# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=452

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

**Page:** 453

---

## [Scope of variables in optimisation](https://discourse.julialang.org/t/scope-of-variables-in-optimisation/37258)

<div class="topic-metadata">

**Author:** [@JohnZ](https://discourse.julialang.org/u/JohnZ)\
**Replies:** 7\
**Last updated:** [April 9, 2020, 5:21pm UTC](https://discourse.julialang.org/t/scope-of-variables-in-optimisation/37258 "2020-04-09T17:21:29Z")

</div>

Hello, folks! I am new to JuMP, so my apologies if it sounds a naive question. I wrap an optimisation problem in a function and then run it by changing input data in a loop. I define the variables as global so that thes…

---

## [JSON3 loading recursive structures](https://discourse.julialang.org/t/json3-loading-recursive-structures/37283)

<div class="topic-metadata">

**Author:** [@racinmat](https://discourse.julialang.org/u/racinmat)\
**Replies:** 0\
**Last updated:** [April 9, 2020, 3:08pm UTC](https://discourse.julialang.org/t/json3-loading-recursive-structures/37283 "2020-04-09T15:08:36Z")

</div>

Hi, I see that GitHub - quinnj/JSON3.jl can be used for writing and reading data to custom structures, specifically from this package https://github.com/pevnak/JsonGrinder.jl/tree/master/src/extractors. I want to use it…

---

## [Bimodal Gaussian Distribution](https://discourse.julialang.org/t/bimodal-gaussian-distribution/37274)

<div class="topic-metadata">

**Author:** [@ennvvy](https://discourse.julialang.org/u/ennvvy)\
**Replies:** 1\
**Last updated:** [April 9, 2020, 12:46pm UTC](https://discourse.julialang.org/t/bimodal-gaussian-distribution/37274 "2020-04-09T12:46:46Z")

</div>

I am trying to generate random numbers using a Gaussian distribution with two means. I looked up the Distributions and StatsBase packages, but could not find functions in them to generate such a function. Can someone sug…

---

## [Sokoban and Julia](https://discourse.julialang.org/t/sokoban-and-julia/37227)

<div class="topic-metadata">

**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 2\
**Last updated:** [April 9, 2020, 8:47am UTC](https://discourse.julialang.org/t/sokoban-and-julia/37227 "2020-04-09T08:47:08Z")

</div>

Hi, just for a curiosity, did played with reinforcement learning to solve sokoban? Is there any repo, which would allow to play with it? Thanks for response, Tomas

---

## [Estimating parameters of a function for curve fitting](https://discourse.julialang.org/t/estimating-parameters-of-a-function-for-curve-fitting/32404)

<div class="topic-metadata">

**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 11\
**Last updated:** [April 9, 2020, 8:37am UTC](https://discourse.julialang.org/t/estimating-parameters-of-a-function-for-curve-fitting/32404 "2020-04-09T08:37:36Z")

</div>

I have some data that has missing values. I am trying to fit a curve on this data, using Richard’s Model which is \\begin{aligned} I(t)=& \\frac{K}{\\left\[1+e^{-r a(t-\\tau)}\\right\] \\frac{1}{a}} \\end{aligned} where K is …

---

## [Best practice for large-scale models in JuMP?](https://discourse.julialang.org/t/best-practice-for-large-scale-models-in-jump/37256)

<div class="topic-metadata">

**Author:** [@olugovoy](https://discourse.julialang.org/u/olugovoy)\
**Replies:** 2\
**Last updated:** [April 9, 2020, 2:23am UTC](https://discourse.julialang.org/t/best-practice-for-large-scale-models-in-jump/37256 "2020-04-09T02:23:12Z")

</div>

Hi there, We are translating a large scale LP model from GAMS to Julia/JuMP. Large-scale means, there are a number of sets (regions, years, sub-annual time resolution - days and hours, technologies, etc.) and 2-5 dimen…

---

## [Issues Importing Turing Linux](https://discourse.julialang.org/t/issues-importing-turing-linux/37132)

<div class="topic-metadata">

**Author:** [@nucklass](https://discourse.julialang.org/u/nucklass)\
**Replies:** 4\
**Last updated:** [April 8, 2020, 7:25pm UTC](https://discourse.julialang.org/t/issues-importing-turing-linux/37132 "2020-04-08T19:25:33Z")

</div>

New to Linux but familiar (enough) with Turing. Having an issue get Turing to run on Ubuntu. I’ve been able to run Turing in windows, but getting some errors I’ve never seen before now. Currently running Julia 1.4.0. Her…

---

## [PPL collaboration](https://discourse.julialang.org/t/ppl-collaboration/26145)

<div class="topic-metadata">

**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 33\
**Last updated:** [April 8, 2020, 3:06pm UTC](https://discourse.julialang.org/t/ppl-collaboration/26145 "2020-04-08T15:06:35Z")

</div>

@mohamed82008 opened this issue on @Elrod’s ProbabilityModels.jl library, closing with Finally, would you be interested in joining forces? There’s some good discussion here, but it drifted a bit from anything specifi…

---

## [\[ANN\] AdversarialPrediction.jl | Easily optimize generic performance metrics in differentiable learning](https://discourse.julialang.org/t/ann-adversarialprediction-jl-easily-optimize-generic-performance-metrics-in-differentiable-learning/31804)

<div class="topic-metadata">

**Author:** [@raff](https://discourse.julialang.org/u/raff)\
**Replies:** 1\
**Last updated:** [April 8, 2020, 1:23pm UTC](https://discourse.julialang.org/t/ann-adversarialprediction-jl-easily-optimize-generic-performance-metrics-in-differentiable-learning/31804 "2020-04-08T13:23:05Z")

</div>

I am excited to announce a new approach for optimizing generic performance metrics (including non-decomposable metrics) in differentiable learning. AdversarialPrediction.jl provides a Julia implementation of the framewor…

---

## [Second order cone constraint in JuMP 0.19 with JuMP solver](https://discourse.julialang.org/t/second-order-cone-constraint-in-jump-0-19-with-jump-solver/37214)

<div class="topic-metadata">

**Author:** [@Chengda\_Ji](https://discourse.julialang.org/u/Chengda_Ji)\
**Replies:** 1\
**Last updated:** [April 8, 2020, 12:18pm UTC](https://discourse.julialang.org/t/second-order-cone-constraint-in-jump-0-19-with-jump-solver/37214 "2020-04-08T12:18:08Z")

</div>

Hi all, When trying to implement the SOCP in JuMP and Mosek, the Mosek solver stalls and SLOW\_PROGRESS JuMP status show up. After checking the results, I notice that it is not feasible, and the upper bounds are depresse…

---

## [Persistent plotly in IJulia](https://discourse.julialang.org/t/persistent-plotly-in-ijulia/37225)

<div class="topic-metadata">

**Author:** [@isentropic](https://discourse.julialang.org/u/isentropic)\
**Replies:** 0\
**Last updated:** [April 8, 2020, 9:00am UTC](https://discourse.julialang.org/t/persistent-plotly-in-ijulia/37225 "2020-04-08T09:00:00Z")

</div>

How can I have Plots.jl plotlyjs backend draw persistent figures in Jupyter notebooks?That is, when a session ends and jupyter is turned off, after coming back to the notebook, the plots produced by plotlyjs disappear. …

---

## [What is the best molecular dynamics analysis library in Julia?](https://discourse.julialang.org/t/what-is-the-best-molecular-dynamics-analysis-library-in-julia/36865)

<div class="topic-metadata">

**Author:** [@dkonstan](https://discourse.julialang.org/u/dkonstan)\
**Replies:** 6\
**Last updated:** [April 8, 2020, 8:18am UTC](https://discourse.julialang.org/t/what-is-the-best-molecular-dynamics-analysis-library-in-julia/36865 "2020-04-08T08:18:55Z")

</div>

So far, I have only seen Chemfiles, which has Julia bindings but is missing important features like a powerful atom selection language. For example, Chemfiles cannot easily select the set of atoms X far away from another…

---

## [Is ParameterizedFunctions.jl still deprecated in favor of ModelingToolkit. jl?](https://discourse.julialang.org/t/is-parameterizedfunctions-jl-still-deprecated-in-favor-of-modelingtoolkit-jl/37210)

<div class="topic-metadata">

**Author:** [@donkeysaddle](https://discourse.julialang.org/u/donkeysaddle)\
**Replies:** 2\
**Last updated:** [April 8, 2020, 3:45am UTC](https://discourse.julialang.org/t/is-parameterizedfunctions-jl-still-deprecated-in-favor-of-modelingtoolkit-jl/37210 "2020-04-08T03:45:27Z")

</div>

Title says it all: Is ParameterizedFunctions.jl still deprecated in favor of ModelingToolkit.jl? The disclaimer in the ParameterizedFunctions Git, “Note that this library is deprecated in favor of ModelingToolkit.jl,” i…

---

## [Looking for findfirst or similar for sol objects of DifferentialEquations](https://discourse.julialang.org/t/looking-for-findfirst-or-similar-for-sol-objects-of-differentialequations/37134)

<div class="topic-metadata">

**Author:** [@klaff](https://discourse.julialang.org/u/klaff)\
**Replies:** 6\
**Last updated:** [April 7, 2020, 6:21pm UTC](https://discourse.julialang.org/t/looking-for-findfirst-or-similar-for-sol-objects-of-differentialequations/37134 "2020-04-07T18:21:52Z")

</div>

Hello! I’m doing some control systems work and wanting to find things like risetime of responses, so I want to find where a simulation variable crosses some value. findfirst works but it searches among the simulation po…

---

## [Strange behavior of integrator interface DiffEq.jl](https://discourse.julialang.org/t/strange-behavior-of-integrator-interface-diffeq-jl/37146)

<div class="topic-metadata">

**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 3\
**Last updated:** [April 7, 2020, 5:02pm UTC](https://discourse.julialang.org/t/strange-behavior-of-integrator-interface-diffeq-jl/37146 "2020-04-07T17:02:27Z")

</div>

Hello, I would like to use the integrator interface of DifferentialEquations.jl for an ensemble, i.e. loop over the different ensemble members and advance forward in time by one time step each of them. However, if I in…

---

## [Minimal examples of how to use MPI in JupyterLab](https://discourse.julialang.org/t/minimal-examples-of-how-to-use-mpi-in-jupyterlab/36852)

<div class="topic-metadata">

**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 3\
**Last updated:** [April 7, 2020, 5:00pm UTC](https://discourse.julialang.org/t/minimal-examples-of-how-to-use-mpi-in-jupyterlab/36852 "2020-04-07T17:00:05Z")

</div>

I am looking for minimal examples of how to use MPI in JupyterLab. In particular, I would be most interested in an approach that comes as close as possible to an all-equal approach instead of a master-slave approach. But…

---

## [Affine expression in objective function](https://discourse.julialang.org/t/affine-expression-in-objective-function/37108)

<div class="topic-metadata">

**Author:** [@bandaya](https://discourse.julialang.org/u/bandaya)\
**Replies:** 9\
**Last updated:** [April 7, 2020, 3:34pm UTC](https://discourse.julialang.org/t/affine-expression-in-objective-function/37108 "2020-04-07T15:34:07Z")

</div>

Hi, In a linear programming problem, I am trying to optimize a constraint, essentially replacing the objective function with LHS of the constraint to minimize. The error from JuMP suggests that it does not support affine…

---

## [Visualizing Newton-Raphson](https://discourse.julialang.org/t/visualizing-newton-raphson/37164)

<div class="topic-metadata">

**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 3\
**Last updated:** [April 7, 2020, 3:33pm UTC](https://discourse.julialang.org/t/visualizing-newton-raphson/37164 "2020-04-07T15:33:47Z")

</div>

I’ve been studying the Newton-Raphson algorithm and coded up a simple example to show some of its shortcomings with particular functions. I’m posting here simply to share with the community and, as always, I welcome feed…

---

## [Improving performance for SDPs with "matrix trace constraints"](https://discourse.julialang.org/t/improving-performance-for-sdps-with-matrix-trace-constraints/37172)

<div class="topic-metadata">

**Author:** [@martincornejo](https://discourse.julialang.org/u/martincornejo)\
**Replies:** 1\
**Last updated:** [April 7, 2020, 2:56pm UTC](https://discourse.julialang.org/t/improving-performance-for-sdps-with-matrix-trace-constraints/37172 "2020-04-07T14:56:35Z")

</div>

I’ve been working on an SDP model with (among other variables) a hermitian variable W of dimensions n x n. Although it would be nice to have support for complex variables in JuMP, a simple workaround is to declare 2 matr…

---

## [JuMP 0.18: how to delete constraints (without reference)?](https://discourse.julialang.org/t/jump-0-18-how-to-delete-constraints-without-reference/37175)

<div class="topic-metadata">

**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 2\
**Last updated:** [April 7, 2020, 2:56pm UTC](https://discourse.julialang.org/t/jump-0-18-how-to-delete-constraints-without-reference/37175 "2020-04-07T14:56:11Z")

</div>

Dear folks, I like to solve the root relaxation of a MILP manually, meaning that I treat the problem as an LP while dynamically adding cutting planes and resolve until no violated cuts are found. I’d like to get rid of …

---

## [Getfield with Measurements -\> access to undefined reference](https://discourse.julialang.org/t/getfield-with-measurements-access-to-undefined-reference/37159)

<div class="topic-metadata">

**Author:** [@MartinOtter](https://discourse.julialang.org/u/MartinOtter)\
**Replies:** 1\
**Last updated:** [April 7, 2020, 1:24pm UTC](https://discourse.julialang.org/t/getfield-with-measurements-access-to-undefined-reference/37159 "2020-04-07T13:24:46Z")

</div>

In this test model, an unexpected error is raised from getfield(…) when applied on an uninitialized struct on a field of type Measurements, and I do not find the reason: module Test\_getfield using Measurements mutable…

---

## [Pkg add Distributions fails with Unable to automatically install 'Rmath'](https://discourse.julialang.org/t/pkg-add-distributions-fails-with-unable-to-automatically-install-rmath/37047)

<div class="topic-metadata">

**Author:** [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Replies:** 3\
**Last updated:** [April 7, 2020, 12:57pm UTC](https://discourse.julialang.org/t/pkg-add-distributions-fails-with-unable-to-automatically-install-rmath/37047 "2020-04-07T12:57:45Z")

</div>

This is on Julia1.3.1, Mac 10.14.5 Activating environment at \`~/myuser/...Project.toml\` \[587475ba\] Flux v0.10.3 \[e88e6eb3\] Zygote v0.4.10 julia\> Pkg.add("Distributions") Updating registry at \`~/.julia/registries/G…

---

## [Solve a system of linear equations many times without allocating memory](https://discourse.julialang.org/t/solve-a-system-of-linear-equations-many-times-without-allocating-memory/36228)

<div class="topic-metadata">

**Author:** [@MartinOtter](https://discourse.julialang.org/u/MartinOtter)\
**Replies:** 18\
**Last updated:** [April 7, 2020, 11:28am UTC](https://discourse.julialang.org/t/solve-a-system-of-linear-equations-many-times-without-allocating-memory/36228 "2020-04-07T11:28:34Z")

</div>

I have the problem that during simulation a linear equation system A\*x=b is solved many times. The desired solution is to allocate memory for all arrays involved in the operation once before simulation starts and during …

---

## [In Flux0.10.4 Warning: Zygote does not have CuArrays in its dependencies](https://discourse.julialang.org/t/in-flux0-10-4-warning-zygote-does-not-have-cuarrays-in-its-dependencies/37142)

<div class="topic-metadata">

**Author:** [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Replies:** 2\
**Last updated:** [April 7, 2020, 8:03am UTC](https://discourse.julialang.org/t/in-flux0-10-4-warning-zygote-does-not-have-cuarrays-in-its-dependencies/37142 "2020-04-07T08:03:11Z")

</div>

from a fresh Julia1.4, adding the new Flux 0.10.4, followed by adding Zygote, results in a warning Package Zygote does not have CuArrays in its dependencies …you may need to report an issue with Zygote. Is this som…

---

## [Model zoo housing.jl - out of date use of Flux.Tracker?](https://discourse.julialang.org/t/model-zoo-housing-jl-out-of-date-use-of-flux-tracker/37144)

<div class="topic-metadata">

**Author:** [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Replies:** 0\
**Last updated:** [April 7, 2020, 5:12am UTC](https://discourse.julialang.org/t/model-zoo-housing-jl-out-of-date-use-of-flux-tracker/37144 "2020-04-07T05:12:50Z")

</div>

The model-zoo/other/housing/ housing.jl is importing Flux.Tracker. Does this mean the example is out-of-date, or does Tracker still work with the current 0.10.x versions of Flux? (My impression was that Tracker does no…

---

## [After adding Flux package, why is it necessary to also add Zygote](https://discourse.julialang.org/t/after-adding-flux-package-why-is-it-necessary-to-also-add-zygote/36983)

<div class="topic-metadata">

**Author:** [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Replies:** 8\
**Last updated:** [April 7, 2020, 5:02am UTC](https://discourse.julialang.org/t/after-adding-flux-package-why-is-it-necessary-to-also-add-zygote/36983 "2020-04-07T05:02:16Z")

</div>

This is a beginner/tooling question about packages, but if I post it there people will not know the particular packages. The question: I want to use Zygote.@nograd, so I put using Zygote however this says that it is …

---

## [Vege-Lite encode :point shape and angle](https://discourse.julialang.org/t/vege-lite-encode-point-shape-and-angle/33327)

<div class="topic-metadata">

**Author:** [@babaq](https://discourse.julialang.org/u/babaq)\
**Replies:** 4\
**Last updated:** [April 7, 2020, 3:36am UTC](https://discourse.julialang.org/t/vege-lite-encode-point-shape-and-angle/33327 "2020-04-07T03:36:04Z")

</div>

I want to draw a scatter plot but use different point shape and angles to show different orientations and directions. the stroke shape and arrow shape seems what I want, but I am have trouble to make it work function f…

---

## [Method Error using round on JuMP Variable](https://discourse.julialang.org/t/method-error-using-round-on-jump-variable/37136)

<div class="topic-metadata">

**Author:** [@Cyrus\_the\_man](https://discourse.julialang.org/u/Cyrus_the_man)\
**Replies:** 1\
**Last updated:** [April 7, 2020, 1:15am UTC](https://discourse.julialang.org/t/method-error-using-round-on-jump-variable/37136 "2020-04-07T01:15:37Z")

</div>

MethodError: no method matching round(::Type{Int64}, ::GenericAffExpr{Float64,VariableRef}) I’m using Julia 1.3.1 on Jupyter Notebooks and have encountered a method error using an Ipop solver. Within dynamic constraint…

---

## [Use Roots.Brent() in fzero Roots.jl](https://discourse.julialang.org/t/use-roots-brent-in-fzero-roots-jl/37126)

<div class="topic-metadata">

**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 3\
**Last updated:** [April 7, 2020, 12:00am UTC](https://discourse.julialang.org/t/use-roots-brent-in-fzero-roots-jl/37126 "2020-04-07T00:00:26Z")

</div>

Hello, I would like to use the method Brent-Dekker in Roots.jl without using the find\_zero wrapper since I will only do one run of root-finding for the function of interest. fzero seems to be the way to go, but I don’t …

---

## [Extracting derivatives (du/dt) from an ODE problem](https://discourse.julialang.org/t/extracting-derivatives-du-dt-from-an-ode-problem/26514)

<div class="topic-metadata">

**Author:** [@Hossein\_Haghi](https://discourse.julialang.org/u/Hossein_Haghi)\
**Replies:** 24\
**Last updated:** [April 6, 2020, 11:28pm UTC](https://discourse.julialang.org/t/extracting-derivatives-du-dt-from-an-ode-problem/26514 "2020-04-06T23:28:28Z")

</div>

I have multiple ODE problems that I am solving. where I need the solutions (u) and derivative of the solutions (du). For smaller ODEs it is practical for me to do the following using DifferentialEquations function SB(d…

[Previous page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=451)

[Next page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=453)