# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=332

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**Page:** 333

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## [I encountered a problem when using a convolutional neural network for training](https://discourse.julialang.org/t/i-encountered-a-problem-when-using-a-convolutional-neural-network-for-training/69087)

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**Author:** [@wondering](https://discourse.julialang.org/u/wondering)\
**Replies:** 0\
**Last updated:** [October 2, 2021, 3:23am UTC](https://discourse.julialang.org/t/i-encountered-a-problem-when-using-a-convolutional-neural-network-for-training/69087 "2021-10-02T03:23:53Z")

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My task contains two neural networks. There is an MLP (Multilayer Perceptron) network named Model\_out in front, and its parameters are stored in: p\_out, re\_out = Flux.destructure(model\_out), and split\_i = length(p\_out); …

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## [Understanding Flux.jl use of \`gradient\` and \`params\`](https://discourse.julialang.org/t/understanding-flux-jl-use-of-gradient-and-params/69077)

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**Author:** [@davibarreira](https://discourse.julialang.org/u/davibarreira)\
**Replies:** 4\
**Last updated:** [October 2, 2021, 4:54pm UTC](https://discourse.julialang.org/t/understanding-flux-jl-use-of-gradient-and-params/69077 "2021-10-02T16:54:23Z")

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I’m reading the “60-minutes blitz” for Flux, and I’m trying to understand more deeply how the package works. Now, I have the following code: using Flux: params W = randn(3, 5) b = zeros(3) x = \[3,1,0,1,2\] y(x) = sum(…

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## [StochasticDiffEq for receiver BER estimation?](https://discourse.julialang.org/t/stochasticdiffeq-for-receiver-ber-estimation/68957)

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**Author:** [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Replies:** 2\
**Last updated:** [October 2, 2021, 3:48pm UTC](https://discourse.julialang.org/t/stochasticdiffeq-for-receiver-ber-estimation/68957 "2021-10-02T15:48:58Z")

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Having an engineering background, I would like to ask the more mathematically inclined experts. One of the key parameters of a radio reception device is its bit error rate (BER) for a given ratio of wanted signal and di…

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## [Is label an attribute of scatter() and lines() in Makie.jl?](https://discourse.julialang.org/t/is-label-an-attribute-of-scatter-and-lines-in-makie-jl/68961)

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**Author:** [@Adam\_Fleischhacker](https://discourse.julialang.org/u/Adam_Fleischhacker)\
**Replies:** 6\
**Last updated:** [October 2, 2021, 2:44pm UTC](https://discourse.julialang.org/t/is-label-an-attribute-of-scatter-and-lines-in-makie-jl/68961 "2021-10-02T14:44:44Z")

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I am working on my understanding of the Makie package. In the plot from the help documentation (https://makie.juliaplots.org/dev/examples/layoutables/legend/), different markers get used with their legend labels determi…

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## [3D quiver plot?](https://discourse.julialang.org/t/3d-quiver-plot/69075)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 10\
**Last updated:** [October 2, 2021, 9:06am UTC](https://discourse.julialang.org/t/3d-quiver-plot/69075 "2021-10-02T09:06:05Z")

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Hello! I am aware of the quiver function, but am not sure how to easily do a 3d quiver plot? Kind regards

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## [How does JuMP.jl (Gurobi solver) take full advantage of the performance of multi-core CPUs](https://discourse.julialang.org/t/how-does-jump-jl-gurobi-solver-take-full-advantage-of-the-performance-of-multi-core-cpus/69103)

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**Author:** [@iiitr](https://discourse.julialang.org/u/iiitr)\
**Replies:** 2\
**Last updated:** [October 2, 2021, 11:07am UTC](https://discourse.julialang.org/t/how-does-jump-jl-gurobi-solver-take-full-advantage-of-the-performance-of-multi-core-cpus/69103 "2021-10-02T11:07:24Z")

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Hi all, In the past, I usually used Yalmip to complete the modeling of mathematical optimization. When I construct a large-scale mixed integer linear programming, I don’t need any additional settings, and Gurobi can alw…

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## [Why are flux models declared in top-level scope?](https://discourse.julialang.org/t/why-are-flux-models-declared-in-top-level-scope/68954)

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**Author:** [@htmj](https://discourse.julialang.org/u/htmj)\
**Replies:** 4\
**Last updated:** [October 1, 2021, 8:48pm UTC](https://discourse.julialang.org/t/why-are-flux-models-declared-in-top-level-scope/68954 "2021-10-01T20:48:28Z")

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From what I understand, one of the big things to avoid in julia is to have stuff be in the global scope (at least unless they are declared constant). In addition I don’t understand how i’m supposed to have several “inst…

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## [How to set max\_iterations for Optim.jl](https://discourse.julialang.org/t/how-to-set-max-iterations-for-optim-jl/61410)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [October 1, 2021, 6:04pm UTC](https://discourse.julialang.org/t/how-to-set-max-iterations-for-optim-jl/61410 "2021-10-01T18:04:32Z")

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I have the following code: lower = \[-20, -20, -20, -20, -20, -20.0, -20, -20, -20, -20, -20, -20\] upper = \[ 20, 20, 20, 20, 20, 20.0, 20, 20, 20, 20, 20, 20\] initial\_x = \[-1.4665866297620287, -3.…

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## [Uploading vector of vectors to GPU in flux.jl](https://discourse.julialang.org/t/uploading-vector-of-vectors-to-gpu-in-flux-jl/68552)

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**Author:** [@mys\_721tx](https://discourse.julialang.org/u/mys_721tx)\
**Replies:** 4\
**Last updated:** [October 1, 2021, 5:55pm UTC](https://discourse.julialang.org/t/uploading-vector-of-vectors-to-gpu-in-flux-jl/68552 "2021-10-01T17:55:52Z")

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Hello all, I am training a many-to-many RNN. My input and output data are both Vector{Vector{Vector{Float32}}}. The jld file of the input and output is about 3GB. I checked the model-zoo and did not find anything exampl…

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## [Multiple texture interpolations at the same time](https://discourse.julialang.org/t/multiple-texture-interpolations-at-the-same-time/69037)

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**Author:** [@lodygaw](https://discourse.julialang.org/u/lodygaw)\
**Replies:** 1\
**Last updated:** [October 1, 2021, 12:07pm UTC](https://discourse.julialang.org/t/multiple-texture-interpolations-at-the-same-time/69037 "2021-10-01T12:07:29Z")

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Hello, I am begginer to Julia and CUDA.jl so please forgive me if the answer to the question is obvious. I couldn’t find the solution by myself. I would like to perform texture interpolation (similar to this) but I hav…

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## [Local, symbolic sensitivity analysis of Euler Angles](https://discourse.julialang.org/t/local-symbolic-sensitivity-analysis-of-euler-angles/68984)

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**Author:** [@JanKap](https://discourse.julialang.org/u/JanKap)\
**Replies:** 6\
**Last updated:** [October 1, 2021, 11:24am UTC](https://discourse.julialang.org/t/local-symbolic-sensitivity-analysis-of-euler-angles/68984 "2021-10-01T11:24:15Z")

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Hey all :slight\_smile: I’m trying to wrap my head around a supposedly simple problem, but it’s not working yet. It is known (see https://www.nxp.com/files-static/sensors/doc/app\_note/AN3461.pdf) that the relationship …

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## [Makie - Cycle colors for all plots](https://discourse.julialang.org/t/makie-cycle-colors-for-all-plots/69033)

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**Author:** [@nandoconde](https://discourse.julialang.org/u/nandoconde)\
**Replies:** 4\
**Last updated:** [October 1, 2021, 11:01am UTC](https://discourse.julialang.org/t/makie-cycle-colors-for-all-plots/69033 "2021-10-01T11:01:11Z")

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Hello! I am trying to substitute the current color cycle by one of my own, but I am not able to do so. I have tried set\_theme!(palette = (color = cgrad(:roma, 4, categorical = true))) and \`Axis(palette = (color = cgrad…

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## [Callbacks interfering with solver output](https://discourse.julialang.org/t/callbacks-interfering-with-solver-output/69001)

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**Author:** [@arkanver](https://discourse.julialang.org/u/arkanver)\
**Replies:** 2\
**Last updated:** [October 1, 2021, 8:35am UTC](https://discourse.julialang.org/t/callbacks-interfering-with-solver-output/69001 "2021-10-01T08:35:39Z")

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Hello all, I am currently working on a MILP using JuMP and Gurobi. As far as I’m aware my versions are all up to date - Julia 1.6.3, JuMP v0.21.10, Gurobi.jl v0.9.14 (and Gurobi - the solver - 9.1.2). I’m solving my pr…

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## [Is there an idiomatic way to select a single value from a SQL query?](https://discourse.julialang.org/t/is-there-an-idiomatic-way-to-select-a-single-value-from-a-sql-query/68962)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 3\
**Last updated:** [October 1, 2021, 7:59am UTC](https://discourse.julialang.org/t/is-there-an-idiomatic-way-to-select-a-single-value-from-a-sql-query/68962 "2021-10-01T07:59:23Z")

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Hi, Some SQL queries (like “SELECT COUNT(\*)…”) return a single value. The shortest way I’ve managed to come up with for obtaining the result of the query is: using SQLite db = SQLite.DB() SQLite.DBInterface.execute(db…

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## [Gurobi callback in JuMP for submitting heuristic solution](https://discourse.julialang.org/t/gurobi-callback-in-jump-for-submitting-heuristic-solution/69006)

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**Author:** [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)\
**Replies:** 2\
**Last updated:** [September 30, 2021, 8:40pm UTC](https://discourse.julialang.org/t/gurobi-callback-in-jump-for-submitting-heuristic-solution/69006 "2021-09-30T20:40:52Z")

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Dear All, I am trying to implement the fix-and-dive heuristic for the traveling salesman problem in JuMP with Gurobi based on the Python+Gurobi code available here: https://github.com/Gurobi/pres-mipheur/blob/master/mip…

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## [Add classname to Interact dropdown widget](https://discourse.julialang.org/t/add-classname-to-interact-dropdown-widget/68993)

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**Author:** [@cwiese](https://discourse.julialang.org/u/cwiese)\
**Replies:** 0\
**Last updated:** [September 30, 2021, 12:04pm UTC](https://discourse.julialang.org/t/add-classname-to-interact-dropdown-widget/68993 "2021-09-30T12:04:27Z")

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I am using Interact (Blink) - I create a dropdown widget ddl = dropdown(Observable(attr\_values)); I would like to add “loader is-active” classname to the Select … when a value is selected and remove when the data come…

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## [Error using DifferentialEquations.jl to simulate a reasonably common SDE](https://discourse.julialang.org/t/error-using-differentialequations-jl-to-simulate-a-reasonably-common-sde/68930)

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**Author:** [@colintbowers](https://discourse.julialang.org/u/colintbowers)\
**Replies:** 13\
**Last updated:** [September 30, 2021, 11:28am UTC](https://discourse.julialang.org/t/error-using-differentialequations-jl-to-simulate-a-reasonably-common-sde/68930 "2021-09-30T11:28:34Z")

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I’m using DifferentialEquations.jl to try to simulate paths of the following SDE: dS = 0.0314 dt + v\*(-0.576) dW\_1 + v\*sqrt(1 - 0.576^2) dW\_2 d(v^2) = 0.035\*(0.636 - v^2) dt + 0.144 v^2 dW\_1 Sorry for the formatting, I…

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## [How to produce this type of graph?](https://discourse.julialang.org/t/how-to-produce-this-type-of-graph/68955)

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**Author:** [@jo-fleck](https://discourse.julialang.org/u/jo-fleck)\
**Replies:** 6\
**Last updated:** [September 30, 2021, 10:08am UTC](https://discourse.julialang.org/t/how-to-produce-this-type-of-graph/68955 "2021-09-30T10:08:22Z")

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I would like to compare three measures which characterize each of the US states. They are measured on three different scales so I am thinking to illustrate the relative ranking of states. I have seen this graph and it …

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## [Allocating different arrays on multiple GPUs](https://discourse.julialang.org/t/allocating-different-arrays-on-multiple-gpus/68836)

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**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 8\
**Last updated:** [September 30, 2021, 6:02am UTC](https://discourse.julialang.org/t/allocating-different-arrays-on-multiple-gpus/68836 "2021-09-30T06:02:15Z")

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i’ve read the docs on unified memory, but think that’s overkill for my use case. is it really not possible to simply switch devices, define another CuArray, and then launch a kernel on it? i get ERROR\_INVALID\_VALUE: j…

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## [MPI Jupyter kernel & cluster in Julia (similar to dask-mpi / ipyparallel)?](https://discourse.julialang.org/t/mpi-jupyter-kernel-cluster-in-julia-similar-to-dask-mpi-ipyparallel/67240)

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**Author:** [@marius311](https://discourse.julialang.org/u/marius311)\
**Replies:** 9\
**Last updated:** [September 30, 2021, 4:51am UTC](https://discourse.julialang.org/t/mpi-jupyter-kernel-cluster-in-julia-similar-to-dask-mpi-ipyparallel/67240 "2021-09-30T04:51:13Z")

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I’m on a cluster where MPI transport is significantly faster than TCP transport, and I’d like to keep my interactive Jupyter-based workflow for parallel work. A key thing is I don’t want to be doing any intercommunicatio…

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## [Max.(v1,v2) on the GPU](https://discourse.julialang.org/t/max-v1-v2-on-the-gpu/68386)

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**Author:** [@gianmariomanca](https://discourse.julialang.org/u/gianmariomanca)\
**Replies:** 5\
**Last updated:** [September 30, 2021, 3:19am UTC](https://discourse.julialang.org/t/max-v1-v2-on-the-gpu/68386 "2021-09-30T03:19:14Z")

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What’s the best way to implement the element wise maximum of for 2 vectors of the same length on the GPU using CUDA.jl or any other package? julia\> v1 = \[1, 2, 3\] 3-element Vector{Int64}: 1 2 3 julia\> v2 = \[4, 3, 2\]…

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## [Porting MATLAB code that uses Mapping Toolbox](https://discourse.julialang.org/t/porting-matlab-code-that-uses-mapping-toolbox/68967)

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**Author:** [@fyzycyst](https://discourse.julialang.org/u/fyzycyst)\
**Replies:** 1\
**Last updated:** [September 29, 2021, 10:27pm UTC](https://discourse.julialang.org/t/porting-matlab-code-that-uses-mapping-toolbox/68967 "2021-09-29T22:27:35Z")

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Looking for opinions/options… I’ve got some old MATLAB code that makes use of Mapping Toolbox that I want to port into Julia. What’s my best bet? Thanks.

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## [Issues with CSV in Julia 1.6.2](https://discourse.julialang.org/t/issues-with-csv-in-julia-1-6-2/67507)

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**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 33\
**Last updated:** [September 29, 2021, 7:13pm UTC](https://discourse.julialang.org/t/issues-with-csv-in-julia-1-6-2/67507 "2021-09-29T19:13:03Z")

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This morning I did a standard upgrade to Julia 1.6.2 and loaded the basic packages I use for Data Science. After adding everything, I tried to get started, beginning with the simple statement ‘using CSV’ and got a pag…

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## [Differentiation matrix stack overflow](https://discourse.julialang.org/t/differentiation-matrix-stack-overflow/68944)

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**Author:** [@GianpieroPascale](https://discourse.julialang.org/u/GianpieroPascale)\
**Replies:** 3\
**Last updated:** [September 29, 2021, 5:14pm UTC](https://discourse.julialang.org/t/differentiation-matrix-stack-overflow/68944 "2021-09-29T17:14:40Z")

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I’m trying to follow along with @stevengj’s lecture notes on 2D differentiation matrices, but I can’t get past the first example without Julia reporting a stack-overflow error. The piece of code in question is # constru…

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## [Issues with HMC/NUTS samplers](https://discourse.julialang.org/t/issues-with-hmc-nuts-samplers/68900)

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**Author:** [@tchebycheff](https://discourse.julialang.org/u/tchebycheff)\
**Replies:** 4\
**Last updated:** [September 29, 2021, 3:53pm UTC](https://discourse.julialang.org/t/issues-with-hmc-nuts-samplers/68900 "2021-09-29T15:53:41Z")

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Hi - I am trying to run MCMC on this model with Turing. Only SMC sampler works. With HMC, NUTS, PG, DynamicHMC I get the error TypeError: in typeassert, expected Float64, got a value of type ForwardDiff.Dual{Nothing, F…

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## [Problems using BacksolveAdjoint for an SDE with DiffEqFlux](https://discourse.julialang.org/t/problems-using-backsolveadjoint-for-an-sde-with-diffeqflux/68049)

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**Author:** [@JoseG](https://discourse.julialang.org/u/JoseG)\
**Replies:** 5\
**Last updated:** [September 29, 2021, 1:15pm UTC](https://discourse.julialang.org/t/problems-using-backsolveadjoint-for-an-sde-with-diffeqflux/68049 "2021-09-29T13:15:19Z")

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I’m trying to train a SDE with DiffEqFlux. I had issues with stack overflows when using TrackerAdjoint (probably because of the size of the problem), so i tried using BacksolveAdjoint but this errors on calculating the g…

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## [Plots -- transparency of surface?](https://discourse.julialang.org/t/plots-transparency-of-surface/24524)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 9\
**Last updated:** [September 29, 2021, 11:47am UTC](https://discourse.julialang.org/t/plots-transparency-of-surface/24524 "2021-09-29T11:47:15Z")

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Can I control the transparency/alpha value of the surface in surface plots? I would like to superimpose the solution of an ode on a surface… fillalpha=0.2 doesn’t have an effect. Another way to do it? (e.g. using wirefra…

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## [Solving a large system of differential equations](https://discourse.julialang.org/t/solving-a-large-system-of-differential-equations/68870)

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**Author:** [@danielw96](https://discourse.julialang.org/u/danielw96)\
**Replies:** 10\
**Last updated:** [September 29, 2021, 10:50am UTC](https://discourse.julialang.org/t/solving-a-large-system-of-differential-equations/68870 "2021-09-29T10:50:18Z")

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Hey :slight\_smile: , I am currently trying to solve a system of differential equations. I create the coefficient matrix as a sparse matrix, but when i try to use the ode solver, it gives me an out of memory error. The c…

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## [Linear constraint optimisation on GPU](https://discourse.julialang.org/t/linear-constraint-optimisation-on-gpu/68692)

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**Author:** [@Huy\_Nguyen](https://discourse.julialang.org/u/Huy_Nguyen)\
**Replies:** 5\
**Last updated:** [September 29, 2021, 9:45am UTC](https://discourse.julialang.org/t/linear-constraint-optimisation-on-gpu/68692 "2021-09-29T09:45:33Z")

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I currently use JuMP and Ipopt to solve Linear Constraints Optimisation problems, primarily with linear equality and inequality constraints. I would like to either solve many of these problems in parallel, or sequentiall…

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## [Display (a different) value under scatter point](https://discourse.julialang.org/t/display-a-different-value-under-scatter-point/10821)

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**Author:** [@biona001](https://discourse.julialang.org/u/biona001)\
**Replies:** 12\
**Last updated:** [September 29, 2021, 7:54am UTC](https://discourse.julialang.org/t/display-a-different-value-under-scatter-point/10821 "2021-09-29T07:54:43Z")

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Plotlyjs is giving me a plot that doesn’t seem to be finding the closest scatter point to my cursor (indicated by black arrow): using Plots plotlyjs() scatter(x1, x2) My question is: How can I display the name…

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