# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=518

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**Page:** 519

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## [GLPK + Homebrew erros - Not properly installed / Key "10.14" not found / Build errors](https://discourse.julialang.org/t/glpk-homebrew-erros-not-properly-installed-key-10-14-not-found-build-errors/17439)

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**Author:** [@miqlliot](https://discourse.julialang.org/u/miqlliot)\
**Replies:** 4\
**Last updated:** [November 13, 2018, 5:04pm UTC](https://discourse.julialang.org/t/glpk-homebrew-erros-not-properly-installed-key-10-14-not-found-build-errors/17439 "2018-11-13T17:04:23Z")

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Hi, I am using Julia for my Operations Research studies, but have struggled for over 3 months getting it running locally and have to use the online JuliaBox service. I have now managed to finally get the atom-integratio…

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## [Reinforcement learning with A\* and a deep heuristic](https://discourse.julialang.org/t/reinforcement-learning-with-a-and-a-deep-heuristic/17480)

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**Author:** [@skariel](https://discourse.julialang.org/u/skariel)\
**Replies:** 0\
**Last updated:** [November 13, 2018, 3:29pm UTC](https://discourse.julialang.org/t/reinforcement-learning-with-a-and-a-deep-heuristic/17480 "2018-11-13T15:29:17Z")

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100% Julia - see paper here: https://github.com/imagry/aleph\_star/blob/master/paper/aleph\_star.pdf and code here: https://github.com/imagry/aleph\_star now the real reason I’m writing this here is since I need help wi…

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## [\`scatter\` plots and marker colors -- change?](https://discourse.julialang.org/t/scatter-plots-and-marker-colors-change/17456)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 8\
**Last updated:** [November 13, 2018, 11:57am UTC](https://discourse.julialang.org/t/scatter-plots-and-marker-colors-change/17456 "2018-11-13T11:57:59Z")

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I get this strange warning when using scatter under Julia v. 1.0.2: julia\> scatter(rand(10)) 'c' argument looks like a single numeric RGB or RGBA sequence, which should be avoided as value-mapp ing will have precedence …

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## [SharedDict for multiple processes?](https://discourse.julialang.org/t/shareddict-for-multiple-processes/17447)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 1\
**Last updated:** [November 12, 2018, 8:08pm UTC](https://discourse.julialang.org/t/shareddict-for-multiple-processes/17447 "2018-11-12T20:08:56Z")

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I am doing a bunch of distributed long calculations and I want to write results to a Dict. Is there a way for multiple Julia processes to share a Dict (with write access)? I don’t care if writing to the Dict in this wa…

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## [Alternative to DataFrame Readtable to read large data files with headers](https://discourse.julialang.org/t/alternative-to-dataframe-readtable-to-read-large-data-files-with-headers/15095)

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**Author:** [@astrowanders](https://discourse.julialang.org/u/astrowanders)\
**Replies:** 17\
**Last updated:** [November 12, 2018, 7:30pm UTC](https://discourse.julialang.org/t/alternative-to-dataframe-readtable-to-read-large-data-files-with-headers/15095 "2018-11-12T19:30:47Z")

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Hello! I’ve been using Julia to work with output from a stellar evolution code. My data files have several columns (~60 or more) and hundreds of rows. In previous versions of Julia, I used readtable in the DataFrame pac…

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## [How to draw heatmap with DataFrames](https://discourse.julialang.org/t/how-to-draw-heatmap-with-dataframes/15321)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 3\
**Last updated:** [November 12, 2018, 7:20pm UTC](https://discourse.julialang.org/t/how-to-draw-heatmap-with-dataframes/15321 "2018-11-12T19:20:02Z")

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Let’s say I have a data frame like this, how do I make a heatmap? I’m already using StatPlots so that would be the preferred way. I tried to look up documentation but couldn’t find it… data = DataFrame( src = \["Lo…

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## [Query.jl @group DataFrame by AbstractType gives Method Error](https://discourse.julialang.org/t/query-jl-group-dataframe-by-abstracttype-gives-method-error/15501)

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**Author:** [@JonasIsensee](https://discourse.julialang.org/u/JonasIsensee)\
**Replies:** 1\
**Last updated:** [November 12, 2018, 7:16pm UTC](https://discourse.julialang.org/t/query-jl-group-dataframe-by-abstracttype-gives-method-error/15501 "2018-11-12T19:16:03Z")

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Hey there, I noticed that it is not possible to @group by an abstract typed column and I’m wondering if this is deliberately so or just a bug. julia\> df = DataFrame(foo=Real\[\]) 0×1 DataFrame julia\> push!(df, Dict(:f…

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## [Moore-Penrose Generalized Inverse of Sparse Matrix](https://discourse.julialang.org/t/moore-penrose-generalized-inverse-of-sparse-matrix/17414)

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**Author:** [@Paul\_McVay](https://discourse.julialang.org/u/Paul_McVay)\
**Replies:** 2\
**Last updated:** [November 12, 2018, 3:01am UTC](https://discourse.julialang.org/t/moore-penrose-generalized-inverse-of-sparse-matrix/17414 "2018-11-12T03:01:46Z")

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Is there any package that provides a function to calculate a generalized inverse of a sparse matrix? I know the LinearAlgebra package provides pinv and the SparseArrays provides capabilities for the creation of sparse ma…

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## [Is there a GLMM package?](https://discourse.julialang.org/t/is-there-a-glmm-package/8655)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 9\
**Last updated:** [November 12, 2018, 2:40pm UTC](https://discourse.julialang.org/t/is-there-a-glmm-package/8655 "2018-11-12T14:40:58Z")

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There is a mixed-effects model package and a generalized linear model package. But is there a package for Generalized linear mixed model (something like R’s glmm package)?

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## [Coloring Different Areas under a Normal Distribution based on X axis](https://discourse.julialang.org/t/coloring-different-areas-under-a-normal-distribution-based-on-x-axis/17412)

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**Author:** [@cjkinni](https://discourse.julialang.org/u/cjkinni)\
**Replies:** 2\
**Last updated:** [November 12, 2018, 2:31pm UTC](https://discourse.julialang.org/t/coloring-different-areas-under-a-normal-distribution-based-on-x-axis/17412 "2018-11-12T14:31:51Z")

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I am trying to achieve results like those below. I am able to get a normal distribution that’s somewhat broken up with vertical bars: 𝜇=1500 𝜎=300 plot(Normal(𝜇,𝜎), title="Normal Distribution N($(𝜇),$(𝜎))", lw=3, label…

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## [How to set the diagonal part of a GPU Array](https://discourse.julialang.org/t/how-to-set-the-diagonal-part-of-a-gpu-array/16975)

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**Author:** [@1115](https://discourse.julialang.org/u/1115)\
**Replies:** 6\
**Last updated:** [November 12, 2018, 1:13pm UTC](https://discourse.julialang.org/t/how-to-set-the-diagonal-part-of-a-gpu-array/16975 "2018-11-12T13:13:36Z")

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Let’s see the code julia\> using CuArrays; julia\> s 4-element CuArray{Float32,1}: 3.2211537 2.1344962 0.7451281 0.3308171 julia\> v 4×4 CuArray{Float32,2}: 0.267688 0.355418 -0.311468 -0.839648 -0.156514 0.…

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## [Is the MAT package going to be updated to version 1.0?](https://discourse.julialang.org/t/is-the-mat-package-going-to-be-updated-to-version-1-0/16525)

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**Author:** [@Evian](https://discourse.julialang.org/u/Evian)\
**Replies:** 3\
**Last updated:** [November 12, 2018, 1:13pm UTC](https://discourse.julialang.org/t/is-the-mat-package-going-to-be-updated-to-version-1-0/16525 "2018-11-12T13:13:30Z")

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HDF5, which depends on, has already been updated but not the MAT package…

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## [Align X axis of heatmap and line plot](https://discourse.julialang.org/t/align-x-axis-of-heatmap-and-line-plot/17421)

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**Author:** [@Donut\_Meepo](https://discourse.julialang.org/u/Donut_Meepo)\
**Replies:** 1\
**Last updated:** [November 12, 2018, 6:58am UTC](https://discourse.julialang.org/t/align-x-axis-of-heatmap-and-line-plot/17421 "2018-11-12T06:58:36Z")

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Hi, I am trying to make subplots of heatmap and line plot. I want to get a square and larger heatmap on top of the thin line plot that are aligned with x axis. The image I attached is what I can get so far. I was tryin…

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## [Solve standard continuous relaxation of model in v0.19-alpha](https://discourse.julialang.org/t/solve-standard-continuous-relaxation-of-model-in-v0-19-alpha/17416)

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**Author:** [@vtjeng](https://discourse.julialang.org/u/vtjeng)\
**Replies:** 1\
**Last updated:** [November 12, 2018, 3:33am UTC](https://discourse.julialang.org/t/solve-standard-continuous-relaxation-of-model-in-v0-19-alpha/17416 "2018-11-12T03:33:42Z")

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JuMP (up to 0.18.4) allowed you to pass the keyword relaxation=True to solve the standard relaxation of a model (for example, onw with integer constraints). JuMP.jl/NEWS.md at 4b04d34fac5af2494611d972c24095d3ecbc20e8 · j…

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## [Performance of view with cuArrays](https://discourse.julialang.org/t/performance-of-view-with-cuarrays/17387)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 11\
**Last updated:** [November 11, 2018, 9:09pm UTC](https://discourse.julialang.org/t/performance-of-view-with-cuarrays/17387 "2018-11-11T21:09:42Z")

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Hi, Let x and y be 2 3D arrays of Float32 with size (200,200,200) I would like to perform the following operation y\[i,:,:\]=x\[i+1,:,:\]-x\[i,:,:\] for i in \[1:199\] I have implement this in a function that can be called b…

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## [Is is possible to merge multiple kernels in CUDAnative to minimize launch overhead and execution overhead?](https://discourse.julialang.org/t/is-is-possible-to-merge-multiple-kernels-in-cudanative-to-minimize-launch-overhead-and-execution-overhead/17139)

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**Author:** [@1115](https://discourse.julialang.org/u/1115)\
**Replies:** 12\
**Last updated:** [November 11, 2018, 3:19pm UTC](https://discourse.julialang.org/t/is-is-possible-to-merge-multiple-kernels-in-cudanative-to-minimize-launch-overhead-and-execution-overhead/17139 "2018-11-11T15:19:24Z")

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I defined several inplace operations on a vector, but the overhead is significant. julia\> using CuArrays, CUDAnative, LinearAlgebra, BenchmarkTools julia\> function ms1!(X::CuArray, a, b, c) function kernel(X…

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## [Adding a new variable to an existing variable array](https://discourse.julialang.org/t/adding-a-new-variable-to-an-existing-variable-array/17390)

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**Author:** [@borelian](https://discourse.julialang.org/u/borelian)\
**Replies:** 1\
**Last updated:** [November 10, 2018, 7:42pm UTC](https://discourse.julialang.org/t/adding-a-new-variable-to-an-existing-variable-array/17390 "2018-11-10T19:42:04Z")

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Hi. I’m teaching Column Generation on Jump. Hence, given a set of columns x\[1:N\] I’ll like add a new variable x\[N+1\] to the previous variable set. If I try @defVar(master, x\[N+1\]\>=0, objective=1) JUMP assumes that I…

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## [Natural Language Processing: where do I start?](https://discourse.julialang.org/t/natural-language-processing-where-do-i-start/15509)

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**Author:** [@johann.spies](https://discourse.julialang.org/u/johann.spies)\
**Replies:** 3\
**Last updated:** [November 10, 2018, 10:09am UTC](https://discourse.julialang.org/t/natural-language-processing-where-do-i-start/15509 "2018-11-10T10:09:27Z")

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I do not know enough about machine learning to ask an informed question. I am not even sure whether this a Machine Learning question. Maybe. I will tell you what I want to achieve in the end: In short we want to clas…

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## [Knet vs Flux etc](https://discourse.julialang.org/t/knet-vs-flux-etc/17057)

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**Author:** [@denizyuret](https://discourse.julialang.org/u/denizyuret)\
**Replies:** 10\
**Last updated:** [November 9, 2018, 3:33pm UTC](https://discourse.julialang.org/t/knet-vs-flux-etc/17057 "2018-11-09T15:33:30Z")

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We have a rich collection of AD, GPU and ML tools and it may be useful to have common benchmarks to find performance bottlenecks, share optimization tricks and push them forward. I started fiddling around in Klutz.jl, so…

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## [Optim and complex numbers: InexactError thrown](https://discourse.julialang.org/t/optim-and-complex-numbers-inexacterror-thrown/17338)

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**Author:** [@axelle](https://discourse.julialang.org/u/axelle)\
**Replies:** 8\
**Last updated:** [November 9, 2018, 1:56pm UTC](https://discourse.julialang.org/t/optim-and-complex-numbers-inexacterror-thrown/17338 "2018-11-09T13:56:00Z")

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Good morning, I encounter some issues when some complex numbers arise in my optimisation. I think it might be due to my function u(c) = c^gamma where sometimes c turns out negative (c being different expressions defined…

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## [Left matrix division with singular matrix](https://discourse.julialang.org/t/left-matrix-division-with-singular-matrix/15503)

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**Author:** [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)\
**Replies:** 8\
**Last updated:** [November 9, 2018, 1:45pm UTC](https://discourse.julialang.org/t/left-matrix-division-with-singular-matrix/15503 "2018-11-09T13:45:22Z")

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I am confused by the result of a left matrix division (the backslash operator, documented in Base.:\\ at Linear Algebra · The Julia Language) in the case of a singular matrix: julia\> \[1.0 0; 0 0\] \\ randn(2) 2-element Arr…

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## [Great news for Dynamics in Julia!](https://discourse.julialang.org/t/great-news-for-dynamics-in-julia/17321)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 1\
**Last updated:** [November 8, 2018, 8:18pm UTC](https://discourse.julialang.org/t/great-news-for-dynamics-in-julia/17321 "2018-11-08T20:18:16Z")

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Hello everyone, Since I don’t have a blog, this is like an announcement of shorts for JuliaDynamics. I bear good news :slight\_smile: DSWeb prize Pretty much everyone is aware of this, but I just want to apologize for n…

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## [Makie: rotating HyperRectangles?](https://discourse.julialang.org/t/makie-rotating-hyperrectangles/17194)

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**Author:** [@kmhaeren](https://discourse.julialang.org/u/kmhaeren)\
**Replies:** 5\
**Last updated:** [November 8, 2018, 5:36pm UTC](https://discourse.julialang.org/t/makie-rotating-hyperrectangles/17194 "2018-11-08T17:36:21Z")

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Hi For my masters thesis I’m trying to write a very basic physics engine, and since Makie is the only package that seems to do graphics in Julia, I want to use it to handle the visualisation of simple moving objects i…

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## [\[JuMP\] Is it possible to switch solver version back and forth? (e.g. Gurobi 7.5 \<-\> 8.0)](https://discourse.julialang.org/t/jump-is-it-possible-to-switch-solver-version-back-and-forth-e-g-gurobi-7-5-8-0/10932)

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**Author:** [@SingingKim](https://discourse.julialang.org/u/SingingKim)\
**Replies:** 5\
**Last updated:** [November 8, 2018, 2:39pm UTC](https://discourse.julialang.org/t/jump-is-it-possible-to-switch-solver-version-back-and-forth-e-g-gurobi-7-5-8-0/10932 "2018-11-08T14:39:00Z")

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Is it possible to switch solver version back and forth? (e.g. Gurobi 7.5 ↔ 8.0) Also, is there any command to display Solver version that I am using on Julia? using JuMP, Gurobi m = Model(solver = GurobiSolver()) @vari…

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## [Fminbox and linesearch issues for box constrained optimization](https://discourse.julialang.org/t/fminbox-and-linesearch-issues-for-box-constrained-optimization/17273)

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**Author:** [@axelle](https://discourse.julialang.org/u/axelle)\
**Replies:** 3\
**Last updated:** [November 8, 2018, 11:41am UTC](https://discourse.julialang.org/t/fminbox-and-linesearch-issues-for-box-constrained-optimization/17273 "2018-11-08T11:41:18Z")

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Good afternoon, I cannot figure out the right syntax for a box constrained optimization but where i need to change the line search as I was getting an error: ArgumentError: Value and slope at step length = 0 must be fin…

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## [Plotting Phase Portrait](https://discourse.julialang.org/t/plotting-phase-portrait/17250)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 1\
**Last updated:** [November 7, 2018, 2:24pm UTC](https://discourse.julialang.org/t/plotting-phase-portrait/17250 "2018-11-07T14:24:39Z")

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Give I have some function (two dimensional), representing some differential equation. How do I point a corresponding phase portrait? (in each point in some grid, plot an arrow corresponding to the direction of movement …

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## [CovarianceMatrices stderr()](https://discourse.julialang.org/t/covariancematrices-stderr/17216)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 2\
**Last updated:** [November 6, 2018, 7:09pm UTC](https://discourse.julialang.org/t/covariancematrices-stderr/17216 "2018-11-06T19:09:33Z")

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this is a minor headscratcher: julia\> using GLM, CovarianceMatrices julia\> yb= \[1.0:10.0;\]; df= DataFrame( y=yb, x1= yb.^2, x2= yb.^3 ); julia\> mylm= glm( @formula(y~x1+x2), df, Normal(), IdentityLink()); julia\> vcov…

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## [JSON Performance Tests](https://discourse.julialang.org/t/json-performance-tests/17133)

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**Author:** [@samoconnor](https://discourse.julialang.org/u/samoconnor)\
**Replies:** 7\
**Last updated:** [November 6, 2018, 6:09am UTC](https://discourse.julialang.org/t/json-performance-tests/17133 "2018-11-06T06:09:10Z")

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I noticed that @kristoffer.carlsson has been working on parsing performance in JSON.jl: A few performance improvements by KristofferC · Pull Request #263 · JuliaIO/JSON.jl · GitHub … and it got me thinking. When I firs…

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## [Geometric ray tracing](https://discourse.julialang.org/t/geometric-ray-tracing/17182)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 2\
**Last updated:** [November 5, 2018, 10:40pm UTC](https://discourse.julialang.org/t/geometric-ray-tracing/17182 "2018-11-05T22:40:55Z")

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Is there anyone out there that is both semi-versed in geometric ray tracing and wants to write a good ray tracing library? To be clear, I’m not talking about ray tracing in graphics but more about ray tracing in physics,…

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## [GraphIO and MetaGraphs](https://discourse.julialang.org/t/graphio-and-metagraphs/17048)

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**Author:** [@cdsousa](https://discourse.julialang.org/u/cdsousa)\
**Replies:** 3\
**Last updated:** [November 5, 2018, 5:42pm UTC](https://discourse.julialang.org/t/graphio-and-metagraphs/17048 "2018-11-05T17:42:57Z")

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Hi, Is it possible to save (and load) MetaGraphs graphs to common formats while maintaining the metadata?

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