## [JuMP writeMPS does not finish writing LP model to file](https://discourse.julialang.org/t/jump-writemps-does-not-finish-writing-lp-model-to-file/81427)

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**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 20\
**Last updated:** [May 25, 2022, 8:31pm UTC](https://discourse.julialang.org/t/jump-writemps-does-not-finish-writing-lp-model-to-file/81427 "2022-05-25T20:31:40Z")

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I’m trying to save a large linear program model created with JuMP v0.18.5 in Julia v0.6.4 to a .mps file on disk using writeMPS, but the file maxes out quickly at 711MB and the Julia script trying to write the file event…

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## [Dynamic expreesion name in JuMP](https://discourse.julialang.org/t/dynamic-expreesion-name-in-jump/80995)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 4\
**Last updated:** [May 25, 2022, 2:15pm UTC](https://discourse.julialang.org/t/dynamic-expreesion-name-in-jump/80995 "2022-05-25T14:15:11Z")

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Hi All, is there a way to create dynamic expression name in Julia? like the code given below Julia 1.2 mod2=Model() @variable(mod2,x\[ i in 1:13\]) @variable(mod2,y\[ i in 1:13\]) @constraint(mod2, \[i in 1:13\], x\[i\]+y\[i\]\>=…

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## [Heatmap from Matrix with custom indices](https://discourse.julialang.org/t/heatmap-from-matrix-with-custom-indices/81596)

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**Author:** [@ctrebbau](https://discourse.julialang.org/u/ctrebbau)\
**Replies:** 20\
**Last updated:** [May 25, 2022, 5:13pm UTC](https://discourse.julialang.org/t/heatmap-from-matrix-with-custom-indices/81596 "2022-05-25T17:13:20Z")

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Hello Community! I have data like so where I would like to visualise a heatmap of the TimeDiff\_mean column and the other two columns (representing a reticulation over geographical datapoints). I have sought for one …

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## [Specifying JuMP solvers for function-wrapped optimization models](https://discourse.julialang.org/t/specifying-jump-solvers-for-function-wrapped-optimization-models/81030)

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**Author:** [@Tominapa](https://discourse.julialang.org/u/Tominapa)\
**Replies:** 2\
**Last updated:** [May 25, 2022, 4:06pm UTC](https://discourse.julialang.org/t/specifying-jump-solvers-for-function-wrapped-optimization-models/81030 "2022-05-25T16:06:54Z")

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I am building a package based around a specific optimization problem, implemented in JuMP. My code builds an optimization model based on input data, with most everything automated behind the scenes for user-friendliness…

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## [CairoMakie broken rendering of axis and ticklabels](https://discourse.julialang.org/t/cairomakie-broken-rendering-of-axis-and-ticklabels/81635)

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**Author:** [@mihrits](https://discourse.julialang.org/u/mihrits)\
**Replies:** 0\
**Last updated:** [May 25, 2022, 9:20am UTC](https://discourse.julialang.org/t/cairomakie-broken-rendering-of-axis-and-ticklabels/81635 "2022-05-25T09:20:58Z")

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I am using CairoMakie to plot some results but found that in some circumstances some characters in axis labels and/or tick labels are rendered as boxes. For example, this code using CairoMakie fig = Figure(size=(200,200…

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## [Precompiling ImageView generates an infinite cascade of windows](https://discourse.julialang.org/t/precompiling-imageview-generates-an-infinite-cascade-of-windows/81575)

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**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 3\
**Last updated:** [May 25, 2022, 7:04am UTC](https://discourse.julialang.org/t/precompiling-imageview-generates-an-infinite-cascade-of-windows/81575 "2022-05-25T07:04:00Z")

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Hi there! I’m trying to install ImageView but precompilation doesn’t work. Instead, it spawns an infinite sequence of other (terminal?) windows and I have no choice but to interrupt the process. Has anyone encountered a…

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## [InexactError on write\_to\_file](https://discourse.julialang.org/t/inexacterror-on-write-to-file/81577)

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**Author:** [@berkorbay](https://discourse.julialang.org/u/berkorbay)\
**Replies:** 4\
**Last updated:** [May 25, 2022, 6:10am UTC](https://discourse.julialang.org/t/inexacterror-on-write-to-file/81577 "2022-05-25T06:10:08Z")

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Hi, I encountered a problem with writing model specs to an LP file. I was replicating the Diet Problem example on JuMP’s page. https://jump.dev/JuMP.jl/stable/tutorials/linear/diet/ Everything went fine until the end. …

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## [Driftless Stochastic differential equation](https://discourse.julialang.org/t/driftless-stochastic-differential-equation/81525)

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**Author:** [@stochasticguy](https://discourse.julialang.org/u/stochasticguy)\
**Replies:** 5\
**Last updated:** [May 24, 2022, 5:46pm UTC](https://discourse.julialang.org/t/driftless-stochastic-differential-equation/81525 "2022-05-24T17:46:21Z")

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Hi everybody, I’m using the GREAT StochasticDiffEq.jl package to define a multidimensional driftless SDE as follows: using StochasticDiffEq function f!(du, u, p, t) du .= p\[1\] return nothing end function g!(d…

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## [Parallel sparse solve and inverse](https://discourse.julialang.org/t/parallel-sparse-solve-and-inverse/81538)

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**Author:** [@sobhan](https://discourse.julialang.org/u/sobhan)\
**Replies:** 0\
**Last updated:** [May 23, 2022, 8:32pm UTC](https://discourse.julialang.org/t/parallel-sparse-solve-and-inverse/81538 "2022-05-23T20:32:42Z")

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So i need to solve a really big (and sparse) system of equation and to my knowledge there are no parallel sparse solvers for julia. I tried the pardiso for MKL but that wasn’t parallel and had performance similar to the …

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## [Missing sparse methods](https://discourse.julialang.org/t/missing-sparse-methods/17596)

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**Author:** [@Paul\_Hines](https://discourse.julialang.org/u/Paul_Hines)\
**Replies:** 3\
**Last updated:** [November 16, 2018, 6:24pm UTC](https://discourse.julialang.org/t/missing-sparse-methods/17596 "2018-11-16T18:24:10Z")

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It seems like there are missing sparse matrix methods. In both 1.0.2 and 0.7 this code: using SparseArrays using LinearAlgebra A = sprand(10,10,.9) b\_dense = Array(sprand(10,1,.8)) # works b\_sparse = sprand(10,1,.8) # …

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## [Freely moving agents in a GridSpace-like environment](https://discourse.julialang.org/t/freely-moving-agents-in-a-gridspace-like-environment/81586)

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**Author:** [@Demlore](https://discourse.julialang.org/u/Demlore)\
**Replies:** 1\
**Last updated:** [May 24, 2022, 1:57pm UTC](https://discourse.julialang.org/t/freely-moving-agents-in-a-gridspace-like-environment/81586 "2022-05-24T13:57:03Z")

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I am currently trying to implement a model similar to the model “Predator-prey dynamics” from the Example Zoo. My current issue is that i need freely moving agents in a space made out of square patches just like the e…

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## [Optimization computational time](https://discourse.julialang.org/t/optimization-computational-time/81558)

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**Author:** [@O\_olalekan](https://discourse.julialang.org/u/O_olalekan)\
**Replies:** 2\
**Last updated:** [May 24, 2022, 11:50am UTC](https://discourse.julialang.org/t/optimization-computational-time/81558 "2022-05-24T11:50:31Z")

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I read several materials on the computational time of optimization models. The MILP computational time has always been faster than the NLP formulation. I then stumbled on an article which got that the computational time …

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## [How to plot ~10 billion datapoint time series efficiently?](https://discourse.julialang.org/t/how-to-plot-10-billion-datapoint-time-series-efficiently/81228)

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**Author:** [@hk69](https://discourse.julialang.org/u/hk69)\
**Replies:** 47\
**Last updated:** [May 24, 2022, 11:26am UTC](https://discourse.julialang.org/t/how-to-plot-10-billion-datapoint-time-series-efficiently/81228 "2022-05-24T11:26:35Z")

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Hi, I am relatively new to Julia. I have a physics model that I implemented in Julia. I solve the differential equations to track the orbit of two blackholes over a period of about 5 years with very small time step. My …

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## [A simple model which I can't get Turing to fit to simulated data](https://discourse.julialang.org/t/a-simple-model-which-i-cant-get-turing-to-fit-to-simulated-data/81572)

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**Author:** [@lgrozinger](https://discourse.julialang.org/u/lgrozinger)\
**Replies:** 1\
**Last updated:** [May 24, 2022, 11:12am UTC](https://discourse.julialang.org/t/a-simple-model-which-i-cant-get-turing-to-fit-to-simulated-data/81572 "2022-05-24T11:12:58Z")

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Having just started with Turing, I am unable to understand why this model does not produce good results. using Turing using MCMCChains λ = Normal(0, 1) data = rand.(Poisson.(exp.(rand(λ, 2^16)))) @model function m(y, …

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## [ERROR: UndefVarError: parameters not defined](https://discourse.julialang.org/t/error-undefvarerror-parameters-not-defined/81385)

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**Author:** [@Hupdup](https://discourse.julialang.org/u/Hupdup)\
**Replies:** 6\
**Last updated:** [May 24, 2022, 7:50am UTC](https://discourse.julialang.org/t/error-undefvarerror-parameters-not-defined/81385 "2022-05-24T07:50:06Z")

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Hi, I want to do some reinforcement learning in Julia, but when I want to perform my action, it always gives me this error. do you know what i should do? I already downloaded the latest version of the packages. functio…

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## [Ever increasing time for garbage collection](https://discourse.julialang.org/t/ever-increasing-time-for-garbage-collection/81543)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 7\
**Last updated:** [May 23, 2022, 11:10pm UTC](https://discourse.julialang.org/t/ever-increasing-time-for-garbage-collection/81543 "2022-05-23T23:10:55Z")

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Hello, I have a simulation that is running in real-time for an undefined period of time (until you stop it). I solve my equation system every 50ms. For one solution about 800 calls to the inner residual function are ne…

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## [Error when trying to specify the initial simplex of Nelder Mead method in GalacticOptim.jl](https://discourse.julialang.org/t/error-when-trying-to-specify-the-initial-simplex-of-nelder-mead-method-in-galacticoptim-jl/81506)

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**Author:** [@martinmestre](https://discourse.julialang.org/u/martinmestre)\
**Replies:** 10\
**Last updated:** [May 23, 2022, 10:22pm UTC](https://discourse.julialang.org/t/error-when-trying-to-specify-the-initial-simplex-of-nelder-mead-method-in-galacticoptim-jl/81506 "2022-05-23T22:22:20Z")

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Hello, I would need help with the following error when trying specify the a,b parameters of the initial simplex constructor. I gives the same error even if I call the constructor without arguments. I have Julia 1.7.2. …

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## [Use add\_to\_expression!() for multi-dimension expressions](https://discourse.julialang.org/t/use-add-to-expression-for-multi-dimension-expressions/81532)

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**Author:** [@xuqingyu](https://discourse.julialang.org/u/xuqingyu)\
**Replies:** 3\
**Last updated:** [May 23, 2022, 9:52pm UTC](https://discourse.julialang.org/t/use-add-to-expression-for-multi-dimension-expressions/81532 "2022-05-23T21:52:51Z")

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Hi all, May I have your suggestions on how to use add\_to\_expression!() to add one multi-dimension expressions to another? Say I have an expression A with dimension (n x m), and an expression B with dimension (n x m). …

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## [Does Makie.save("name", scene) also save the legends on the plot automatically?](https://discourse.julialang.org/t/does-makie-save-name-scene-also-save-the-legends-on-the-plot-automatically/81492)

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**Author:** [@Nihilol1](https://discourse.julialang.org/u/Nihilol1)\
**Replies:** 6\
**Last updated:** [May 23, 2022, 8:00pm UTC](https://discourse.julialang.org/t/does-makie-save-name-scene-also-save-the-legends-on-the-plot-automatically/81492 "2022-05-23T20:00:27Z")

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My simplified code looks as follows: using GLMakie fig1 = Figure() ax1 = Axis(fig1\[1,1\], xlabel = “What”, ylabel = “is going on”) GLMakie.scatter!(ax1, xvalues, yvalues, makersize = 4, color = colours, label = “pleas…

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## [Interpolating scattered data points to create topological EEG voltage map](https://discourse.julialang.org/t/interpolating-scattered-data-points-to-create-topological-eeg-voltage-map/78622)

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**Author:** [@AAlshammaa](https://discourse.julialang.org/u/AAlshammaa)\
**Replies:** 2\
**Last updated:** [May 23, 2022, 6:11pm UTC](https://discourse.julialang.org/t/interpolating-scattered-data-points-to-create-topological-eeg-voltage-map/78622 "2022-05-23T18:11:01Z")

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I have a dataset with EEG data that I read into Julia from Matlab file. The data is for a single time point from simultaneous 64 channels. Each channel has x, y coordinates, and value at those coordinates. My aim is to i…

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## [JuMP Termination\_status category](https://discourse.julialang.org/t/jump-termination-status-category/81524)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 1\
**Last updated:** [May 23, 2022, 5:29pm UTC](https://discourse.julialang.org/t/jump-termination-status-category/81524 "2022-05-23T17:29:00Z")

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JuMP’s docs break termination status into 3 groups Solved, Solved to relaxed tolerances, limits, and problemantic. Is there a way to take a termination status and get which one of these groups it is in? I could write …

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## [Makie Layoutables documentation and SliderGrid Example Error](https://discourse.julialang.org/t/makie-layoutables-documentation-and-slidergrid-example-error/81478)

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**Author:** [@nelsonah](https://discourse.julialang.org/u/nelsonah)\
**Replies:** 5\
**Last updated:** [May 23, 2022, 4:57pm UTC](https://discourse.julialang.org/t/makie-layoutables-documentation-and-slidergrid-example-error/81478 "2022-05-23T16:57:59Z")

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I am having difficulty finding documentation on Makie layoutables. Blocks & Widgets has some nice examples but where can I find more detailed documentation on the various CURRENT blocks? In addition, the SliderGrid exa…

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## [Warning when using "DiffEqFlux.sciml\_train" and "ModelingToolkit.structural\_simplify"](https://discourse.julialang.org/t/warning-when-using-diffeqflux-sciml-train-and-modelingtoolkit-structural-simplify/81449)

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**Author:** [@mzhenirovskyy](https://discourse.julialang.org/u/mzhenirovskyy)\
**Replies:** 8\
**Last updated:** [May 23, 2022, 3:56pm UTC](https://discourse.julialang.org/t/warning-when-using-diffeqflux-sciml-train-and-modelingtoolkit-structural-simplify/81449 "2022-05-23T15:56:43Z")

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Hi All, I want to use “DiffEqFlux.sciml\_train” to get parameters after using “ModelingToolkit.structural\_simplify”. I’m able to get a reasonable result but have a weird warning: Warning: Warning: Unrecognized keyword …

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## [How how send file with post in StippleUI.form?](https://discourse.julialang.org/t/how-how-send-file-with-post-in-stippleui-form/81390)

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**Author:** [@Rafael\_Brus](https://discourse.julialang.org/u/Rafael_Brus)\
**Replies:** 2\
**Last updated:** [May 23, 2022, 3:47pm UTC](https://discourse.julialang.org/t/how-how-send-file-with-post-in-stippleui-form/81390 "2022-05-23T15:47:19Z")

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Why doesn’t this work? using Genie, Stipple using Genie.Requests using StippleUI Genie.config.cors\_headers\["Access-Control-Allow-Origin"\] = "\*" Genie.config.cors\_headers\["Access-Control-Allow-Headers"\] = "Content-Typ…

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## [Declare type of @variable (e.g. complex) in ModelingToolkit.jl](https://discourse.julialang.org/t/declare-type-of-variable-e-g-complex-in-modelingtoolkit-jl/59563)

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**Author:** [@Sciemon](https://discourse.julialang.org/u/Sciemon)\
**Replies:** 4\
**Last updated:** [May 23, 2022, 12:57pm UTC](https://discourse.julialang.org/t/declare-type-of-variable-e-g-complex-in-modelingtoolkit-jl/59563 "2022-05-23T12:57:27Z")

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Is there a way to declare the type of a variable in ModelingToolkit.jl? For example something like @variables a(t)::complex I’m excited to start with ModelingToolkit.jl having followed its development for a while. In m…

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## [MLJ.fit! complain "UndefVarError: level not defined" in a sysimage](https://discourse.julialang.org/t/mlj-fit-complain-undefvarerror-level-not-defined-in-a-sysimage/81499)

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**Author:** [@tiZ](https://discourse.julialang.org/u/tiZ)\
**Replies:** 1\
**Last updated:** [May 23, 2022, 9:48am UTC](https://discourse.julialang.org/t/mlj-fit-complain-undefvarerror-level-not-defined-in-a-sysimage/81499 "2022-05-23T09:48:45Z")

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Hello, I try to fit a simple logistic regression in Julia, with a sysimage, which loaded these packages : “OhMyREPL” “Plots” “GLMakie” “DataFrames” “RCall” “PyCall” “CSV” “Flux” “Random” “TensorBoardLogger” Here is m…

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## [Define variables on each elemnts of a vector of vectors](https://discourse.julialang.org/t/define-variables-on-each-elemnts-of-a-vector-of-vectors/81495)

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**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 2\
**Last updated:** [May 23, 2022, 9:42am UTC](https://discourse.julialang.org/t/define-variables-on-each-elemnts-of-a-vector-of-vectors/81495 "2022-05-23T09:42:54Z")

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I’m trying to find a way to define a varible x\_ijk where i in I is an n-elemnts vector of vectors, j in J and k in K are both vectors. In my case, always the length of K is equal to the number of vectors in I . The que…

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