# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=292

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**Page:** 293

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## [Adaptive SDESolver yields "Warning: dt \<= dtmin. Aborting", unsure why, large non-adaptive dt works fine](https://discourse.julialang.org/t/adaptive-sdesolver-yields-warning-dt-dtmin-aborting-unsure-why-large-non-adaptive-dt-works-fine/78859)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 5\
**Last updated:** [April 4, 2022, 4:20pm UTC](https://discourse.julialang.org/t/adaptive-sdesolver-yields-warning-dt-dtmin-aborting-unsure-why-large-non-adaptive-dt-works-fine/78859 "2022-04-04T16:20:26Z")

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I have a simple model, which I am trying to simulate, however, I am getting ┌ Warning: dt \<= dtmin. Aborting. There is either an error in your model specification or the true solution is unstable. └ @ SciMLBase /home/SL…

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## [How to calculate derivative by Lagrange interpolation](https://discourse.julialang.org/t/how-to-calculate-derivative-by-lagrange-interpolation/74905)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 5\
**Last updated:** [April 4, 2022, 4:11pm UTC](https://discourse.julialang.org/t/how-to-calculate-derivative-by-lagrange-interpolation/74905 "2022-04-04T16:11:42Z")

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hi All, is there a pkg to calculate derivative at untabulated points using langrange interpolation? Thanks M

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## [Plot of OSM.test\_map() offered in agents.jl seem incorrect](https://discourse.julialang.org/t/plot-of-osm-test-map-offered-in-agents-jl-seem-incorrect/78948)

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**Author:** [@imantha](https://discourse.julialang.org/u/imantha)\
**Replies:** 4\
**Last updated:** [April 4, 2022, 3:35pm UTC](https://discourse.julialang.org/t/plot-of-osm-test-map-offered-in-agents-jl-seem-incorrect/78948 "2022-04-04T15:35:02Z")

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Hi, I recently updated agents.jl → 5.0.0 and InteractiveDynamics.jl → 0.20.1. I am trying to use abmvideo() and ambplot() functions to plot an openstreet test map offered by the package. However something seems to be in…

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## [Dense layer field alias](https://discourse.julialang.org/t/dense-layer-field-alias/78993)

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**Author:** [@Rasmus\_Hoier](https://discourse.julialang.org/u/Rasmus_Hoier)\
**Replies:** 2\
**Last updated:** [April 4, 2022, 10:28am UTC](https://discourse.julialang.org/t/dense-layer-field-alias/78993 "2022-04-04T10:28:45Z")

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Hi, I am writing a custom layer and am trying to emulate the UI of Flux layers. In the definition of Flux’s Dense layer the Dense struct has a field weight, but this field also has a kind of alias W. How/where is this a…

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## [A piece-wise defined objective function can be solved by Gurobi?](https://discourse.julialang.org/t/a-piece-wise-defined-objective-function-can-be-solved-by-gurobi/78959)

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**Author:** [@Jian\_ZUO](https://discourse.julialang.org/u/Jian_ZUO)\
**Replies:** 7\
**Last updated:** [April 4, 2022, 7:44am UTC](https://discourse.julialang.org/t/a-piece-wise-defined-objective-function-can-be-solved-by-gurobi/78959 "2022-04-04T07:44:04Z")

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Hi, I have an optimization with a piece-wise defined objective as follows: using JuMP, Ipopt using Gurobi T\_fc = \[0, 185, 348, 515, 658, 830\] R\_fc = \[0.1803, 0.1978, 0.2033, 0.2092, 0.2157, 0.2254\] const R0 = R\_fc\[1\] …

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## [Doc2Vec in Julia](https://discourse.julialang.org/t/doc2vec-in-julia/78907)

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**Author:** [@Salvatore\_Cosentino](https://discourse.julialang.org/u/Salvatore_Cosentino)\
**Replies:** 2\
**Last updated:** [April 4, 2022, 3:42am UTC](https://discourse.julialang.org/t/doc2vec-in-julia/78907 "2022-04-04T03:42:57Z")

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Hello everybody. I would like one of students to start learning Julia and move from Python. The project is working on uses Gensim module for Python, which allows for modelling semantic NLP problems. Specifically he is…

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## [Processing multiple large zipped csv files](https://discourse.julialang.org/t/processing-multiple-large-zipped-csv-files/78957)

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**Author:** [@thedacheng](https://discourse.julialang.org/u/thedacheng)\
**Replies:** 2\
**Last updated:** [April 4, 2022, 3:38am UTC](https://discourse.julialang.org/t/processing-multiple-large-zipped-csv-files/78957 "2022-04-04T03:38:40Z")

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I am trying to process multiple large zipped csv files. Memory consumption is my main concern at the moment. It seems CSV.File always load everything in memory, so I am using CSV.Rows to iterate through processing. I enc…

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## [Plot image at (x,y) location on scatter plot](https://discourse.julialang.org/t/plot-image-at-x-y-location-on-scatter-plot/78928)

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**Author:** [@afishy](https://discourse.julialang.org/u/afishy)\
**Replies:** 3\
**Last updated:** [April 4, 2022, 1:42am UTC](https://discourse.julialang.org/t/plot-image-at-x-y-location-on-scatter-plot/78928 "2022-04-04T01:42:55Z")

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Let’s say I’ve done some clustering on my data (like in the image below) and want to show a representative image (i.e. an MxN matrix) from that cluster overlaid at an (x,y) coordinate near that cluster’s center. Is this …

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## [Implementing r's stan\_glm() in Julia](https://discourse.julialang.org/t/implementing-rs-stan-glm-in-julia/78916)

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**Author:** [@charperflow](https://discourse.julialang.org/u/charperflow)\
**Replies:** 5\
**Last updated:** [April 3, 2022, 7:56pm UTC](https://discourse.julialang.org/t/implementing-rs-stan-glm-in-julia/78916 "2022-04-03T19:56:55Z")

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I am working through “Regression and Other Stories” for a class. All of the examples are done in R and I have been trying to recreate them in Julia for practice. For the most part it has been no problem, however, I am h…

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## [Turing: problem using MCMCthreads()](https://discourse.julialang.org/t/turing-problem-using-mcmcthreads/78906)

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**Author:** [@mcreel](https://discourse.julialang.org/u/mcreel)\
**Replies:** 8\
**Last updated:** [April 3, 2022, 4:12pm UTC](https://discourse.julialang.org/t/turing-problem-using-mcmcthreads/78906 "2022-04-03T16:12:15Z")

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I am getting an error when trying to use MCMCthreads() for sampling. The following code works fine: chain = sample(MSM(m, S, model), MH(:θt =\> AdvancedMH.RandomWalkProposal(MvNormal(zeros(size(m,1)), tuning\*Σp))), …

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## [A few questions about my workflow for quickly investigating data!](https://discourse.julialang.org/t/a-few-questions-about-my-workflow-for-quickly-investigating-data/78913)

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**Author:** [@charperflow](https://discourse.julialang.org/u/charperflow)\
**Replies:** 10\
**Last updated:** [April 3, 2022, 10:47am UTC](https://discourse.julialang.org/t/a-few-questions-about-my-workflow-for-quickly-investigating-data/78913 "2022-04-03T10:47:12Z")

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I am taking an upper level stats course taught in r. I have been doing a duplicate of the assignments in Julia, which has been a lot of fun. However, I have come across a few sticking points. I’ll just stick to one in th…

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## [TorchDrug equivalence in Julia?](https://discourse.julialang.org/t/torchdrug-equivalence-in-julia/78910)

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**Author:** [@DoktorMike](https://discourse.julialang.org/u/DoktorMike)\
**Replies:** 3\
**Last updated:** [April 2, 2022, 7:24pm UTC](https://discourse.julialang.org/t/torchdrug-equivalence-in-julia/78910 "2022-04-02T19:24:52Z")

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I ran into TorchDrug a few months ago and it looks really useful. Is anyone in this community doing drug discovery using Julia? My question is mainly due to thinking about how useful/hard it would be to create a communit…

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## [How to train Flux to learn a sequence conditional to some initial "seeds"?](https://discourse.julialang.org/t/how-to-train-flux-to-learn-a-sequence-conditional-to-some-initial-seeds/78330)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 4\
**Last updated:** [April 2, 2022, 7:15pm UTC](https://discourse.julialang.org/t/how-to-train-flux-to-learn-a-sequence-conditional-to-some-initial-seeds/78330 "2022-04-02T19:15:35Z")

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I am trying to write a RNN that given an initial “seed” sequence, it reproduces the continuation of the sequence. In the code above dummy sequences are generated as function of these initial seed points and a RNN approa…

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## [Join / Append dataLoaders structures](https://discourse.julialang.org/t/join-append-dataloaders-structures/78873)

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**Author:** [@lgmendes](https://discourse.julialang.org/u/lgmendes)\
**Replies:** 3\
**Last updated:** [April 2, 2022, 4:55pm UTC](https://discourse.julialang.org/t/join-append-dataloaders-structures/78873 "2022-04-02T16:55:54Z")

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Hi all, How can I add / join /append two dataLoaders structures ?

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## [JuMP--how to take the gradient of quadratic constraints?](https://discourse.julialang.org/t/jump-how-to-take-the-gradient-of-quadratic-constraints/78893)

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**Author:** [@rjuly](https://discourse.julialang.org/u/rjuly)\
**Replies:** 2\
**Last updated:** [April 2, 2022, 2:45pm UTC](https://discourse.julialang.org/t/jump-how-to-take-the-gradient-of-quadratic-constraints/78893 "2022-04-02T14:45:37Z")

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I need to get the constraint Jacobian for a model which contains linear, quadratic, and nonlinear constraints. For the nonlinear constraints, I can use the NLPEvaluator with function eval\_constraint\_jacobian. For the lin…

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## [Resources for Distributed Training w/ Flux](https://discourse.julialang.org/t/resources-for-distributed-training-w-flux/78105)

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**Author:** [@austinbean](https://discourse.julialang.org/u/austinbean)\
**Replies:** 1\
**Last updated:** [April 2, 2022, 5:07am UTC](https://discourse.julialang.org/t/resources-for-distributed-training-w-flux/78105 "2022-04-02T05:07:39Z")

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Hello - Is there a current (c. 2022) guide to parallel / distributed training in Flux, especially on GPUs? I found this archived repo but if there’s anything more current or if anyone has done this recently, I’d love …

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## [Zygote.jl: @adjoint! (mutating / inplace adjoints)](https://discourse.julialang.org/t/zygote-jl-adjoint-mutating-inplace-adjoints/78241)

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**Author:** [@MaximilianGelbrecht](https://discourse.julialang.org/u/MaximilianGelbrecht)\
**Replies:** 1\
**Last updated:** [April 2, 2022, 5:05am UTC](https://discourse.julialang.org/t/zygote-jl-adjoint-mutating-inplace-adjoints/78241 "2022-04-02T05:05:13Z")

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Inspecting the Zygote code, I can see that aside from @adjoint there is also @adjoint! that is used to declare the adjoints of some mutating functions (like push! etc). I can’t find any doc strings or documentation when …

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## [A problem with JuMP Tutorial-linear problem-cannery problem](https://discourse.julialang.org/t/a-problem-with-jump-tutorial-linear-problem-cannery-problem/78795)

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**Author:** [@mahon](https://discourse.julialang.org/u/mahon)\
**Replies:** 15\
**Last updated:** [April 2, 2022, 4:26am UTC](https://discourse.julialang.org/t/a-problem-with-jump-tutorial-linear-problem-cannery-problem/78795 "2022-04-02T04:26:13Z")

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when I code like this , it leads a error

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## [JuMP optimize! used two much time and memory to solve a cplex model, do anyone knows why?](https://discourse.julialang.org/t/jump-optimize-used-two-much-time-and-memory-to-solve-a-cplex-model-do-anyone-knows-why/77966)

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**Author:** [@yahengcui](https://discourse.julialang.org/u/yahengcui)\
**Replies:** 12\
**Last updated:** [April 1, 2022, 9:24pm UTC](https://discourse.julialang.org/t/jump-optimize-used-two-much-time-and-memory-to-solve-a-cplex-model-do-anyone-knows-why/77966 "2022-04-01T21:24:54Z")

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I am solving cplex models using julia, while writing (in julia) the model (to .lp file) and solve the .lp file directly by cplex can be done in secs and mins, but when I want to solve the model directly in julia by using…

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## [Issue using Convex with HiGHS for QP](https://discourse.julialang.org/t/issue-using-convex-with-highs-for-qp/78883)

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**Author:** [@Graham\_Gill](https://discourse.julialang.org/u/Graham_Gill)\
**Replies:** 1\
**Last updated:** [April 1, 2022, 8:05pm UTC](https://discourse.julialang.org/t/issue-using-convex-with-highs-for-qp/78883 "2022-04-01T20:05:29Z")

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I’ve been using HiGHS with Convex.jl lately for some MILPs and needed also to solve a simple continuous sum of squares minimisation. HiGHS can do this and HiGHS.jl should support this since https://github.com/jump-dev/Hi…

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## [Ways to plot LEO orbit](https://discourse.julialang.org/t/ways-to-plot-leo-orbit/75336)

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**Author:** [@yashi](https://discourse.julialang.org/u/yashi)\
**Replies:** 4\
**Last updated:** [April 1, 2022, 7:56pm UTC](https://discourse.julialang.org/t/ways-to-plot-leo-orbit/75336 "2022-04-01T19:56:16Z")

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What would be a good way to start ploting an LEO orbit using Plots, or in Pluto.jl? I’d like to make sliders for 6 Keplerian elements to visualize how each parameter interact with the orbit. One is something like Wolfr…

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## [Malloc error with Model(Cbc.Optimizer) on v1.8.0-beta3 and M1](https://discourse.julialang.org/t/malloc-error-with-model-cbc-optimizer-on-v1-8-0-beta3-and-m1/78876)

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**Author:** [@evad](https://discourse.julialang.org/u/evad)\
**Replies:** 2\
**Last updated:** [April 1, 2022, 7:48pm UTC](https://discourse.julialang.org/t/malloc-error-with-model-cbc-optimizer-on-v1-8-0-beta3-and-m1/78876 "2022-04-01T19:48:25Z")

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I have the following error crashing julia 1.8.0-beta3 on M1 MacOS when using m=Model(Cbc.Optimizer): julia(17828,0x100220580) malloc: \*\*\* error for object 0xe00000000000000: pointer being freed was not allocated julia(1…

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## [How to use distributed and pmap across GPU cores](https://discourse.julialang.org/t/how-to-use-distributed-and-pmap-across-gpu-cores/78852)

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**Author:** [@Nadou407](https://discourse.julialang.org/u/Nadou407)\
**Replies:** 2\
**Last updated:** [April 1, 2022, 1:04pm UTC](https://discourse.julialang.org/t/how-to-use-distributed-and-pmap-across-gpu-cores/78852 "2022-04-01T13:04:25Z")

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Hi all, I’m still new to Julia GPU and Julia in general so got quite confused about how to do parallel computation using a GPU. Any help would be greatly appreciated! My current code (a simple example) using 20 CPU cor…

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## [Comparison between Nonconvex.jl, JuMP and CasADi for large sparse nonlinear optimization](https://discourse.julialang.org/t/comparison-between-nonconvex-jl-jump-and-casadi-for-large-sparse-nonlinear-optimization/78825)

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**Author:** [@A\_C](https://discourse.julialang.org/u/A_C)\
**Replies:** 8\
**Last updated:** [April 1, 2022, 3:05am UTC](https://discourse.julialang.org/t/comparison-between-nonconvex-jl-jump-and-casadi-for-large-sparse-nonlinear-optimization/78825 "2022-04-01T03:05:23Z")

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I have an example which implements time-optimal control for Dubins vehicle. I have found that Nonconvex.jl is slower than JuMP. I think it is because Nonconvex.jl does not provide sparsity information to Ipopt. The nonze…

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## [How to plot in grayscale with gadfly?](https://discourse.julialang.org/t/how-to-plot-in-grayscale-with-gadfly/78780)

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**Author:** [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)\
**Replies:** 3\
**Last updated:** [March 31, 2022, 11:17pm UTC](https://discourse.julialang.org/t/how-to-plot-in-grayscale-with-gadfly/78780 "2022-03-31T23:17:48Z")

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Hi, I have some code roughly like this: using DataFrames using Gadfly df = DataFrame( :percent\_barrier =\> sqrt.(rand(100)) .\* 100, :stop\_reason =\> ifelse.(rand(100) .\> 0.75, "Solved", "Timeout") ) plot( df,…

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## [Help me outperform Matlab in numerical solution of semidiscretized PDE system as much as possible](https://discourse.julialang.org/t/help-me-outperform-matlab-in-numerical-solution-of-semidiscretized-pde-system-as-much-as-possible/76777)

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**Author:** [@RobertS](https://discourse.julialang.org/u/RobertS)\
**Replies:** 26\
**Last updated:** [March 31, 2022, 7:30pm UTC](https://discourse.julialang.org/t/help-me-outperform-matlab-in-numerical-solution-of-semidiscretized-pde-system-as-much-as-possible/76777 "2022-03-31T19:30:44Z")

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I am new to Julia and I am considering to adopt it in my professional life, where I often have to solve systems of partial differential equations (often mixed with algebraic and ordinary differential equations). I typic…

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## [Change xlabel position](https://discourse.julialang.org/t/change-xlabel-position/78812)

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**Author:** [@jewh](https://discourse.julialang.org/u/jewh)\
**Replies:** 2\
**Last updated:** [March 31, 2022, 5:28pm UTC](https://discourse.julialang.org/t/change-xlabel-position/78812 "2022-03-31T17:28:45Z")

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How can I adjust the position of the x-label in a plot using Plots.jl? e.g. if I do using Plots gr() # making it explicit I'm using the GR backend plot(1:10, rand(1:2, 10)) xlabel!("my nice xlabel") I get a plot with …

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## [Legend grows outside the image](https://discourse.julialang.org/t/legend-grows-outside-the-image/78823)

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**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 1\
**Last updated:** [March 31, 2022, 5:05pm UTC](https://discourse.julialang.org/t/legend-grows-outside-the-image/78823 "2022-03-31T17:05:51Z")

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I realized that when using Plots with GR the legend can grow outside the image. Is there a way to center the legend? The right edge of the legend seems to be fixed at the center of the image as it grows. plot(rand(10)…

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## [CUDA.jl - Atomic Addition Error To A Sparse Array Inside CUDA Kernel](https://discourse.julialang.org/t/cuda-jl-atomic-addition-error-to-a-sparse-array-inside-cuda-kernel/78789)

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**Author:** [@moukann](https://discourse.julialang.org/u/moukann)\
**Replies:** 4\
**Last updated:** [March 31, 2022, 11:18am UTC](https://discourse.julialang.org/t/cuda-jl-atomic-addition-error-to-a-sparse-array-inside-cuda-kernel/78789 "2022-03-31T11:18:47Z")

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Hello all, I am trying to assemble many individual elements of a huge system to a global system. The global system is sparse, It is a certain thing. Also it is wasteful to store all zero elements in memory, I just need …

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## [Slow backward gradients in ODEs](https://discourse.julialang.org/t/slow-backward-gradients-in-odes/78333)

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**Author:** [@deismic](https://discourse.julialang.org/u/deismic)\
**Replies:** 7\
**Last updated:** [March 31, 2022, 10:59am UTC](https://discourse.julialang.org/t/slow-backward-gradients-in-odes/78333 "2022-03-31T10:59:16Z")

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Hi all, I am new to Julia and I am trying to solve an ODE and obtain its gradients wrt parameters p. The ODE is the Hodgkin-Huxley model, a standard model in neuroscience (full ODE at the end of this message). I can so…

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