# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=297

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**Page:** 298

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## [Makie examples in PortAudio](https://discourse.julialang.org/t/makie-examples-in-portaudio/77614)

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**Author:** [@bramtayl](https://discourse.julialang.org/u/bramtayl)\
**Replies:** 0\
**Last updated:** [March 9, 2022, 1:40am UTC](https://discourse.julialang.org/t/makie-examples-in-portaudio/77614 "2022-03-09T01:40:11Z")

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I’m trying to get all of the examples in the PortAudio repo to run as part of CI. I’ve gotten most of the examples to run but I’m struggling with the two examples that use Makie. What I’ve got so far is in this PR: https…

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## [Bonmin\_jll](https://discourse.julialang.org/t/bonmin-jll/77612)

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**Author:** [@Francisco\_Javier\_Mar](https://discourse.julialang.org/u/Francisco_Javier_Mar)\
**Replies:** 1\
**Last updated:** [March 9, 2022, 1:12am UTC](https://discourse.julialang.org/t/bonmin-jll/77612 "2022-03-09T01:12:01Z")

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I got this error message. I am using Bonmin\_jll to solve my model. What can I do? The provided optimizer\_constructor is invalid. It must be callable with zero arguments. For example, "Ipopt.Optimizer" or "() -\> ECOS.Opt…

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## [Addprocs behavior changed in recent update -- have to enter password now](https://discourse.julialang.org/t/addprocs-behavior-changed-in-recent-update-have-to-enter-password-now/77537)

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**Author:** [@chelseas](https://discourse.julialang.org/u/chelseas)\
**Replies:** 2\
**Last updated:** [March 8, 2022, 9:46pm UTC](https://discourse.julialang.org/t/addprocs-behavior-changed-in-recent-update-have-to-enter-password-now/77537 "2022-03-08T21:46:59Z")

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I have passwordless ssh login setup to my server like: ssh csidrane@myserver But then when I go into my terminal and I type: using Distributed addprocs(\[(“myserver”, 1)\]) it used to work just fine! About a month ago…

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## [Factor of two in Zygote complex gradient](https://discourse.julialang.org/t/factor-of-two-in-zygote-complex-gradient/77545)

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**Author:** [@goerz](https://discourse.julialang.org/u/goerz)\
**Replies:** 5\
**Last updated:** [March 8, 2022, 8:14pm UTC](https://discourse.julialang.org/t/factor-of-two-in-zygote-complex-gradient/77545 "2022-03-08T20:14:59Z")

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Either Zygote’s gradients for a scalar function with respect to a complex vector are off by a factor of two, I’ve been doing matrix algebra wrong for the last 10 years, or I’m just being stupid here. Consider the followi…

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## [Eigenvectors of a symmetric tensor and a matrix](https://discourse.julialang.org/t/eigenvectors-of-a-symmetric-tensor-and-a-matrix/77604)

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**Author:** [@FrootLoops](https://discourse.julialang.org/u/FrootLoops)\
**Replies:** 2\
**Last updated:** [March 8, 2022, 8:09pm UTC](https://discourse.julialang.org/t/eigenvectors-of-a-symmetric-tensor-and-a-matrix/77604 "2022-03-08T20:09:35Z")

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Hi, I have a problem calculating the eigenvectors of a matrix/tensor. Maybe someone can explain why the outputs differ from each other. using LinearAlgebra, Tensors A = \[-24.978551803697826 -51.42238499537693 0.0; -51…

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## [Social Media Mapping](https://discourse.julialang.org/t/social-media-mapping/77605)

<div class="topic-metadata">

**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 0\
**Last updated:** [March 8, 2022, 7:25pm UTC](https://discourse.julialang.org/t/social-media-mapping/77605 "2022-03-08T19:25:18Z")

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Is there anyone that has experience making maps of social networks, by friends or by posts?

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## [Stratified and weighted sampling in dataframes](https://discourse.julialang.org/t/stratified-and-weighted-sampling-in-dataframes/77565)

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**Author:** [@George\_Githinji](https://discourse.julialang.org/u/George_Githinji)\
**Replies:** 8\
**Last updated:** [March 8, 2022, 7:11pm UTC](https://discourse.julialang.org/t/stratified-and-weighted-sampling-in-dataframes/77565 "2022-03-08T19:11:37Z")

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I have a function that can take a random sample from a dataframe. However I ran into an issue when working with grouped a dataframe in which case I have grouped the data by several columns and I would like to sample with…

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## [Tuning the gamma parameter in FrankWolfe.jl](https://discourse.julialang.org/t/tuning-the-gamma-parameter-in-frankwolfe-jl/77023)

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**Author:** [@dridz](https://discourse.julialang.org/u/dridz)\
**Replies:** 7\
**Last updated:** [March 8, 2022, 5:47pm UTC](https://discourse.julialang.org/t/tuning-the-gamma-parameter-in-frankwolfe-jl/77023 "2022-03-08T17:47:33Z")

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Hi, I found out about the FrankWolfe.jl package and it looks great ! I am dealing with an optimization problem for which I have a lot of intuition about a good warm start and also about the order of magnitude of a good …

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## [Scalar indexing error when loading MNIST](https://discourse.julialang.org/t/scalar-indexing-error-when-loading-mnist/77496)

<div class="topic-metadata">

**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 2\
**Last updated:** [March 8, 2022, 5:37pm UTC](https://discourse.julialang.org/t/scalar-indexing-error-when-loading-mnist/77496 "2022-03-08T17:37:14Z")

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The following code in a fresh session produces a scalar indexing error: using Flux using MLDatasets categories = 0:9 xtrain, ytrain = MNIST.traindata(Float32) xtest, ytest = MNIST.testdata(Float32) ytrain, ytest = Flu…

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## [How to print multiple values in a loop](https://discourse.julialang.org/t/how-to-print-multiple-values-in-a-loop/77474)

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**Author:** [@Eric.O](https://discourse.julialang.org/u/Eric.O)\
**Replies:** 8\
**Last updated:** [March 8, 2022, 4:48pm UTC](https://discourse.julialang.org/t/how-to-print-multiple-values-in-a-loop/77474 "2022-03-08T16:48:05Z")

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I want to print my output in Julia, I have written it in the form presented below but I want to use a for loop to make it more concise. Any help on how to write the code below using for loop will be appreciated please. …

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## [MPI on Raspberry pi distributed computer](https://discourse.julialang.org/t/mpi-on-raspberry-pi-distributed-computer/77588)

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**Author:** [@Isonoglu](https://discourse.julialang.org/u/Isonoglu)\
**Replies:** 1\
**Last updated:** [March 8, 2022, 3:28pm UTC](https://discourse.julialang.org/t/mpi-on-raspberry-pi-distributed-computer/77588 "2022-03-08T15:28:51Z")

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Hello everyone. I’m a total beginner in Julia and cluster computing. I have already made a Raspberry pi distributed computer with 4 nodes. Any node can SSH to every other. Every node should perform some calculations “loc…

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## [Finding crossing points of two vectors of vertices](https://discourse.julialang.org/t/finding-crossing-points-of-two-vectors-of-vertices/15786)

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**Author:** [@jcook](https://discourse.julialang.org/u/jcook)\
**Replies:** 15\
**Last updated:** [March 8, 2022, 12:54pm UTC](https://discourse.julialang.org/t/finding-crossing-points-of-two-vectors-of-vertices/15786 "2022-03-08T12:54:32Z")

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Is there a tool out there that is able to find the locations of where two lines cross one another? By line I mean a vector of positions in the 2D plane, where the positions are connected by straight lines. I would prefer…

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## [Default norm used in ODE error control](https://discourse.julialang.org/t/default-norm-used-in-ode-error-control/70995)

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**Author:** [@Bernard\_GODARD](https://discourse.julialang.org/u/Bernard_GODARD)\
**Replies:** 4\
**Last updated:** [March 8, 2022, 1:47pm UTC](https://discourse.julialang.org/t/default-norm-used-in-ode-error-control/70995 "2022-03-08T13:47:41Z")

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The error control in DifferentialEquations using the default internal norm is as follow: Compute tolerance on i-th component: tolerance\_i = absoluteTolerance\_i + relativeTolerance\_i \* max( \\lvert previousState\_i \\rver…

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## [CBC solver](https://discourse.julialang.org/t/cbc-solver/77548)

<div class="topic-metadata">

**Author:** [@Francisco\_Javier\_Mar](https://discourse.julialang.org/u/Francisco_Javier_Mar)\
**Replies:** 18\
**Last updated:** [March 8, 2022, 1:08pm UTC](https://discourse.julialang.org/t/cbc-solver/77548 "2022-03-08T13:08:01Z")

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I got this error while trying to test Alpine: Failed to precompile Cbc. What can I do to fix this ? Any suggestion ? My Julia version: JuliaPro\_v1.5.3-1

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## [Powermodels.jl SCS for a mixed-integer problem with SDP relaxation](https://discourse.julialang.org/t/powermodels-jl-scs-for-a-mixed-integer-problem-with-sdp-relaxation/77244)

<div class="topic-metadata">

**Author:** [@lostamcimber](https://discourse.julialang.org/u/lostamcimber)\
**Replies:** 4\
**Last updated:** [March 8, 2022, 12:44pm UTC](https://discourse.julialang.org/t/powermodels-jl-scs-for-a-mixed-integer-problem-with-sdp-relaxation/77244 "2022-03-08T12:44:23Z")

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Hi all, I am trying to solve a mixed integer problem of a network with switches (switches are my binary variables). I can solve my OPF problem with quadratic relaxations like ‘SOCWRPowerModel’, ‘QCRMPowerModel’, ‘QCLSPo…

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## [GPU computing on AMD consumer hardware?](https://discourse.julialang.org/t/gpu-computing-on-amd-consumer-hardware/53841)

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**Author:** [@tp2750](https://discourse.julialang.org/u/tp2750)\
**Replies:** 11\
**Last updated:** [March 8, 2022, 12:40pm UTC](https://discourse.julialang.org/t/gpu-computing-on-amd-consumer-hardware/53841 "2022-03-08T12:40:55Z")

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I’m putting together a new computer and would like to be able to experiment with GPU computing in Julia (on Ubuntu). I would greatly prefer an AMD GPU because of the in-kernel driver support on Linux. My understanding i…

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## [How to add grid lines on top of a heatmap in Makie?](https://discourse.julialang.org/t/how-to-add-grid-lines-on-top-of-a-heatmap-in-makie/77578)

<div class="topic-metadata">

**Author:** [@ForceBru](https://discourse.julialang.org/u/ForceBru)\
**Replies:** 2\
**Last updated:** [March 8, 2022, 12:30pm UTC](https://discourse.julialang.org/t/how-to-add-grid-lines-on-top-of-a-heatmap-in-makie/77578 "2022-03-08T12:30:52Z")

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I have some code which boils down to heatmap(matrix, colormap=Reverse(:grays)) and produces this plot: There’s a lot of white in the plot, and I’d like to emphasize that it’s not empty space, so I wanted to add grid …

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## [Solving KKT linear system (which solver for LDLᵀ factorization?)](https://discourse.julialang.org/t/solving-kkt-linear-system-which-solver-for-ldl-factorization/77544)

<div class="topic-metadata">

**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 3\
**Last updated:** [March 8, 2022, 8:47am UTC](https://discourse.julialang.org/t/solving-kkt-linear-system-which-solver-for-ldl-factorization/77544 "2022-03-08T08:47:48Z")

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I would like to solve a system of linear equations given in a vector form as \\begin{bmatrix} Q & A^\\top \\\\ A & 0\\end{bmatrix}\\begin{bmatrix}x\\\\ \\lambda\\end{bmatrix} = \\begin{bmatrix} c \\\\ -b \\end{bmatrix} The matrix Q…

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## [How to standardize arrays in Julia?](https://discourse.julialang.org/t/how-to-standardize-arrays-in-julia/54046)

<div class="topic-metadata">

**Author:** [@Shazman](https://discourse.julialang.org/u/Shazman)\
**Replies:** 7\
**Last updated:** [March 8, 2022, 7:46am UTC](https://discourse.julialang.org/t/how-to-standardize-arrays-in-julia/54046 "2022-03-08T07:46:16Z")

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I have two arrays (m and n) and each has one column with 100 elements. the first array is sampled from a normal distribution with mean 0 and standard deviation 1, the second one is sampled from a normal distribution with…

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## [Neos Server](https://discourse.julialang.org/t/neos-server/77549)

<div class="topic-metadata">

**Author:** [@Francisco\_Javier\_Mar](https://discourse.julialang.org/u/Francisco_Javier_Mar)\
**Replies:** 1\
**Last updated:** [March 8, 2022, 2:19am UTC](https://discourse.julialang.org/t/neos-server/77549 "2022-03-08T02:19:13Z")

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I got this error while trying to install NEOSServer. What can I do ? ERROR: Unsatisfiable requirements detected for package HTTP \[cd3eb016\]: HTTP \[cd3eb016\] log: ├─possible versions are: \[0.6.10-0.6.14, 0.7.0-0.7.1, 0…

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## [Automotive/EV projects/packages?](https://discourse.julialang.org/t/automotive-ev-projects-packages/77533)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 2\
**Last updated:** [March 7, 2022, 7:46pm UTC](https://discourse.julialang.org/t/automotive-ev-projects-packages/77533 "2022-03-07T19:46:56Z")

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So I’m looking to dabble a bit with data from an OBD2 scanner, mostly to explore aspects of my EV’s energy consumption, and/or something about how the charging infrastructure is evolving, if I can find an appropriate API…

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## [CUDA.jl initialization test failing](https://discourse.julialang.org/t/cuda-jl-initialization-test-failing/77526)

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**Author:** [@RonRahaman](https://discourse.julialang.org/u/RonRahaman)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 5:56pm UTC](https://discourse.julialang.org/t/cuda-jl-initialization-test-failing/77526 "2022-03-07T17:56:06Z")

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Hi all, I’m running tests for CUDA.jl (\]test CUDA) and I have one test failing. Should I be concerned, or can I safely ignore it? Error in testset initialization: Test Failed at /usr/local/pace-apps/manual/packages/jul…

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## [OneNote/Microsoft Graph API](https://discourse.julialang.org/t/onenote-microsoft-graph-api/76264)

<div class="topic-metadata">

**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 0\
**Last updated:** [February 11, 2022, 6:05pm UTC](https://discourse.julialang.org/t/onenote-microsoft-graph-api/76264 "2022-02-11T18:05:59Z")

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Has anyone experimented at all with the OneNote REST API?

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## [Error using system CUDA in CUDA.jl](https://discourse.julialang.org/t/error-using-system-cuda-in-cuda-jl/77423)

<div class="topic-metadata">

**Author:** [@RonRahaman](https://discourse.julialang.org/u/RonRahaman)\
**Replies:** 3\
**Last updated:** [March 7, 2022, 4:19pm UTC](https://discourse.julialang.org/t/error-using-system-cuda-in-cuda-jl/77423 "2022-03-07T16:19:17Z")

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Hi all, I’m trying to install CUDA.jl using my system’s CUDA toolkit. The installation completes, but I get errors when I try to test it by running CUDA.version(). I set JULIA\_CUDA\_USE\_BINARYBUILDER=false and ensured t…

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## [Start using Molly.jl: place\_atoms not defined in module Molly?](https://discourse.julialang.org/t/start-using-molly-jl-place-atoms-not-defined-in-module-molly/77521)

<div class="topic-metadata">

**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 3\
**Last updated:** [March 7, 2022, 4:14pm UTC](https://discourse.julialang.org/t/start-using-molly-jl-place-atoms-not-defined-in-module-molly/77521 "2022-03-07T16:14:53Z")

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I started looking into Molly.jl and attempting to run one its examples. I get the error described below. Insight would be nice to receive. Thx! julia\> using Molly julia\> n\_atoms = 100 100 julia\> atom\_mass = 10.0u"u" …

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## [Concrete Operators in DiffEqOperators.jl for time-indepedent problems](https://discourse.julialang.org/t/concrete-operators-in-diffeqoperators-jl-for-time-indepedent-problems/77415)

<div class="topic-metadata">

**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 9\
**Last updated:** [March 7, 2022, 3:31pm UTC](https://discourse.julialang.org/t/concrete-operators-in-diffeqoperators-jl-for-time-indepedent-problems/77415 "2022-03-07T15:31:59Z")

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We are looking into the use of DiffEqOperators for time-independent problems. We are considering the Poisson equation on the unit interval and unit square. First a 1D implementation was made to figure out how to use it. …

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## [Outdated / bogus CUDA.jl documentation at https://juliagpu.gitlab.io/CUDA.jl?](https://discourse.julialang.org/t/outdated-bogus-cuda-jl-documentation-at-https-juliagpu-gitlab-io-cuda-jl/77515)

<div class="topic-metadata">

**Author:** [@complyue](https://discourse.julialang.org/u/complyue)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 3:13pm UTC](https://discourse.julialang.org/t/outdated-bogus-cuda-jl-documentation-at-https-juliagpu-gitlab-io-cuda-jl/77515 "2022-03-07T15:13:49Z")

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By CUDA.jl - Google Search , the first hit is the github repo, which is good, but the second hit is https://juliagpu.gitlab.io/CUDA.jl , which seems outdated, compared to https://cuda.juliagpu.org . But the later doesn’t…

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## [Stencil operations and Symbolics.jl](https://discourse.julialang.org/t/stencil-operations-and-symbolics-jl/75685)

<div class="topic-metadata">

**Author:** [@vlc](https://discourse.julialang.org/u/vlc)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 3:11pm UTC](https://discourse.julialang.org/t/stencil-operations-and-symbolics-jl/75685 "2022-03-07T15:11:36Z")

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Hi there, I’m writing a little package that solves classical PDEs on Cartesian grids, and am seeking advice on how to leverage Symbolics.jl to speed up operations such as matrix-vector products. As a MWE, I’ll focus on…

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## [Zygote and TimerOutputs, derivative of timed function](https://discourse.julialang.org/t/zygote-and-timeroutputs-derivative-of-timed-function/44234)

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**Author:** [@racinmat](https://discourse.julialang.org/u/racinmat)\
**Replies:** 3\
**Last updated:** [March 7, 2022, 12:45pm UTC](https://discourse.julialang.org/t/zygote-and-timeroutputs-derivative-of-timed-function/44234 "2022-03-07T12:45:00Z")

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Hi, sometimes I want to benchmark my code on my neural networks, especially their forward pass, using TimerOutputs.jl, but I don’t want to comment out all this when calculating gradients. Currently it’s crashing, not b…

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## [Make this more efficient?](https://discourse.julialang.org/t/make-this-more-efficient/77104)

<div class="topic-metadata">

**Author:** [@r0b0ty](https://discourse.julialang.org/u/r0b0ty)\
**Replies:** 11\
**Last updated:** [March 7, 2022, 12:37pm UTC](https://discourse.julialang.org/t/make-this-more-efficient/77104 "2022-03-07T12:37:52Z")

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Hello, all. I have a DataFrame column, df.polygons, with strings of ten numbers separated by commas as shown below julia\> df.polygons 400000-element Vector{String}: “79,8,79.09999999999999,8,79.09999999999999,7.9,79…

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