# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=506

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**Page:** 507

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## [Julia 1.0.3 segfaults when trying to read a csv DataFrame with non-quoted headers and strings](https://discourse.julialang.org/t/julia-1-0-3-segfaults-when-trying-to-read-a-csv-dataframe-with-non-quoted-headers-and-strings/21547)

<div class="topic-metadata">

**Author:** [@tanhevg](https://discourse.julialang.org/u/tanhevg)\
**Replies:** 2\
**Last updated:** [March 7, 2019, 6:02am UTC](https://discourse.julialang.org/t/julia-1-0-3-segfaults-when-trying-to-read-a-csv-dataframe-with-non-quoted-headers-and-strings/21547 "2019-03-07T06:02:36Z")

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Hello, My code goes: using Queryverse df = load("my\_file.csv") |\> DataFrame And the file contents are: query\_domain,template\_domain,tm\_score d1qbaa2,d2a73b2,0.52434 d1qbaa2,d2wnxa1,0.51702 d1qbaa2,d1p35a\_,0.50272 d1q…

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## [Generating high-dimensional Sobol sequences](https://discourse.julialang.org/t/generating-high-dimensional-sobol-sequences/21521)

<div class="topic-metadata">

**Author:** [@jocklawrie](https://discourse.julialang.org/u/jocklawrie)\
**Replies:** 2\
**Last updated:** [March 7, 2019, 4:54am UTC](https://discourse.julialang.org/t/generating-high-dimensional-sobol-sequences/21521 "2019-03-07T04:54:42Z")

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Hi there, I am using Sobol sequences to generate say 10,000 draws from the Multivariate Normal with dimension 100, mean vector 0 and covariance matrix equal to the identity matrix. Generating the sequence is fine, but …

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## [Adding local lazy constraints in Gurobi with JuMP v0.18](https://discourse.julialang.org/t/adding-local-lazy-constraints-in-gurobi-with-jump-v0-18/21517)

<div class="topic-metadata">

**Author:** [@Wei\_Wang](https://discourse.julialang.org/u/Wei_Wang)\
**Replies:** 2\
**Last updated:** [March 6, 2019, 3:48pm UTC](https://discourse.julialang.org/t/adding-local-lazy-constraints-in-gurobi-with-jump-v0-18/21517 "2019-03-06T15:48:00Z")

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Hi all, I am using JuMP v0.18. I want to locally add lazy constraints but when I setting localcut to true I get the following error MethodError: no method matching cbaddlazylocal!(::Gurobi.GurobiCallbackData, ::Array{I…

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## [Deep forest NLP](https://discourse.julialang.org/t/deep-forest-nlp/21526)

<div class="topic-metadata">

**Author:** [@yash](https://discourse.julialang.org/u/yash)\
**Replies:** 6\
**Last updated:** [March 6, 2019, 11:43am UTC](https://discourse.julialang.org/t/deep-forest-nlp/21526 "2019-03-06T11:43:39Z")

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Is there any Deep forest implementation in julia.???

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## [Trouble with boundary conditions in DiffEqOperators.jl](https://discourse.julialang.org/t/trouble-with-boundary-conditions-in-diffeqoperators-jl/21488)

<div class="topic-metadata">

**Author:** [@danielc](https://discourse.julialang.org/u/danielc)\
**Replies:** 9\
**Last updated:** [March 6, 2019, 12:12am UTC](https://discourse.julialang.org/t/trouble-with-boundary-conditions-in-diffeqoperators-jl/21488 "2019-03-06T00:12:14Z")

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Hello, I’m trying to learn how to use the DiffEqOperators.jl module. It’s quite new. Chris Rackauckas gave a talk at JuliaCon 2018. To get started, I tried to choose a very simple problem: Compute the second derivati…

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## [JuMP 19.0: constraint\_by\_name fails for vectorized constraints](https://discourse.julialang.org/t/jump-19-0-constraint-by-name-fails-for-vectorized-constraints/21481)

<div class="topic-metadata">

**Author:** [@torgo](https://discourse.julialang.org/u/torgo)\
**Replies:** 6\
**Last updated:** [March 5, 2019, 6:15pm UTC](https://discourse.julialang.org/t/jump-19-0-constraint-by-name-fails-for-vectorized-constraints/21481 "2019-03-05T18:15:38Z")

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using JuMP m = Model() @variable(m, x\[1:2\]) @constraint(m, mycons, x .== 0) cn = constraint\_by\_name(m, "mycons") # returns nothing Should cn be nothing? I expected it would return an array of constraint references.

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## [Makie hypersphere with radius other than 1?](https://discourse.julialang.org/t/makie-hypersphere-with-radius-other-than-1/21460)

<div class="topic-metadata">

**Author:** [@kmhaeren](https://discourse.julialang.org/u/kmhaeren)\
**Replies:** 3\
**Last updated:** [March 5, 2019, 5:12pm UTC](https://discourse.julialang.org/t/makie-hypersphere-with-radius-other-than-1/21460 "2019-03-05T17:12:47Z")

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Hi I’m using Makie to display a physics engine, and I’m trying to draw 3D spheres of different radii, however, when I try to display “Sphere(Point3(0),5)” for example, it still shows a sphere with a radius of 1. I look…

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## [Boundaries for @NLparameters](https://discourse.julialang.org/t/boundaries-for-nlparameters/21490)

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**Author:** [@tamasgal](https://discourse.julialang.org/u/tamasgal)\
**Replies:** 4\
**Last updated:** [March 5, 2019, 1:47pm UTC](https://discourse.julialang.org/t/boundaries-for-nlparameters/21490 "2019-03-05T13:47:43Z")

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I am currently discovering the world of JuMP.jl and I have to say, I am amazed, thanks for this package! TL;DR: how do I add constraints or limits to parameters which are not defined by @variable but @NLparameter? Full…

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## [State of reverse mode AD tools](https://discourse.julialang.org/t/state-of-reverse-mode-ad-tools/21467)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 8\
**Last updated:** [March 5, 2019, 10:51am UTC](https://discourse.julialang.org/t/state-of-reverse-mode-ad-tools/21467 "2019-03-05T10:51:09Z")

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(Opening a new topic instead of resurrecting some older ones.) I am wondering about the current state of libraries for reverse mode AD, specifically for differentiating \\mathbb{R}^n \\to \\mathbb{R} functions that accep…

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## [Bug? Using Flux & getting Float32 response on 64 bit Ubuntu OS](https://discourse.julialang.org/t/bug-using-flux-getting-float32-response-on-64-bit-ubuntu-os/21440)

<div class="topic-metadata">

**Author:** [@samq](https://discourse.julialang.org/u/samq)\
**Replies:** 4\
**Last updated:** [March 4, 2019, 6:53pm UTC](https://discourse.julialang.org/t/bug-using-flux-getting-float32-response-on-64-bit-ubuntu-os/21440 "2019-03-04T18:53:25Z")

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Julia version 1.1.0 Ubuntu 16.04 64 bit Flux version (?) please tell me how to see the version of Flux I get Float32 responses instead of Float64 when doing the following: using Flux model = Flux.Dense(2, 1, σ) mod…

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## [Example of simple 1 layer Perception in Flux](https://discourse.julialang.org/t/example-of-simple-1-layer-perception-in-flux/21413)

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**Author:** [@samq](https://discourse.julialang.org/u/samq)\
**Replies:** 8\
**Last updated:** [March 4, 2019, 6:38pm UTC](https://discourse.julialang.org/t/example-of-simple-1-layer-perception-in-flux/21413 "2019-03-04T18:38:33Z")

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I saw the Flux pages, but the examples are not clear to me. Since Flux is simple and fast, would someone please post an example of how to make a simple 1 layer Perceptron using Flux? Such an example would be a springbo…

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## [Adding CPLEX callbacks with JuMP v0.19](https://discourse.julialang.org/t/adding-cplex-callbacks-with-jump-v0-19/21449)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 7\
**Last updated:** [March 4, 2019, 3:28pm UTC](https://discourse.julialang.org/t/adding-cplex-callbacks-with-jump-v0-19/21449 "2019-03-04T15:28:14Z")

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Dear community, I use CPLEX 12.8 and made an update from JuMP v18.5 to v0.19. Due to major changes in the new version I have to adapt my code, and I do not succeed to add callbacks. The release notes say that callbacks …

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## [A Qubit DSL?](https://discourse.julialang.org/t/a-qubit-dsl/8599)

<div class="topic-metadata">

**Author:** [@grant](https://discourse.julialang.org/u/grant)\
**Replies:** 50\
**Last updated:** [March 4, 2019, 2:28pm UTC](https://discourse.julialang.org/t/a-qubit-dsl/8599 "2019-03-04T14:28:48Z")

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I have a general question, is it possible to design a DSL using Dirac’s bra ket notation? It seems that |\> is already used in the language, which corresponds to kets, so I’m not sure what the possibilities are. For exam…

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## [Unexpected? result of multiplication with adjoint()](https://discourse.julialang.org/t/unexpected-result-of-multiplication-with-adjoint/21447)

<div class="topic-metadata">

**Author:** [@ivanslapnicar](https://discourse.julialang.org/u/ivanslapnicar)\
**Replies:** 1\
**Last updated:** [March 4, 2019, 12:20pm UTC](https://discourse.julialang.org/t/unexpected-result-of-multiplication-with-adjoint/21447 "2019-03-04T12:20:25Z")

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On Julia Version 1.0.2 the output of the following code using LinearAlgebra unblock(A) = mapreduce(identity, hcat, \[mapreduce(identity, vcat, A\[:,i\]) for i = 1:size(A,2)\]) x=Vector{Any}(undef,2) x\[1\]=\[1+2im 1-im;-3 4+3i…

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## [Why Julia machine learning is so unfriendly? Very "unsmooth" experience from foolish guy](https://discourse.julialang.org/t/why-julia-machine-learning-is-so-unfriendly-very-unsmooth-experience-from-foolish-guy/21174)

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**Author:** [@kirtsar](https://discourse.julialang.org/u/kirtsar)\
**Replies:** 15\
**Last updated:** [March 3, 2019, 4:19pm UTC](https://discourse.julialang.org/t/why-julia-machine-learning-is-so-unfriendly-very-unsmooth-experience-from-foolish-guy/21174 "2019-03-03T16:19:01Z")

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Ok, so let’s imagine that I’m a newcomer in a field of machine learning, and the very first task i want to do in Julia is something like knn-classifier. Nice! So let’s try to do it step by step, using all those cool libr…

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## [JuliaDB: How to find the number of rows and columns?](https://discourse.julialang.org/t/juliadb-how-to-find-the-number-of-rows-and-columns/21406)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 1\
**Last updated:** [March 3, 2019, 2:11am UTC](https://discourse.julialang.org/t/juliadb-how-to-find-the-number-of-rows-and-columns/21406 "2019-03-03T02:11:31Z")

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I loaded a JuliaDB table, but how do I find the number of rows and columns? size doesn’t work.

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## [\[DiffEqFlux\] How to do composition of layers?](https://discourse.julialang.org/t/diffeqflux-how-to-do-composition-of-layers/21291)

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**Author:** [@pochoi](https://discourse.julialang.org/u/pochoi)\
**Replies:** 4\
**Last updated:** [March 2, 2019, 10:16pm UTC](https://discourse.julialang.org/t/diffeqflux-how-to-do-composition-of-layers/21291 "2019-03-02T22:16:03Z")

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How to do composition of layers in DiffEqFlux? For example, I want do composite a layer of neural ODE with a layer of NN: dudt = Chain(Dense(2,40,tanh), Dense(40,2)) tspan = (0.0f0,1.0f0) t = range(tspan\[1\],tspan\[2\],le…

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## [Out-of-core MUMPS.jl Implementation](https://discourse.julialang.org/t/out-of-core-mumps-jl-implementation/21372)

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**Author:** [@Uche](https://discourse.julialang.org/u/Uche)\
**Replies:** 1\
**Last updated:** [March 2, 2019, 6:27pm UTC](https://discourse.julialang.org/t/out-of-core-mumps-jl-implementation/21372 "2019-03-02T18:27:48Z")

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So how does the out-of-core MUMPS.jl work? Is there any specific thing a user should do to use this option? Thanks. Uche.

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## [Parallel calls to build-in functions](https://discourse.julialang.org/t/parallel-calls-to-build-in-functions/21300)

<div class="topic-metadata">

**Author:** [@stakaz](https://discourse.julialang.org/u/stakaz)\
**Replies:** 4\
**Last updated:** [March 2, 2019, 5:23pm UTC](https://discourse.julialang.org/t/parallel-calls-to-build-in-functions/21300 "2019-03-02T17:23:23Z")

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Hello, I am not new to julia but until now never was forced to do any parallel computations with it. Now, I have a simple case where I want to use Thread or Processes to speed up the computations but I don’t really see …

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## [Understanding BigInt](https://discourse.julialang.org/t/understanding-bigint/21337)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 3\
**Last updated:** [March 1, 2019, 11:46am UTC](https://discourse.julialang.org/t/understanding-bigint/21337 "2019-03-01T11:46:49Z")

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Playing aroudn with types yesterday I found typemax(BigInt) does not exist. Which makes perfect sense. the Julia documentation on Arbitrary Precision Arithmetic refers to the Gnu GMP. Would this be the best place to rea…

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## [Engarde - Python defensive data analysis](https://discourse.julialang.org/t/engarde-python-defensive-data-analysis/21334)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 3\
**Last updated:** [March 1, 2019, 10:42am UTC](https://discourse.julialang.org/t/engarde-python-defensive-data-analysis/21334 "2019-03-01T10:42:56Z")

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I went to a Meet up o data engineering at https://www.quantumblack.com/ Engarde was mentioned: Engarde! — engarde 0.4.0+9.ge7ea040 documentation Looks very useful. Is there anything similar in Julia?

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## [Rounding to a multiple of float](https://discourse.julialang.org/t/rounding-to-a-multiple-of-float/21295)

<div class="topic-metadata">

**Author:** [@cedeerwe](https://discourse.julialang.org/u/cedeerwe)\
**Replies:** 25\
**Last updated:** [February 28, 2019, 9:52pm UTC](https://discourse.julialang.org/t/rounding-to-a-multiple-of-float/21295 "2019-02-28T21:52:22Z")

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I am trying to solve a simple problem - rounding a number to a nearest multiple of a given float. As an example, I would like roundmult(3811.47123123, 0.01) = 3811.47. However, the simplest implementation of roundmult(va…

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## [Parallel Computations](https://discourse.julialang.org/t/parallel-computations/21070)

<div class="topic-metadata">

**Author:** [@ennvvy](https://discourse.julialang.org/u/ennvvy)\
**Replies:** 6\
**Last updated:** [February 22, 2019, 2:07pm UTC](https://discourse.julialang.org/t/parallel-computations/21070 "2019-02-22T14:07:54Z")

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I have migrated to Julia very recently. To be able to lower computation time, I have been trying to implement parallel programming concepts in my serial code. @time begin @everywhere N = 100 ; @everywhere agents = co…

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## [DiffEqFlux: how do declare a system of ODE which is backpropagatable?](https://discourse.julialang.org/t/diffeqflux-how-do-declare-a-system-of-ode-which-is-backpropagatable/21254)

<div class="topic-metadata">

**Author:** [@pochoi](https://discourse.julialang.org/u/pochoi)\
**Replies:** 2\
**Last updated:** [February 28, 2019, 5:58am UTC](https://discourse.julialang.org/t/diffeqflux-how-do-declare-a-system-of-ode-which-is-backpropagatable/21254 "2019-02-28T05:58:38Z")

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Here is a simple example. Flux’s parameter seems to be not so friendly with matrix multiplication. When doing p .\* A where p is a parameter and A is a matrix, things go bad… using DifferentialEquations using Flux, Dif…

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## [\[solved\] Can't install MPI.jl in julia 1.0.1/0.7.0 on a CENTOS 7.4](https://discourse.julialang.org/t/solved-cant-install-mpi-jl-in-julia-1-0-1-0-7-0-on-a-centos-7-4/16532)

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**Author:** [@GM\_44](https://discourse.julialang.org/u/GM_44)\
**Replies:** 13\
**Last updated:** [February 28, 2019, 12:47am UTC](https://discourse.julialang.org/t/solved-cant-install-mpi-jl-in-julia-1-0-1-0-7-0-on-a-centos-7-4/16532 "2019-02-28T00:47:19Z")

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Hello, I’m new to Julia. I hope this post is at the right place. So, I have to install MPI.jl module for one of our users. It doesn’t work. I have installed Linux 64 bits binary versions of julia 0.7.0 and 1.0.1 julia…

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## [Is there any microsimulation package in Julia?](https://discourse.julialang.org/t/is-there-any-microsimulation-package-in-julia/20049)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 4\
**Last updated:** [February 27, 2019, 11:26pm UTC](https://discourse.julialang.org/t/is-there-any-microsimulation-package-in-julia/20049 "2019-02-27T23:26:08Z")

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Something along the lines of LIAM2 in Python or MicSim in R.

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## [Group KFold?](https://discourse.julialang.org/t/group-kfold/21165)

<div class="topic-metadata">

**Author:** [@charlesll](https://discourse.julialang.org/u/charlesll)\
**Replies:** 4\
**Last updated:** [February 27, 2019, 10:30pm UTC](https://discourse.julialang.org/t/group-kfold/21165 "2019-02-27T22:30:46Z")

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Hi, I am trying to implement a Group KFold function for my problem, where I need to slit the dataset as a function of some label. There is no function like that in MLDataUtils or MLbase to my knowledge, so I am trying …

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## [Flux.jl and the state of multi-processing](https://discourse.julialang.org/t/flux-jl-and-the-state-of-multi-processing/21170)

<div class="topic-metadata">

**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 2\
**Last updated:** [February 27, 2019, 7:51am UTC](https://discourse.julialang.org/t/flux-jl-and-the-state-of-multi-processing/21170 "2019-02-27T07:51:56Z")

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I try to implement a convolutional auto encoder in Flux. The model is composed essentially of several convolutional layers, max pool, interpolation to the nearest neighborhood (using repeat(...; inner = (2,2,1,1)). The …

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## [JuMP uses all available memory, can't do anything else after](https://discourse.julialang.org/t/jump-uses-all-available-memory-cant-do-anything-else-after/21238)

<div class="topic-metadata">

**Author:** [@cosmia](https://discourse.julialang.org/u/cosmia)\
**Replies:** 1\
**Last updated:** [February 27, 2019, 7:50am UTC](https://discourse.julialang.org/t/jump-uses-all-available-memory-cant-do-anything-else-after/21238 "2019-02-27T07:50:04Z")

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Hey guys, so I have an optimization problem in which JuMP with Ipopt uses 90% of my available RAM memory for automatic differentiation. In my layman’s understanding, after it calculates the hessian and all, it stores it…

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## [Strange behavior inside a for-loop with ArrayFire](https://discourse.julialang.org/t/strange-behavior-inside-a-for-loop-with-arrayfire/21187)

<div class="topic-metadata">

**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 3\
**Last updated:** [February 26, 2019, 4:58pm UTC](https://discourse.julialang.org/t/strange-behavior-inside-a-for-loop-with-arrayfire/21187 "2019-02-26T16:58:50Z")

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Hello everyone, I have a issue and I don’t even know the exactly cause. I am using ArrayFire to speed up some matrix multiplications. However, I cannot retrieve the data unless I do some useless operation into my data. …

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