# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=203

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 204

---

## [Apple M1 GPU from Julia?](https://discourse.julialang.org/t/apple-m1-gpu-from-julia/69563)

<div class="topic-metadata">

**Author:** [@Per](https://discourse.julialang.org/u/Per)\
**Replies:** 20\
**Last updated:** [March 31, 2023, 8:49am UTC](https://discourse.julialang.org/t/apple-m1-gpu-from-julia/69563 "2023-03-31T08:49:13Z")

</div>

Does anyone know if it is possible to access the GPU of the Apple M1 chip from Julia? I really just need Float32 matrix-matrix multiplication (SGEMM). Anything else would be a bonus.

---

## [More Extreme Moves in a Downtrending Market?](https://discourse.julialang.org/t/more-extreme-moves-in-a-downtrending-market/96875)

<div class="topic-metadata">

**Author:** [@dm13450](https://discourse.julialang.org/u/dm13450)\
**Replies:** 0\
**Last updated:** [March 31, 2023, 5:26am UTC](https://discourse.julialang.org/t/more-extreme-moves-in-a-downtrending-market/96875 "2023-03-31T05:26:28Z")

</div>

I’ve written a blog post about that explores whether there are more extreme moves in a down trending market: More Extreme Moves in a Downtrending Market? | Dean Markwick

---

## [Using JuMP for variational data assimilation -- scalability and memory usage](https://discourse.julialang.org/t/using-jump-for-variational-data-assimilation-scalability-and-memory-usage/96686)

<div class="topic-metadata">

**Author:** [@zornsllama](https://discourse.julialang.org/u/zornsllama)\
**Replies:** 9\
**Last updated:** [March 31, 2023, 1:49am UTC](https://discourse.julialang.org/t/using-jump-for-variational-data-assimilation-scalability-and-memory-usage/96686 "2023-03-31T01:49:57Z")

</div>

Hi! I have been using JuMP over the last few months to perform variational data assimilation. Specifically, I am trying to estimate ODE parameters by direct transcription of the equations into a nonlinear program, utiliz…

---

## [Sm90 (H100) support for cuda.jl](https://discourse.julialang.org/t/sm90-h100-support-for-cuda-jl/96809)

<div class="topic-metadata">

**Author:** [@smartalecH](https://discourse.julialang.org/u/smartalecH)\
**Replies:** 3\
**Last updated:** [March 30, 2023, 5:43pm UTC](https://discourse.julialang.org/t/sm90-h100-support-for-cuda-jl/96809 "2023-03-30T17:43:55Z")

</div>

Does CUDA.jl not yet support Hopper gpus (sm90)? I get the following error when trying to execute any kernels: ERROR: LoadError: CUDA error: device kernel image is invalid (code 300, ERROR\_INVALID\_SOURCE) Here’s my en…

---

## [Stockwell Transform in Julia](https://discourse.julialang.org/t/stockwell-transform-in-julia/96847)

<div class="topic-metadata">

**Author:** [@marianoarnaiz](https://discourse.julialang.org/u/marianoarnaiz)\
**Replies:** 1\
**Last updated:** [March 30, 2023, 5:17pm UTC](https://discourse.julialang.org/t/stockwell-transform-in-julia/96847 "2023-03-30T17:17:32Z")

</div>

Hi all. Any one has a Stockwell Transform code? I need to apply it to denoise some time signals :slight\_smile: Thanks! https://en.wikipedia.org/wiki/S\_transform

---

## [Accuracy of method of integration DifferentialEquations.jl](https://discourse.julialang.org/t/accuracy-of-method-of-integration-differentialequations-jl/96833)

<div class="topic-metadata">

**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 8\
**Last updated:** [March 30, 2023, 3:40pm UTC](https://discourse.julialang.org/t/accuracy-of-method-of-integration-differentialequations-jl/96833 "2023-03-30T15:40:26Z")

</div>

I have limit cycle in phase space, when i scale trajectory in phase space i see different lines. This is due to the accuracy of the integration method or this is problem of CairoMakie? Code: function Res(u, p, t)…

---

## [Indices of a sub-dataframe](https://discourse.julialang.org/t/indices-of-a-sub-dataframe/96650)

<div class="topic-metadata">

**Author:** [@johnbb](https://discourse.julialang.org/u/johnbb)\
**Replies:** 23\
**Last updated:** [March 30, 2023, 10:33am UTC](https://discourse.julialang.org/t/indices-of-a-sub-dataframe/96650 "2023-03-30T10:33:20Z")

</div>

Assume I have two dataframes A and B where A is a subset of B. How can I get the rowindices of A?

---

## [Multipliers of limit cycles](https://discourse.julialang.org/t/multipliers-of-limit-cycles/96827)

<div class="topic-metadata">

**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 4\
**Last updated:** [March 30, 2023, 8:18am UTC](https://discourse.julialang.org/t/multipliers-of-limit-cycles/96827 "2023-03-30T08:18:07Z")

</div>

Hello Are there packages for computing multipliers of limit cycles? I know about that i can calculate Poincare map with package DynamicalSystems, but how can i get multipliers of limit cycles?

---

## [How to find out sub-options under a module's option when using GMT in julia？](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829)

<div class="topic-metadata">

**Author:** [@dk-zen](https://discourse.julialang.org/u/dk-zen)\
**Replies:** 4\
**Last updated:** [March 30, 2023, 7:39am UTC](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829 "2023-03-30T07:39:03Z")

</div>

I’m new in GMT.jl. I follow the examples from Tutorial in Julia — GMT 6.4.0 documentation, and make a geographic map with a image pasted. It works. However, I don’t know how to query all options and suboptions under a m…

---

## [@SDconstraint not working](https://discourse.julialang.org/t/sdconstraint-not-working/96685)

<div class="topic-metadata">

**Author:** [@shaurya](https://discourse.julialang.org/u/shaurya)\
**Replies:** 2\
**Last updated:** [March 29, 2023, 8:00pm UTC](https://discourse.julialang.org/t/sdconstraint-not-working/96685 "2023-03-29T20:00:18Z")

</div>

Hi, I’m new to Julia and this might be something very simple but I’m struggling to implement in JuMP. julia\> using JuMP julia\> using MosekTools julia\> model = Model(); julia\> @variable(model, x) x julia\> a = \[x 2x …

---

## [Rounding solution output in JuMP](https://discourse.julialang.org/t/rounding-solution-output-in-jump/96786)

<div class="topic-metadata">

**Author:** [@samerb](https://discourse.julialang.org/u/samerb)\
**Replies:** 5\
**Last updated:** [March 29, 2023, 7:32pm UTC](https://discourse.julialang.org/t/rounding-solution-output-in-jump/96786 "2023-03-29T19:32:55Z")

</div>

When I solve a problem in JuMP, my code ends with optimize!(model); @show value(m); end and then it prints the solution m to the problem–as directed by the @show value(m) line. But it prints many decimal places of m…

---

## [Set\_start\_value to reduce iterations](https://discourse.julialang.org/t/set-start-value-to-reduce-iterations/96760)

<div class="topic-metadata">

**Author:** [@Annaquest](https://discourse.julialang.org/u/Annaquest)\
**Replies:** 1\
**Last updated:** [March 29, 2023, 6:27pm UTC](https://discourse.julialang.org/t/set-start-value-to-reduce-iterations/96760 "2023-03-29T18:27:54Z")

</div>

I have written an algorithm where I update a penalty parameter, ρ, if some conditions are not satisfied. Then I update the objective function with the new increased parameter and call optimize! Like this, ρ = ρ\*10 init…

---

## [Suppress error for infeasible problem in Jump](https://discourse.julialang.org/t/suppress-error-for-infeasible-problem-in-jump/96758)

<div class="topic-metadata">

**Author:** [@umbe](https://discourse.julialang.org/u/umbe)\
**Replies:** 5\
**Last updated:** [March 29, 2023, 5:51pm UTC](https://discourse.julialang.org/t/suppress-error-for-infeasible-problem-in-jump/96758 "2023-03-29T17:51:44Z")

</div>

Hello to everyone! I am trying to solve a series of optimizations using Jump and Gurobi. When a problem is found to be infeasible because of the impossibility to satisfy all the boundaries/constraints, Jump stops the p…

---

## [Dealing with views and cuda array wrappers](https://discourse.julialang.org/t/dealing-with-views-and-cuda-array-wrappers/96725)

<div class="topic-metadata">

**Author:** [@smartalecH](https://discourse.julialang.org/u/smartalecH)\
**Replies:** 2\
**Last updated:** [March 29, 2023, 4:52pm UTC](https://discourse.julialang.org/t/dealing-with-views-and-cuda-array-wrappers/96725 "2023-03-29T16:52:18Z")

</div>

I’m working with an array wrapper that uses a CuArray under the hood. When I try to @view into it, I get a complicated SubArray that calls the Base.fill!() routine rather than the Cuda.fill!() routine (i.e. it’s scalar i…

---

## [Error with gradient function in quantum reinforcement learning algorithm](https://discourse.julialang.org/t/error-with-gradient-function-in-quantum-reinforcement-learning-algorithm/96787)

<div class="topic-metadata">

**Author:** [@SatvikDuddukuru](https://discourse.julialang.org/u/SatvikDuddukuru)\
**Replies:** 0\
**Last updated:** [March 29, 2023, 4:26pm UTC](https://discourse.julialang.org/t/error-with-gradient-function-in-quantum-reinforcement-learning-algorithm/96787 "2023-03-29T16:26:22Z")

</div>

Hello. I am trying to implement the REINFORCE algorithm with parametrized quantum circuits from this Python tutorial (Parametrized Quantum Circuits for Reinforcement Learning | TensorFlow Quantum). To do this, I’ve imp…

---

## [JumpProblem: controlling saving behavior](https://discourse.julialang.org/t/jumpproblem-controlling-saving-behavior/96716)

<div class="topic-metadata">

**Author:** [@lmshk](https://discourse.julialang.org/u/lmshk)\
**Replies:** 7\
**Last updated:** [March 29, 2023, 3:57pm UTC](https://discourse.julialang.org/t/jumpproblem-controlling-saving-behavior/96716 "2023-03-29T15:57:12Z")

</div>

I have a JumpProcesses.JumpProblem that I am stepping through piecewise (using integrator = init(...)/step!(integrator, dt, true)) and I would like to save states only during some of these intervals according to a fixed …

---

## [Indexing symbolic arrays inside Differential Equation solution](https://discourse.julialang.org/t/indexing-symbolic-arrays-inside-differential-equation-solution/96764)

<div class="topic-metadata">

**Author:** [@Daniel\_Doyle](https://discourse.julialang.org/u/Daniel_Doyle)\
**Replies:** 4\
**Last updated:** [March 29, 2023, 2:34pm UTC](https://discourse.julialang.org/t/indexing-symbolic-arrays-inside-differential-equation-solution/96764 "2023-03-29T14:34:43Z")

</div>

Hello, I was running into an issue with indexing symbolic arrays from a solution and was wondering if anyone had some insight. Below is a simplified example: using ModelingToolkit, StochasticDiffEq using Plots @variab…

---

## [How to read GraphML with node and vertex metadata](https://discourse.julialang.org/t/how-to-read-graphml-with-node-and-vertex-metadata/96770)

<div class="topic-metadata">

**Author:** [@ArtHarg](https://discourse.julialang.org/u/ArtHarg)\
**Replies:** 2\
**Last updated:** [March 29, 2023, 12:54pm UTC](https://discourse.julialang.org/t/how-to-read-graphml-with-node-and-vertex-metadata/96770 "2023-03-29T12:54:54Z")

</div>

Is there an efficient way to read a GraphML file and produce a MetaGraph? My use case: I have a file containing 210,157 vertices and 1,016,092 edges, all with metadata. I can succesfully read the graph using g = loadg…

---

## [Create a \`Raster\` from OPeNDAP (netCDF)](https://discourse.julialang.org/t/create-a-raster-from-opendap-netcdf/96756)

<div class="topic-metadata">

**Author:** [@ryofurue](https://discourse.julialang.org/u/ryofurue)\
**Replies:** 1\
**Last updated:** [March 29, 2023, 8:38am UTC](https://discourse.julialang.org/t/create-a-raster-from-opendap-netcdf/96756 "2023-03-29T08:38:43Z")

</div>

The netCDF library has a builtin capability of lazily reading data from an OPeNDAP server as the following code demonstrates. I was wondering how to tell Raster to do the same. using NCDatasets: NCDataset using Rasters …

---

## [Have HTTP.jl accept self-signed certificates for SSL](https://discourse.julialang.org/t/have-http-jl-accept-self-signed-certificates-for-ssl/96746)

<div class="topic-metadata">

**Author:** [@screw\_dog](https://discourse.julialang.org/u/screw_dog)\
**Replies:** 1\
**Last updated:** [March 29, 2023, 5:51am UTC](https://discourse.julialang.org/t/have-http-jl-accept-self-signed-certificates-for-ssl/96746 "2023-03-29T05:51:09Z")

</div>

Hi, I’m writing a package to wrap a REST API using HTTP.jl and want to use a simple Julia local server for testing. Since all the REST calls use HTTPS I’ve generated a self-signed certificate for this test server but, o…

---

## [Discrete Optimization](https://discourse.julialang.org/t/discrete-optimization/96731)

<div class="topic-metadata">

**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 5\
**Last updated:** [March 29, 2023, 5:28am UTC](https://discourse.julialang.org/t/discrete-optimization/96731 "2023-03-29T05:28:37Z")

</div>

Is there a Julia optimization package that minimizes an objective function subject to constraints, where the unknowns are discrete (i.e., integer-valued), similar to MATLAB’s ga?

---

## [Alternative to FluxOptTools?](https://discourse.julialang.org/t/alternative-to-fluxopttools/96747)

<div class="topic-metadata">

**Author:** [@gnicolosi](https://discourse.julialang.org/u/gnicolosi)\
**Replies:** 2\
**Last updated:** [March 29, 2023, 5:13am UTC](https://discourse.julialang.org/t/alternative-to-fluxopttools/96747 "2023-03-29T05:13:44Z")

</div>

Dear all, I have an optimization problem in which some of the functions are approximated by NNs, thus I am using Flux to represent them. The package FluxOptTools has allowed me to use Optim to optimize my “loss” functi…

---

## [Questions on the DynamicalODE integrators](https://discourse.julialang.org/t/questions-on-the-dynamicalode-integrators/96721)

<div class="topic-metadata">

**Author:** [@henry2004y](https://discourse.julialang.org/u/henry2004y)\
**Replies:** 5\
**Last updated:** [March 29, 2023, 2:44am UTC](https://discourse.julialang.org/t/questions-on-the-dynamicalode-integrators/96721 "2023-03-29T02:44:06Z")

</div>

Hi! I have a question about the integrators in the differential equation community. The integrators for DynamicalODEProblem are listed in Dynamical, Hamiltonian, and 2nd Order ODE Solvers · DifferentialEquations.jl. Whi…

---

## [How do I do a plot in spherical coordinates?](https://discourse.julialang.org/t/how-do-i-do-a-plot-in-spherical-coordinates/96583)

<div class="topic-metadata">

**Author:** [@rmfritz](https://discourse.julialang.org/u/rmfritz)\
**Replies:** 7\
**Last updated:** [March 28, 2023, 10:45pm UTC](https://discourse.julialang.org/t/how-do-i-do-a-plot-in-spherical-coordinates/96583 "2023-03-28T22:45:36Z")

</div>

I either want to see a 3D surface or web of points. I suppose I can just take the 3D surface example as a model, but if possible, I would like to have angle axes. Is that possible with existing graphics libraries?

---

## [What is the best way to calculate the numerical gradient of a matrix, representing multiple points in 3D space?](https://discourse.julialang.org/t/what-is-the-best-way-to-calculate-the-numerical-gradient-of-a-matrix-representing-multiple-points-in-3d-space/96727)

<div class="topic-metadata">

**Author:** [@Dale\_James\_Black](https://discourse.julialang.org/u/Dale_James_Black)\
**Replies:** 10\
**Last updated:** [March 28, 2023, 10:04pm UTC](https://discourse.julialang.org/t/what-is-the-best-way-to-calculate-the-numerical-gradient-of-a-matrix-representing-multiple-points-in-3d-space/96727 "2023-03-28T22:04:10Z")

</div>

Given a matrix, where each row represents a point in 3D space and each column represents the x, y, and z location. What is the recommended way to calculate the gradient at each point (at each row)? points = \[ 202 2…

---

## [ModelingToolkit & DifferentialEquations -- \`save\_idxs\`?](https://discourse.julialang.org/t/modelingtoolkit-differentialequations-save-idxs/96709)

<div class="topic-metadata">

**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 1\
**Last updated:** [March 28, 2023, 1:15pm UTC](https://discourse.julialang.org/t/modelingtoolkit-differentialequations-save-idxs/96709 "2023-03-28T13:15:41Z")

</div>

Coding my own models using DifferentialEquations solvers, it is possible to specify keyword save\_idxs to specify which variables are saved. What if I write the model using MTK instead? Will save\_idxs only work with a …

---

## [GPU sum closure throwing an error](https://discourse.julialang.org/t/gpu-sum-closure-throwing-an-error/96658)

<div class="topic-metadata">

**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 3\
**Last updated:** [March 28, 2023, 6:57am UTC](https://discourse.julialang.org/t/gpu-sum-closure-throwing-an-error/96658 "2023-03-28T06:57:36Z")

</div>

I’m trying to streamline some code using KernelAbstractions and it’s almost working perfectly. I’m getting hung up when I try to write a sum closure like this within the kernel using KernelAbstractions using CUDA u = CU…

---

## [(relative) newbie, looking for suggestions](https://discourse.julialang.org/t/relative-newbie-looking-for-suggestions/96677)

<div class="topic-metadata">

**Author:** [@skypuppy](https://discourse.julialang.org/u/skypuppy)\
**Replies:** 3\
**Last updated:** [March 28, 2023, 3:04am UTC](https://discourse.julialang.org/t/relative-newbie-looking-for-suggestions/96677 "2023-03-28T03:04:54Z")

</div>

“Pro” programmer since 1977, mostly with C and “Zim DBMS” (now defunct.) I want to play with neural networks now. Base hardware ultimate is Jetson Nano or Orin, for robot/drone tinkering and LIDAR image processing and …

---

## [Zygote Warning within FluxOptTools - 'cannot track gradients'](https://discourse.julialang.org/t/zygote-warning-within-fluxopttools-cannot-track-gradients/96630)

<div class="topic-metadata">

**Author:** [@gnicolosi](https://discourse.julialang.org/u/gnicolosi)\
**Replies:** 2\
**Last updated:** [March 27, 2023, 11:12pm UTC](https://discourse.julialang.org/t/zygote-warning-within-fluxopttools-cannot-track-gradients/96630 "2023-03-27T23:12:15Z")

</div>

I am using NNs created using Flux to parameterize a function which I want to approximate in an optimal control problem. I formulate the associated optimization problem and call Optim, which works thanks to FLuXOptTools. …

---

## [Parallel merge in Cilk+ vs Julia](https://discourse.julialang.org/t/parallel-merge-in-cilk-vs-julia/34903)

<div class="topic-metadata">

**Author:** [@eaubanel](https://discourse.julialang.org/u/eaubanel)\
**Replies:** 18\
**Last updated:** [March 27, 2023, 10:02pm UTC](https://discourse.julialang.org/t/parallel-merge-in-cilk-vs-julia/34903 "2023-03-27T22:02:55Z")

</div>

As my first Julia program, I had some fun debugging a Julia implementation of a parallel merge, which I had already developed in Cilk+. I thought I’d make my first post by pointing the following out to warn others develo…

[Previous page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=202)

[Next page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=204)