# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=465

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**Page:** 466

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## [Error installing Pajarito solver](https://discourse.julialang.org/t/error-installing-pajarito-solver/34223)

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**Author:** [@biswajit216](https://discourse.julialang.org/u/biswajit216)\
**Replies:** 1\
**Last updated:** [February 5, 2020, 10:25pm UTC](https://discourse.julialang.org/t/error-installing-pajarito-solver/34223 "2020-02-05T22:25:36Z")

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Hi, I was trying to add Pajarito package to my Julia but I was getting this error. My JuMP version is 0.20.1 pkg\> add Pajarito Resolving package versions… ERROR: Unsatisfiable requirements detected for package JuMP \[4…

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## [The error of using GLPKMathProgInterface pkg](https://discourse.julialang.org/t/the-error-of-using-glpkmathproginterface-pkg/34142)

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**Author:** [@mahsap58](https://discourse.julialang.org/u/mahsap58)\
**Replies:** 3\
**Last updated:** [February 5, 2020, 10:21pm UTC](https://discourse.julialang.org/t/the-error-of-using-glpkmathproginterface-pkg/34142 "2020-02-05T22:21:36Z")

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i have faced to this error in using GLPKMathProgInterface pkg please help me to fix that. Failed to precompile GLPK \[60bf3e95-4087-53dc-ae20-288a0d20c6a6\]

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## [Add Package on every processor?](https://discourse.julialang.org/t/add-package-on-every-processor/33853)

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**Author:** [@squirrel](https://discourse.julialang.org/u/squirrel)\
**Replies:** 6\
**Last updated:** [February 5, 2020, 7:30pm UTC](https://discourse.julialang.org/t/add-package-on-every-processor/33853 "2020-02-05T19:30:25Z")

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I’m trying to use DistributedArrays (per the example), but it seems like the package needs to be added to every processor. Is this right? When I first start Julia, and run using Distributed addprocs() @everywhere using…

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## [AlexNet import to Julia](https://discourse.julialang.org/t/alexnet-import-to-julia/34209)

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**Author:** [@samantp](https://discourse.julialang.org/u/samantp)\
**Replies:** 1\
**Last updated:** [February 5, 2020, 4:13pm UTC](https://discourse.julialang.org/t/alexnet-import-to-julia/34209 "2020-02-05T16:13:46Z")

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I am trying to download and modify AlexNet, the well known pre-trained neural network into Julia. Are there any packages that have already done this or have well known pre-trained NN’s that are open to modification? I a…

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## [How to check if a solver supports SOS2 constraints](https://discourse.julialang.org/t/how-to-check-if-a-solver-supports-sos2-constraints/34186)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 3\
**Last updated:** [February 5, 2020, 2:22pm UTC](https://discourse.julialang.org/t/how-to-check-if-a-solver-supports-sos2-constraints/34186 "2020-02-05T14:22:59Z")

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I have a piece of code that adds SOS2 constraints to a model. If the solver supports it, I would like to use its interface, if not I would assemble the constraints myself. Is there a way to check if an optimizer suppor…

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## [How to set the zoomspeed for Camera3D in Makie.jl](https://discourse.julialang.org/t/how-to-set-the-zoomspeed-for-camera3d-in-makie-jl/34205)

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**Author:** [@JesperMartinsson](https://discourse.julialang.org/u/JesperMartinsson)\
**Replies:** 0\
**Last updated:** [February 5, 2020, 11:58am UTC](https://discourse.julialang.org/t/how-to-set-the-zoomspeed-for-camera3d-in-makie-jl/34205 "2020-02-05T11:58:11Z")

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Is there a way to adjust the zoom speed (when scrolling the mouse) in Makie.jl and using a 3D camera? I can set the rotationspeed in 3D and zoomspeed in 2D but not zoomspeed in 3D. Thanks for a great package by the way!

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## [Debugging in CUDAnative](https://discourse.julialang.org/t/debugging-in-cudanative/34193)

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**Author:** [@Michael\_Benton](https://discourse.julialang.org/u/Michael_Benton)\
**Replies:** 1\
**Last updated:** [February 5, 2020, 7:01am UTC](https://discourse.julialang.org/t/debugging-in-cudanative/34193 "2020-02-05T07:01:51Z")

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struggling to find the source of problems in some kernels I write due to I don’t know of a julia CUDA debugger, I’ve found some for C. I get: CUDA error: unspecified launch failure (code 719, ERROR\_LAUNCH\_FAILED) and …

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## [CuArray can't find libcuda](https://discourse.julialang.org/t/cuarray-cant-find-libcuda/34175)

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**Author:** [@cuchxq](https://discourse.julialang.org/u/cuchxq)\
**Replies:** 10\
**Last updated:** [February 5, 2020, 6:59am UTC](https://discourse.julialang.org/t/cuarray-cant-find-libcuda/34175 "2020-02-05T06:59:33Z")

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I installed cuda10.2 on a ubuntu 18.10, and was able to build and run the some examples from the Cuda example folder, such as devicequery. But when I use Julia1.0.5LTS, and CuArray can’t find libcuda. and using JULIA\_D…

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## [\[ANN\] Flux v0.10](https://discourse.julialang.org/t/ann-flux-v0-10/31660)

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**Author:** [@dhairyagandhi96](https://discourse.julialang.org/u/dhairyagandhi96)\
**Replies:** 36\
**Last updated:** [February 4, 2020, 7:57pm UTC](https://discourse.julialang.org/t/ann-flux-v0-10/31660 "2020-02-04T19:57:14Z")

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We are delighted to announce the release of Flux v0.10. This is a huge release including the work of many contributors; the major development is that Flux now uses Zygote as its default backend for gradients, removing m…

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## [Warning for adding constraints: zero or small (\< 1e-13) coefficients, ignored](https://discourse.julialang.org/t/warning-for-adding-constraints-zero-or-small-1e-13-coefficients-ignored/34137)

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**Author:** [@Arega\_Getaneh](https://discourse.julialang.org/u/Arega_Getaneh)\
**Replies:** 8\
**Last updated:** [February 4, 2020, 5:32pm UTC](https://discourse.julialang.org/t/warning-for-adding-constraints-zero-or-small-1e-13-coefficients-ignored/34137 "2020-02-04T17:32:31Z")

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I asked this question and it seems no one wants to help me: I am just using Gurobi 9.0 which solves non convex problems as well. I get this error: Warning for adding constraints: zero or small (\< 1e-13) coefficients, ig…

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## [Zygote: treating a model output as a constant](https://discourse.julialang.org/t/zygote-treating-a-model-output-as-a-constant/34172)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 2\
**Last updated:** [February 4, 2020, 5:18pm UTC](https://discourse.julialang.org/t/zygote-treating-a-model-output-as-a-constant/34172 "2020-02-04T17:18:46Z")

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Say I have a model m = Dense(1,1), a function f(x) = x, and a loss(a,b,c) = m(a) - b - f(c). I don’t want zygote to differentiate on f(c) when calling gradient(() -\> loss(a,b,c), m) . How do I tell it that ? It is a pro…

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## [Different results for same model with DifferentialEquations.jl](https://discourse.julialang.org/t/different-results-for-same-model-with-differentialequations-jl/34155)

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**Author:** [@moesphere](https://discourse.julialang.org/u/moesphere)\
**Replies:** 4\
**Last updated:** [February 4, 2020, 2:54pm UTC](https://discourse.julialang.org/t/different-results-for-same-model-with-differentialequations-jl/34155 "2020-02-04T14:54:52Z")

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I am defining two ODEProblems, where they are both the same but the implementation is different. There is a parameter I specify for one problem directly inside the function and for the other problem as an argument to the…

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## [DifferentialEquations + RecursiveArrayTools Broadcasting / CuArrays Kernel compilation error --](https://discourse.julialang.org/t/differentialequations-recursivearraytools-broadcasting-cuarrays-kernel-compilation-error/34132)

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**Author:** [@cmarcotte](https://discourse.julialang.org/u/cmarcotte)\
**Replies:** 6\
**Last updated:** [February 4, 2020, 2:53pm UTC](https://discourse.julialang.org/t/differentialequations-recursivearraytools-broadcasting-cuarrays-kernel-compilation-error/34132 "2020-02-04T14:53:03Z")

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Hi, Finally have access to a CUDA capable GPU, so I’m trying to accelerate some finite-difference PDE solves using CuArrays and DifferentialEquations. I began with Chris’ simple reaction-diffusion demonstration here, a…

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## [Choosing a binary value with a certain probability (Biased random generator)](https://discourse.julialang.org/t/choosing-a-binary-value-with-a-certain-probability-biased-random-generator/34141)

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**Author:** [@HoldenCaulfield](https://discourse.julialang.org/u/HoldenCaulfield)\
**Replies:** 4\
**Last updated:** [February 4, 2020, 2:46pm UTC](https://discourse.julialang.org/t/choosing-a-binary-value-with-a-certain-probability-biased-random-generator/34141 "2020-02-04T14:46:49Z")

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I want to determine a random binary variable according to its probability. So let’s say that I have a binary variable with a probability of 70%, so I want it to become 1 with the probability of 70% and zero with a probab…

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## [JuMP precompiling error on an AWS EC2 Ubuntu server instance](https://discourse.julialang.org/t/jump-precompiling-error-on-an-aws-ec2-ubuntu-server-instance/33154)

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**Author:** [@newstatement](https://discourse.julialang.org/u/newstatement)\
**Replies:** 15\
**Last updated:** [February 4, 2020, 11:12am UTC](https://discourse.julialang.org/t/jump-precompiling-error-on-an-aws-ec2-ubuntu-server-instance/33154 "2020-02-04T11:12:35Z")

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I am trying to use an AWS EC2 instance (t2.micro with Ubuntu Server 18.04) to run an optimization model designed in JuMP. I’m using Julia v1.3.1 and when I try to load JuMP package a fail occurs at precompiling. Some one…

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## [How to plot next to each other and in rows small matrices as images (greyscale)](https://discourse.julialang.org/t/how-to-plot-next-to-each-other-and-in-rows-small-matrices-as-images-greyscale/34149)

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**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 4\
**Last updated:** [February 4, 2020, 8:21am UTC](https://discourse.julialang.org/t/how-to-plot-next-to-each-other-and-in-rows-small-matrices-as-images-greyscale/34149 "2020-02-04T08:21:49Z")

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Hi guys, my question is: how to plot next to each other and in rows small matrices as images (greyscale)? Thank you very much in advance for your support. Cheers. Ergnoor

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## [Using DifferentialEquations.jl to solve routine optimal control problems](https://discourse.julialang.org/t/using-differentialequations-jl-to-solve-routine-optimal-control-problems/34096)

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**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 7\
**Last updated:** [February 3, 2020, 8:38pm UTC](https://discourse.julialang.org/t/using-differentialequations-jl-to-solve-routine-optimal-control-problems/34096 "2020-02-03T20:38:18Z")

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I’m using DifferentialEquations.jl to solve a standard consumption-savings problem. I wanna see if there is a way to solve these issues before I submit feature-requests. using DifferentialEquations, BoundaryValueDiffEq…

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## [How to generate a random unitary matrix perfectly in Julia](https://discourse.julialang.org/t/how-to-generate-a-random-unitary-matrix-perfectly-in-julia/34102)

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**Author:** [@JunjieWu](https://discourse.julialang.org/u/JunjieWu)\
**Replies:** 10\
**Last updated:** [February 3, 2020, 4:18pm UTC](https://discourse.julialang.org/t/how-to-generate-a-random-unitary-matrix-perfectly-in-julia/34102 "2020-02-03T16:18:00Z")

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Dear friends, I am trying to implement a function that generates a random unitary matrix. However, I found that I met a precision issue. Is any idea how to solve this problem? using LinearAlgebra function RandomUnitar…

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## [How to minimize a function of single integer variable?](https://discourse.julialang.org/t/how-to-minimize-a-function-of-single-integer-variable/34115)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 2\
**Last updated:** [February 3, 2020, 4:08pm UTC](https://discourse.julialang.org/t/how-to-minimize-a-function-of-single-integer-variable/34115 "2020-02-03T16:08:22Z")

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Let’s suppose I have a function f(m): \\mathbb{N}\\rightarrow\\mathbb{R}. What method should I use to minimize it? The function is supposed to be smooth if we continue it from \\mathbb{N} to \[1,+\\infty). Also, it’s contin…

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## [Initializing a grid with coordinates on the GPU](https://discourse.julialang.org/t/initializing-a-grid-with-coordinates-on-the-gpu/34107)

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**Author:** [@stabbles](https://discourse.julialang.org/u/stabbles)\
**Replies:** 1\
**Last updated:** [February 3, 2020, 12:50pm UTC](https://discourse.julialang.org/t/initializing-a-grid-with-coordinates-on-the-gpu/34107 "2020-02-03T12:50:21Z")

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I’m trying to build a tensor A of size 3 x ℓ x m x n where A\[:, i, j, k\] is a 3D coordinate at (i, j, k) in a uniform grid for \[0, 1\]^3. On the CPU this code looks like this: function mesh(n) r = range(0.0f0, 1.0f0, …

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## [Blockdiag for dense matrices](https://discourse.julialang.org/t/blockdiag-for-dense-matrices/33941)

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**Author:** [@olof3](https://discourse.julialang.org/u/olof3)\
**Replies:** 10\
**Last updated:** [February 3, 2020, 9:51am UTC](https://discourse.julialang.org/t/blockdiag-for-dense-matrices/33941 "2020-02-03T09:51:42Z")

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Quite often I want to form dense block diagonal matrices from a few dense matrices. Is there an easy way to do this? There is blockdiag for sparse matrices: help?\> blockdiag search: blockdiag blockdiag(A...) Conca…

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## [Problem using Optim.optimize](https://discourse.julialang.org/t/problem-using-optim-optimize/33728)

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**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 36\
**Last updated:** [February 3, 2020, 5:00am UTC](https://discourse.julialang.org/t/problem-using-optim-optimize/33728 "2020-02-03T05:00:41Z")

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Hi guys, I am trying to translate a piece of code from Matlab to Julia, please see following first the original Matlab code: options = optimset('Largescale', 'off', 'MaxFunEvals', 500, 'GradObj','on', 'Display','notify'…

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## [Jump code errors](https://discourse.julialang.org/t/jump-code-errors/34090)

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**Author:** [@bandaya](https://discourse.julialang.org/u/bandaya)\
**Replies:** 2\
**Last updated:** [February 2, 2020, 9:23pm UTC](https://discourse.julialang.org/t/jump-code-errors/34090 "2020-02-02T21:23:52Z")

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Hi, I am new to Julia and I am having problems in running simple examples of Jump. I have given links to two examples below: Manual · MathOptInterface https://nbviewer.jupyter.org/github/JuliaOpt/juliaopt-notebooks/bl…

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## [How to use LBFGS to minimise the cost function for regularised logistic regression](https://discourse.julialang.org/t/how-to-use-lbfgs-to-minimise-the-cost-function-for-regularised-logistic-regression/34058)

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**Author:** [@PyDataBlog](https://discourse.julialang.org/u/PyDataBlog)\
**Replies:** 7\
**Last updated:** [February 2, 2020, 11:12am UTC](https://discourse.julialang.org/t/how-to-use-lbfgs-to-minimise-the-cost-function-for-regularised-logistic-regression/34058 "2020-02-02T11:12:33Z")

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I am currently stuck trying to utilize the Optim package in Julia in an attempt to minimize a cost function. The cost function is the cost function for an L2 regularised logistic regression. It is constructed as follows; …

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## [Implement berHu loss in Flux](https://discourse.julialang.org/t/implement-berhu-loss-in-flux/31707)

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**Author:** [@jchen975](https://discourse.julialang.org/u/jchen975)\
**Replies:** 9\
**Last updated:** [February 1, 2020, 9:06pm UTC](https://discourse.julialang.org/t/implement-berhu-loss-in-flux/31707 "2020-02-01T21:06:06Z")

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Hi, I was trying to build this loss function from this paper: I wanted to see if it outperforms squared L2 norm in another regression problem I’m working on. Here is my attempt: function berhu(x, y) x = model…

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## [Julia alternative for turtle graphics](https://discourse.julialang.org/t/julia-alternative-for-turtle-graphics/31683)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 8\
**Last updated:** [January 31, 2020, 10:56pm UTC](https://discourse.julialang.org/t/julia-alternative-for-turtle-graphics/31683 "2020-01-31T22:56:12Z")

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A while back I made a nice visualization of the Ramanujan tau function using python turtle graphics, which I made for the 100th anniversary of this function. The turtle interface was very nice for making the graphics, wh…

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## [Sample conditional multivariate random variable?](https://discourse.julialang.org/t/sample-conditional-multivariate-random-variable/34035)

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**Author:** [@Alex1](https://discourse.julialang.org/u/Alex1)\
**Replies:** 4\
**Last updated:** [January 31, 2020, 10:40pm UTC](https://discourse.julialang.org/t/sample-conditional-multivariate-random-variable/34035 "2020-01-31T22:40:03Z")

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There’s multivariate random variable, future prices of assets, 5 years from now: X = \[Gold, Silver, SP500\] There’s historical prices for X available for last 50 years. It’s possible to fit historical prices to get mult…

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## [\[JuMP\] Use ConstraintRef to add additional constraint](https://discourse.julialang.org/t/jump-use-constraintref-to-add-additional-constraint/34046)

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**Author:** [@acauligi](https://discourse.julialang.org/u/acauligi)\
**Replies:** 1\
**Last updated:** [January 31, 2020, 8:09pm UTC](https://discourse.julialang.org/t/jump-use-constraintref-to-add-additional-constraint/34046 "2020-01-31T20:09:07Z")

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Hi, I have an affine inequality constraint in a JuMP model (that was constructed off-line) and would like to add a new constraint using the expression from the ConstraintRef associated with the affine constraint. e.g.: …

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## [What does and does-not get computed on the GPU? (CuArrays)](https://discourse.julialang.org/t/what-does-and-does-not-get-computed-on-the-gpu-cuarrays/34042)

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**Author:** [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Replies:** 1\
**Last updated:** [January 31, 2020, 6:41pm UTC](https://discourse.julialang.org/t/what-does-and-does-not-get-computed-on-the-gpu-cuarrays/34042 "2020-01-31T18:41:26Z")

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Is there a easy explanation or “rule of thumb” about which computations are run on the GPU? For example, if there is a matrix ‘W’ and array ‘a’, both on the gpu, I am sure that W\*a is computed on the GPU. But what abou…

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## [\[Convex.jl\] Suppress warnings when printing problem tree](https://discourse.julialang.org/t/convex-jl-suppress-warnings-when-printing-problem-tree/34029)

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**Author:** [@4aHxKzD](https://discourse.julialang.org/u/4aHxKzD)\
**Replies:** 2\
**Last updated:** [January 31, 2020, 3:22pm UTC](https://discourse.julialang.org/t/convex-jl-suppress-warnings-when-printing-problem-tree/34029 "2020-01-31T15:22:48Z")

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Is there a way to suppress warnings such as Warning: Expression not DCP compliant. when printing the problem tree?

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