# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=198

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**Page:** 199

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## [How to efficiently differentiate backslash operator for sparse matrix?](https://discourse.julialang.org/t/how-to-efficiently-differentiate-backslash-operator-for-sparse-matrix/43778)

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**Author:** [@Liang\_Chen](https://discourse.julialang.org/u/Liang_Chen)\
**Replies:** 23\
**Last updated:** [May 1, 2023, 4:21pm UTC](https://discourse.julialang.org/t/how-to-efficiently-differentiate-backslash-operator-for-sparse-matrix/43778 "2023-05-01T16:21:24Z")

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My problem is to calculate the gradient, dL(u)/dp, where L() is a loss function which takes a vector u as the input and outputs a scalar value. The vector p are parameters that defines a large sparse matrix K, such that K…

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## [How to fix this error when I use JUMP to maximize a function?](https://discourse.julialang.org/t/how-to-fix-this-error-when-i-use-jump-to-maximize-a-function/98155)

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**Author:** [@maoc](https://discourse.julialang.org/u/maoc)\
**Replies:** 1\
**Last updated:** [May 1, 2023, 9:53am UTC](https://discourse.julialang.org/t/how-to-fix-this-error-when-i-use-jump-to-maximize-a-function/98155 "2023-05-01T09:53:57Z")

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I’m trying to optimize a likelihood function a little different from the traditional ones. I’m going to call this likelihood function of mine “faux”. To show my problem, first see how well this example (I took this examp…

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## [OpenStreetMapX: How to efficiently convert node\_id to vertex\_id?](https://discourse.julialang.org/t/openstreetmapx-how-to-efficiently-convert-node-id-to-vertex-id/98139)

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**Author:** [@Yao\_Vang](https://discourse.julialang.org/u/Yao_Vang)\
**Replies:** 2\
**Last updated:** [May 1, 2023, 9:05am UTC](https://discourse.julialang.org/t/openstreetmapx-how-to-efficiently-convert-node-id-to-vertex-id/98139 "2023-05-01T09:05:24Z")

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Hello all When calling any routing opetion in openstreetmapX it expects node\_id and in the answer it also returns node\_id. for example: m = get\_map\_data(File\_path, use\_cache=false, trim\_to\_connected\_graph=true ); a,b =…

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## [Render Pipeline in Metal.jl](https://discourse.julialang.org/t/render-pipeline-in-metal-jl/97847)

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**Author:** [@dchang10](https://discourse.julialang.org/u/dchang10)\
**Replies:** 9\
**Last updated:** [April 30, 2023, 5:07pm UTC](https://discourse.julialang.org/t/render-pipeline-in-metal-jl/97847 "2023-04-30T17:07:49Z")

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I’m currently trying to set up a render pipeline with Metal.jl by defining a vertex shader, rasterizer and fragment shader, but am not sure how to go about it. Is there an example or description of how this is done with …

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## [Vectorization, or boundary tracing in julia](https://discourse.julialang.org/t/vectorization-or-boundary-tracing-in-julia/97638)

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**Author:** [@alex-s-gardner](https://discourse.julialang.org/u/alex-s-gardner)\
**Replies:** 10\
**Last updated:** [April 30, 2023, 4:14pm UTC](https://discourse.julialang.org/t/vectorization-or-boundary-tracing-in-julia/97638 "2023-04-30T16:14:38Z")

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Does anyone know of a julia package that can generate vectors/polygons (i,j) for the boundaries of areas found within a BitMatrix.

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## [Microsimulation with Agents?](https://discourse.julialang.org/t/microsimulation-with-agents/98119)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 3\
**Last updated:** [April 30, 2023, 1:10pm UTC](https://discourse.julialang.org/t/microsimulation-with-agents/98119 "2023-04-30T13:10:46Z")

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Is it possible to do a micro-simulation using Agents.jl? Some software pretend to do ABM and micro-simulation. Can it be real? What would be the right packages to do it in Julia?

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## [How to draw a circle of 500m away from a point on a map? or how to highlight all connected ways?](https://discourse.julialang.org/t/how-to-draw-a-circle-of-500m-away-from-a-point-on-a-map-or-how-to-highlight-all-connected-ways/98093)

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**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 5\
**Last updated:** [April 30, 2023, 12:42pm UTC](https://discourse.julialang.org/t/how-to-draw-a-circle-of-500m-away-from-a-point-on-a-map-or-how-to-highlight-all-connected-ways/98093 "2023-04-30T12:42:36Z")

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Is it possible to draw a circle around a coordinates? I knew that with folium one can plot a points on a map: using OpenStreetMapX using PyCall points = LLA(43.658813, -79.397574, 0.0) using PyCall flm = pyimport("f…

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## [Prefixing output columns which are returned as Dataframe](https://discourse.julialang.org/t/prefixing-output-columns-which-are-returned-as-dataframe/98098)

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**Author:** [@mreichMPI-BGC](https://discourse.julialang.org/u/mreichMPI-BGC)\
**Replies:** 9\
**Last updated:** [April 30, 2023, 9:36am UTC](https://discourse.julialang.org/t/prefixing-output-columns-which-are-returned-as-dataframe/98098 "2023-04-30T09:36:31Z")

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Sorry, I am stuck a bit…: Suppose I have a function that takes Vectors and returns a DataFrame of the same length as the Vectors (e.g. my calc function below). function calc(x1,x2) y1 = accumulate(+, x1+x2 .+ 0.1ra…

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## [Problem processing TCP CONNECT REFUSED in Julia](https://discourse.julialang.org/t/problem-processing-tcp-connect-refused-in-julia/98096)

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**Author:** [@Charles\_Brauer](https://discourse.julialang.org/u/Charles_Brauer)\
**Replies:** 3\
**Last updated:** [April 30, 2023, 1:36am UTC](https://discourse.julialang.org/t/problem-processing-tcp-connect-refused-in-julia/98096 "2023-04-30T01:36:23Z")

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Hey Guys, I am trying to convert some C# code that processes real-time data streaming of financial data. My application uses the TCP socket-based client from https://www.IQFeed.net to receive the data during market hou…

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## [Robust Mahalanobis distance in high-dimensions with limited samples](https://discourse.julialang.org/t/robust-mahalanobis-distance-in-high-dimensions-with-limited-samples/98089)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 2\
**Last updated:** [April 29, 2023, 9:15pm UTC](https://discourse.julialang.org/t/robust-mahalanobis-distance-in-high-dimensions-with-limited-samples/98089 "2023-04-29T21:15:51Z")

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Hello, I would like to use an iterative algorithm to estimate the parameters of a t-distribution \\pi\_X characterized by a mean \\mu \\in \\mathbb{R}^n, a PSD scale matrix C \\in \\mathbb{R}^{Nx \\times Nx}, and a degree of fr…

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## [Package for KPCA](https://discourse.julialang.org/t/package-for-kpca/74248)

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**Author:** [@roh\_codeur](https://discourse.julialang.org/u/roh_codeur)\
**Replies:** 3\
**Last updated:** [April 29, 2023, 9:17pm UTC](https://discourse.julialang.org/t/package-for-kpca/74248 "2023-04-29T21:17:18Z")

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Hi, I am a newbie to Julia. I am looking for a package for KPCA please. I tried using MultivariateStats, unfortunately, ran into the below issue https://github.com/JuliaStats/MultivariateStats.jl/issues/164 I couldn’t …

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## [How to get the variables/constraint names using MathProgBase?](https://discourse.julialang.org/t/how-to-get-the-variables-constraint-names-using-mathprogbase/40511)

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**Author:** [@sugyeong-jo](https://discourse.julialang.org/u/sugyeong-jo)\
**Replies:** 12\
**Last updated:** [April 29, 2023, 1:51pm UTC](https://discourse.julialang.org/t/how-to-get-the-variables-constraint-names-using-mathprogbase/40511 "2023-04-29T13:51:05Z")

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Is there any method for getting the variables/constraint name not a just index from the MPS file format? I just want to make a dictionary for “variable name - index, constraint name - index” model = MathProgBase.Linear…

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## [Maximum likelihood for t-distribution by gradient descent](https://discourse.julialang.org/t/maximum-likelihood-for-t-distribution-by-gradient-descent/97954)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 24\
**Last updated:** [April 28, 2023, 5:37pm UTC](https://discourse.julialang.org/t/maximum-likelihood-for-t-distribution-by-gradient-descent/97954 "2023-04-28T17:37:38Z")

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Hello, I am interested in the estimation of parameters of a multivariate t-distribution from samples. A multivariate random variable X \\in \\mathbb{R}^n with density \\pi\_X is characterized by a mean vector \\mu \\in \\math…

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## [Last Call: Optimization Modeling session @ fall INFORMS](https://discourse.julialang.org/t/last-call-optimization-modeling-session-fall-informs/98053)

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**Author:** [@4er](https://discourse.julialang.org/u/4er)\
**Replies:** 0\
**Last updated:** [April 28, 2023, 5:11pm UTC](https://discourse.julialang.org/t/last-call-optimization-modeling-session-fall-informs/98053 "2023-04-28T17:11:48Z")

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LAST CALL! Optimization Modeling Software session INFORMS Annual Meeting, October 15-18, 2023 Deadline for speaker names: Tuesday, May 2 Deadline for abstracts: Tuesday, May 16 To participate in this session, you ne…

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## [Cannot precompile CImGui for Julia 1.8.5 on MacOS (Ventura 13.3.1)](https://discourse.julialang.org/t/cannot-precompile-cimgui-for-julia-1-8-5-on-macos-ventura-13-3-1/98037)

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**Author:** [@Fummelknabe](https://discourse.julialang.org/u/Fummelknabe)\
**Replies:** 0\
**Last updated:** [April 28, 2023, 11:56am UTC](https://discourse.julialang.org/t/cannot-precompile-cimgui-for-julia-1-8-5-on-macos-ventura-13-3-1/98037 "2023-04-28T11:56:20Z")

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I’ve been using the great Julia wrapper for the CImGui for quiet a while now and never encountered any problems. Recently I wanted to run Julia on MacOS and CImGui failed at precompiling. I am using CImGui.jl v1.79.0. T…

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## [Twinx shows left yticks on right y axis](https://discourse.julialang.org/t/twinx-shows-left-yticks-on-right-y-axis/57372)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 6\
**Last updated:** [April 28, 2023, 11:44am UTC](https://discourse.julialang.org/t/twinx-shows-left-yticks-on-right-y-axis/57372 "2023-04-28T11:44:24Z")

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I am struggling to generate a plot with two y-axes. The left y-ticks show up on the right y-axis. Also, I am uisng rightmargin = 1.5Plots.cm, box = :on because the label margins are broken. using Plots pyplot() plot(…

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## [Using feasRelax in Julia with Gurobi and JuMP](https://discourse.julialang.org/t/using-feasrelax-in-julia-with-gurobi-and-jump/97935)

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**Author:** [@umbe](https://discourse.julialang.org/u/umbe)\
**Replies:** 3\
**Last updated:** [April 28, 2023, 10:17am UTC](https://discourse.julialang.org/t/using-feasrelax-in-julia-with-gurobi-and-jump/97935 "2023-04-28T10:17:01Z")

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Hello to everyone! I have an optimization problem that, according to some input data, can be unfeasible. I would like to check the termination status and, in case of infeasibility, try to solve it relaxing some constrai…

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## [Plot in plot at grdipoint using Plots.jl](https://discourse.julialang.org/t/plot-in-plot-at-grdipoint-using-plots-jl/98002)

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**Author:** [@psterzinger](https://discourse.julialang.org/u/psterzinger)\
**Replies:** 2\
**Last updated:** [April 28, 2023, 7:11am UTC](https://discourse.julialang.org/t/plot-in-plot-at-grdipoint-using-plots-jl/98002 "2023-04-28T07:11:07Z")

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I am trying to make a plot, in which I want to position another shrunk plot at certain coordinates of my first plot (MWE below). Following the example at the end of the Layouts manual, I can, given a base plot p, use P…

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## [Code was trapped at display(plt) step](https://discourse.julialang.org/t/code-was-trapped-at-display-plt-step/98013)

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**Author:** [@jianqixi](https://discourse.julialang.org/u/jianqixi)\
**Replies:** 1\
**Last updated:** [April 27, 2023, 9:28pm UTC](https://discourse.julialang.org/t/code-was-trapped-at-display-plt-step/98013 "2023-04-27T21:28:16Z")

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Hi I am trying to use Plots.jl with default backends GR to plot figures. But the code was trapped in the display(plt) process. Any ideas about what happened? Thank you Here is my code: plt=scatter3d(tar\_xs,tar\_ys,tar\_z…

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## [MPIClusterManagers task split across nodes](https://discourse.julialang.org/t/mpiclustermanagers-task-split-across-nodes/97983)

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**Author:** [@sparrowhawk](https://discourse.julialang.org/u/sparrowhawk)\
**Replies:** 2\
**Last updated:** [April 28, 2023, 2:02am UTC](https://discourse.julialang.org/t/mpiclustermanagers-task-split-across-nodes/97983 "2023-04-28T02:02:31Z")

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Hi all, I’ve been using Julia on the cluster quite successfully with MPIClusterManagers.jl and MPI.jl with the MPIClusterManagers.start\_main\_loop(MPI\_TRANSPORT\_ALL) option and using native julia constructs after that su…

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## [Plots.jl: Polar Plot w 0° at the Nadir](https://discourse.julialang.org/t/plots-jl-polar-plot-w-0-at-the-nadir/98010)

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**Author:** [@rmfritz](https://discourse.julialang.org/u/rmfritz)\
**Replies:** 1\
**Last updated:** [April 27, 2023, 8:47pm UTC](https://discourse.julialang.org/t/plots-jl-polar-plot-w-0-at-the-nadir/98010 "2023-04-27T20:47:59Z")

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Now that GR supports this, I’m trying to get it to work with plots.jl, and so far I can’t figure out how. This is one version of the code I tried and it doesn’t work. Am I missing something obvious? using Plots plot(deg…

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## [multiple-GPUs per process](https://discourse.julialang.org/t/multiple-gpus-per-process/98008)

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**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 3\
**Last updated:** [April 27, 2023, 8:18pm UTC](https://discourse.julialang.org/t/multiple-gpus-per-process/98008 "2023-04-27T20:18:26Z")

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i’m not sure whether i should file an issue on github because this is a bug, or post a plea for help here because i’m doing something wrong, but riffing on the multiple GPUs per process example, and adding to it an Array…

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## [Multiple independent random number streams](https://discourse.julialang.org/t/multiple-independent-random-number-streams/98004)

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**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 4\
**Last updated:** [April 27, 2023, 7:33pm UTC](https://discourse.julialang.org/t/multiple-independent-random-number-streams/98004 "2023-04-27T19:33:45Z")

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Goal Across many, e.g., 10,000, simulations, generate random data. Each simulation should be independent of the others. Must be able to recreate a particular simulation s without first running previous s-1 simulations. …

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## [Performance of Interpolations in Modeling toolkit](https://discourse.julialang.org/t/performance-of-interpolations-in-modeling-toolkit/97997)

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**Author:** [@HamzaKh99](https://discourse.julialang.org/u/HamzaKh99)\
**Replies:** 1\
**Last updated:** [April 27, 2023, 2:51pm UTC](https://discourse.julialang.org/t/performance-of-interpolations-in-modeling-toolkit/97997 "2023-04-27T14:51:51Z")

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Hello, I’m trying to create a lookup table function in modeling toolkit, for that I used Interpolations.jl to make an interpolation between elements of a table, my code is working perfectly fine but the problem is in th…

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## [Passing array as parameter to a PDESystem](https://discourse.julialang.org/t/passing-array-as-parameter-to-a-pdesystem/97407)

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**Author:** [@Mixpap](https://discourse.julialang.org/u/Mixpap)\
**Replies:** 12\
**Last updated:** [April 27, 2023, 12:08pm UTC](https://discourse.julialang.org/t/passing-array-as-parameter-to-a-pdesystem/97407 "2023-04-27T12:08:41Z")

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Hello, I am trying to solve an inverse diffusion+source problem based on some data on the surface of a cylinder. I already tried several PINN implementations I have used before but with no luck. What I am trying to do i…

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## [Monotone cubic spline interpolation on an irregular grid](https://discourse.julialang.org/t/monotone-cubic-spline-interpolation-on-an-irregular-grid/97977)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 2\
**Last updated:** [April 27, 2023, 10:45am UTC](https://discourse.julialang.org/t/monotone-cubic-spline-interpolation-on-an-irregular-grid/97977 "2023-04-27T10:45:49Z")

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Is there a package in Julia for interpolation using a monotone cubic spline interpolation on an irregular grid? I seem to be failing to find one. Interpolations.jl does provide monotone option, but only on a regular gri…

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## [Plotting Polygons in geomakie](https://discourse.julialang.org/t/plotting-polygons-in-geomakie/97948)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 2\
**Last updated:** [April 27, 2023, 7:33am UTC](https://discourse.julialang.org/t/plotting-polygons-in-geomakie/97948 "2023-04-27T07:33:46Z")

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Hello, I’m trying to make map of administrative regions in GeoMakie but the poly! function does not work with Polygons, unlike specified in the documentation (poly · Makie). Here’s a MWE: GeoJSON.write("data/DE\_regions.…

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## [Simulating a dynamic satellite constellation network using SatelliteToolbox.jl](https://discourse.julialang.org/t/simulating-a-dynamic-satellite-constellation-network-using-satellitetoolbox-jl/97979)

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**Author:** [@rafiulnakib](https://discourse.julialang.org/u/rafiulnakib)\
**Replies:** 1\
**Last updated:** [April 27, 2023, 6:20am UTC](https://discourse.julialang.org/t/simulating-a-dynamic-satellite-constellation-network-using-satellitetoolbox-jl/97979 "2023-04-27T06:20:43Z")

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Hi everyone, I am trying to simulate a dynamic satellite constellation network using SatelliteToolbox. The goal is to use this network and integrate it with the QuNet package for benchmarking and performance analysis as…

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## [Tagging values unique to a group in a dataframe](https://discourse.julialang.org/t/tagging-values-unique-to-a-group-in-a-dataframe/97967)

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**Author:** [@George9000](https://discourse.julialang.org/u/George9000)\
**Replies:** 2\
**Last updated:** [April 27, 2023, 1:59am UTC](https://discourse.julialang.org/t/tagging-values-unique-to-a-group-in-a-dataframe/97967 "2023-04-27T01:59:12Z")

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Say that I have a dataframe: function exampl() grp = Int8\[\] for i in 1:5 grp = append!(grp, fill(i, 7)) end values = Int8\[\] for i in 1:7 values = append!(values, rand(1:15, 5)) e…

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## [Naming constraints error](https://discourse.julialang.org/t/naming-constraints-error/97959)

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**Author:** [@irene\_ub](https://discourse.julialang.org/u/irene_ub)\
**Replies:** 1\
**Last updated:** [April 26, 2023, 10:57pm UTC](https://discourse.julialang.org/t/naming-constraints-error/97959 "2023-04-26T22:57:36Z")

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Hello, I have an optimization model, for which I’m trying to give names to its constraints so that I can write them to an lp file and find them easily. However, I’m having some trouble. The constraint specifically that…

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