# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=462

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

**Page:** 463

---

## [Potential bug related to initialization of a quadratic program](https://discourse.julialang.org/t/potential-bug-related-to-initialization-of-a-quadratic-program/34848)

<div class="topic-metadata">

**Author:** [@DR59](https://discourse.julialang.org/u/DR59)\
**Replies:** 8\
**Last updated:** [February 19, 2020, 8:52pm UTC](https://discourse.julialang.org/t/potential-bug-related-to-initialization-of-a-quadratic-program/34848 "2020-02-19T20:52:41Z")

</div>

Hi all, Consider the code below (a convex, quadratically constraint, quadratic program I pulled out of a hat). As it stands, it runs fine. However, if I comment out the for loop (i.e. I don’t manually set the starting v…

---

## [TypeError using ODEs in Turing.jl](https://discourse.julialang.org/t/typeerror-using-odes-in-turing-jl/34857)

<div class="topic-metadata">

**Author:** [@virgile-baudrot](https://discourse.julialang.org/u/virgile-baudrot)\
**Replies:** 2\
**Last updated:** [February 19, 2020, 8:33pm UTC](https://discourse.julialang.org/t/typeerror-using-odes-in-turing-jl/34857 "2020-02-19T20:33:27Z")

</div>

Hi all, I try using ODEs within Turing model, but I have the following error: TypeError: in typeassert, expected Float64, got ForwardDiff.Dual{Nothing,Float64,1} Here is my code: function myODE(du,u,p,t) du\[1\] = …

---

## [Allocations in Zygote for a simple derivative](https://discourse.julialang.org/t/allocations-in-zygote-for-a-simple-derivative/34871)

<div class="topic-metadata">

**Author:** [@edwinb-ai](https://discourse.julialang.org/u/edwinb-ai)\
**Replies:** 0\
**Last updated:** [February 19, 2020, 5:41pm UTC](https://discourse.julialang.org/t/allocations-in-zygote-for-a-simple-derivative/34871 "2020-02-19T17:41:57Z")

</div>

Hello everyone, somewhat new to Julia and very new to Zygote. I want to use Zygote’s AD functionality to compute derivatives of some simple functions, like in the following code using Zygote using Random using Benchmark…

---

## [Congratulations to VideoIO and Makie maintainers](https://discourse.julialang.org/t/congratulations-to-videoio-and-makie-maintainers/34844)

<div class="topic-metadata">

**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 0\
**Last updated:** [February 19, 2020, 11:55am UTC](https://discourse.julialang.org/t/congratulations-to-videoio-and-makie-maintainers/34844 "2020-02-19T11:55:30Z")

</div>

Quite often in the past I have moaned on here about VideoIO not working to read data from a webcam. I have filed several issues on the VideoIO repository. I am very pleased to say that I loaded VideoIO and Makie on a De…

---

## [Is it possible to use batching in Flux for sequences of different lengths?](https://discourse.julialang.org/t/is-it-possible-to-use-batching-in-flux-for-sequences-of-different-lengths/34594)

<div class="topic-metadata">

**Author:** [@jmeeks29ig](https://discourse.julialang.org/u/jmeeks29ig)\
**Replies:** 3\
**Last updated:** [February 19, 2020, 12:32am UTC](https://discourse.julialang.org/t/is-it-possible-to-use-batching-in-flux-for-sequences-of-different-lengths/34594 "2020-02-19T00:32:56Z")

</div>

I have sequences that are of the dimensions 8 by N, where N is a number fluctuating between 1 and 400. I would like to be able to do batch processing on these sequences, but have not had any luck in doing so inside of Fl…

---

## [When plotting, option "showaxis" does not accept "Symbol" or "String" type](https://discourse.julialang.org/t/when-plotting-option-showaxis-does-not-accept-symbol-or-string-type/34782)

<div class="topic-metadata">

**Author:** [@tferic](https://discourse.julialang.org/u/tferic)\
**Replies:** 2\
**Last updated:** [February 18, 2020, 11:00pm UTC](https://discourse.julialang.org/t/when-plotting-option-showaxis-does-not-accept-symbol-or-string-type/34782 "2020-02-18T23:00:52Z")

</div>

Hi, I am using Julia 1.0.3 in JuliaBox. I am facing an error when trying to use the “showaxis” option in plotting. I am trying to hide the labels of the x-axis, and display the labels of the y-axis. According to the d…

---

## [What is replacement for Not column selection in DataFrames (inverted index) in DataFrames v0.20.0?](https://discourse.julialang.org/t/what-is-replacement-for-not-column-selection-in-dataframes-inverted-index-in-dataframes-v0-20-0/34823)

<div class="topic-metadata">

**Author:** [@js135005](https://discourse.julialang.org/u/js135005)\
**Replies:** 6\
**Last updated:** [February 18, 2020, 7:25pm UTC](https://discourse.julialang.org/t/what-is-replacement-for-not-column-selection-in-dataframes-inverted-index-in-dataframes-v0-20-0/34823 "2020-02-18T19:25:54Z")

</div>

I was making extensive of the Not function for column selection in DataFrames. However this is deprecated in v0.20.0 and I haven’t yet found how to do the equivalent in the latest documentation. Indeed the DataFrames do…

---

## [I managed to make Flux.jl work with GPUs again!](https://discourse.julialang.org/t/i-managed-to-make-flux-jl-work-with-gpus-again/19386)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 6\
**Last updated:** [February 18, 2020, 2:14pm UTC](https://discourse.julialang.org/t/i-managed-to-make-flux-jl-work-with-gpus-again/19386 "2020-02-18T14:14:21Z")

</div>

If you look at the model zoo for mnist mlp for Flux.jl you may notice the line using CuArrays is commented out. Presumably, this was because the rest of the code would fail if that line was turned on. Of course, CuArrays…

---

## [Dimensional Data: Using 2-dimensional lat,lon dims when defining a DimensionalArray?](https://discourse.julialang.org/t/dimensional-data-using-2-dimensional-lat-lon-dims-when-defining-a-dimensionalarray/34794)

<div class="topic-metadata">

**Author:** [@k945](https://discourse.julialang.org/u/k945)\
**Replies:** 0\
**Last updated:** [February 18, 2020, 7:48am UTC](https://discourse.julialang.org/t/dimensional-data-using-2-dimensional-lat-lon-dims-when-defining-a-dimensionalarray/34794 "2020-02-18T07:48:17Z")

</div>

While it is possible to create a DimensionalArray with 1d dims. For example using DimensionalData arr = rand(4,4) x = rand(4); y = rand(4); z = 1:4 l = DimensionalArray(arr, (X(x), Y(y), Z(z))) is there a way to create…

---

## [CSV.jl : how to specify the columns types when the total columns number is not known?](https://discourse.julialang.org/t/csv-jl-how-to-specify-the-columns-types-when-the-total-columns-number-is-not-known/34753)

<div class="topic-metadata">

**Author:** [@Fred](https://discourse.julialang.org/u/Fred)\
**Replies:** 8\
**Last updated:** [February 18, 2020, 6:27am UTC](https://discourse.julialang.org/t/csv-jl-how-to-specify-the-columns-types-when-the-total-columns-number-is-not-known/34753 "2020-02-18T06:27:12Z")

</div>

Hi, I have to read large tables, I don’t know the total number of columns of the tables but I do know that the first one contains strings and all the others are Float64. I can easily specify the type of the first one li…

---

## [Filtfilt in DSP.jl - I really don't get it](https://discourse.julialang.org/t/filtfilt-in-dsp-jl-i-really-dont-get-it/10437)

<div class="topic-metadata">

**Author:** [@ceysa75](https://discourse.julialang.org/u/ceysa75)\
**Replies:** 3\
**Last updated:** [February 17, 2020, 11:21pm UTC](https://discourse.julialang.org/t/filtfilt-in-dsp-jl-i-really-dont-get-it/10437 "2020-02-17T23:21:49Z")

</div>

Hi dear community members, while making bigger steps forwards switching completely from Matlab to Julia here and there I am often struggling to solve some issues. This is mainly due to the poor/missing documentation of…

---

## [Can Makie render a scene at resolutions larger than the display?](https://discourse.julialang.org/t/can-makie-render-a-scene-at-resolutions-larger-than-the-display/34772)

<div class="topic-metadata">

**Author:** [@NiclasMattsson](https://discourse.julialang.org/u/NiclasMattsson)\
**Replies:** 0\
**Last updated:** [February 17, 2020, 8:13pm UTC](https://discourse.julialang.org/t/can-makie-render-a-scene-at-resolutions-larger-than-the-display/34772 "2020-02-17T20:13:58Z")

</div>

For example, suppose I want the simple line demo in the Makie docs rendered into a 5000x3000 PNG: using Makie x = range(0, stop = 2pi, length = 40) f(x) = sin.(x) y = f(x) scene = lines(x, y, color = :blue; resolution=…

---

## [Pie charts](https://discourse.julialang.org/t/pie-charts/34707)

<div class="topic-metadata">

**Author:** [@Michaela\_Maskova](https://discourse.julialang.org/u/Michaela_Maskova)\
**Replies:** 11\
**Last updated:** [February 17, 2020, 8:07pm UTC](https://discourse.julialang.org/t/pie-charts/34707 "2020-02-17T20:07:07Z")

</div>

Hello everyone, I am trying to plot a pie chart, unfortunately the only thing I could plot was the simplest version of it. I was unable to find any documentation and would love some help. I did find some examples using …

---

## [Automate training MLJ models](https://discourse.julialang.org/t/automate-training-mlj-models/32284)

<div class="topic-metadata">

**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 14\
**Last updated:** [February 17, 2020, 2:44am UTC](https://discourse.julialang.org/t/automate-training-mlj-models/32284 "2020-02-17T02:44:54Z")

</div>

I’d like to train 3 models in MLJ: ARDRegressor, AdaBoostRegressor, BaggingRegressor Currently, I train them 1 at a time for example: using Pkg; Pkg.activate("."); Pkg.instantiate(); using RDatasets, MLJ, Statistics, P…

---

## [ANN: JuliaActuary](https://discourse.julialang.org/t/ann-juliaactuary/31996)

<div class="topic-metadata">

**Author:** [@Alec\_Loudenback](https://discourse.julialang.org/u/Alec_Loudenback)\
**Replies:** 1\
**Last updated:** [February 16, 2020, 10:52pm UTC](https://discourse.julialang.org/t/ann-juliaactuary/31996 "2020-02-16T22:52:05Z")

</div>

I have created a GitHub organization to focus on extending Julia functionality into the actuarial domain: https://github.com/JuliaActuary I think there’s a lot of untapped potential to use Julia in the Actuarial profes…

---

## [Package for Confidence Intervals?](https://discourse.julialang.org/t/package-for-confidence-intervals/33902)

<div class="topic-metadata">

**Author:** [@Usor](https://discourse.julialang.org/u/Usor)\
**Replies:** 19\
**Last updated:** [February 16, 2020, 10:42pm UTC](https://discourse.julialang.org/t/package-for-confidence-intervals/33902 "2020-02-16T22:42:02Z")

</div>

Is there a package dealing with these kinds of computations, or should I make my own functions for my purposes?

---

## [Possible reasons that MixedModels would not create the property "sigmas"?](https://discourse.julialang.org/t/possible-reasons-that-mixedmodels-would-not-create-the-property-sigmas/34073)

<div class="topic-metadata">

**Author:** [@kai](https://discourse.julialang.org/u/kai)\
**Replies:** 4\
**Last updated:** [February 16, 2020, 10:11pm UTC](https://discourse.julialang.org/t/possible-reasons-that-mixedmodels-would-not-create-the-property-sigmas/34073 "2020-02-16T22:11:53Z")

</div>

I want to fit a linear mixed model inside my function and extract estimates of random effect standard deviations (sigmas from a LinearMixedModel object). So I wrote the following function, and it runs perfectly in REPL …

---

## [CuArrays: error calling CuArray() (ERROR\_INVALID\_DEVICE)](https://discourse.julialang.org/t/cuarrays-error-calling-cuarray-error-invalid-device/18654)

<div class="topic-metadata">

**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 25\
**Last updated:** [February 16, 2020, 5:47pm UTC](https://discourse.julialang.org/t/cuarrays-error-calling-cuarray-error-invalid-device/18654 "2020-02-16T17:47:54Z")

</div>

Hi all, I am new to Julia and would like to try out CuArrays. However, I get the following error when following the basic example from the Julia doc: julia\> using CuArrays julia\> julia\> B = ones(10\_000) ./ 2; julia\> …

---

## [Vegalite.jl Linear Fitting & Question of Controlling Interface](https://discourse.julialang.org/t/vegalite-jl-linear-fitting-question-of-controlling-interface/34681)

<div class="topic-metadata">

**Author:** [@Usor](https://discourse.julialang.org/u/Usor)\
**Replies:** 3\
**Last updated:** [February 16, 2020, 2:55pm UTC](https://discourse.julialang.org/t/vegalite-jl-linear-fitting-question-of-controlling-interface/34681 "2020-02-16T14:55:14Z")

</div>

What is the easiest most basic example of quickly fitting to a simple scatterplot using Vegalite.jl? (Say, with two columns of some numbers.) My other question is whether there are any plans to again have that higher ge…

---

## [Is Distributions.jl currently accepting PRs for new distributions?](https://discourse.julialang.org/t/is-distributions-jl-currently-accepting-prs-for-new-distributions/34078)

<div class="topic-metadata">

**Author:** [@johnczito](https://discourse.julialang.org/u/johnczito)\
**Replies:** 1\
**Last updated:** [February 15, 2020, 10:53pm UTC](https://discourse.julialang.org/t/is-distributions-jl-currently-accepting-prs-for-new-distributions/34078 "2020-02-15T22:53:22Z")

</div>

What is the current “policy” regarding merging new distributions into Distributions.jl? It would appear that the last time someone tried https://github.com/JuliaStats/Distributions.jl/pull/972 they got partially tied …

---

## [Stochastic programming UndefVarError](https://discourse.julialang.org/t/stochastic-programming-undefvarerror/34608)

<div class="topic-metadata">

**Author:** [@bandaya](https://discourse.julialang.org/u/bandaya)\
**Replies:** 4\
**Last updated:** [February 15, 2020, 6:09pm UTC](https://discourse.julialang.org/t/stochastic-programming-undefvarerror/34608 "2020-02-15T18:09:02Z")

</div>

Hi, I am looking at this package StochasticPrograms and I tried to run the farmer example given on the link below. I am getting an error message: “UndefVarError: @stochastic\_model not defined”. This line in the code ma…

---

## [PlotlyJS: How to add another set of data to an existing plot?](https://discourse.julialang.org/t/plotlyjs-how-to-add-another-set-of-data-to-an-existing-plot/15914)

<div class="topic-metadata">

**Author:** [@Moses](https://discourse.julialang.org/u/Moses)\
**Replies:** 6\
**Last updated:** [February 15, 2020, 10:06am UTC](https://discourse.julialang.org/t/plotlyjs-how-to-add-another-set-of-data-to-an-existing-plot/15914 "2020-02-15T10:06:35Z")

</div>

I am trying to update an existing plot with a second trace using PlotlyJS with Julia 1.0 and Atom on Windows 8.1. using Plots using PlotlyJS plotlyjs() # intended to switch to the according backend x = \[range(0, lengt…

---

## [Determining the sign of a function over a given interval](https://discourse.julialang.org/t/determining-the-sign-of-a-function-over-a-given-interval/33231)

<div class="topic-metadata">

**Author:** [@ArjunNarayanan](https://discourse.julialang.org/u/ArjunNarayanan)\
**Replies:** 15\
**Last updated:** [February 15, 2020, 1:01am UTC](https://discourse.julialang.org/t/determining-the-sign-of-a-function-over-a-given-interval/33231 "2020-02-15T01:01:25Z")

</div>

I am interested in determining the bounds of a function f(x) over a given interval int. Specifically, I want to determine if f is uniformly positive/negative over int or contains at least one root. f is continuous and fi…

---

## [Plotting a series of discontinuous lines with PyPlot](https://discourse.julialang.org/t/plotting-a-series-of-discontinuous-lines-with-pyplot/34659)

<div class="topic-metadata">

**Author:** [@totorotoby](https://discourse.julialang.org/u/totorotoby)\
**Replies:** 0\
**Last updated:** [February 14, 2020, 10:50pm UTC](https://discourse.julialang.org/t/plotting-a-series-of-discontinuous-lines-with-pyplot/34659 "2020-02-14T22:50:14Z")

</div>

I am attempting to use matplotlib’s LineCollection in PyPlot to multiple sets of discontinuous lines in a loop. I started writing my code after reading this: http://julia-programming-language.2336112.n4.nabble.com/PyPlot…

---

## [Plotting markdown in the legend](https://discourse.julialang.org/t/plotting-markdown-in-the-legend/34637)

<div class="topic-metadata">

**Author:** [@crinders](https://discourse.julialang.org/u/crinders)\
**Replies:** 2\
**Last updated:** [February 14, 2020, 6:55pm UTC](https://discourse.julialang.org/t/plotting-markdown-in-the-legend/34637 "2020-02-14T18:55:09Z")

</div>

I am trying to plot Markdown in the legend of a plot. According to this blog post by @Tamas\_Papp LaTeXStrings.jl can be used to display latex math and that works, but when I want to typeset other LaTeX commands it doesn…

---

## [How to use parallel computing or GPU to make calculations fasterwhen the M=10000](https://discourse.julialang.org/t/how-to-use-parallel-computing-or-gpu-to-make-calculations-fasterwhen-the-m-10000/34623)

<div class="topic-metadata">

**Author:** [@11125](https://discourse.julialang.org/u/11125)\
**Replies:** 1\
**Last updated:** [February 14, 2020, 4:52pm UTC](https://discourse.julialang.org/t/how-to-use-parallel-computing-or-gpu-to-make-calculations-fasterwhen-the-m-10000/34623 "2020-02-14T16:52:03Z")

</div>

using CuArrays,CUDAnative,CUDAdrv,BenchmarkTools N = 3 k = ones(N,N)\*5 M = 100 rho = zeros(N,N) aa = range(-5,5,length=N) K = zeros(N,N) A = repeat(-aa’,N,1) B = repeat(aa,1,N) C=ones(N,N)-10 phi = repeat(range…

---

## [\[ANN\] New package GRUtils](https://discourse.julialang.org/t/ann-new-package-grutils/29019)

<div class="topic-metadata">

**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 15\
**Last updated:** [February 14, 2020, 10:30am UTC](https://discourse.julialang.org/t/ann-new-package-grutils/29019 "2020-02-14T10:30:08Z")

</div>

Hi, I would like to announce the release of version 0.1.0 of GRUtils, an experimental package that provides yet another interface to plot with GR in Julia. Why on earth would anyone need it? - you may ask. Plots is alre…

---

## [Performance problems with parallel ensemble simulation on GPU](https://discourse.julialang.org/t/performance-problems-with-parallel-ensemble-simulation-on-gpu/34596)

<div class="topic-metadata">

**Author:** [@nnagyd](https://discourse.julialang.org/u/nnagyd)\
**Replies:** 3\
**Last updated:** [February 14, 2020, 8:06am UTC](https://discourse.julialang.org/t/performance-problems-with-parallel-ensemble-simulation-on-gpu/34596 "2020-02-14T08:06:32Z")

</div>

We are doing some performance analysis of different ODE solvers on GPU’s. When I compare the run times of the Julia code to the odeint and MPGOS codes of the same system, Julia does not perform too well. We are solving t…

---

## [JuMP vs OpenMDAO](https://discourse.julialang.org/t/jump-vs-openmdao/34602)

<div class="topic-metadata">

**Author:** [@josemaria](https://discourse.julialang.org/u/josemaria)\
**Replies:** 1\
**Last updated:** [February 14, 2020, 4:51am UTC](https://discourse.julialang.org/t/jump-vs-openmdao/34602 "2020-02-14T04:51:27Z")

</div>

Does any of you have experience with both? How do they compare?

---

## [Gradient-based methods are not moving some parameters](https://discourse.julialang.org/t/gradient-based-methods-are-not-moving-some-parameters/34549)

<div class="topic-metadata">

**Author:** [@cosmia](https://discourse.julialang.org/u/cosmia)\
**Replies:** 3\
**Last updated:** [February 13, 2020, 4:16pm UTC](https://discourse.julialang.org/t/gradient-based-methods-are-not-moving-some-parameters/34549 "2020-02-13T16:16:34Z")

</div>

Hi all, I have a maximum likelihood estimator in which I need to integrate using a mixture of two normal distributions with zero mean. Without getting into much details, this entails estimating 3 parameters of the distri…

[Previous page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=461)

[Next page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=463)