# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=542

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

**Page:** 543

---

## [Long & complex non-linear functions use in non-linear constraints](https://discourse.julialang.org/t/long-complex-non-linear-functions-use-in-non-linear-constraints/9706)

<div class="topic-metadata">

**Author:** [@Stani83](https://discourse.julialang.org/u/Stani83)\
**Replies:** 5\
**Last updated:** [March 15, 2018, 8:32pm UTC](https://discourse.julialang.org/t/long-complex-non-linear-functions-use-in-non-linear-constraints/9706 "2018-03-15T20:32:41Z")

</div>

Hi There, I am new to JuMP and I am trying to set-up an optimization model that I already made work in Matlab, but now taking many advantages of JuMP Out of many questions I have I would start with few simple ones, hop…

---

## [\[ANN\] Flux v0.5](https://discourse.julialang.org/t/ann-flux-v0-5/9620)

<div class="topic-metadata">

**Author:** [@MikeInnes](https://discourse.julialang.org/u/MikeInnes)\
**Replies:** 11\
**Last updated:** [March 15, 2018, 3:53pm UTC](https://discourse.julialang.org/t/ann-flux-v0-5/9620 "2018-03-15T15:53:08Z")

</div>

Hey all, I’m pleased to announce the 0.5 release of the Flux machine learning library. Here’s an incomplete list of things that have changed since the last announcement. Experimental JIT compilation work for models, a…

---

## [\[ANN\] StructuredOptimization.jl](https://discourse.julialang.org/t/ann-structuredoptimization-jl/9735)

<div class="topic-metadata">

**Author:** [@nantonel](https://discourse.julialang.org/u/nantonel)\
**Replies:** 0\
**Last updated:** [March 15, 2018, 12:28pm UTC](https://discourse.julialang.org/t/ann-structuredoptimization-jl/9735 "2018-03-15T12:28:20Z")

</div>

Hi all, I am happy to announce together with @lostella StructuredOptimization.jl. StructuredOptimization.jl is a high-level modeling language that utilizes a syntax that is very close to the mathematical formulation of…

---

## [Problems with Flux](https://discourse.julialang.org/t/problems-with-flux/9719)

<div class="topic-metadata">

**Author:** [@jacobcvt12](https://discourse.julialang.org/u/jacobcvt12)\
**Replies:** 2\
**Last updated:** [March 14, 2018, 8:10pm UTC](https://discourse.julialang.org/t/problems-with-flux/9719 "2018-03-14T20:10:54Z")

</div>

I’m having trouble fitting a really basic neural network in Flux. I wanted to get a handle on the syntax by simulating simple data from a logistic regression, but the model isn’t converging to anything reasonable. I thin…

---

## [Parallel Monte Carlo Simulations](https://discourse.julialang.org/t/parallel-monte-carlo-simulations/9692)

<div class="topic-metadata">

**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 0\
**Last updated:** [March 13, 2018, 5:58pm UTC](https://discourse.julialang.org/t/parallel-monte-carlo-simulations/9692 "2018-03-13T17:58:06Z")

</div>

I am simulating a large number of SDEs and looking at the results. Things starts to take quite a while and I figured that I had 8 cores on my computer, might as well try to use them. Unfortunate I cannot get things to wo…

---

## [Unusual error: no method matching lufact!(::SparseMatrixCSC{Float32,Int64}, ::Type{Val{true}})](https://discourse.julialang.org/t/unusual-error-no-method-matching-lufact-sparsematrixcsc-float32-int64-type-val-true/9666)

<div class="topic-metadata">

**Author:** [@Ian\_Williamson](https://discourse.julialang.org/u/Ian_Williamson)\
**Replies:** 12\
**Last updated:** [March 13, 2018, 5:18pm UTC](https://discourse.julialang.org/t/unusual-error-no-method-matching-lufact-sparsematrixcsc-float32-int64-type-val-true/9666 "2018-03-13T17:18:09Z")

</div>

Greetings, I am new to Julia and have been looking at using it to solve sparse systems. When I run the following simple code snippet: A = sprand(Float32, 10, 10, .5); b = rand(Float32, 10); A\\b I get the following err…

---

## [How can I "fetch" without caching the struct?](https://discourse.julialang.org/t/how-can-i-fetch-without-caching-the-struct/9688)

<div class="topic-metadata">

**Author:** [@Christian\_Dengler](https://discourse.julialang.org/u/Christian_Dengler)\
**Replies:** 0\
**Last updated:** [March 13, 2018, 4:27pm UTC](https://discourse.julialang.org/t/how-can-i-fetch-without-caching-the-struct/9688 "2018-03-13T16:27:50Z")

</div>

Greetings, I ran into trouble, or maybe my approach is just wrong . What I want is to create an object on remote workers, which perform some kind of work. Then I need to grab some data from this object. The problem is …

---

## [Cutting plane algorithm performance varies with Gurobi and CPLEX](https://discourse.julialang.org/t/cutting-plane-algorithm-performance-varies-with-gurobi-and-cplex/8597)

<div class="topic-metadata">

**Author:** [@varun7rs](https://discourse.julialang.org/u/varun7rs)\
**Replies:** 6\
**Last updated:** [March 13, 2018, 7:46am UTC](https://discourse.julialang.org/t/cutting-plane-algorithm-performance-varies-with-gurobi-and-cplex/8597 "2018-03-13T07:46:50Z")

</div>

I’ve implemented a cutting plane algorithm (using lazy callback mechanism) to robustify the solution obtained from the deterministic MIP akin to the work “Reformulation versus cutting-planes for robust optimization”. Wh…

---

## [Invalid Gurobi Licence when instance size increases using lazy constraints to generate cuts](https://discourse.julialang.org/t/invalid-gurobi-licence-when-instance-size-increases-using-lazy-constraints-to-generate-cuts/9664)

<div class="topic-metadata">

**Author:** [@tlagos](https://discourse.julialang.org/u/tlagos)\
**Replies:** 3\
**Last updated:** [March 13, 2018, 2:22am UTC](https://discourse.julialang.org/t/invalid-gurobi-licence-when-instance-size-increases-using-lazy-constraints-to-generate-cuts/9664 "2018-03-13T02:22:48Z")

</div>

Hello, I’m using CPLEX and Gurobi to solve a benders decomposition scheme for the mining problem. I defined the master problem using CPLEX solver and the cut generation subproblems using Gurobi. Whenever I increase th…

---

## [PyPlot not projecting netcdf as expected](https://discourse.julialang.org/t/pyplot-not-projecting-netcdf-as-expected/9446)

<div class="topic-metadata">

**Author:** [@k945](https://discourse.julialang.org/u/k945)\
**Replies:** 10\
**Last updated:** [March 11, 2018, 11:14pm UTC](https://discourse.julialang.org/t/pyplot-not-projecting-netcdf-as-expected/9446 "2018-03-11T23:14:48Z")

</div>

Hi, I am ending up with when trying to plot the following netcdf data As far as I can tell I have chosen the appropriate projections. using NetCDF, PyPlot, PyCall; @pyimport seaborn as sns; @pyimport cartopy.crs a…

---

## [Is the warp function in ImageTransformation.jl same as \_warp\_fast in python?](https://discourse.julialang.org/t/is-the-warp-function-in-imagetransformation-jl-same-as-warp-fast-in-python/9643)

<div class="topic-metadata">

**Author:** [@tosalonijain](https://discourse.julialang.org/u/tosalonijain)\
**Replies:** 0\
**Last updated:** [March 11, 2018, 8:45am UTC](https://discourse.julialang.org/t/is-the-warp-function-in-imagetransformation-jl-same-as-warp-fast-in-python/9643 "2018-03-11T08:45:21Z")

</div>

https://github.com/JuliaImages/ImageTransformations.jl/blob/master/src/warp.jl This is the link for warp in julia. https://github.com/scikit-image/scikit-image/blob/master/skimage/transform/\_warps\_cy.pyx#L37 This is t…

---

## [Matix with equations for elements](https://discourse.julialang.org/t/matix-with-equations-for-elements/9632)

<div class="topic-metadata">

**Author:** [@Somayeh\_Esmaeili](https://discourse.julialang.org/u/Somayeh_Esmaeili)\
**Replies:** 1\
**Last updated:** [March 10, 2018, 2:33pm UTC](https://discourse.julialang.org/t/matix-with-equations-for-elements/9632 "2018-03-10T14:33:19Z")

</div>

0 down vote favorite I have this constraint in my code. i=number of supplier p=type of productions t=number of period constraint=@NLconstraint(con1\[i=1:3,p=1:2,t=1:3\],E(I)\[i,p,t \]= sum(Q\[i,p,s\] fors=1:t)-sum(E(D)…

---

## [Google Summer of Code 2018](https://discourse.julialang.org/t/google-summer-of-code-2018/9628)

<div class="topic-metadata">

**Author:** [@arijitkar98](https://discourse.julialang.org/u/arijitkar98)\
**Replies:** 1\
**Last updated:** [March 10, 2018, 12:00pm UTC](https://discourse.julialang.org/t/google-summer-of-code-2018/9628 "2018-03-10T12:00:07Z")

</div>

Hello everyone, I am really interested in contributing towards JuliaImages, and have been doing the same. ImageFiltering.jl Images.jl I would like to continue doing so through GSoC '18. I am interested in working tow…

---

## [Interest for DFT simulations job control package?](https://discourse.julialang.org/t/interest-for-dft-simulations-job-control-package/9546)

<div class="topic-metadata">

**Author:** [@louisponet](https://discourse.julialang.org/u/louisponet)\
**Replies:** 10\
**Last updated:** [March 10, 2018, 8:34am UTC](https://discourse.julialang.org/t/interest-for-dft-simulations-job-control-package/9546 "2018-03-10T08:34:19Z")

</div>

Hi all, I’ve worked on a package that automates a lot of tedious work one has to do when working with Density Functional Theory packages/simulations. It’s pretty fully featured, although ofcourse a lot extra could be ad…

---

## [Update image data in existing imshow](https://discourse.julialang.org/t/update-image-data-in-existing-imshow/9609)

<div class="topic-metadata">

**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 3\
**Last updated:** [March 9, 2018, 8:37pm UTC](https://discourse.julialang.org/t/update-image-data-in-existing-imshow/9609 "2018-03-09T20:37:50Z")

</div>

Because of its zoom and pan capabilities, I’m hijacking ImageView.imshow as a UI for a user to pick points from an image. To accomplish that I connected to the canvas button presses (for more details see the drawing exam…

---

## [About QR decomposition - linear algebra](https://discourse.julialang.org/t/about-qr-decomposition-linear-algebra/9606)

<div class="topic-metadata">

**Author:** [@klacru](https://discourse.julialang.org/u/klacru)\
**Replies:** 12\
**Last updated:** [March 9, 2018, 4:58pm UTC](https://discourse.julialang.org/t/about-qr-decomposition-linear-algebra/9606 "2018-03-09T16:58:45Z")

</div>

A fully pivoted QR-factorization of a (m,n)-matrix A of floating point real or complex numbers has the purpose to provide a de-composition (1) Pr \* A \* Pc = Q \* R where Pr and Pc are permutations of rows and columns of…

---

## [Using GLPKSolverLP](https://discourse.julialang.org/t/using-glpksolverlp/9575)

<div class="topic-metadata">

**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 13\
**Last updated:** [March 9, 2018, 3:43pm UTC](https://discourse.julialang.org/t/using-glpksolverlp/9575 "2018-03-09T15:43:17Z")

</div>

How use the solver GLPKSolverLP ?

---

## [MathOptInterface and upcoming breaking changes in JuMP 0.19](https://discourse.julialang.org/t/mathoptinterface-and-upcoming-breaking-changes-in-jump-0-19/4874)

<div class="topic-metadata">

**Author:** [@miles.lubin](https://discourse.julialang.org/u/miles.lubin)\
**Replies:** 8\
**Last updated:** [March 7, 2018, 11:52pm UTC](https://discourse.julialang.org/t/mathoptinterface-and-upcoming-breaking-changes-in-jump-0-19/4874 "2018-03-07T23:52:04Z")

</div>

As I recently alluded to, we will be replacing our solver abstraction layer MathProgBase (MPB) with MathOptInterface (MOI). The MOI manual, under construction, lists the key design considerations. At a high level, the ma…

---

## [SASLib.jl v0.5.0 breaking changes](https://discourse.julialang.org/t/saslib-jl-v0-5-0-breaking-changes/9562)

<div class="topic-metadata">

**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 0\
**Last updated:** [March 7, 2018, 8:28am UTC](https://discourse.julialang.org/t/saslib-jl-v0-5-0-breaking-changes/9562 "2018-03-07T08:28:00Z")

</div>

Hi, This post is to inform everyone that the latest version of SASLib.jl (in master branch) contains breaking changes. If there isn’t much controversy, I will tag the repo within the next week. The data returned from …

---

## [External processes called by Julia locked to 100% cpu use, even when run in parallel?](https://discourse.julialang.org/t/external-processes-called-by-julia-locked-to-100-cpu-use-even-when-run-in-parallel/8762)

<div class="topic-metadata">

**Author:** [@Elrod](https://discourse.julialang.org/u/Elrod)\
**Replies:** 1\
**Last updated:** [February 23, 2018, 7:42pm UTC](https://discourse.julialang.org/t/external-processes-called-by-julia-locked-to-100-cpu-use-even-when-run-in-parallel/8762 "2018-02-23T19:42:50Z")

</div>

Am I don’t something wrong / is this a known issue / what are the workaround? Below I added some sample C++ code. All it is a bunch of calls to sin to burn enough time so I can watch system resources in top. $ g++ -Of…

---

## [How to add ffmpeg to Travis?](https://discourse.julialang.org/t/how-to-add-ffmpeg-to-travis/9366)

<div class="topic-metadata">

**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 9\
**Last updated:** [March 6, 2018, 10:19am UTC](https://discourse.julialang.org/t/how-to-add-ffmpeg-to-travis/9366 "2018-03-06T10:19:39Z")

</div>

In order to test Plots.jl’ gif creation in Travis, i.e. something like this: using Base.Test, Plots anim = @animate for i=1:2 plot(rand(2)) end name = tempname()\*".gif" gif(anim, name) @test isfile(name) we have to…

---

## ["imgtrans" function under ImageProjectiveGeometry.jl not defined or identified](https://discourse.julialang.org/t/imgtrans-function-under-imageprojectivegeometry-jl-not-defined-or-identified/9513)

<div class="topic-metadata">

**Author:** [@tosalonijain](https://discourse.julialang.org/u/tosalonijain)\
**Replies:** 1\
**Last updated:** [March 6, 2018, 7:23am UTC](https://discourse.julialang.org/t/imgtrans-function-under-imageprojectivegeometry-jl-not-defined-or-identified/9513 "2018-03-06T07:23:50Z")

</div>

I am trying to utilise the function mentioned as imgtrans but getting : julia\> using ImageProjectiveGeometry julia\> newimg = imgtrans(I, p) ERROR: UndefVarError: imgtrans not defined I am prefering https://github.com…

---

## [Automatically use getvalue() for all variables in model - JuMP](https://discourse.julialang.org/t/automatically-use-getvalue-for-all-variables-in-model-jump/9480)

<div class="topic-metadata">

**Author:** [@holger](https://discourse.julialang.org/u/holger)\
**Replies:** 4\
**Last updated:** [March 5, 2018, 7:17pm UTC](https://discourse.julialang.org/t/automatically-use-getvalue-for-all-variables-in-model-jump/9480 "2018-03-05T19:17:51Z")

</div>

Hi, After solving my JuMP model, I would like to use getvalue() on all variables in my model in an automated way. Say I have the following example problem: using JuMP using Clp m=Model(solver=ClpSolver()) @variable(m,x…

---

## [Can't PaddedView be used to pad a grey scale or coloured image?](https://discourse.julialang.org/t/cant-paddedview-be-used-to-pad-a-grey-scale-or-coloured-image/9498)

<div class="topic-metadata">

**Author:** [@tosalonijain](https://discourse.julialang.org/u/tosalonijain)\
**Replies:** 5\
**Last updated:** [March 5, 2018, 5:35pm UTC](https://discourse.julialang.org/t/cant-paddedview-be-used-to-pad-a-grey-scale-or-coloured-image/9498 "2018-03-05T17:35:29Z")

</div>

If not then how shall I pad a non-binary image? I need this in the implementation of my radon transform code. I have been striving hard to complete the code for radon and iradon transform, your replies are awaited. Than…

---

## [Broken incremental compilation for Plots](https://discourse.julialang.org/t/broken-incremental-compilation-for-plots/9505)

<div class="topic-metadata">

**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 4\
**Last updated:** [March 5, 2018, 1:41pm UTC](https://discourse.julialang.org/t/broken-incremental-compilation-for-plots/9505 "2018-03-05T13:41:43Z")

</div>

I’m getting the following incremental compilation warning from \_\_precompile()ing a module that is using Plots: \_ \_ \_(\_)\_ | A fresh approach to technical computing (\_) | (\_) (\_) | Documentation: h…

---

## [CSV.read stopped working](https://discourse.julialang.org/t/csv-read-stopped-working/9159)

<div class="topic-metadata">

**Author:** [@johann.spies](https://discourse.julialang.org/u/johann.spies)\
**Replies:** 5\
**Last updated:** [March 5, 2018, 1:41pm UTC](https://discourse.julialang.org/t/csv-read-stopped-working/9159 "2018-03-05T13:41:09Z")

</div>

I have a script that I have used regularly in the past to read a CSV-file and output a PostgreSQL-dumpfile to create a table and populate it with data. This script does not work anymore and it seems that something has c…

---

## [Running JuMP using KNITRO: killed](https://discourse.julialang.org/t/running-jump-using-knitro-killed/9164)

<div class="topic-metadata">

**Author:** [@huckl3b3rry87](https://discourse.julialang.org/u/huckl3b3rry87)\
**Replies:** 3\
**Last updated:** [March 5, 2018, 3:51am UTC](https://discourse.julialang.org/t/running-jump-using-knitro-killed/9164 "2018-03-05T03:51:27Z")

</div>

I am running a bunch optimization problems in a row with different parameters using JuMP and KNITRO and after about 5-7 hours the process simply says Killed and is sent back to the terminal with no additional information…

---

## [Returning Array instead of DataFrame with ODBC](https://discourse.julialang.org/t/returning-array-instead-of-dataframe-with-odbc/9489)

<div class="topic-metadata">

**Author:** [@Max-Zara](https://discourse.julialang.org/u/Max-Zara)\
**Replies:** 0\
**Last updated:** [March 4, 2018, 2:44pm UTC](https://discourse.julialang.org/t/returning-array-instead-of-dataframe-with-odbc/9489 "2018-03-04T14:44:04Z")

</div>

Hi, If I want to run a query from ODBC connected to PostgreSQL, but don’t want to receive a DataFrame, how do I go about doing this? using ODBC.query(dsn\_connection, “my query string…”, sink =??) I have tried sink = O…

---

## [histogram2d with logarithmic z-axis?](https://discourse.julialang.org/t/histogram2d-with-logarithmic-z-axis/9455)

<div class="topic-metadata">

**Author:** [@massemanet](https://discourse.julialang.org/u/massemanet)\
**Replies:** 2\
**Last updated:** [March 4, 2018, 1:26pm UTC](https://discourse.julialang.org/t/histogram2d-with-logarithmic-z-axis/9455 "2018-03-04T13:26:02Z")

</div>

is it possible to control the behavior of the z axis in histogram2d? e.g. making it logarithmic.

---

## [Automatic Differentiation and Parallelism](https://discourse.julialang.org/t/automatic-differentiation-and-parallelism/9478)

<div class="topic-metadata">

**Author:** [@Juser](https://discourse.julialang.org/u/Juser)\
**Replies:** 2\
**Last updated:** [March 3, 2018, 8:30pm UTC](https://discourse.julialang.org/t/automatic-differentiation-and-parallelism/9478 "2018-03-03T20:30:33Z")

</div>

I am trying to optimize a function that is expensive to evaluate but has many component parts that can be computed in parallel. However, DualNumbers are not bits-types and therefore cannot be stored in SharedArrays. Is…

[Previous page](https://discourse.julialang.org/c/domain/10.md?page=541)

[Next page](https://discourse.julialang.org/c/domain/10.md?page=543)