# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=390

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

**Page:** 391

---

## [Is autodifferentiation possible in this situation?](https://discourse.julialang.org/t/is-autodifferentiation-possible-in-this-situation/54807)

<div class="topic-metadata">

**Author:** [@marcobonici](https://discourse.julialang.org/u/marcobonici)\
**Replies:** 20\
**Last updated:** [February 8, 2021, 1:52am UTC](https://discourse.julialang.org/t/is-autodifferentiation-possible-in-this-situation/54807 "2021-02-08T01:52:40Z")

</div>

Dear all, I am here to ask the help of the community. I am a Physicist, working in the domain of Astrophysics/Cosmology. About a month ago I discovered Julia and I started translating my Python code in this new language…

---

## [@polyvar does not allow two-dimensional variables](https://discourse.julialang.org/t/polyvar-does-not-allow-two-dimensional-variables/52395)

<div class="topic-metadata">

**Author:** [@aliceee](https://discourse.julialang.org/u/aliceee)\
**Replies:** 4\
**Last updated:** [February 7, 2021, 6:15pm UTC](https://discourse.julialang.org/t/polyvar-does-not-allow-two-dimensional-variables/52395 "2021-02-07T18:15:42Z")

</div>

I want define a polyvar with size 2\*3. Several weeks ago, the following code works using TypedPolynomials @polyvar B\[1:2,1:3\] But now I get this error: Unsupported syntax. Expected x\[a:b\] for literal integers a and b…

---

## [Very simple MPI implementation question](https://discourse.julialang.org/t/very-simple-mpi-implementation-question/53641)

<div class="topic-metadata">

**Author:** [@abader](https://discourse.julialang.org/u/abader)\
**Replies:** 3\
**Last updated:** [February 7, 2021, 11:20am UTC](https://discourse.julialang.org/t/very-simple-mpi-implementation-question/53641 "2021-02-07T11:20:34Z")

</div>

I’m trying to do some simple MPI calculations but have had some difficulty finding good tutorials online. For this implementation we cannot use threading, because of some interface issues with other codes (most advice I…

---

## [Share system of equations solution between g(x) and dg(x)dx functions (i.e. constraint and its jacobian) in IPOPT](https://discourse.julialang.org/t/share-system-of-equations-solution-between-g-x-and-dg-x-dx-functions-i-e-constraint-and-its-jacobian-in-ipopt/51608)

<div class="topic-metadata">

**Author:** [@nico](https://discourse.julialang.org/u/nico)\
**Replies:** 6\
**Last updated:** [February 7, 2021, 8:50am UTC](https://discourse.julialang.org/t/share-system-of-equations-solution-between-g-x-and-dg-x-dx-functions-i-e-constraint-and-its-jacobian-in-ipopt/51608 "2021-02-07T08:50:31Z")

</div>

Hi, I planning to use IPOPT in an optimization project. I would like to know if there is a way to share the solution of a system of equations (like Ax=b) between different functions called by IPOPT, say the constraint …

---

## [Solving ODE system with PINN](https://discourse.julialang.org/t/solving-ode-system-with-pinn/54750)

<div class="topic-metadata">

**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 7\
**Last updated:** [February 7, 2021, 2:27am UTC](https://discourse.julialang.org/t/solving-ode-system-with-pinn/54750 "2021-02-07T02:27:04Z")

</div>

Dear All, I am trying to solve system of two ordinary differential equations. 𝝫’(x) = (λ-1/v(x))f(x) v’(x) = x^3(λf(x)/(λf(x)x-2𝝫(x)))^2 With boundary conditions 𝝫(x\_low) = 0 𝝫(x\_high) = 0 v(x) and 𝝫(x) are unknow…

---

## [Sparse vectors and BigFloat Heisenbug](https://discourse.julialang.org/t/sparse-vectors-and-bigfloat-heisenbug/54707)

<div class="topic-metadata">

**Author:** [@mbesancon](https://discourse.julialang.org/u/mbesancon)\
**Replies:** 4\
**Last updated:** [February 6, 2021, 10:14am UTC](https://discourse.julialang.org/t/sparse-vectors-and-bigfloat-heisenbug/54707 "2021-02-06T10:14:28Z")

</div>

I have in some weird side effect with structs of sparse vectors of BigFloats, where operating on a copy of the sum seems to change the struct itself. In spirit, the structure of the code looks like below. After a copyin…

---

## [Getindex in Model Constraints assign](https://discourse.julialang.org/t/getindex-in-model-constraints-assign/54678)

<div class="topic-metadata">

**Author:** [@user1200](https://discourse.julialang.org/u/user1200)\
**Replies:** 3\
**Last updated:** [February 5, 2021, 9:20pm UTC](https://discourse.julialang.org/t/getindex-in-model-constraints-assign/54678 "2021-02-05T21:20:16Z")

</div>

Hello Is there a way to use getIndex or findfirst function in Constraints in Model? Usage: Get maximum value from “1 vector(column)”-but remember just its index, for example 8th. Then get value from “another vector(co…

---

## [Vectorising Turing models](https://discourse.julialang.org/t/vectorising-turing-models/54700)

<div class="topic-metadata">

**Author:** [@drbenvincent](https://discourse.julialang.org/u/drbenvincent)\
**Replies:** 1\
**Last updated:** [February 5, 2021, 7:49pm UTC](https://discourse.julialang.org/t/vectorising-turing-models/54700 "2021-02-05T19:49:44Z")

</div>

I’m testing out vectorization in Turing models. I’ve managed to get a model that too 195 seconds, down to 60 seconds. But I wonder if there is anything obvious I’m missing in order to get even further benefits? using Tu…

---

## [JLBoost key error](https://discourse.julialang.org/t/jlboost-key-error/54702)

<div class="topic-metadata">

**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 0\
**Last updated:** [February 5, 2021, 7:25pm UTC](https://discourse.julialang.org/t/jlboost-key-error/54702 "2021-02-05T19:25:33Z")

</div>

Hi All, I am trying to blindly use JLBoost on a big dataset with 2381 features and 600 000 samples. I have automatically converted the feature matrix to the DataFrame using df = DataFrame(x, :auto), add labels as df.y =…

---

## [How to add multiple same rows in a array](https://discourse.julialang.org/t/how-to-add-multiple-same-rows-in-a-array/54695)

<div class="topic-metadata">

**Author:** [@Shazman](https://discourse.julialang.org/u/Shazman)\
**Replies:** 3\
**Last updated:** [February 5, 2021, 4:58pm UTC](https://discourse.julialang.org/t/how-to-add-multiple-same-rows-in-a-array/54695 "2021-02-05T16:58:27Z")

</div>

Hi I have a array P (1x41227) and I want to add 27856 rows with same elements like P. how can I do it ? thanks 1×41227 Array{Float64,2}: 0.0361328 -0.00634766 0.774414 0.620117 … 0.255859 0.491211 0.666992

---

## [Composing probabilistic models](https://discourse.julialang.org/t/composing-probabilistic-models/54604)

<div class="topic-metadata">

**Author:** [@plafl](https://discourse.julialang.org/u/plafl)\
**Replies:** 6\
**Last updated:** [February 5, 2021, 4:20pm UTC](https://discourse.julialang.org/t/composing-probabilistic-models/54604 "2021-02-05T16:20:35Z")

</div>

Hi, I’m quite new to Julia and I have stumbled upon Turing. It looks great and the documentation is nice but either I have missed something or simply it’s not possible. I want to define models in a modular way and combi…

---

## [Solve function for non full rank systems of equations](https://discourse.julialang.org/t/solve-function-for-non-full-rank-systems-of-equations/54611)

<div class="topic-metadata">

**Author:** [@Andres\_Legarra](https://discourse.julialang.org/u/Andres_Legarra)\
**Replies:** 4\
**Last updated:** [February 5, 2021, 1:27pm UTC](https://discourse.julialang.org/t/solve-function-for-non-full-rank-systems-of-equations/54611 "2021-02-05T13:27:05Z")

</div>

Typical OLS ( X'X a = X'y ) with 2 or more dummy (or cross-classified) effects are not full rank and they have infinite solutions. (Minimal example below.) They are conceptually solved using generalized inverses, to obta…

---

## [Elegant kernel for vectors in matrix](https://discourse.julialang.org/t/elegant-kernel-for-vectors-in-matrix/54648)

<div class="topic-metadata">

**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 3\
**Last updated:** [February 5, 2021, 12:57pm UTC](https://discourse.julialang.org/t/elegant-kernel-for-vectors-in-matrix/54648 "2021-02-05T12:57:32Z")

</div>

Hello, I’m trying to write a kernel that does some operations on vectors using CUDA.jl and @cuda. My code is essentially this: points = Nx3 matrix with x,y,z coordinates of points elements = Nx4 matrix with integers th…

---

## [Plots.jl - Combined Histogram and Distribution](https://discourse.julialang.org/t/plots-jl-combined-histogram-and-distribution/54656)

<div class="topic-metadata">

**Author:** [@phillc](https://discourse.julialang.org/u/phillc)\
**Replies:** 4\
**Last updated:** [February 5, 2021, 9:03am UTC](https://discourse.julialang.org/t/plots-jl-combined-histogram-and-distribution/54656 "2021-02-05T09:03:50Z")

</div>

I’m trying to convert some plots from R based examples to Julia. The R examples are found here: Essentially the single plot is a histogram of a probability distribution, with the corresponding Beta distribution plotte…

---

## [Sum of Flux.params](https://discourse.julialang.org/t/sum-of-flux-params/54608)

<div class="topic-metadata">

**Author:** [@anon74562486](https://discourse.julialang.org/u/anon74562486)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 8:32pm UTC](https://discourse.julialang.org/t/sum-of-flux-params/54608 "2021-02-04T20:32:58Z")

</div>

I tried these two functions to get the l2 regularization term for a NN model: function ℓ₂(a) s = zero(Float32) for i in a s += sum(i.^2) end s end function l₂(a) s = zero(Float32) Lₐ = l…

---

## [Bounded parameters w/ Optim](https://discourse.julialang.org/t/bounded-parameters-w-optim/54552)

<div class="topic-metadata">

**Author:** [@pyrex41](https://discourse.julialang.org/u/pyrex41)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 6:51pm UTC](https://discourse.julialang.org/t/bounded-parameters-w-optim/54552 "2021-02-04T18:51:13Z")

</div>

I have been working on fitting some non-linear models, and have been using Optim. For models where the parameters space is bounded, one can obviously use Box Constraints. Before I read how to this, however, I had been tr…

---

## [Which Optimization package for large-scale structured nonlinear problems](https://discourse.julialang.org/t/which-optimization-package-for-large-scale-structured-nonlinear-problems/54449)

<div class="topic-metadata">

**Author:** [@egvila](https://discourse.julialang.org/u/egvila)\
**Replies:** 6\
**Last updated:** [February 4, 2021, 6:43pm UTC](https://discourse.julialang.org/t/which-optimization-package-for-large-scale-structured-nonlinear-problems/54449 "2021-02-04T18:43:52Z")

</div>

Hello everyone, As the title says, I would like some insight on what Julia Optimization package would be most appropriate to efficiently solve nonlinear problems with potentially exploitable sparsity structures (e.g. bl…

---

## [How to export data from an array](https://discourse.julialang.org/t/how-to-export-data-from-an-array/54555)

<div class="topic-metadata">

**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 3\
**Last updated:** [February 4, 2021, 6:29pm UTC](https://discourse.julialang.org/t/how-to-export-data-from-an-array/54555 "2021-02-04T18:29:49Z")

</div>

Maybe my question is a little repetitive compared to the last one I posted here. In this model, I would like to export the data that is in i to a .CSV file. When compiling the model the answer I have in .CSV is this: …

---

## [For Loops in Luxor](https://discourse.julialang.org/t/for-loops-in-luxor/54197)

<div class="topic-metadata">

**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 20\
**Last updated:** [February 4, 2021, 5:51pm UTC](https://discourse.julialang.org/t/for-loops-in-luxor/54197 "2021-02-04T17:51:09Z")

</div>

When I create a checker pattern using the rect function, it works perfectly: @svg begin Drawing(2000,2000) background("white") sethue("black") rect(500,0,500,500,:fill) rect(1500,0,500,500,:fill) rect(0,500,500,50…

---

## [Linear system problems](https://discourse.julialang.org/t/linear-system-problems/54519)

<div class="topic-metadata">

**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 35\
**Last updated:** [February 4, 2021, 10:57am UTC](https://discourse.julialang.org/t/linear-system-problems/54519 "2021-02-04T10:57:31Z")

</div>

Hello, I’m writing some code that solves A\*x=b, where A can be quite big (say 10000x10000, hopefully bigger in the future). A is not sparse (at least for now) and might be poorly conditioned. Might even have multiple so…

---

## [Seeking advice on contributing to Julia: A faster Lasso solver](https://discourse.julialang.org/t/seeking-advice-on-contributing-to-julia-a-faster-lasso-solver/42023)

<div class="topic-metadata">

**Author:** [@barankarakus](https://discourse.julialang.org/u/barankarakus)\
**Replies:** 9\
**Last updated:** [February 4, 2021, 7:02am UTC](https://discourse.julialang.org/t/seeking-advice-on-contributing-to-julia-a-faster-lasso-solver/42023 "2021-02-04T07:02:31Z")

</div>

Hi there, I’m a Master’s student in Statistics. I’ve recently been researching ‘safe screening rules’ for accelerating Lasso solvers. These can improve computation times by orders of magnitude when the number of feature…

---

## [Gradient penalty problems with relu](https://discourse.julialang.org/t/gradient-penalty-problems-with-relu/54594)

<div class="topic-metadata">

**Author:** [@ancorso](https://discourse.julialang.org/u/ancorso)\
**Replies:** 0\
**Last updated:** [February 4, 2021, 6:25am UTC](https://discourse.julialang.org/t/gradient-penalty-problems-with-relu/54594 "2021-02-04T06:25:32Z")

</div>

I am trying to implement the gradient penalty of WGAN-GP in Flux and Zygote, but am getting an error when I have relus in my model. See the following MWE. If I switch the relu to a tanh then it works fine. Thoughts? usi…

---

## [EnsembleSummary deprecated?](https://discourse.julialang.org/t/ensemblesummary-deprecated/54570)

<div class="topic-metadata">

**Author:** [@zenkavi](https://discourse.julialang.org/u/zenkavi)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 12:22am UTC](https://discourse.julialang.org/t/ensemblesummary-deprecated/54570 "2021-02-04T00:22:48Z")

</div>

I’m very new to Julia so I might be misinterpreting what’s happening here. The EnsembleSummary function stopped working for me which doesn’t seem to make sense since it is part of SciMLBase so maybe dependencies are mes…

---

## [Optim with autodiff return error when optimize paralleled objective function](https://discourse.julialang.org/t/optim-with-autodiff-return-error-when-optimize-paralleled-objective-function/54496)

<div class="topic-metadata">

**Author:** [@zxjroger](https://discourse.julialang.org/u/zxjroger)\
**Replies:** 9\
**Last updated:** [February 4, 2021, 12:22am UTC](https://discourse.julialang.org/t/optim-with-autodiff-return-error-when-optimize-paralleled-objective-function/54496 "2021-02-04T00:22:45Z")

</div>

I have a very complicated objective function which involves some distributed call. I would like to optimize the function using Optim with Forward Difference. However, it reports an error. This is the MWE: using Distribu…

---

## [Network ODE Model; Type error with ForwardDiff Dual](https://discourse.julialang.org/t/network-ode-model-type-error-with-forwarddiff-dual/54379)

<div class="topic-metadata">

**Author:** [@PavanChaggar](https://discourse.julialang.org/u/PavanChaggar)\
**Replies:** 9\
**Last updated:** [February 3, 2021, 10:37pm UTC](https://discourse.julialang.org/t/network-ode-model-type-error-with-forwarddiff-dual/54379 "2021-02-03T22:37:59Z")

</div>

Hello, I am new to Turing and trying to use it for my research on network ODE models. I have started with a simple model (network diffusion) \\frac{du}{dt} = - \\rho \\mathbf{L} \\mathbf{u} and am trying to infer the va…

---

## [Is there @code\_warntype output documentation anywhere?](https://discourse.julialang.org/t/is-there-code-warntype-output-documentation-anywhere/54506)

<div class="topic-metadata">

**Author:** [@zenkavi](https://discourse.julialang.org/u/zenkavi)\
**Replies:** 3\
**Last updated:** [February 3, 2021, 7:41pm UTC](https://discourse.julialang.org/t/is-there-code-warntype-output-documentation-anywhere/54506 "2021-02-03T19:41:35Z")

</div>

Where can I find more information on understanding the output of @code\_warntype mentioned in Turing Performance Tips? I’m trying to use it to debug some ForwardDiff Dual Type errors mentioned often (e.g. one recent exam…

---

## [GLMakie: recording a movie without displaying intermediate frames?](https://discourse.julialang.org/t/glmakie-recording-a-movie-without-displaying-intermediate-frames/54537)

<div class="topic-metadata">

**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 1\
**Last updated:** [February 3, 2021, 7:30pm UTC](https://discourse.julialang.org/t/glmakie-recording-a-movie-without-displaying-intermediate-frames/54537 "2021-02-03T19:30:29Z")

</div>

Hi, I would like to use GLMakie on a remote machine without exporting a display. Note that I was not able to use WGLMakie because of speed issue neither CairoMakie because these are 3D plots. Is it possible to record …

---

## [Issue with MvNormal and Turing](https://discourse.julialang.org/t/issue-with-mvnormal-and-turing/54541)

<div class="topic-metadata">

**Author:** [@Carter](https://discourse.julialang.org/u/Carter)\
**Replies:** 8\
**Last updated:** [February 3, 2021, 7:29pm UTC](https://discourse.julialang.org/t/issue-with-mvnormal-and-turing/54541 "2021-02-03T19:29:07Z")

</div>

I’m trying to recreate the model from chapter 5.1 to estimate correlation from the book Bayesian Cognitive Modeling: A Practical Course using Turing. However, I keep running into an issue with MvNormal where it does not …

---

## [Calculating power transfer distribution factor (PTDF) matrix using PowerModels.jl](https://discourse.julialang.org/t/calculating-power-transfer-distribution-factor-ptdf-matrix-using-powermodels-jl/42668)

<div class="topic-metadata">

**Author:** [@gobs](https://discourse.julialang.org/u/gobs)\
**Replies:** 7\
**Last updated:** [February 3, 2021, 5:46pm UTC](https://discourse.julialang.org/t/calculating-power-transfer-distribution-factor-ptdf-matrix-using-powermodels-jl/42668 "2021-02-03T17:46:10Z")

</div>

I want to obtain a PTDF matrix to use in my power system optimisation model using data in PowerModels.jl format (I also raised an issue for this to be integrated into PowerModels.jl itself: https://github.com/lanl-ansi/P…

---

## [Package for visualizing wireframe cube](https://discourse.julialang.org/t/package-for-visualizing-wireframe-cube/54400)

<div class="topic-metadata">

**Author:** [@EL-Bakkali-Jaafar](https://discourse.julialang.org/u/EL-Bakkali-Jaafar)\
**Replies:** 6\
**Last updated:** [February 3, 2021, 3:41pm UTC](https://discourse.julialang.org/t/package-for-visualizing-wireframe-cube/54400 "2021-02-03T15:41:37Z")

</div>

Hi all, What I am looking for is a package to draw a wireframe cube and to draw segment connecting two 3d points. Thanks.

[Previous page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=389)

[Next page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=391)