# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=511

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**Page:** 512

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## [Get rid of a JuMP model](https://discourse.julialang.org/t/get-rid-of-a-jump-model/19721)

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**Author:** [@Rasoul](https://discourse.julialang.org/u/Rasoul)\
**Replies:** 4\
**Last updated:** [January 16, 2019, 11:05pm UTC](https://discourse.julialang.org/t/get-rid-of-a-jump-model/19721 "2019-01-16T23:05:49Z")

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Hi All, I have a function in my code that builds a model and solve it and return the result. I have to call this function repeatedly. Although my code works properly I get the following warning after calling the functio…

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## [MPI.jl: Functions for cartesian process topology](https://discourse.julialang.org/t/mpi-jl-functions-for-cartesian-process-topology/19437)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 3\
**Last updated:** [January 21, 2019, 8:20am UTC](https://discourse.julialang.org/t/mpi-jl-functions-for-cartesian-process-topology/19437 "2019-01-21T08:20:21Z")

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Hi all, I cannot find any functions to create and use a cartesian process topology on the list of supported functions on the github page of MPI.jl. In particular, I am missing the functions: MPI\_Dims\_create MPI\_Cart\_c…

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## [JuliaDB: How to modify multiple existing columns with setcol using functions](https://discourse.julialang.org/t/juliadb-how-to-modify-multiple-existing-columns-with-setcol-using-functions/19847)

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**Author:** [@pazzo83](https://discourse.julialang.org/u/pazzo83)\
**Replies:** 1\
**Last updated:** [January 20, 2019, 10:13pm UTC](https://discourse.julialang.org/t/juliadb-how-to-modify-multiple-existing-columns-with-setcol-using-functions/19847 "2019-01-20T22:13:48Z")

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Hi, I am trying to modify several existing columns with one call to setcol using functions. Essentially I have a table where i need to divide 4 of the columns by 10 to get the proper value. I know this is the proper sy…

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## [A uniform way to generate a random element based on a given probability distritution function, a random number genarator and a given element interval?](https://discourse.julialang.org/t/a-uniform-way-to-generate-a-random-element-based-on-a-given-probability-distritution-function-a-random-number-genarator-and-a-given-element-interval/19843)

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**Author:** [@bsnyh](https://discourse.julialang.org/u/bsnyh)\
**Replies:** 1\
**Last updated:** [January 20, 2019, 3:18pm UTC](https://discourse.julialang.org/t/a-uniform-way-to-generate-a-random-element-based-on-a-given-probability-distritution-function-a-random-number-genarator-and-a-given-element-interval/19843 "2019-01-20T15:18:17Z")

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Dispatching is one of Julia’s strong suits. I was wondering, is there a single function which would generate a random element based on a given probability distribution function, a random number genarator and a given ele…

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## [Extend SparseMatrixCSC interface (nzrange - rowvals - nonzeros) to views of sparse matrices](https://discourse.julialang.org/t/extend-sparsematrixcsc-interface-nzrange-rowvals-nonzeros-to-views-of-sparse-matrices/19837)

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**Author:** [@klacru](https://discourse.julialang.org/u/klacru)\
**Replies:** 0\
**Last updated:** [January 20, 2019, 10:23am UTC](https://discourse.julialang.org/t/extend-sparsematrixcsc-interface-nzrange-rowvals-nonzeros-to-views-of-sparse-matrices/19837 "2019-01-20T10:23:47Z")

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I want to extend the nzrange - rowvals - nonzeros interface from SparseMatrixCSC to views of sparse matrices. That would allow to re-formulate many of the standard algorithms for SparseMatrixCSC and extend them to the vi…

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## [Reading huge csv files](https://discourse.julialang.org/t/reading-huge-csv-files/15924)

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**Author:** [@jayce\_ram](https://discourse.julialang.org/u/jayce_ram)\
**Replies:** 5\
**Last updated:** [January 19, 2019, 10:52pm UTC](https://discourse.julialang.org/t/reading-huge-csv-files/15924 "2019-01-19T22:52:29Z")

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I would like to read a huge csv file around 9G and apply filters to the rows in order to build another dataframe carrying only the values I want to. I have installed the pack DataBase and I have just tried the simple com…

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## [Different syntax for MixedModels? What's the difference?](https://discourse.julialang.org/t/different-syntax-for-mixedmodels-whats-the-difference/19754)

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**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 2\
**Last updated:** [January 19, 2019, 11:07am UTC](https://discourse.julialang.org/t/different-syntax-for-mixedmodels-whats-the-difference/19754 "2019-01-19T11:07:22Z")

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Hello. I would like to use MixedModels.jl to fit regression models with random effects. Looking at the official docs and some examples on the Internet I’ve found different syntaxes. For example if I want to fit a Logi…

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## [\[ANN\] MOID.jl and VSOP87.jl](https://discourse.julialang.org/t/ann-moid-jl-and-vsop87-jl/19785)

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**Author:** [@mkretlow](https://discourse.julialang.org/u/mkretlow)\
**Replies:** 0\
**Last updated:** [January 18, 2019, 2:14pm UTC](https://discourse.julialang.org/t/ann-moid-jl-and-vsop87-jl/19785 "2019-01-18T14:14:22Z")

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Hello Julians. I like to announce two packages: https://github.com/mkretlow/MOID.jl and https://github.com/mkretlow/VSOP87.jl MOID.jl computes the Minimum Orbit Intersection Distance (MOID) for two given confocal, el…

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## [Flux.jl - Best way to do efficient division by a parameter.](https://discourse.julialang.org/t/flux-jl-best-way-to-do-efficient-division-by-a-parameter/19773)

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**Author:** [@JJB](https://discourse.julialang.org/u/JJB)\
**Replies:** 0\
**Last updated:** [January 18, 2019, 8:16am UTC](https://discourse.julialang.org/t/flux-jl-best-way-to-do-efficient-division-by-a-parameter/19773 "2019-01-18T08:16:22Z")

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The following function evaluation: function OneDiv(x) return 1.0 ./ x end @code\_warntype OneDiv(Flux.param(\[0.1\])) Compiles to: Body::Any 1 ─ %1 = (Core.tuple)(1.0, x)::Tuple{Float64,TrackedArray{…,Array{Float64,…

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## [MPI.jl - Different behaviors using MPIManager and mpirun](https://discourse.julialang.org/t/mpi-jl-different-behaviors-using-mpimanager-and-mpirun/19758)

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**Author:** [@jalving](https://discourse.julialang.org/u/jalving)\
**Replies:** 0\
**Last updated:** [January 17, 2019, 8:01pm UTC](https://discourse.julialang.org/t/mpi-jl-different-behaviors-using-mpimanager-and-mpirun/19758 "2019-01-17T20:01:39Z")

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I’m getting some interesting behavior using the MPIManager with a parallel optimization solver and I’m trying to rule out whether the MPIManager is doing something different than just using MPI.Init() and running with my…

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## [Memoizing finite horizon dynamic programming](https://discourse.julialang.org/t/memoizing-finite-horizon-dynamic-programming/19731)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 1\
**Last updated:** [January 17, 2019, 5:49am UTC](https://discourse.julialang.org/t/memoizing-finite-horizon-dynamic-programming/19731 "2019-01-17T05:49:08Z")

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So I am trying to program a simple finite horizon dynamic programming problem. I’m trying to use memoization to speed-up computation time. using Optim V2dict = Dict() function V2(t, K) if t \>= T return 0.…

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## [Error of view on CuArrays with discrete indices](https://discourse.julialang.org/t/error-of-view-on-cuarrays-with-discrete-indices/19730)

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**Author:** [@findmyway](https://discourse.julialang.org/u/findmyway)\
**Replies:** 0\
**Last updated:** [January 17, 2019, 4:29am UTC](https://discourse.julialang.org/t/error-of-view-on-cuarrays-with-discrete-indices/19730 "2019-01-17T04:29:31Z")

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It seems that I can’t pass discrete indices (\[1,2,1\]) with view. I test the following code on both master and v0.9.0. Is there any workaround? julia\> xs = randn(3,3) 3×3 Array{Float64,2}: 1.37316 -0.378109 0.90757…

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## [CuArray dot fuction error](https://discourse.julialang.org/t/cuarray-dot-fuction-error/19532)

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**Author:** [@jianghaizhu](https://discourse.julialang.org/u/jianghaizhu)\
**Replies:** 2\
**Last updated:** [January 16, 2019, 6:22pm UTC](https://discourse.julialang.org/t/cuarray-dot-fuction-error/19532 "2019-01-16T18:22:08Z")

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I am playing around some code to run on GPU. I encountered the following error. Here is a MWE. julia\> B = rand(100, 100, 2) julia\> B\_g = cu(B) julia\> B\_gv = reshape(B\_g, 10000, 2) julia\> dot(view(B\_g, :, :, 1), view(B…

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## [Mopdify OBBT in PowerModels.jl to be applicable on model constructor in PowerModelsAnnex](https://discourse.julialang.org/t/mopdify-obbt-in-powermodels-jl-to-be-applicable-on-model-constructor-in-powermodelsannex/19047)

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**Author:** [@Rasoul](https://discourse.julialang.org/u/Rasoul)\
**Replies:** 6\
**Last updated:** [January 16, 2019, 4:04pm UTC](https://discourse.julialang.org/t/mopdify-obbt-in-powermodels-jl-to-be-applicable-on-model-constructor-in-powermodelsannex/19047 "2019-01-16T16:04:05Z")

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Hi All, I have developed a new model constructor in PowerModelsAnnex and want to apply the OBBT.jl in PowerModels to the model. Can you please guide me how can I do that? In other words, is it possible to call the model…

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## [Using Juniper with Pyomo](https://discourse.julialang.org/t/using-juniper-with-pyomo/19694)

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**Author:** [@Utkarsh\_Konge](https://discourse.julialang.org/u/Utkarsh_Konge)\
**Replies:** 3\
**Last updated:** [January 16, 2019, 3:23pm UTC](https://discourse.julialang.org/t/using-juniper-with-pyomo/19694 "2019-01-16T15:23:06Z")

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I want to know whether is there a way to use Juniper to solve optimization models generated by Pyomo. Pyomo can generate model file (problem.lp or problem.nl) which can be passed to some solvers. Does Juniper have such f…

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## [When to use SVD and when to use Eigendecomposition for PCA?](https://discourse.julialang.org/t/when-to-use-svd-and-when-to-use-eigendecomposition-for-pca/19689)

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**Author:** [@gdkrmr](https://discourse.julialang.org/u/gdkrmr)\
**Replies:** 5\
**Last updated:** [January 16, 2019, 2:14pm UTC](https://discourse.julialang.org/t/when-to-use-svd-and-when-to-use-eigendecomposition-for-pca/19689 "2019-01-16T14:14:07Z")

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As a long time R user I was always under the impression that SVD is superior to and eigenvalue decomposition of the correlation matrix (see the documentation for prcomp and princomp) in terms of numerical accuracy and co…

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## [Error after updating packages](https://discourse.julialang.org/t/error-after-updating-packages/19660)

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**Author:** [@muriloasouza](https://discourse.julialang.org/u/muriloasouza)\
**Replies:** 9\
**Last updated:** [January 16, 2019, 9:07am UTC](https://discourse.julialang.org/t/error-after-updating-packages/19660 "2019-01-16T09:07:06Z")

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I got this error today after updating my packages: WARNING: Couldn't initialize gr. (might need to install it?) INFO: To do a standard install of gr, copy and run this: Pkg.add("GR") Pkg.build("GR") ERROR: LoadError…

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## [ERROR: MethodError: no method matching pin(::String, ::VersionNumber)](https://discourse.julialang.org/t/error-methoderror-no-method-matching-pin-string-versionnumber/19672)

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**Author:** [@bsnyh](https://discourse.julialang.org/u/bsnyh)\
**Replies:** 5\
**Last updated:** [January 16, 2019, 8:57am UTC](https://discourse.julialang.org/t/error-methoderror-no-method-matching-pin-string-versionnumber/19672 "2019-01-16T08:57:58Z")

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I was using Julia 0.7 to install a package JEMSS.jl from this link: https://github.com/uoa-ems-research/JEMSS.jl During the process, I need to use the Julia 0.6 command “Pkg.pin( “GDAL”, v"0.1.2” )" But when I tried i…

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## [Subplots in Plots.jl with separate legend](https://discourse.julialang.org/t/subplots-in-plots-jl-with-separate-legend/1968)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 12\
**Last updated:** [January 15, 2019, 4:59pm UTC](https://discourse.julialang.org/t/subplots-in-plots-jl-with-separate-legend/1968 "2019-01-15T16:59:23Z")

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I am plotting 20+ timeseries with various scales from a DataFrame using Plots.jl, separated into subplots because the original plot is too crowded. Everything works nicely, but I would like a separate legend (with only t…

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## [Problem in installing SPICE.jl](https://discourse.julialang.org/t/problem-in-installing-spice-jl/19657)

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**Author:** [@theeJoker](https://discourse.julialang.org/u/theeJoker)\
**Replies:** 0\
**Last updated:** [January 15, 2019, 2:08pm UTC](https://discourse.julialang.org/t/problem-in-installing-spice-jl/19657 "2019-01-15T14:08:55Z")

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It has been two days since I am trying to install SPICE.jl but got no luck. I have tried it on Julia 1.0 I am getting the error ERROR: Unsatisfiable requirements detected for package Requests \[df88083b\]: \*\* Requests …

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## [Question about Flux.jl data inputs](https://discourse.julialang.org/t/question-about-flux-jl-data-inputs/19630)

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**Author:** [@zjroth](https://discourse.julialang.org/u/zjroth)\
**Replies:** 1\
**Last updated:** [January 15, 2019, 1:27pm UTC](https://discourse.julialang.org/t/question-about-flux-jl-data-inputs/19630 "2019-01-15T13:27:01Z")

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I’m playing around with Flux.jl, and I came across an error that I have some questions about. With a Dense layer, I can provide a matrix input in which each column represents a single input value. Additionally, the num…

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## [Help on convex quadratic IP with cut generation](https://discourse.julialang.org/t/help-on-convex-quadratic-ip-with-cut-generation/19650)

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**Author:** [@WangQuanmeng](https://discourse.julialang.org/u/WangQuanmeng)\
**Replies:** 3\
**Last updated:** [January 15, 2019, 12:33pm UTC](https://discourse.julialang.org/t/help-on-convex-quadratic-ip-with-cut-generation/19650 "2019-01-15T12:33:10Z")

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Hi, I am solving a convex quadratic integer programming problem, min f( x , y ) s.t. Ax + By \<= b y being integral vector where f is a convex quadratic function. I have a set of valid inequalites for the feasib…

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## [Efficiency when handling jobs larger than VRAM](https://discourse.julialang.org/t/efficiency-when-handling-jobs-larger-than-vram/19570)

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**Author:** [@wsphillips](https://discourse.julialang.org/u/wsphillips)\
**Replies:** 3\
**Last updated:** [January 15, 2019, 7:08am UTC](https://discourse.julialang.org/t/efficiency-when-handling-jobs-larger-than-vram/19570 "2019-01-15T07:08:37Z")

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Hi! GPGPU beginner here using the CUDAnative/CuArrays stack (Thank you @maleadt for this amazing work) I am hoping to find some help regarding efficiently transferring data to and from host/device when handling input an…

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## [Odd Mux.jl + Interact.jl behavior: widget only works in "/" but not pages within such as "/page1"](https://discourse.julialang.org/t/odd-mux-jl-interact-jl-behavior-widget-only-works-in-but-not-pages-within-such-as-page1/18723)

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**Author:** [@amckay1](https://discourse.julialang.org/u/amckay1)\
**Replies:** 2\
**Last updated:** [January 15, 2019, 5:47am UTC](https://discourse.julialang.org/t/odd-mux-jl-interact-jl-behavior-widget-only-works-in-but-not-pages-within-such-as-page1/18723 "2019-01-15T05:47:49Z")

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I swear this was working fine a couple weeks ago and I didn’t think I upgraded anything, but I put together this example code that does not work the way I would expect. The same Interact.jl widget, when accessed from app…

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## ["Fancy" matrix variable transformations in TransformVariables.jl / DynamicHMC.jl](https://discourse.julialang.org/t/fancy-matrix-variable-transformations-in-transformvariables-jl-dynamichmc-jl/19618)

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**Author:** [@hessammehr](https://discourse.julialang.org/u/hessammehr)\
**Replies:** 2\
**Last updated:** [January 14, 2019, 1:22pm UTC](https://discourse.julialang.org/t/fancy-matrix-variable-transformations-in-transformvariables-jl-dynamichmc-jl/19618 "2019-01-14T13:22:32Z")

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Lately I’ve been using @Tamas\_Papp’s excellent DynamicHMC package (thank you, Tamas!) and it’s been a lot of fun, but was hoping someone could point me in the right direction with a few more esoteric variable transformat…

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## [Plotting .mat data](https://discourse.julialang.org/t/plotting-mat-data/19600)

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**Author:** [@svpillai](https://discourse.julialang.org/u/svpillai)\
**Replies:** 6\
**Last updated:** [January 14, 2019, 10:18am UTC](https://discourse.julialang.org/t/plotting-mat-data/19600 "2019-01-14T10:18:50Z")

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I have a .mat file that I’ve opened using Matlab.jl with read\_matfile(filename) (is there a better way/command to load .mat data on to Julia?), and I need to plot certain rows of the .mat file. How do I do so? using Plot…

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## [Fastest plot backend for Interact + Mux](https://discourse.julialang.org/t/fastest-plot-backend-for-interact-mux/19349)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 13\
**Last updated:** [January 13, 2019, 7:07pm UTC](https://discourse.julialang.org/t/fastest-plot-backend-for-interact-mux/19349 "2019-01-13T19:07:52Z")

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I am experimenting with Interact.jl for teaching (interactively exploring implications of a macroeconomic model). I also have no clue about web technologies. The idea is to have model parameters as sliders, solve and si…

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## [How to deal with sparse Jacobians?](https://discourse.julialang.org/t/how-to-deal-with-sparse-jacobians/19561)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 13\
**Last updated:** [January 13, 2019, 10:06am UTC](https://discourse.julialang.org/t/how-to-deal-with-sparse-jacobians/19561 "2019-01-13T10:06:05Z")

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I believe I’ve been solving large and sparse linear systems most of my career, both as the end solution of a problem or in the calculation of non-linear least-squares iterations. I imagine a lot of people share my experi…

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## [How to sample vector of independent Bernoulli variables efficiently?](https://discourse.julialang.org/t/how-to-sample-vector-of-independent-bernoulli-variables-efficiently/19563)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 4\
**Last updated:** [January 12, 2019, 11:10pm UTC](https://discourse.julialang.org/t/how-to-sample-vector-of-independent-bernoulli-variables-efficiently/19563 "2019-01-12T23:10:06Z")

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Hi, everyone. I am trying to perform disorder averaging over different realizations of a lattice with some of the nodes randomly thrown away. Specifically, consider the following model: we have a lattice (graph) with N…

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## [TensorFlow test failing - my config?](https://discourse.julialang.org/t/tensorflow-test-failing-my-config/19463)

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**Author:** [@Colin\_Beckingham](https://discourse.julialang.org/u/Colin_Beckingham)\
**Replies:** 1\
**Last updated:** [January 12, 2019, 11:00am UTC](https://discourse.julialang.org/t/tensorflow-test-failing-my-config/19463 "2019-01-12T11:00:58Z")

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I updated my custom libtensorflow.so with bazel and I think everything went well, but test TF is failing in Julia so I wonder if the following is correct? pip is updated, Python has latest. Error on test begins with: E…

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