# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=493

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**Page:** 494

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## [Select a device for the entire program](https://discourse.julialang.org/t/select-a-device-for-the-entire-program/25603)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 3\
**Last updated:** [June 24, 2019, 4:22pm UTC](https://discourse.julialang.org/t/select-a-device-for-the-entire-program/25603 "2019-06-24T16:22:20Z")

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Question: To my understanding, CuArrays/CUDAnative/CUDAdrv selects the device 0 by default. How can I select a different device at the beginning of my program, that will be used in the rest of the program for any GPU op…

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## [Autodiff on image convolution](https://discourse.julialang.org/t/autodiff-on-image-convolution/25574)

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**Author:** [@francesco.alemanno](https://discourse.julialang.org/u/francesco.alemanno)\
**Replies:** 6\
**Last updated:** [June 24, 2019, 1:55pm UTC](https://discourse.julialang.org/t/autodiff-on-image-convolution/25574 "2019-06-24T13:55:15Z")

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Hello everyone, i was trying to leverage julia Autodiff tools, to solve this problem: I have two images A,B and a convolution kernel K i tried to use Flux.tracker, ForwardDiff, Zygote, and Knet.AutoGrad to minimize th…

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## [Using Distributed: computational efficiency](https://discourse.julialang.org/t/using-distributed-computational-efficiency/25570)

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**Author:** [@FujiwaraTakumiEH](https://discourse.julialang.org/u/FujiwaraTakumiEH)\
**Replies:** 5\
**Last updated:** [June 24, 2019, 12:50pm UTC](https://discourse.julialang.org/t/using-distributed-computational-efficiency/25570 "2019-06-24T12:50:12Z")

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Background: I want to add elements to the matrix and want to use @distributed for acceleration,here is my code: function fill(N) S = zeros(N,N) for i in 1:length(S) S\[i\] = i end end @btime fill(10…

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## [Estimate parameters of a Delay Differential Equation](https://discourse.julialang.org/t/estimate-parameters-of-a-delay-differential-equation/25159)

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**Author:** [@Farnazmdi](https://discourse.julialang.org/u/Farnazmdi)\
**Replies:** 6\
**Last updated:** [June 24, 2019, 4:53am UTC](https://discourse.julialang.org/t/estimate-parameters-of-a-delay-differential-equation/25159 "2019-06-24T04:53:54Z")

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Hi! I am new to Julia and I’m trying to fit my data to a DDE, but have a problem with optimize(). It is not recognized, here is my code, and the error. I would appreciate if anyone could provide a toy example for how t…

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## [Batch Training with TensorFlow.jl](https://discourse.julialang.org/t/batch-training-with-tensorflow-jl/25575)

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**Author:** [@oli](https://discourse.julialang.org/u/oli)\
**Replies:** 0\
**Last updated:** [June 23, 2019, 4:21pm UTC](https://discourse.julialang.org/t/batch-training-with-tensorflow-jl/25575 "2019-06-23T16:21:54Z")

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Hi, I have an existing DNN project that works in Python, but I want to transition towards Julia. I’m having problems when it comes to using batches for training. Since my project is quite large, I will simply summarize …

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## [Questions about getting started with parallel computing](https://discourse.julialang.org/t/questions-about-getting-started-with-parallel-computing/25341)

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**Author:** [@FujiwaraTakumiEH](https://discourse.julialang.org/u/FujiwaraTakumiEH)\
**Replies:** 18\
**Last updated:** [June 22, 2019, 2:01pm UTC](https://discourse.julialang.org/t/questions-about-getting-started-with-parallel-computing/25341 "2019-06-22T14:01:03Z")

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Background: I have already written a program with julia. In order to pursue speed, I now want to solve this problem with parallel computing. OpenMP C++: I know that when I used C++ before, I used OpenMP to speed up my p…

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## [How do I use Cbc with JuMP 0.19?](https://discourse.julialang.org/t/how-do-i-use-cbc-with-jump-0-19/25502)

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**Author:** [@dburch](https://discourse.julialang.org/u/dburch)\
**Replies:** 1\
**Last updated:** [June 22, 2019, 2:24am UTC](https://discourse.julialang.org/t/how-do-i-use-cbc-with-jump-0-19/25502 "2019-06-22T02:24:14Z")

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How do I use Cbc with JuMP 0.19? The new syntax is throwing me off. All of the documentation I can find is using the old syntax. Old Syntax model = Model(solver=CbcSolver()) I know that GLPK with new syntax is like th…

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## [Flux.jl vanilla ANN loss goes to NaN with mini batch](https://discourse.julialang.org/t/flux-jl-vanilla-ann-loss-goes-to-nan-with-mini-batch/25511)

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**Author:** [@jchen975](https://discourse.julialang.org/u/jchen975)\
**Replies:** 0\
**Last updated:** [June 21, 2019, 4:14am UTC](https://discourse.julialang.org/t/flux-jl-vanilla-ann-loss-goes-to-nan-with-mini-batch/25511 "2019-06-21T04:14:00Z")

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I’m building a vanilla NN with 1 or 2 hidden layers for a regression problem that’s basically as follows: I take N sets of known values (x\_1, y\_1), ..., (x\_k, y\_k) as input to an approximation solver that returns N sets…

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## [Error solving multiple JuMP models in parallel](https://discourse.julialang.org/t/error-solving-multiple-jump-models-in-parallel/3047)

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**Author:** [@FabsOliveira](https://discourse.julialang.org/u/FabsOliveira)\
**Replies:** 6\
**Last updated:** [April 9, 2017, 9:53am UTC](https://discourse.julialang.org/t/error-solving-multiple-jump-models-in-parallel/3047 "2017-04-09T09:53:44Z")

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Hi everyone, I’m struggling with an error that I can’t really understand. I am trying to solve several JuMP.Models in parallel as a step of a decomposition algorithm that can exploit a specific structure of my model. I…

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## [Advice about refactoring LinearFractional.jl for JuMP 0.19 and Julia 0.7](https://discourse.julialang.org/t/advice-about-refactoring-linearfractional-jl-for-jump-0-19-and-julia-0-7/12966)

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**Author:** [@ianfiske](https://discourse.julialang.org/u/ianfiske)\
**Replies:** 7\
**Last updated:** [June 21, 2019, 3:07pm UTC](https://discourse.julialang.org/t/advice-about-refactoring-linearfractional-jl-for-jump-0-19-and-julia-0-7/12966 "2019-06-21T15:07:29Z")

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A short while ago, I shared GitHub - nexteraanalytics/LinearFractional.jl: Linear fractional programming with Julia and JuMP for solving linear fractional programs with JuMP. I’m now looking into a big refactor to take …

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## [Givens matrix for an integer vector](https://discourse.julialang.org/t/givens-matrix-for-an-integer-vector/25520)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 6\
**Last updated:** [June 21, 2019, 2:23pm UTC](https://discourse.julialang.org/t/givens-matrix-for-an-integer-vector/25520 "2019-06-21T14:23:48Z")

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As a newcomer to Julia I am still struggling with various type-related issues. One of them is this: using LinearAlgebra julia\> x = \[3,4\] 2-element Array{Int64,1}: 3 4 julia\> G,r = givens(x,1,2) ERROR: MethodError: no…

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## [StatsPlots corrplot is not executing](https://discourse.julialang.org/t/statsplots-corrplot-is-not-executing/25524)

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**Author:** [@GdMacmillan](https://discourse.julialang.org/u/GdMacmillan)\
**Replies:** 2\
**Last updated:** [June 21, 2019, 1:53pm UTC](https://discourse.julialang.org/t/statsplots-corrplot-is-not-executing/25524 "2019-06-21T13:53:12Z")

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Interesting problem here. Perhaps this would be best written as an issue in the StatsPlots git repo so I’m here to find out I am running my work in a Jupyter notebook (v4.4), Julia 1.1.1 MacBook Pro (Retina, 13-inch, E…

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## [What is the future of WebIO, web-based GUIs?](https://discourse.julialang.org/t/what-is-the-future-of-webio-web-based-guis/9607)

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**Author:** [@jwikmark](https://discourse.julialang.org/u/jwikmark)\
**Replies:** 1\
**Last updated:** [March 9, 2018, 10:00pm UTC](https://discourse.julialang.org/t/what-is-the-future-of-webio-web-based-guis/9607 "2018-03-09T22:00:43Z")

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We’re building a small application that uses WebIO and I’m curious about the future of this package and its relatives (InteractNext etc), as well as the general state of tools to build web-based GUI applications in Julia…

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## [Montecarlo DAE](https://discourse.julialang.org/t/montecarlo-dae/25497)

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**Author:** [@alewolf](https://discourse.julialang.org/u/alewolf)\
**Replies:** 4\
**Last updated:** [June 21, 2019, 7:21am UTC](https://discourse.julialang.org/t/montecarlo-dae/25497 "2019-06-21T07:21:54Z")

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Hi everyone - I am having a little problem defining a montecarlo DAE problem with varying parameters - Any help would be appreciated. Here is toy example, comparinng standard correct solution and montecarlo results. …

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## [Towards a common Manifold Framework / Package](https://discourse.julialang.org/t/towards-a-common-manifold-framework-package/24910)

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**Author:** [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Replies:** 10\
**Last updated:** [June 21, 2019, 7:13am UTC](https://discourse.julialang.org/t/towards-a-common-manifold-framework-package/24910 "2019-06-21T07:13:29Z")

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Continuing the discussion from \[ANN\] Manopt.jl I would like to collect Ideas and approaches towards a common package that should be the base for “Things on manifolds”: Solving optimization problems (disclaimer, I am deve…

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## [Flux ready for a beginner deep learning project?](https://discourse.julialang.org/t/flux-ready-for-a-beginner-deep-learning-project/9262)

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**Author:** [@datnamer](https://discourse.julialang.org/u/datnamer)\
**Replies:** 31\
**Last updated:** [June 20, 2019, 10:59pm UTC](https://discourse.julialang.org/t/flux-ready-for-a-beginner-deep-learning-project/9262 "2019-06-20T22:59:05Z")

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Hi, I’m about to embark on a client facing Deep learning project where I’d need to get up to speed on some basic DL things and then start a research project within a couple of weeks or so. (they are aware of my curren…

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## [Pmap over data frame](https://discourse.julialang.org/t/pmap-over-data-frame/25432)

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**Author:** [@abx](https://discourse.julialang.org/u/abx)\
**Replies:** 1\
**Last updated:** [June 20, 2019, 6:18pm UTC](https://discourse.julialang.org/t/pmap-over-data-frame/25432 "2019-06-20T18:18:13Z")

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I am trying to pmap a function over a DataFrame, probably I am missing something really obvious. As per the example below, I would each DataFrameRow to be an element of the pmap, and each column value of the DataFrameRo…

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## [Retriving the Tableau from Gurobi](https://discourse.julialang.org/t/retriving-the-tableau-from-gurobi/25468)

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**Author:** [@rcallen24](https://discourse.julialang.org/u/rcallen24)\
**Replies:** 2\
**Last updated:** [June 20, 2019, 3:11pm UTC](https://discourse.julialang.org/t/retriving-the-tableau-from-gurobi/25468 "2019-06-20T15:11:33Z")

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I am trying to get the tableau from Gurobi and running into some problems. I went through the gurobi github and reference manual and was able to put this together but it is erroring out. # dummy model m = direct\_model(G…

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## [Predict impact locations of astroid 2006QV89](https://discourse.julialang.org/t/predict-impact-locations-of-astroid-2006qv89/25416)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 10\
**Last updated:** [June 20, 2019, 5:53am UTC](https://discourse.julialang.org/t/predict-impact-locations-of-astroid-2006qv89/25416 "2019-06-20T05:53:26Z")

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Could someone use Julia to predict what location on Earth would be affected if 2006QV89 impacts Earth? I imagine it would depend on the Earth’s daily rotation at the time. Please let me know if somebody can predict what…

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## [Estimate most probable value from data](https://discourse.julialang.org/t/estimate-most-probable-value-from-data/25451)

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**Author:** [@favba](https://discourse.julialang.org/u/favba)\
**Replies:** 7\
**Last updated:** [June 19, 2019, 9:33pm UTC](https://discourse.julialang.org/t/estimate-most-probable-value-from-data/25451 "2019-06-19T21:33:05Z")

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I have discrete data from a continuous field. The data probability distribution is not known, but it has only one peak value, what I guess is called “mode” of the pdf. The normalized histograms from the data look like s…

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## [Write out an animation incrementally](https://discourse.julialang.org/t/write-out-an-animation-incrementally/25410)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 12\
**Last updated:** [June 19, 2019, 5:05pm UTC](https://discourse.julialang.org/t/write-out-an-animation-incrementally/25410 "2019-06-19T17:05:02Z")

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Context Until now, I have been using the following approach to create animations: using Plots anim = Animation(); for it = 1:nt # Computations # ... # Visualization (e.g. every 10th time step) if mod(i…

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## [Mapslices causes an error with Flux and GPU arrays](https://discourse.julialang.org/t/mapslices-causes-an-error-with-flux-and-gpu-arrays/25448)

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**Author:** [@tanhevg](https://discourse.julialang.org/u/tanhevg)\
**Replies:** 2\
**Last updated:** [June 19, 2019, 3:46pm UTC](https://discourse.julialang.org/t/mapslices-causes-an-error-with-flux-and-gpu-arrays/25448 "2019-06-19T15:46:49Z")

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I wonder, if this is a known issue. Quick Google search has not revealed anything. using CuArrays, Flux f(x) = sum(mapslices(t-\>sqrt(sum(t.\*t)), x, dims=2)) df(x) = Tracker.gradient(f, x) x = rand(10, 10) |\> gpu df(x) E…

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## [How to pass the output of custom layers into Dense layer](https://discourse.julialang.org/t/how-to-pass-the-output-of-custom-layers-into-dense-layer/25421)

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**Author:** [@stu](https://discourse.julialang.org/u/stu)\
**Replies:** 1\
**Last updated:** [June 19, 2019, 2:16pm UTC](https://discourse.julialang.org/t/how-to-pass-the-output-of-custom-layers-into-dense-layer/25421 "2019-06-19T14:16:03Z")

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I am trying to do the following example: using Flux encoderA = Dense(10, 2) encoderB(x) = atan(x\[2\], x\[1\]) decoderA(x) = \[\[cos(x)\], \[sin(x)\]\] decoderB = Dense(2, 10) m1 = Chain(encoderA, encoderB, decoderA, decoderB) …

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## [How to make parallel subprocesses?](https://discourse.julialang.org/t/how-to-make-parallel-subprocesses/25005)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 6\
**Last updated:** [June 19, 2019, 10:56am UTC](https://discourse.julialang.org/t/how-to-make-parallel-subprocesses/25005 "2019-06-19T10:56:46Z")

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I am trying to create small subprocesses that would operate in parallel to my main process. In the example below I have 10 different agents that are callable and that generate some numbers. I am interested in saving thes…

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## [What datatypes can you pass into train!](https://discourse.julialang.org/t/what-datatypes-can-you-pass-into-train/25377)

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**Author:** [@stu](https://discourse.julialang.org/u/stu)\
**Replies:** 3\
**Last updated:** [June 18, 2019, 7:02pm UTC](https://discourse.julialang.org/t/what-datatypes-can-you-pass-into-train/25377 "2019-06-18T19:02:10Z")

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cannot find good documentation of this anywhere

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## [JuliaDB w/ Workers on Remote Machine](https://discourse.julialang.org/t/juliadb-w-workers-on-remote-machine/25412)

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**Author:** [@versipellis](https://discourse.julialang.org/u/versipellis)\
**Replies:** 2\
**Last updated:** [June 18, 2019, 6:25pm UTC](https://discourse.julialang.org/t/juliadb-w-workers-on-remote-machine/25412 "2019-06-18T18:25:36Z")

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I have a workflow set up right now where I want to use my laptop as the master process, with addprocs(machine\_spec) pointing to a remote machine I’m SSHing to (with Julia and all dependencies installed). The data is stor…

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## [JuMP: filtering the output of JuMP.value.(x)](https://discourse.julialang.org/t/jump-filtering-the-output-of-jump-value-x/25391)

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**Author:** [@PatrickHealy](https://discourse.julialang.org/u/PatrickHealy)\
**Replies:** 3\
**Last updated:** [June 18, 2019, 4:42pm UTC](https://discourse.julialang.org/t/jump-filtering-the-output-of-jump-value-x/25391 "2019-06-18T16:42:48Z")

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Is there a nice idiom for filtering all of the elements of a JuMP array of binaries that are set? Even with iterating over the elements of JuMP.value.(x) in a for-loop I don’t seem to be able to catch the indices in a u…

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## [JuMP v0.19 and CPLEX versions](https://discourse.julialang.org/t/jump-v0-19-and-cplex-versions/25253)

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**Author:** [@PatrickHealy](https://discourse.julialang.org/u/PatrickHealy)\
**Replies:** 5\
**Last updated:** [June 18, 2019, 2:09pm UTC](https://discourse.julialang.org/t/jump-v0-19-and-cplex-versions/25253 "2019-06-18T14:09:06Z")

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Greetings. While upgrading to julia 1.1.1 I thought it would be a good time to upgrade to JuMP 0.19. However, I could not add the CPLEX package (the executable and libraries could not be found) because CPLEX12.6 is not…

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## [Optimization using SAMIN()](https://discourse.julialang.org/t/optimization-using-samin/25351)

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**Author:** [@Farnazmdi](https://discourse.julialang.org/u/Farnazmdi)\
**Replies:** 10\
**Last updated:** [June 18, 2019, 10:00am UTC](https://discourse.julialang.org/t/optimization-using-samin/25351 "2019-06-18T10:00:31Z")

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Hi, I am trying to use SAMIN() for constrained optimization for a DDE parameter estimation, I have seen the example in \[Optim.jl\] and I am following the same syntax, but get the error of Dimension mismatch. resid is t…

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## [Method error for maxpool(x,(2,2))](https://discourse.julialang.org/t/method-error-for-maxpool-x-2-2/24693)

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**Author:** [@Don\_Burgess](https://discourse.julialang.org/u/Don_Burgess)\
**Replies:** 4\
**Last updated:** [June 18, 2019, 6:15am UTC](https://discourse.julialang.org/t/method-error-for-maxpool-x-2-2/24693 "2019-06-18T06:15:50Z")

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This call from a formerly work code seems to throw a method error: x → maxpool(x, (2,2)), ERROR: MethodError: no method matching maxpool(::TrackedArray{…,Array{Float32,4}}, ::Tuple{Int64,Int64}) ======= Has the inter…

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