# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=533

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

**Page:** 534

---

## [BoundsError when re-solving a model](https://discourse.julialang.org/t/boundserror-when-re-solving-a-model/12050)

<div class="topic-metadata">

**Author:** [@varun7rs](https://discourse.julialang.org/u/varun7rs)\
**Replies:** 6\
**Last updated:** [June 30, 2018, 5:51pm UTC](https://discourse.julialang.org/t/boundserror-when-re-solving-a-model/12050 "2018-06-30T17:51:12Z")

</div>

I’ve implemented a neighbourhood search technique wherein I deepcopy the original model, hot-start it and then solve it repeatedly. While the first iteration went smooth, during the second iteration however, I get this e…

---

## [Can I change the nvcc location in CUDAnative?](https://discourse.julialang.org/t/can-i-change-the-nvcc-location-in-cudanative/12000)

<div class="topic-metadata">

**Author:** [@cuchxq](https://discourse.julialang.org/u/cuchxq)\
**Replies:** 5\
**Last updated:** [June 29, 2018, 3:05pm UTC](https://discourse.julialang.org/t/can-i-change-the-nvcc-location-in-cudanative/12000 "2018-06-29T15:05:18Z")

</div>

Hi, when I am building “CUDAnative” package on a server, I get the following error: \_ \_ \_ \_(\_)\_ | A fresh approach to technical computing (\_) | (\_) (\_) | Documentation: https://doc…

---

## [Assignment of a \`missing\` value fails in DataFrames 0.11.1](https://discourse.julialang.org/t/assignment-of-a-missing-value-fails-in-dataframes-0-11-1/7379)

<div class="topic-metadata">

**Author:** [@mwsohn](https://discourse.julialang.org/u/mwsohn)\
**Replies:** 28\
**Last updated:** [June 28, 2018, 7:15pm UTC](https://discourse.julialang.org/t/assignment-of-a-missing-value-fails-in-dataframes-0-11-1/7379 "2018-06-28T19:15:39Z")

</div>

The following simple assignment fails. I think this defeats the very purpose of using DataFrames, i.e., allowing missing as legit values. Shouldn’t we have Array{Union{Missing,T},1} as the default type to avoid this issu…

---

## [Eliminating Diagonal in LowerTriangular](https://discourse.julialang.org/t/eliminating-diagonal-in-lowertriangular/12012)

<div class="topic-metadata">

**Author:** [@avoss3](https://discourse.julialang.org/u/avoss3)\
**Replies:** 5\
**Last updated:** [June 28, 2018, 1:13pm UTC](https://discourse.julialang.org/t/eliminating-diagonal-in-lowertriangular/12012 "2018-06-28T13:13:11Z")

</div>

Does anyone know if it is possible to not include the diagonal when using the LowerTriangular() function or if there is a function that can exclude the diagonal from the output? LowerTriangular() would work perfectly for…

---

## [Refining eigvals, svdvals](https://discourse.julialang.org/t/refining-eigvals-svdvals/12024)

<div class="topic-metadata">

**Author:** [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)\
**Replies:** 12\
**Last updated:** [June 28, 2018, 12:34pm UTC](https://discourse.julialang.org/t/refining-eigvals-svdvals/12024 "2018-06-28T12:34:40Z")

</div>

Out of the box, DoubleFloats work with these LinearAlgebra functions: isdiag, ishermitian, isposdef, issymmetric, istril, istriu norm, det, dot, tr, condskeel, logdet, logabsdet transpose, adjoint, tril, triu diag, diag…

---

## [Type for square matrix](https://discourse.julialang.org/t/type-for-square-matrix/12027)

<div class="topic-metadata">

**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [June 28, 2018, 9:08am UTC](https://discourse.julialang.org/t/type-for-square-matrix/12027 "2018-06-28T09:08:42Z")

</div>

I am wondering if it would make sense to have an abstract type for \<: AbstractMatrix types which are by construction square, eg abstract type SquareMatrix{T} \<: AbstractMatrix{T} end Subtypes would be Diagonal, various…

---

## [Strange glitch in ImageView hoverinfo](https://discourse.julialang.org/t/strange-glitch-in-imageview-hoverinfo/11959)

<div class="topic-metadata">

**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 4\
**Last updated:** [June 27, 2018, 8:33pm UTC](https://discourse.julialang.org/t/strange-glitch-in-imageview-hoverinfo/11959 "2018-06-27T20:33:47Z")

</div>

After creating a 500x500 pixel image and displaying it: using ImageView imshow(rand(500, 500)) I found out that the hoverinfo is wrong by ~50 pixels regardless of the size of the displayed image (the cursor was at the …

---

## [How to solve two symbolic nonlinear equations in Julia?](https://discourse.julialang.org/t/how-to-solve-two-symbolic-nonlinear-equations-in-julia/11916)

<div class="topic-metadata">

**Author:** [@Seif\_Shebl](https://discourse.julialang.org/u/Seif_Shebl)\
**Replies:** 27\
**Last updated:** [June 27, 2018, 11:54am UTC](https://discourse.julialang.org/t/how-to-solve-two-symbolic-nonlinear-equations-in-julia/11916 "2018-06-27T11:54:22Z")

</div>

Sorry if that seems an easy question but I searched for a simple answer in many packages without success. I have two equations like this: 𝐹\_1: 𝑥^2+𝑥𝑦+\\sin⁡(𝑦)=3 𝐹\_2: 𝑥^3−4𝑥+\\sin⁡(2𝑦)=0 and I need to solve them symboli…

---

## [Float64 and binary variables in constraints](https://discourse.julialang.org/t/float64-and-binary-variables-in-constraints/11961)

<div class="topic-metadata">

**Author:** [@mm0063](https://discourse.julialang.org/u/mm0063)\
**Replies:** 2\
**Last updated:** [June 27, 2018, 8:20am UTC](https://discourse.julialang.org/t/float64-and-binary-variables-in-constraints/11961 "2018-06-27T08:20:46Z")

</div>

Hi all, My problem formulation consists of float64 parameters and variables and binary variables: using JuMP using Mosek M = 1000.0; @variable(m, y\_connect2\[t in ts, cg in cgs, lt in lts\], Bin) @variable(m, x\_conne…

---

## [Fastest way to solve Laplace equation on 3d orthogonal grids that are partially trimmed](https://discourse.julialang.org/t/fastest-way-to-solve-laplace-equation-on-3d-orthogonal-grids-that-are-partially-trimmed/11964)

<div class="topic-metadata">

**Author:** [@aminsadeghi](https://discourse.julialang.org/u/aminsadeghi)\
**Replies:** 0\
**Last updated:** [June 26, 2018, 1:07pm UTC](https://discourse.julialang.org/t/fastest-way-to-solve-laplace-equation-on-3d-orthogonal-grids-that-are-partially-trimmed/11964 "2018-06-26T13:07:16Z")

</div>

I’m trying to solve the Laplace equation in 3d on orthogonal grids that are partially trimmed, i.e. some of the internal grid points are removed from the domain. These grids come from micro-ct tomography images and corre…

---

## [Help debugging \`nlopt failure: -1\` errors](https://discourse.julialang.org/t/help-debugging-nlopt-failure-1-errors/11907)

<div class="topic-metadata">

**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 10\
**Last updated:** [June 26, 2018, 1:36pm UTC](https://discourse.julialang.org/t/help-debugging-nlopt-failure-1-errors/11907 "2018-06-26T13:36:05Z")

</div>

Any tips on debugging nlopt failure: -1 errors? There is no information in the error message to understand what happened. Sometimes I have found that this occurs because I am computing something wrong in the gradient. Bu…

---

## [Modifying NLobjective in JuMP?](https://discourse.julialang.org/t/modifying-nlobjective-in-jump/11942)

<div class="topic-metadata">

**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 1\
**Last updated:** [June 25, 2018, 8:55pm UTC](https://discourse.julialang.org/t/modifying-nlobjective-in-jump/11942 "2018-06-25T20:55:43Z")

</div>

I have a nonlinear optimization problem setup in JuMP that I just solved. Now I want to modify the objective. If I just call @NLobjective with the new objective, will I get a hot-start in the next call to solve?

---

## [Post Processing JuMP results - Transforming JuMP variables](https://discourse.julialang.org/t/post-processing-jump-results-transforming-jump-variables/11041)

<div class="topic-metadata">

**Author:** [@tfk17lstm](https://discourse.julialang.org/u/tfk17lstm)\
**Replies:** 6\
**Last updated:** [June 25, 2018, 8:16pm UTC](https://discourse.julialang.org/t/post-processing-jump-results-transforming-jump-variables/11041 "2018-06-25T20:16:07Z")

</div>

Hi guys! I have finished my implementation of my unit commitment problem and I would like to know if there is any possibility of including this kind of plot in my final results: Extracted from: Unit commitment - YAL…

---

## [Simple model not working in Turing](https://discourse.julialang.org/t/simple-model-not-working-in-turing/11305)

<div class="topic-metadata">

**Author:** [@jacobcvt12](https://discourse.julialang.org/u/jacobcvt12)\
**Replies:** 3\
**Last updated:** [June 25, 2018, 6:27pm UTC](https://discourse.julialang.org/t/simple-model-not-working-in-turing/11305 "2018-06-25T18:27:18Z")

</div>

I’ve been exploring Turing, but so far haven’t had much luck. I’ve written the following very simple model using Distributions, Turing import Mamba: describe xs = rand(Normal(3.4, 1.0), 1000) @model gaussian(xs) = be…

---

## [Engineering domain?](https://discourse.julialang.org/t/engineering-domain/11774)

<div class="topic-metadata">

**Author:** [@CrashBurnRepeat](https://discourse.julialang.org/u/CrashBurnRepeat)\
**Replies:** 16\
**Last updated:** [June 25, 2018, 4:10pm UTC](https://discourse.julialang.org/t/engineering-domain/11774 "2018-06-25T16:10:49Z")

</div>

Coming from an aerospace/automotive engineering background, I’d be curious to gage the interest for a engineering-focused domain. I’ve seen some projects that would fit, like JuliaFEM, JuliaControls, NLOptControl, and Mo…

---

## [Coordinates for annotations in plot](https://discourse.julialang.org/t/coordinates-for-annotations-in-plot/11809)

<div class="topic-metadata">

**Author:** [@jcrbloch](https://discourse.julialang.org/u/jcrbloch)\
**Replies:** 3\
**Last updated:** [June 25, 2018, 11:30am UTC](https://discourse.julialang.org/t/coordinates-for-annotations-in-plot/11809 "2018-06-25T11:30:47Z")

</div>

When using annotations in plot, I understand that the coordinates correspond to those displayed on the axis. Is there a way to also give “window” coordinates like in gnuplot, where the coordinates in horizontal and verti…

---

## [How to compare JuMP variables?](https://discourse.julialang.org/t/how-to-compare-jump-variables/11882)

<div class="topic-metadata">

**Author:** [@jayce\_ram](https://discourse.julialang.org/u/jayce_ram)\
**Replies:** 8\
**Last updated:** [June 25, 2018, 9:06am UTC](https://discourse.julialang.org/t/how-to-compare-jump-variables/11882 "2018-06-25T09:06:54Z")

</div>

I have a LP problem with many variables that represent different things. One of my variables can assume negatives or positives values, according to the timeslice. Inside an expression(@expression) I would like to accumul…

---

## [Way to automatically distinguish branch of roots in parametric sweep?](https://discourse.julialang.org/t/way-to-automatically-distinguish-branch-of-roots-in-parametric-sweep/11732)

<div class="topic-metadata">

**Author:** [@djsegal](https://discourse.julialang.org/u/djsegal)\
**Replies:** 7\
**Last updated:** [June 22, 2018, 10:26pm UTC](https://discourse.julialang.org/t/way-to-automatically-distinguish-branch-of-roots-in-parametric-sweep/11732 "2018-06-22T22:26:59Z")

</div>

Let’s say you have some nonlinear function that you plug into a root solver to get all the roots // where the maximum number of real roots possible \<= N (i.e. N = 3) Then you sweep this function over M other values to …

---

## [Optim.optimize() uses excessive memory with autodiff?](https://discourse.julialang.org/t/optim-optimize-uses-excessive-memory-with-autodiff/11872)

<div class="topic-metadata">

**Author:** [@tyleransom](https://discourse.julialang.org/u/tyleransom)\
**Replies:** 11\
**Last updated:** [June 22, 2018, 3:17pm UTC](https://discourse.julialang.org/t/optim-optimize-uses-excessive-memory-with-autodiff/11872 "2018-06-22T15:17:01Z")

</div>

I’m using Optim.optimize() to estimate a likelihood-type model. Having read that autodiff is a great feature, I have implemented it. I have three questions that I’m hoping someone can shed more light on. For reference, …

---

## [Depth First Search in Julia](https://discourse.julialang.org/t/depth-first-search-in-julia/11860)

<div class="topic-metadata">

**Author:** [@ksh](https://discourse.julialang.org/u/ksh)\
**Replies:** 3\
**Last updated:** [June 22, 2018, 1:10am UTC](https://discourse.julialang.org/t/depth-first-search-in-julia/11860 "2018-06-22T01:10:58Z")

</div>

Hi, does anyone have a working depth first search (recursive) code in Julia? I would rather not use the existing lightgraphs.jl or graphs.jl.

---

## [@code\_warntype ODEProblem shows \`Any\`](https://discourse.julialang.org/t/code-warntype-odeproblem-shows-any/11839)

<div class="topic-metadata">

**Author:** [@shipengcheng1230](https://discourse.julialang.org/u/shipengcheng1230)\
**Replies:** 1\
**Last updated:** [June 21, 2018, 3:52am UTC](https://discourse.julialang.org/t/code-warntype-odeproblem-shows-any/11839 "2018-06-21T03:52:04Z")

</div>

I tried the example here and see what @code\_warntype returns: julia\> using DifferentialEquations julia\> function lorenz(du,u,p,t) du\[1\] = 10.0\*(u\[2\]-u\[1\]) du\[2\] = u\[1\]\*(28.0-u\[3\]) - u\[2\] du\[3\] =…

---

## [JuMP anonymous variables](https://discourse.julialang.org/t/jump-anonymous-variables/11831)

<div class="topic-metadata">

**Author:** [@ksh](https://discourse.julialang.org/u/ksh)\
**Replies:** 1\
**Last updated:** [June 20, 2018, 9:35pm UTC](https://discourse.julialang.org/t/jump-anonymous-variables/11831 "2018-06-20T21:35:56Z")

</div>

Hi, I’m trying to call anonymous variables based on the edges that exist in my tree-graph, but I’m getting the error with my first constraint stating that “t doesn’t exist.” I show only the relevant code below. t is a c…

---

## [Atomic Operations are too expensive.](https://discourse.julialang.org/t/atomic-operations-are-too-expensive/11827)

<div class="topic-metadata">

**Author:** [@SohamTamb](https://discourse.julialang.org/u/SohamTamb)\
**Replies:** 3\
**Last updated:** [June 20, 2018, 4:53pm UTC](https://discourse.julialang.org/t/atomic-operations-are-too-expensive/11827 "2018-06-20T16:53:44Z")

</div>

Are atomic operations supposed to be this costly? Is memory and allocations required for simple read/write operations? julia\> a = Atomic{Int64}(0) Atomic{Int64}(0) julia\> @btime a\[\] 100.546 ns (1 allocation: 16 byte…

---

## [Symmetric Indefinite Solvers (with block diagonal pivoting)](https://discourse.julialang.org/t/symmetric-indefinite-solvers-with-block-diagonal-pivoting/8541)

<div class="topic-metadata">

**Author:** [@jacob-roth](https://discourse.julialang.org/u/jacob-roth)\
**Replies:** 6\
**Last updated:** [June 20, 2018, 2:14am UTC](https://discourse.julialang.org/t/symmetric-indefinite-solvers-with-block-diagonal-pivoting/8541 "2018-06-20T02:14:16Z")

</div>

Are there any modules that provide access to (sparse) symmetric indefinite solvers with Bunch-Kaufman-Parlett pivoting where I can access the L and D matrices, or would it be useful to build a module that does this? Righ…

---

## [Discrepancy between .~ and .==false for BitArrays](https://discourse.julialang.org/t/discrepancy-between-and-false-for-bitarrays/11787)

<div class="topic-metadata">

**Author:** [@tyleransom](https://discourse.julialang.org/u/tyleransom)\
**Replies:** 2\
**Last updated:** [June 19, 2018, 4:57pm UTC](https://discourse.julialang.org/t/discrepancy-between-and-false-for-bitarrays/11787 "2018-06-19T16:57:37Z")

</div>

Hi, I’m having trouble understanding why the following don’t yield equivalent objects: srand(1234) x = rand(50,1); y=rand(50,1).\>0.5; z=rand(50,1).\>0.5; size(x\[.~y .& .~z\]) size(x\[y.==false .& z.==false\]) size(x\[.~y\])…

---

## [Way to find positive roots by treating complex numbers as negatives? \[SymEngine + Roots\]](https://discourse.julialang.org/t/way-to-find-positive-roots-by-treating-complex-numbers-as-negatives-symengine-roots/11688)

<div class="topic-metadata">

**Author:** [@djsegal](https://discourse.julialang.org/u/djsegal)\
**Replies:** 14\
**Last updated:** [June 19, 2018, 12:42pm UTC](https://discourse.julialang.org/t/way-to-find-positive-roots-by-treating-complex-numbers-as-negatives-symengine-roots/11688 "2018-06-19T12:42:40Z")

</div>

Let’s say you had some hideous nonlinear equation like so: cur\_equation = -1.0 + 32.5\*(0.237334965250543\*(0.0155717178747169 + 1.42646372678281e-11\*(I\_P^0.96)^6.4516129032258) + 8.02921230974917e-05\*(-(0.210126719741548…

---

## [SatelliteToolbox.jl can now read lots of gravity models! And everything is validated :)](https://discourse.julialang.org/t/satellitetoolbox-jl-can-now-read-lots-of-gravity-models-and-everything-is-validated/11723)

<div class="topic-metadata">

**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 19\
**Last updated:** [June 19, 2018, 9:14am UTC](https://discourse.julialang.org/t/satellitetoolbox-jl-can-now-read-lots-of-gravity-models-and-everything-is-validated/11723 "2018-06-19T09:14:02Z")

</div>

Hi guys! I have heavily modified the way I was implementing the gravitational model (EGM96 and 2008). It turns out that all the static models (in which the coefficients do not change with time) use the very same equatio…

---

## [Optim.jl ArgumentError: Value and slope at step length = 0 must be finite](https://discourse.julialang.org/t/optim-jl-argumenterror-value-and-slope-at-step-length-0-must-be-finite/11770)

<div class="topic-metadata">

**Author:** [@tlagos](https://discourse.julialang.org/u/tlagos)\
**Replies:** 7\
**Last updated:** [June 19, 2018, 9:10am UTC](https://discourse.julialang.org/t/optim-jl-argumenterror-value-and-slope-at-step-length-0-must-be-finite/11770 "2018-06-19T09:10:24Z")

</div>

Hello, I’m minimizing the analitic center of a set of inequalities (see problem 9.30 Convex Optimization Boyd and Vandenberghe). I generate a random instance as follows: n=8 m=7 A=rand(m,n) Then I create the necessar…

---

## [Wrappers for GLM](https://discourse.julialang.org/t/wrappers-for-glm/11761)

<div class="topic-metadata">

**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 11\
**Last updated:** [June 19, 2018, 7:32am UTC](https://discourse.julialang.org/t/wrappers-for-glm/11761 "2018-06-19T07:32:38Z")

</div>

Based off of Chris’s comment here this is something that I have been wondering about myself. It would be nice to get some discussion about the regression ecosystem. We have StatsModels.jl which is used to create forumul…

---

## [How to change plot size in jupyter?](https://discourse.julialang.org/t/how-to-change-plot-size-in-jupyter/11589)

<div class="topic-metadata">

**Author:** [@davide](https://discourse.julialang.org/u/davide)\
**Replies:** 5\
**Last updated:** [June 18, 2018, 11:14pm UTC](https://discourse.julialang.org/t/how-to-change-plot-size-in-jupyter/11589 "2018-06-18T23:14:21Z")

</div>

Hi, is it possible to change size of plotted figures in jupyter notebook? (E.g., with the R kernel I can use “options(repr.plot.width=4, repr.plot.height=3)” but I didn’t find something similar for the Julia kernel). T…

[Previous page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=532)

[Next page](https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=534)