# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=524

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**Page:** 525

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## [InitError with PyPlot on Julia 1.0.1](https://discourse.julialang.org/t/initerror-with-pyplot-on-julia-1-0-1/15792)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 1\
**Last updated:** [October 2, 2018, 8:34pm UTC](https://discourse.julialang.org/t/initerror-with-pyplot-on-julia-1-0-1/15792 "2018-10-02T20:34:00Z")

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I posted this https://github.com/JuliaPy/PyPlot.jl/issues/394 in case it’s a genuine issue, but since upgrading to 1.0.1, something has changed and my PyPlot module generates a stack trace (see the link).

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## [Does anyone know how to retrieve the number of generated cuts in the informational callback?](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370)

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**Author:** [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Replies:** 9\
**Last updated:** [October 2, 2018, 9:44am UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370 "2018-10-02T09:44:40Z")

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Hi, I would like to retrieve the information contained at the end of the Gurobi log (the summary section MIP Logging) In particular, I am interested in saving the number of cuts applied to my MIP (MIP\_CUTCNT : http://w…

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## [Announce: A different way to read JSON data, LazyJSON.jl](https://discourse.julialang.org/t/announce-a-different-way-to-read-json-data-lazyjson-jl/9046)

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**Author:** [@samoconnor](https://discourse.julialang.org/u/samoconnor)\
**Replies:** 19\
**Last updated:** [October 2, 2018, 2:07am UTC](https://discourse.julialang.org/t/announce-a-different-way-to-read-json-data-lazyjson-jl/9046 "2018-10-02T02:07:34Z")

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LazyJSON.jl implements yet another a different way of reading JSON data in Julia. I wrote this as a proof of concept and it is probably not production ready, but if you work with JSON data in a performance sensitive appl…

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## [CSV.write() to Unix Pipe (e.g., lz4 or bzip2)](https://discourse.julialang.org/t/csv-write-to-unix-pipe-e-g-lz4-or-bzip2/15759)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 6\
**Last updated:** [October 1, 2018, 11:32pm UTC](https://discourse.julialang.org/t/csv-write-to-unix-pipe-e-g-lz4-or-bzip2/15759 "2018-10-01T23:32:43Z")

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I am wondering whether CSV.write() can write to a different non-gzip compressor. julia\> using DataFrames, CSV julia\> textbz2= open("test.txt.bz2", "w") IOStream(\<file test.txt.bz2\>) julia\> open( \`bzip2 -c\`, "w", text…

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## [Memory Allocation of Channel Buffers of type Array](https://discourse.julialang.org/t/memory-allocation-of-channel-buffers-of-type-array/15655)

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**Author:** [@rohanmclure](https://discourse.julialang.org/u/rohanmclure)\
**Replies:** 0\
**Last updated:** [September 29, 2018, 7:55am UTC](https://discourse.julialang.org/t/memory-allocation-of-channel-buffers-of-type-array/15655 "2018-09-29T07:55:27Z")

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I have distributed workers wishing to perform an in-place distributed transpose. In this particular example, each worker has access to a ‘column block’ of a dense matrix, and workers must send off-diagonal sections of th…

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## [Is post deleted deleted deleted](https://discourse.julialang.org/t/is-post-deleted-deleted-deleted/15746)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 0\
**Last updated:** [October 1, 2018, 5:36pm UTC](https://discourse.julialang.org/t/is-post-deleted-deleted-deleted/15746 "2018-10-01T17:36:57Z")

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deleted deleteddeleteddeleteddeleted

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## [Knet 1.1.1 is out: performance improvements, new monitoring tools, new gpu memory manager](https://discourse.julialang.org/t/knet-1-1-1-is-out-performance-improvements-new-monitoring-tools-new-gpu-memory-manager/15745)

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**Author:** [@denizyuret](https://discourse.julialang.org/u/denizyuret)\
**Replies:** 0\
**Last updated:** [October 1, 2018, 5:20pm UTC](https://discourse.julialang.org/t/knet-1-1-1-is-out-performance-improvements-new-monitoring-tools-new-gpu-memory-manager/15745 "2018-10-01T17:20:27Z")

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Knet 1.1.0 introduced the new interface allowing the use of structs in models and callable objects for model / layer definitions. Knet 1.1.1 focuses on performance. There is a number of performance improvements the most…

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## [Row wise operations in DataFrames](https://discourse.julialang.org/t/row-wise-operations-in-dataframes/15682)

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**Author:** [@cosmia](https://discourse.julialang.org/u/cosmia)\
**Replies:** 3\
**Last updated:** [September 30, 2018, 7:29pm UTC](https://discourse.julialang.org/t/row-wise-operations-in-dataframes/15682 "2018-09-30T19:29:24Z")

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Hey guys, I have a very big DataFrame, where I want to do row wise linear algebra operations if certain conditions are met. What i need is that for every row, check if column (variable) is 1 or 0, and for each case, do …

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## [Problem with unzippig file and reading it with CSV](https://discourse.julialang.org/t/problem-with-unzippig-file-and-reading-it-with-csv/15645)

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**Author:** [@alejandromerchan](https://discourse.julialang.org/u/alejandromerchan)\
**Replies:** 2\
**Last updated:** [September 29, 2018, 5:35am UTC](https://discourse.julialang.org/t/problem-with-unzippig-file-and-reading-it-with-csv/15645 "2018-09-29T05:35:57Z")

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I’m having issues now with a code that was working before and will appreciate any help to solve this, because despite some comments from @quinnj on the Slack, I still haven’t been able to figure it out. I’m downloading …

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## [When solving non-diagonal noise SDE: Function g called twice in each timestep, changing u inbetween?](https://discourse.julialang.org/t/when-solving-non-diagonal-noise-sde-function-g-called-twice-in-each-timestep-changing-u-inbetween/15618)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 2\
**Last updated:** [September 28, 2018, 9:39pm UTC](https://discourse.julialang.org/t/when-solving-non-diagonal-noise-sde-function-g-called-twice-in-each-timestep-changing-u-inbetween/15618 "2018-09-28T21:39:23Z")

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In short: When making solving SDEs the noise function seems to be called twice in every timestep, with the variable values being changed in between. This causes out of domain errors when my positive\_domain callback canno…

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## [Convert external to internal indexing in PowerModels.jl](https://discourse.julialang.org/t/convert-external-to-internal-indexing-in-powermodels-jl/15630)

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**Author:** [@Rasoul](https://discourse.julialang.org/u/Rasoul)\
**Replies:** 1\
**Last updated:** [September 28, 2018, 7:49pm UTC](https://discourse.julialang.org/t/convert-external-to-internal-indexing-in-powermodels-jl/15630 "2018-09-28T19:49:52Z")

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Some Matpower test systems have their own indexing feature (e.g., nesta\_case73\_ieee\_rts) in which bus indexing is not compatible with actual bus number. Matpower has provided the ext2int script which converts the test ca…

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## [\[JuMP\] Sectionwise definition of matrix with @expression](https://discourse.julialang.org/t/jump-sectionwise-definition-of-matrix-with-expression/15639)

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**Author:** [@korpuskel](https://discourse.julialang.org/u/korpuskel)\
**Replies:** 0\
**Last updated:** [September 28, 2018, 7:21pm UTC](https://discourse.julialang.org/t/jump-sectionwise-definition-of-matrix-with-expression/15639 "2018-09-28T19:21:52Z")

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I need to define an expression/variable that resembles a matrix. This matrix is defined sectionwise, so I tried: @expression(m, O\[b=1:n, i=1:n, j=1:n\], 0) @expression(m, O\[b=1:n, i=n+1, j=1:n\], 0.5T\_i\[b\]\[j\]) @expres…

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## [Generic code, iterative methods and automatic differentiation](https://discourse.julialang.org/t/generic-code-iterative-methods-and-automatic-differentiation/15528)

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**Author:** [@Bernard\_GODARD](https://discourse.julialang.org/u/Bernard_GODARD)\
**Replies:** 3\
**Last updated:** [September 28, 2018, 4:37pm UTC](https://discourse.julialang.org/t/generic-code-iterative-methods-and-automatic-differentiation/15528 "2018-09-28T16:37:08Z")

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In Julia it is quite easy to write generic code that can be used with many numbers type (eg BigFloat) or many automatic differentiation algorithms. However if this code contains some iterative parts eg such as: find t s…

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## [How to set series colors from parameter?](https://discourse.julialang.org/t/how-to-set-series-colors-from-parameter/15582)

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**Author:** [@martinzh](https://discourse.julialang.org/u/martinzh)\
**Replies:** 2\
**Last updated:** [September 28, 2018, 4:16pm UTC](https://discourse.julialang.org/t/how-to-set-series-colors-from-parameter/15582 "2018-09-28T16:16:35Z")

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I’m plotting different series (from the columns in a 2D Array) and I would like to set the color of each series according to a parameter. In the example, I would like to set the color of the line at the bottom to the bla…

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## [Anyone can help explain about these statements?](https://discourse.julialang.org/t/anyone-can-help-explain-about-these-statements/15545)

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**Author:** [@LeoK987](https://discourse.julialang.org/u/LeoK987)\
**Replies:** 12\
**Last updated:** [September 28, 2018, 1:25am UTC](https://discourse.julialang.org/t/anyone-can-help-explain-about-these-statements/15545 "2018-09-28T01:25:05Z")

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I am trying to find out an issue that causes julia to freeze when my large script uses with new releases of CSV and Tables. I tried to cook up simple demo code but none could reproduce the issue. So I tried to dig into…

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## [Nobs() -\> Float or Int?](https://discourse.julialang.org/t/nobs-float-or-int/15485)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 5\
**Last updated:** [September 27, 2018, 4:28pm UTC](https://discourse.julialang.org/t/nobs-float-or-int/15485 "2018-09-27T16:28:26Z")

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minor question: shouldn’t nobs() return an integer for a GLM lm model? julia\> y= \[1:10;\] ; X= hcat( fill(1,10), y.^2, y.^3 ); julia\> nobs( GLM.lm(X,y) ) 10.0 are there cases where this can become a fraction?

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## [How does the future of ParallelAccelerator look like?](https://discourse.julialang.org/t/how-does-the-future-of-parallelaccelerator-look-like/15510)

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**Author:** [@MiguelGoncalves](https://discourse.julialang.org/u/MiguelGoncalves)\
**Replies:** 3\
**Last updated:** [September 27, 2018, 9:36am UTC](https://discourse.julialang.org/t/how-does-the-future-of-parallelaccelerator-look-like/15510 "2018-09-27T09:36:25Z")

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It seems I cannot add ParallelAccelerator to Julia 1.0 because it requires version 0.6. That being said, the last commit to the package is from October 2017. Are there any plans for: making the package compatible with …

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## [Memory usage in JuMP model](https://discourse.julialang.org/t/memory-usage-in-jump-model/15475)

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**Author:** [@Reza](https://discourse.julialang.org/u/Reza)\
**Replies:** 1\
**Last updated:** [September 27, 2018, 2:54am UTC](https://discourse.julialang.org/t/memory-usage-in-jump-model/15475 "2018-09-27T02:54:52Z")

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Hi I am using JuMP model calling CPLEX 12.6 solver for my problem. My problem is like that I am running a loop and at each iteration, I am solving a convex optimization problem by calling CPLEX in JuMP. At each iteratio…

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## [Getting variable values in PowerModels.jl](https://discourse.julialang.org/t/getting-variable-values-in-powermodels-jl/15192)

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**Author:** [@Rasoul](https://discourse.julialang.org/u/Rasoul)\
**Replies:** 20\
**Last updated:** [September 26, 2018, 11:39pm UTC](https://discourse.julialang.org/t/getting-variable-values-in-powermodels-jl/15192 "2018-09-26T23:39:48Z")

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Does anyone know how I can get the value of the lifted variables (e.g., \_td) in PowerModels.jl? Thanks in advance!

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## [Vtk.js for web visualization](https://discourse.julialang.org/t/vtk-js-for-web-visualization/15497)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 2\
**Last updated:** [September 26, 2018, 2:21pm UTC](https://discourse.julialang.org/t/vtk-js-for-web-visualization/15497 "2018-09-26T14:21:37Z")

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I recently saw itk-vtk-viewer ITK/VTK Image Viewer is a Web based viewer for loading 2D/3D images and more… Looks like there has been activity in writing VTK files with Julia, but it stalled a year ago. Is the philosop…

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## [Optim.jl returns \`Stopped by an increasing objective: true\`](https://discourse.julialang.org/t/optim-jl-returns-stopped-by-an-increasing-objective-true/15428)

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**Author:** [@gasagna](https://discourse.julialang.org/u/gasagna)\
**Replies:** 5\
**Last updated:** [September 26, 2018, 11:54am UTC](https://discourse.julialang.org/t/optim-jl-returns-stopped-by-an-increasing-objective-true/15428 "2018-09-26T11:54:56Z")

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Hi, Under exactly what conditions does optimize in Optim.jl return Stopped by an increasing objective: true? I have a fairly complicated optimisation problem using LBFGS which terminates at some point with this stateme…

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## [Why does RemoteChannel have few constructors.](https://discourse.julialang.org/t/why-does-remotechannel-have-few-constructors/15502)

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**Author:** [@YonghyunRyu](https://discourse.julialang.org/u/YonghyunRyu)\
**Replies:** 1\
**Last updated:** [September 26, 2018, 9:30am UTC](https://discourse.julialang.org/t/why-does-remotechannel-have-few-constructors/15502 "2018-09-26T09:30:49Z")

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The constructor that creates a RemoteChannel with a specific size and type requires a function as the first argument like RemoteChannel(()-\>Channel{Int}(10), pid). Using lambda functions as parameters is inconvenient be…

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## [Data spread over multiple files](https://discourse.julialang.org/t/data-spread-over-multiple-files/15464)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 3\
**Last updated:** [September 26, 2018, 4:55am UTC](https://discourse.julialang.org/t/data-spread-over-multiple-files/15464 "2018-09-26T04:55:45Z")

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Hi, I would like to ask, if someone has dealt in principle manner with problem, where the data for machine learning is spread over several files. I have once defined an iterator, which takes loadfunction and list of fi…

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## [Unexpected behavior of Flux.jl](https://discourse.julialang.org/t/unexpected-behavior-of-flux-jl/15460)

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**Author:** [@jling](https://discourse.julialang.org/u/jling)\
**Replies:** 0\
**Last updated:** [September 25, 2018, 9:21am UTC](https://discourse.julialang.org/t/unexpected-behavior-of-flux-jl/15460 "2018-09-25T09:21:39Z")

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julia\> f(x) = 3x^2 + 2x +1 f (generic function with 1 method) julia\> Tracker.gradient(f,-2) ERROR: DomainError with log: -2.0 will only return a complex Is this documented somewhere and I’m missing it?

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## [Trouble understanding rem\_pio2\_kernel](https://discourse.julialang.org/t/trouble-understanding-rem-pio2-kernel/15409)

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**Author:** [@dpsanders](https://discourse.julialang.org/u/dpsanders)\
**Replies:** 2\
**Last updated:** [September 24, 2018, 4:21pm UTC](https://discourse.julialang.org/t/trouble-understanding-rem-pio2-kernel/15409 "2018-09-24T16:21:31Z")

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I’m having trouble understanding Base.Math.rem\_pio2\_kernel. Consider the following: julia\> const rempio2 = Base.Math.rem\_pio2\_kernel rem\_pio2\_kernel (generic function with 2 methods) julia\> rempio2(0.0) (-1, Base.Math…

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## [HTTP and MbedTLS installation issues](https://discourse.julialang.org/t/http-and-mbedtls-installation-issues/15422)

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**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 1\
**Last updated:** [September 24, 2018, 1:30pm UTC](https://discourse.julialang.org/t/http-and-mbedtls-installation-issues/15422 "2018-09-24T13:30:14Z")

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I have some code requiring HTTP (and thus MbedTLS) which I need to run on a Linux machine with glib 2.12. I had to pin the MbedTLS version to 0.6.1 because of some glib incompatibilities (https://github.com/JuliaWeb/Mbe…

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## [Changing font style for latex rendering using PyPlot](https://discourse.julialang.org/t/changing-font-style-for-latex-rendering-using-pyplot/5910)

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**Author:** [@josimar](https://discourse.julialang.org/u/josimar)\
**Replies:** 11\
**Last updated:** [September 23, 2018, 6:36pm UTC](https://discourse.julialang.org/t/changing-font-style-for-latex-rendering-using-pyplot/5910 "2018-09-23T18:36:40Z")

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Hi all, I am trying to make plots, using PyPlot, that have latex equations. Does anyone know how to change the font of the default latex render in PyPlot ? Right now I am using the following: PyPlot.matplotlib\[:rc\]("te…

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## [Julia/Knet deep learning tutorial available with free GPUs from Google Colab](https://discourse.julialang.org/t/julia-knet-deep-learning-tutorial-available-with-free-gpus-from-google-colab/15352)

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**Author:** [@denizyuret](https://discourse.julialang.org/u/denizyuret)\
**Replies:** 6\
**Last updated:** [September 23, 2018, 3:29pm UTC](https://discourse.julialang.org/t/julia-knet-deep-learning-tutorial-available-with-free-gpus-from-google-colab/15352 "2018-09-23T15:29:53Z")

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To try it out, please follow the instructions at https://github.com/denizyuret/Knet.jl/tree/dy/1.1/tutorial and let me know if anything does not work. Thanks @jekbradbury for figuring this out.

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## [Support for Sparse Matrices on GPU (CUSPARSE)](https://discourse.julialang.org/t/support-for-sparse-matrices-on-gpu-cusparse/15294)

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**Author:** [@mboratko](https://discourse.julialang.org/u/mboratko)\
**Replies:** 1\
**Last updated:** [September 22, 2018, 4:34pm UTC](https://discourse.julialang.org/t/support-for-sparse-matrices-on-gpu-cusparse/15294 "2018-09-22T16:34:17Z")

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Do any of the ML libraries (Flux, KNet) support sparse matrices on the GPU?

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## [Makie coloring of surface plots](https://discourse.julialang.org/t/makie-coloring-of-surface-plots/15298)

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**Author:** [@lwhitefox](https://discourse.julialang.org/u/lwhitefox)\
**Replies:** 2\
**Last updated:** [September 22, 2018, 2:30pm UTC](https://discourse.julialang.org/t/makie-coloring-of-surface-plots/15298 "2018-09-22T14:30:16Z")

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My understanding is that when generating surface plots in Makie, colors are assigned per vertex. I’m surprised that when I run the small sample code below, which assigns one color value for each vertex in a 4 by 3 set o…

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