# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=272

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**Page:** 273

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## [Using Optim.jl but failing to find minimum](https://discourse.julialang.org/t/using-optim-jl-but-failing-to-find-minimum/82751)

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**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 6\
**Last updated:** [June 19, 2022, 1:44pm UTC](https://discourse.julialang.org/t/using-optim-jl-but-failing-to-find-minimum/82751 "2022-06-19T13:44:05Z")

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I’m trying to minimize parameters to fit an HMM. It works part of the way, but it seems to get stuck for some points, often not too distant from the initial guess. If I examine the one-dimensional path of the objective …

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## [HPC systems with Julia support](https://discourse.julialang.org/t/hpc-systems-with-julia-support/82951)

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**Author:** [@sloede](https://discourse.julialang.org/u/sloede)\
**Replies:** 4\
**Last updated:** [June 19, 2022, 10:30am UTC](https://discourse.julialang.org/t/hpc-systems-with-julia-support/82951 "2022-06-19T10:30:23Z")

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Hey everyone! I am trying to collect information about HPC systems (from university compute clusters to supercomputers) where Julia is available as a pre-installed module and, optimally, officially supported. This is par…

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## [COSMO.jl: SecondOrderCone](https://discourse.julialang.org/t/cosmo-jl-secondordercone/82497)

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**Author:** [@DanDoe](https://discourse.julialang.org/u/DanDoe)\
**Replies:** 4\
**Last updated:** [June 19, 2022, 10:15am UTC](https://discourse.julialang.org/t/cosmo-jl-secondordercone/82497 "2022-06-19T10:15:03Z")

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I would like to use the COSMO optimizing package for a second order cone program. I have a constraint of the form \\Vert A \\boldsymbol x + \\boldsymbol b \\Vert\_2 \\leq 1 which seems to be a perfect fit for the COSMO.Cons…

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## [How to define a lower triangular decision matrix](https://discourse.julialang.org/t/how-to-define-a-lower-triangular-decision-matrix/82677)

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**Author:** [@Tri](https://discourse.julialang.org/u/Tri)\
**Replies:** 7\
**Last updated:** [June 19, 2022, 3:35am UTC](https://discourse.julialang.org/t/how-to-define-a-lower-triangular-decision-matrix/82677 "2022-06-19T03:35:34Z")

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Is there an efficient way to define a lower triangular matrix (other than defining n by n matrix and adding a constraint that sets every upper triangular element to be zero). I tried the following but it resulted in an …

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## [Parallel reductions](https://discourse.julialang.org/t/parallel-reductions/30180)

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**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 23\
**Last updated:** [June 19, 2022, 2:43am UTC](https://discourse.julialang.org/t/parallel-reductions/30180 "2022-06-19T02:43:50Z")

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“Parallel mapreduce” is a really common need, and it’s surprisingly hard to find a Julia implementation. Say we have julia\> x = randn(10000000); julia\> f = log∘sqrt∘abs #56 (generic function with 1 method) The goal i…

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## [Makie - how to get mesh coordinates after transformation of the parent scene](https://discourse.julialang.org/t/makie-how-to-get-mesh-coordinates-after-transformation-of-the-parent-scene/82987)

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**Author:** [@danbulnet](https://discourse.julialang.org/u/danbulnet)\
**Replies:** 0\
**Last updated:** [June 18, 2022, 11:54pm UTC](https://discourse.julialang.org/t/makie-how-to-get-mesh-coordinates-after-transformation-of-the-parent-scene/82987 "2022-06-18T23:54:51Z")

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Hello, I’ve got stuck with this: I don’t know how to find the actual mesh coordinates (mesh created using mesh!(scene, ...) function) after rotation and translation have been applied on the parent scene. I tried with m…

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## [@variables parsing breaks on default value?](https://discourse.julialang.org/t/variables-parsing-breaks-on-default-value/82970)

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**Author:** [@dodoplus](https://discourse.julialang.org/u/dodoplus)\
**Replies:** 3\
**Last updated:** [June 18, 2022, 6:18pm UTC](https://discourse.julialang.org/t/variables-parsing-breaks-on-default-value/82970 "2022-06-18T18:18:39Z")

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This code snippet: sts = @variables begin m\_flow(t), \[connect=Flow\], T(t)=T0, \[connect=Stream\] end Fails with: LoadError: AssertionError: @variables expects a tuple of expressions or an expression of a tuple (…

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## [Catalyst Jump model and callbacks](https://discourse.julialang.org/t/catalyst-jump-model-and-callbacks/82967)

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**Author:** [@jae0](https://discourse.julialang.org/u/jae0)\
**Replies:** 7\
**Last updated:** [June 18, 2022, 1:46pm UTC](https://discourse.julialang.org/t/catalyst-jump-model-and-callbacks/82967 "2022-06-18T13:46:57Z")

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Hello, this is a question that looks related to the following: I am hoping to perturb the system state at multiple times using Catalyst / DiscreteProblem / JumpProblem. I have found the above answer as well as the re…

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## [Parallelizing GSA - A size issue](https://discourse.julialang.org/t/parallelizing-gsa-a-size-issue/82964)

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**Author:** [@xztt](https://discourse.julialang.org/u/xztt)\
**Replies:** 1\
**Last updated:** [June 18, 2022, 12:43pm UTC](https://discourse.julialang.org/t/parallelizing-gsa-a-size-issue/82964 "2022-06-18T12:43:27Z")

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Hi, I am looking to try and speed up my code and trying to following the example in the documentation here On running the below x = \[prob.u0;prob.p\] function circ(x) prob\_func(prob,i,repeat) = remake(prob;u0 = x\[1…

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## [How to define constraints on a collection of vectors separately?](https://discourse.julialang.org/t/how-to-define-constraints-on-a-collection-of-vectors-separately/82926)

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**Author:** [@Kevin\_12](https://discourse.julialang.org/u/Kevin_12)\
**Replies:** 2\
**Last updated:** [June 18, 2022, 9:28am UTC](https://discourse.julialang.org/t/how-to-define-constraints-on-a-collection-of-vectors-separately/82926 "2022-06-18T09:28:15Z")

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The original problem is so larg. But, Suppose we have this small set of vectors A = \[ \[ \[13, 48,99\] , \[71, 58, 99\]\], \[\[91, 59, 22\], \[94, 86, 22\], \[71, 58, 22\], \[19,55,22\]\], \[\[41, 79, 12\], \[23, 16, 12\],…

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## [Automatic differentiation and Trapz](https://discourse.julialang.org/t/automatic-differentiation-and-trapz/82135)

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**Author:** [@chupin](https://discourse.julialang.org/u/chupin)\
**Replies:** 10\
**Last updated:** [June 18, 2022, 5:53am UTC](https://discourse.julialang.org/t/automatic-differentiation-and-trapz/82135 "2022-06-18T05:53:18Z")

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It seems that Nonconvex is not able to deal with the trapz function, but maybe, I’ve done something wrong. The code (that is a nonsense toy code) : using Nonconvex Nonconvex.@load Ipopt using Trapz function obj(hV,N,M)…

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## [Xpress Julia API has bug with fixing variables](https://discourse.julialang.org/t/xpress-julia-api-has-bug-with-fixing-variables/82895)

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**Author:** [@Popeye](https://discourse.julialang.org/u/Popeye)\
**Replies:** 5\
**Last updated:** [June 18, 2022, 5:38am UTC](https://discourse.julialang.org/t/xpress-julia-api-has-bug-with-fixing-variables/82895 "2022-06-18T05:38:40Z")

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Fixing variables does not seems to be working with the Xpress solver. I used the example below (which was posted by someone on this forum) to create this MWE. I fix one of the variables as zero but it seems like JuMP is…

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## [Very simple statistic needed](https://discourse.julialang.org/t/very-simple-statistic-needed/82923)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 6\
**Last updated:** [June 17, 2022, 3:54pm UTC](https://discourse.julialang.org/t/very-simple-statistic-needed/82923 "2022-06-17T15:54:33Z")

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I have a very simple task: I have a list of CAN bus addresses like this: 1236454-element Vector{Union{Missing, Int64}}: 65 65 48 48 49 49 50 50 ⋮ 57 65 58 58 65 59 59 Because all numbers are below 128 …

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## [Background image with specific coordinates in Plots.jl](https://discourse.julialang.org/t/background-image-with-specific-coordinates-in-plots-jl/82905)

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**Author:** [@unis](https://discourse.julialang.org/u/unis)\
**Replies:** 1\
**Last updated:** [June 17, 2022, 12:08pm UTC](https://discourse.julialang.org/t/background-image-with-specific-coordinates-in-plots-jl/82905 "2022-06-17T12:08:03Z")

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How can a background image be added at specific coordinates (and with a specific scale) on a Plots.jl plot? Assume you have an image of a floor plan whose corner points are associated with specific coordinates, and you’…

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## [How to plot a 2D rotated array](https://discourse.julialang.org/t/how-to-plot-a-2d-rotated-array/47603)

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**Author:** [@luraess](https://discourse.julialang.org/u/luraess)\
**Replies:** 17\
**Last updated:** [June 17, 2022, 8:58am UTC](https://discourse.julialang.org/t/how-to-plot-a-2d-rotated-array/47603 "2022-06-17T08:58:01Z")

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I am trying to plot a heatmap (or contourf, or similar) of a 2D array as function of rotated x and y coordinates. Here a code snippet of what I am trying to achieve: using Plots α = 10.0 lx, ly = 300.0, 100.0 nx, n…

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## [MultivariateStats.transform ,MethodError:](https://discourse.julialang.org/t/multivariatestats-transform-methoderror/82825)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 3\
**Last updated:** [June 17, 2022, 7:23am UTC](https://discourse.julialang.org/t/multivariatestats-transform-methoderror/82825 "2022-06-17T07:23:19Z")

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How to overcome that Method error ? Data 7043×2 Matrix{Float64}: -1.27735 -1.16024 0.0663227 -0.259611 -1.23664 -0.362635 0.514215 -0.746482 -1.23664 0.197351 -0.992332 1.15946 -0.422287 …

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## [Watch folder and plot new data in Makie](https://discourse.julialang.org/t/watch-folder-and-plot-new-data-in-makie/82796)

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**Author:** [@garrek](https://discourse.julialang.org/u/garrek)\
**Replies:** 1\
**Last updated:** [June 17, 2022, 4:30am UTC](https://discourse.julialang.org/t/watch-folder-and-plot-new-data-in-makie/82796 "2022-06-17T04:30:54Z")

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I have an experiment where a detector collects data and then writes a file. I want to watch a folder and when a new file appears, I want to load the data and plot it using GLMakie. I am almost there but I’m hitting one …

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## [ParseError: KaTeX parse error: No such environment: tabular at position 7: \\begin{̲t̲a̲b̲u̲l̲a̲r̲}̲ {l | r | r | r…](https://discourse.julialang.org/t/parseerror-katex-parse-error-no-such-environment-tabular-at-position-7-begin-t-a-b-u-l-a-r-l-r-r-r/82889)

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**Author:** [@Aesth\_Estheticism](https://discourse.julialang.org/u/Aesth_Estheticism)\
**Replies:** 3\
**Last updated:** [June 17, 2022, 3:25am UTC](https://discourse.julialang.org/t/parseerror-katex-parse-error-no-such-environment-tabular-at-position-7-begin-t-a-b-u-l-a-r-l-r-r-r/82889 "2022-06-17T03:25:21Z")

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When I used the default code of MixedModels package, and a error happened that “ParseError: KaTeX parse error: No such environment: tabular at position 7: \\begin{̲t̲a̲b̲u̲l̲a̲r̲}̲ {l | r | r | r…”. The default code are …

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## [Is it possible to train sparse neural networks in GPU?](https://discourse.julialang.org/t/is-it-possible-to-train-sparse-neural-networks-in-gpu/82680)

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**Author:** [@paulobruno](https://discourse.julialang.org/u/paulobruno)\
**Replies:** 3\
**Last updated:** [June 17, 2022, 2:57am UTC](https://discourse.julialang.org/t/is-it-possible-to-train-sparse-neural-networks-in-gpu/82680 "2022-06-17T02:57:34Z")

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I would like to train a sparse neural network using Flux. I can train it in CPU, but I would like to do it using GPU, profiting from CuSparseMatrixCSC. However, when I try to run the code below I get ERROR: LoadError: Th…

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## [JuMP -- MethodError: no method matching \_parse\_section](https://discourse.julialang.org/t/jump-methoderror-no-method-matching-parse-section/82884)

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**Author:** [@freiburgermsu](https://discourse.julialang.org/u/freiburgermsu)\
**Replies:** 1\
**Last updated:** [June 16, 2022, 8:44pm UTC](https://discourse.julialang.org/t/jump-methoderror-no-method-matching-parse-section/82884 "2022-06-16T20:44:25Z")

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Hello, I receive the following error message ERROR: MethodError: no method matching \_parse\_section(::Val{:header}, ::MathOptInterface.Utilities.GenericModel{Float64, MathOptInterface.Utilities.ObjectiveContainer{Float6…

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## [Fixing MIP problem integer variables to get Duals](https://discourse.julialang.org/t/fixing-mip-problem-integer-variables-to-get-duals/82885)

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**Author:** [@Di11on](https://discourse.julialang.org/u/Di11on)\
**Replies:** 1\
**Last updated:** [June 16, 2022, 6:41pm UTC](https://discourse.julialang.org/t/fixing-mip-problem-integer-variables-to-get-duals/82885 "2022-06-16T18:41:50Z")

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Hi folks, We are solving large models iteratively. It’s a mip problem and to calculate duals, we fix the binary and integer variables and use unset\_binary() and then unset\_integer() to remove the constraints, then solve…

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## [JuMP register polynomial with its gradient](https://discourse.julialang.org/t/jump-register-polynomial-with-its-gradient/82876)

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**Author:** [@Luca](https://discourse.julialang.org/u/Luca)\
**Replies:** 1\
**Last updated:** [June 16, 2022, 6:39pm UTC](https://discourse.julialang.org/t/jump-register-polynomial-with-its-gradient/82876 "2022-06-16T18:39:55Z")

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Dear all, I am using jump and I want to register a polynomial function with its gradient, with register(model2, :poly, num\_var, poly, gradient) I build the polynomial with AbstractAlgebra.jl and the gradient with the …

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## [MTK and JuMP](https://discourse.julialang.org/t/mtk-and-jump/58161)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 6\
**Last updated:** [June 16, 2022, 3:15pm UTC](https://discourse.julialang.org/t/mtk-and-jump/58161 "2022-06-16T15:15:24Z")

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I would like to use MTK to build a physical model and than use the equations and convert them into a JuMP model. Any ideas how to do that? My thoughs (based on Automatic Conversion of Julia Code to C Functions · Symboli…

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## [Computing Concave hull/alpha shape for a point cloud](https://discourse.julialang.org/t/computing-concave-hull-alpha-shape-for-a-point-cloud/82746)

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**Author:** [@arsh](https://discourse.julialang.org/u/arsh)\
**Replies:** 14\
**Last updated:** [June 16, 2022, 2:56pm UTC](https://discourse.julialang.org/t/computing-concave-hull-alpha-shape-for-a-point-cloud/82746 "2022-06-16T14:56:14Z")

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I have a point cloud and I want to find it’s outline(also includes holes). Eg: A delaunay triangulation of such point cloud might look like I have tried to use existing tools in the ecosystem but most of them don’t s…

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## [RFC: Mitsuba2.jl - differentiable physics-based renderer](https://discourse.julialang.org/t/rfc-mitsuba2-jl-differentiable-physics-based-renderer/82879)

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**Author:** [@alhirzel](https://discourse.julialang.org/u/alhirzel)\
**Replies:** 0\
**Last updated:** [June 16, 2022, 2:21pm UTC](https://discourse.julialang.org/t/rfc-mitsuba2-jl-differentiable-physics-based-renderer/82879 "2022-06-16T14:21:24Z")

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Hey all, I wanted to share a package I started, and I am hoping to get feedback from anyone who is interested in physics-based rendering. My package, Mitsuba2.jl, brings the Mitsuba 2 renderer into Julia via its Python i…

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## [I didn't ask for plan\_bfft, but got MethodError: no method matching plan\_bfft(::Vector{Number}, ::UnitRange{Int64})](https://discourse.julialang.org/t/i-didnt-ask-for-plan-bfft-but-got-methoderror-no-method-matching-plan-bfft-vector-number-unitrange-int64/82791)

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**Author:** [@Yly](https://discourse.julialang.org/u/Yly)\
**Replies:** 3\
**Last updated:** [June 16, 2022, 6:57am UTC](https://discourse.julialang.org/t/i-didnt-ask-for-plan-bfft-but-got-methoderror-no-method-matching-plan-bfft-vector-number-unitrange-int64/82791 "2022-06-16T06:57:24Z")

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While coding an iterative FFT function, I came upon a strange bug that depends on the arguments to the function in a complicated way. I’ve managed to reduce the problematic code to the following: using FFTW unitize(x::…

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## [Plotting a weighted tree graph](https://discourse.julialang.org/t/plotting-a-weighted-tree-graph/82637)

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**Author:** [@devanshu](https://discourse.julialang.org/u/devanshu)\
**Replies:** 14\
**Last updated:** [June 16, 2022, 5:31am UTC](https://discourse.julialang.org/t/plotting-a-weighted-tree-graph/82637 "2022-06-16T05:31:14Z")

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I am trying to plot a weighted graph using SimpleWeightedGraphs using GraphPlot. g = SimpleWeightedGraph(5) add\_edge!(g, 1, 2, 0.5) add\_edge!(g, 1, 3, 2.0) add\_edge!(g, 1, 4, 3.5) add\_edge!(g, 1, 5, 5.0) gplot(g) Bu…

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## [Inserting margins above plot title](https://discourse.julialang.org/t/inserting-margins-above-plot-title/82801)

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**Author:** [@neuro\_enthusiast](https://discourse.julialang.org/u/neuro_enthusiast)\
**Replies:** 2\
**Last updated:** [June 16, 2022, 3:54am UTC](https://discourse.julialang.org/t/inserting-margins-above-plot-title/82801 "2022-06-16T03:54:19Z")

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Hi all! I’m trying to insert margin above the plot title but am unsure how. Any help would be great! For context, I have been using Plots.jl and Measures.jl to insert margins but top\_margin only inserted space between t…

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## [Solar radiation hitting different parts of earth's surface at specific time](https://discourse.julialang.org/t/solar-radiation-hitting-different-parts-of-earths-surface-at-specific-time/82565)

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**Author:** [@water](https://discourse.julialang.org/u/water)\
**Replies:** 5\
**Last updated:** [June 15, 2022, 11:14pm UTC](https://discourse.julialang.org/t/solar-radiation-hitting-different-parts-of-earths-surface-at-specific-time/82565 "2022-06-15T23:14:36Z")

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Hi, I want to calculate how much solar radiation is hitting different parts of earth’s surface at a specific time. I imagine a function that takes a datetime and returns a 361x181 matrix (where the array indices can be…

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## [Display ArchGDAL geotiff raster wants unsigned type?](https://discourse.julialang.org/t/display-archgdal-geotiff-raster-wants-unsigned-type/82813)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 2\
**Last updated:** [June 15, 2022, 8:02pm UTC](https://discourse.julialang.org/t/display-archgdal-geotiff-raster-wants-unsigned-type/82813 "2022-06-15T20:02:06Z")

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I wanted to look at this raster with ArchGDAL: using ArchGDAL (loaded raster from disk) julia\> e GDAL Dataset (Driver: GTiff/GeoTIFF) File(s): /Users/florian.oswald/Downloads/population\_fra\_2019-07-01\_geotiff/popula…

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