# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=540

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**Page:** 541

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## [Is there interest in having a Julian API for the NCDC's Climate Data Online (CDO)](https://discourse.julialang.org/t/is-there-interest-in-having-a-julian-api-for-the-ncdcs-climate-data-online-cdo/9753)

<div class="topic-metadata">

**Author:** [@Nosferican](https://discourse.julialang.org/u/Nosferican)\
**Replies:** 26\
**Last updated:** [March 30, 2018, 5:34pm UTC](https://discourse.julialang.org/t/is-there-interest-in-having-a-julian-api-for-the-ncdcs-climate-data-online-cdo/9753 "2018-03-30T17:34:12Z")

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For my work, I have used the National Oceanic and Atmospheric Administration (NOAA) weather and climate data extensively. I have automated several pipelines using their API in R. There is also R’s opensci/rnoaa interface…

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## [Type of groupby(df,id) elements are Any](https://discourse.julialang.org/t/type-of-groupby-df-id-elements-are-any/9872)

<div class="topic-metadata">

**Author:** [@tbeason](https://discourse.julialang.org/u/tbeason)\
**Replies:** 6\
**Last updated:** [March 28, 2018, 10:59pm UTC](https://discourse.julialang.org/t/type-of-groupby-df-id-elements-are-any/9872 "2018-03-28T22:59:14Z")

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Can someone shed some light on this? I just don’t understand what is going wrong here. This is on DataFrames master and Julia v0.7 and v0.6.2. I don’t think this was an issue before. using DataFrames function sumall(df,…

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## [Problems When Compiling PyPlot in Julia](https://discourse.julialang.org/t/problems-when-compiling-pyplot-in-julia/10031)

<div class="topic-metadata">

**Author:** [@Ximo](https://discourse.julialang.org/u/Ximo)\
**Replies:** 7\
**Last updated:** [March 28, 2018, 9:27pm UTC](https://discourse.julialang.org/t/problems-when-compiling-pyplot-in-julia/10031 "2018-03-28T21:27:05Z")

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Hi, I am trying to use the PyPlot package on Ubuntu 16.04 which runs Julia 0.6. Julia fails to compile and throws the following error: Code executed: using PyPlot plot(rnm, spdup\_flop\_applyQ.(rnm), “b-”, rnm, st2m^2/…

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## [Ccall: could not find function \*\* in library /usr/local/cuda-7.0/lib64/libcusolver.so.7.0.28](https://discourse.julialang.org/t/ccall-could-not-find-function-in-library-usr-local-cuda-7-0-lib64-libcusolver-so-7-0-28/10009)

<div class="topic-metadata">

**Author:** [@cuchxq](https://discourse.julialang.org/u/cuchxq)\
**Replies:** 1\
**Last updated:** [March 28, 2018, 3:49pm UTC](https://discourse.julialang.org/t/ccall-could-not-find-function-in-library-usr-local-cuda-7-0-lib64-libcusolver-so-7-0-28/10009 "2018-03-28T15:49:33Z")

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Hi everyone, I am trying to use QR factorization to solve linear systems using CuArrays package. I am following this CUDA documentation (written in C) and I am trying to do it in Julia. I am using julia 0.6.0. Here is v…

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## [Can ImageViewer be used to display dynamically changing data?](https://discourse.julialang.org/t/can-imageviewer-be-used-to-display-dynamically-changing-data/10010)

<div class="topic-metadata">

**Author:** [@Phil\_Tomson](https://discourse.julialang.org/u/Phil_Tomson)\
**Replies:** 4\
**Last updated:** [March 28, 2018, 2:06am UTC](https://discourse.julialang.org/t/can-imageviewer-be-used-to-display-dynamically-changing-data/10010 "2018-03-28T02:06:48Z")

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Let’s say you’re training a neural net (for example) and you want to see how the results are looking after each epoch. You can do an imshow (from ImageViewer) on each epoch, but that’s going to open a new window, display…

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## [Cut generation not working lazy constraints - lagrangian relaxation](https://discourse.julialang.org/t/cut-generation-not-working-lazy-constraints-lagrangian-relaxation/9948)

<div class="topic-metadata">

**Author:** [@tlagos](https://discourse.julialang.org/u/tlagos)\
**Replies:** 6\
**Last updated:** [March 27, 2018, 9:54pm UTC](https://discourse.julialang.org/t/cut-generation-not-working-lazy-constraints-lagrangian-relaxation/9948 "2018-03-27T21:54:03Z")

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Hello, I have the following implementation to generate cuts for the Lagrangian relaxation problem for the shortest path with time constraints: \\max\_{\\lambda\\ge0} { L( \\lambda ) } X is a set of extreme points function s…

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## [Quadratic objective SDP](https://discourse.julialang.org/t/quadratic-objective-sdp/10003)

<div class="topic-metadata">

**Author:** [@migarstka](https://discourse.julialang.org/u/migarstka)\
**Replies:** 1\
**Last updated:** [March 27, 2018, 4:38pm UTC](https://discourse.julialang.org/t/quadratic-objective-sdp/10003 "2018-03-27T16:38:44Z")

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I want to solve the following problem using either JuMP or Convex: \\min\_x \\quad x^TPx+2q^Tx+q^TPq\\\\ \\text{s.t.} \\quad \\text{mat}\\{x\\} \\in \\mathcal{S}\_+^n , where x \\in \\mathbb{R}^{n^2} is the vectorized decision vari…

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## [Learning Plots... now: marker\_z?](https://discourse.julialang.org/t/learning-plots-now-marker-z/9996)

<div class="topic-metadata">

**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 6\
**Last updated:** [March 27, 2018, 12:33pm UTC](https://discourse.julialang.org/t/learning-plots-now-marker-z/9996 "2018-03-27T12:33:23Z")

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I’m trying to learn Plots, and now: the marker\_z keyword. With xm=randn(100); ym=randn(100); the following two commands (pyplot backend) give almost the same plots: scatter(xm,ym) plot(xm,ym, markershape=:circle,li…

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## [3D line plots?](https://discourse.julialang.org/t/3d-line-plots/9921)

<div class="topic-metadata">

**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 3\
**Last updated:** [March 27, 2018, 1:39am UTC](https://discourse.julialang.org/t/3d-line-plots/9921 "2018-03-27T01:39:24Z")

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Yesterday, March 22, I did a 3D line plot using Plots/PyPlot: x = linspace(-2π,2π) plot(x,sin.(x),cos.(x)) This worked fine. Today, I did Pkg.update(), and re-ran the code. Doesn’t work, and I get long error message… …

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## [PostgreSQL.jl no longer works in v0.6](https://discourse.julialang.org/t/postgresql-jl-no-longer-works-in-v0-6/4581)

<div class="topic-metadata">

**Author:** [@essenciary](https://discourse.julialang.org/u/essenciary)\
**Replies:** 27\
**Last updated:** [March 26, 2018, 4:05pm UTC](https://discourse.julialang.org/t/postgresql-jl-no-longer-works-in-v0-6/4581 "2018-03-26T16:05:44Z")

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Sadly, PostgreSQL.jl (https://github.com/JuliaDB/PostgreSQL.jl) has been lacking a maintainer for a year, and in Julia v0.6 is now dead as a dodo. I tried updating it in various occasions but in all honesty, low-level C…

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## [Problem with error reporting in Mocha](https://discourse.julialang.org/t/problem-with-error-reporting-in-mocha/9958)

<div class="topic-metadata">

**Author:** [@Alejandro](https://discourse.julialang.org/u/Alejandro)\
**Replies:** 3\
**Last updated:** [March 26, 2018, 2:46am UTC](https://discourse.julialang.org/t/problem-with-error-reporting-in-mocha/9958 "2018-03-26T02:46:51Z")

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Hello. My name is Alejandro, nice to meet you all. On to business… I am a total Machine Learning novice beyond the theoretical aspect though now it seems I need to get to work in some applications if I am to actually ma…

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## [Decide and queue when core is available?](https://discourse.julialang.org/t/decide-and-queue-when-core-is-available/9949)

<div class="topic-metadata">

**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 5\
**Last updated:** [March 25, 2018, 2:43am UTC](https://discourse.julialang.org/t/decide-and-queue-when-core-is-available/9949 "2018-03-25T02:43:14Z")

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dear julia experts—I would like to queue tasks onto open CPU cores until one of my tasks has happened to find the correct solution. then I want to be done. In particular, I need to know how my master waits for many sla…

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## [Problem in cloning or adding OpenCV.jl](https://discourse.julialang.org/t/problem-in-cloning-or-adding-opencv-jl/9945)

<div class="topic-metadata">

**Author:** [@tosalonijain](https://discourse.julialang.org/u/tosalonijain)\
**Replies:** 4\
**Last updated:** [March 24, 2018, 7:42pm UTC](https://discourse.julialang.org/t/problem-in-cloning-or-adding-opencv-jl/9945 "2018-03-24T19:42:40Z")

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julia\> Pkg.clone(“http://github.com/maxruby/OpenCV.jl”) INFO: Cloning OpenCV from http://github.com/maxruby/OpenCV.jl ERROR: OpenCV already exists Stacktrace: \[1\] clone(::String, ::SubString{String}) at ./pkg/entry.j…

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## [Quadratic Sieve and NFS factorization in Julia](https://discourse.julialang.org/t/quadratic-sieve-and-nfs-factorization-in-julia/9942)

<div class="topic-metadata">

**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 5\
**Last updated:** [March 24, 2018, 5:58pm UTC](https://discourse.julialang.org/t/quadratic-sieve-and-nfs-factorization-in-julia/9942 "2018-03-24T17:58:28Z")

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Hello. What’s the most advanced method used in primes.jl to factorize numbers? I’m looking for implementations of SIQS and NFS in Julia. I’ve only found this basic one of QS: https://github.com/hamukazu/quadratic\_sie…

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## [CUDAnative use multiple GPUs](https://discourse.julialang.org/t/cudanative-use-multiple-gpus/8274)

<div class="topic-metadata">

**Author:** [@fnoelscher](https://discourse.julialang.org/u/fnoelscher)\
**Replies:** 5\
**Last updated:** [March 24, 2018, 1:15pm UTC](https://discourse.julialang.org/t/cudanative-use-multiple-gpus/8274 "2018-03-24T13:15:32Z")

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Hi, I am using julia on docker from maleadt/juliagpu and I’d like to use multiple GPUs, instead of one. The docs mention this: dev = CuDevice(0) CuContext(dev) do ctx # allocate things in this context @cuda ..…

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## [Uses of packages: JuliaDB, ExcelReaders, ExcelFiles and SymPy](https://discourse.julialang.org/t/uses-of-packages-juliadb-excelreaders-excelfiles-and-sympy/9920)

<div class="topic-metadata">

**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 4\
**Last updated:** [March 23, 2018, 7:13pm UTC](https://discourse.julialang.org/t/uses-of-packages-juliadb-excelreaders-excelfiles-and-sympy/9920 "2018-03-23T19:13:04Z")

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Whenever I try to install packages like: JuliaDB, ExcelReaders, ExcelFiles and SymPy, the program shows this message in the console: GitError (Code: ENOTFOUND, Class: Repository, Could not find repository from ‘DocString…

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## [Gtk, get coordinates of keypress](https://discourse.julialang.org/t/gtk-get-coordinates-of-keypress/9923)

<div class="topic-metadata">

**Author:** [@Kurt\_Franke](https://discourse.julialang.org/u/Kurt_Franke)\
**Replies:** 1\
**Last updated:** [March 23, 2018, 4:53pm UTC](https://discourse.julialang.org/t/gtk-get-coordinates-of-keypress/9923 "2018-03-23T16:53:01Z")

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Hi, I’m trying to get a keypress to do something based on the mouse coordinate in a GtkCanvas widget. I can receive the keypress in the main GtkWindow, and I’d like to translate the coordinates with the library call gtk\_…

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## [ANN: Octo.jl: SQL Query DSL in Julia](https://discourse.julialang.org/t/ann-octo-jl-sql-query-dsl-in-julia/9912)

<div class="topic-metadata">

**Author:** [@wookyoung](https://discourse.julialang.org/u/wookyoung)\
**Replies:** 2\
**Last updated:** [March 23, 2018, 1:53pm UTC](https://discourse.julialang.org/t/ann-octo-jl-sql-query-dsl-in-julia/9912 "2018-03-23T13:53:06Z")

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Hi. this package requires at least Julia 0.7-DEV, but I think that it needs some tests before to register the package. visit here and play SQL. https://github.com/wookay/Octo.jl Before using Repo, please install kind…

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## [Status of @tranform altering columns in DataFramesMeta](https://discourse.julialang.org/t/status-of-tranform-altering-columns-in-dataframesmeta/9904)

<div class="topic-metadata">

**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 5\
**Last updated:** [March 22, 2018, 8:49pm UTC](https://discourse.julialang.org/t/status-of-tranform-altering-columns-in-dataframesmeta/9904 "2018-03-22T20:49:15Z")

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What is the status of altering a column that has already been altered in a @tranform block with DataFramesMeta? I have a dataframe with some messy descriptions in years and months in spanish, and I need to do some clean…

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## [Debugging, but code in conjugate gradient implementation. ](https://discourse.julialang.org/t/debugging-but-code-in-conjugate-gradient-implementation/9884)

<div class="topic-metadata">

**Author:** [@Marcom](https://discourse.julialang.org/u/Marcom)\
**Replies:** 4\
**Last updated:** [March 22, 2018, 1:14pm UTC](https://discourse.julialang.org/t/debugging-but-code-in-conjugate-gradient-implementation/9884 "2018-03-22T13:14:51Z")

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Not sure this is the right place, but there seems to be an issue with how Julia is interpreting the inputs of a function. I am certain my code is correct as far as implementation of the problem statement. However, I keep…

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## [Using Julia with @parallel pmap or blank makes no difference in speed.](https://discourse.julialang.org/t/using-julia-with-parallel-pmap-or-blank-makes-no-difference-in-speed/9885)

<div class="topic-metadata">

**Author:** [@Tillie](https://discourse.julialang.org/u/Tillie)\
**Replies:** 3\
**Last updated:** [March 22, 2018, 1:08pm UTC](https://discourse.julialang.org/t/using-julia-with-parallel-pmap-or-blank-makes-no-difference-in-speed/9885 "2018-03-22T13:08:23Z")

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Hi, the follwoing three test examples are minmal examples of my code. I do not understand why the speed is always the same. Moreover, Julia seems to use only one core. The whole CPU usage is only around 30%. If I us…

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## [Cross-correlation function in Julia vs. Python](https://discourse.julialang.org/t/cross-correlation-function-in-julia-vs-python/7573)

<div class="topic-metadata">

**Author:** [@Duls91](https://discourse.julialang.org/u/Duls91)\
**Replies:** 12\
**Last updated:** [March 21, 2018, 7:29pm UTC](https://discourse.julialang.org/t/cross-correlation-function-in-julia-vs-python/7573 "2018-03-21T19:29:49Z")

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Hi there, I am new to Julia. I want to perform a cross-correlation with two 2d arrays (both 5X5). Using crosscor() (StatsBase.jl) returns a 9x5x5 array. What I would like is the cross-correlation matrix of dims M+N-1, s…

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## [Looking for guidance - signal processing team](https://discourse.julialang.org/t/looking-for-guidance-signal-processing-team/9855)

<div class="topic-metadata">

**Author:** [@sirtom67](https://discourse.julialang.org/u/sirtom67)\
**Replies:** 1\
**Last updated:** [March 21, 2018, 11:44am UTC](https://discourse.julialang.org/t/looking-for-guidance-signal-processing-team/9855 "2018-03-21T11:44:58Z")

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Anyone interested in helping contribute to the DSP.jl project? I could use some help and guidance on how to contribute. The “esprit” function that I added this week finds the frequencies of sinusoidal signals: https://…

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## [distributed-memory QR / TSQR / linear algebra](https://discourse.julialang.org/t/distributed-memory-qr-tsqr-linear-algebra/9849)

<div class="topic-metadata">

**Author:** [@nychiang](https://discourse.julialang.org/u/nychiang)\
**Replies:** 1\
**Last updated:** [March 20, 2018, 11:39pm UTC](https://discourse.julialang.org/t/distributed-memory-qr-tsqr-linear-algebra/9849 "2018-03-20T23:39:40Z")

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I’m looking for a distributed-memory parallel TSQR (tall and skinny QR) factorization package in Julia. However, it seems that there is no such implementation inside Julia, and what I can do is the following: — use MPI…

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## [\[ANN\] JDBC.jl Rejuvenated](https://discourse.julialang.org/t/ann-jdbc-jl-rejuvenated/9827)

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**Author:** [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)\
**Replies:** 3\
**Last updated:** [March 20, 2018, 2:01pm UTC](https://discourse.julialang.org/t/ann-jdbc-jl-rejuvenated/9827 "2018-03-20T14:01:48Z")

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Announcing JDBC.jl v0.3.0. This should provide you with a quick-and-easy way to get access to your databases with a Julia API almost immediately. It is very easy to get your data into a dataframe, for example using JD…

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## [Stepsize control in ODEProblem](https://discourse.julialang.org/t/stepsize-control-in-odeproblem/9772)

<div class="topic-metadata">

**Author:** [@fedxa](https://discourse.julialang.org/u/fedxa)\
**Replies:** 11\
**Last updated:** [March 19, 2018, 1:31am UTC](https://discourse.julialang.org/t/stepsize-control-in-odeproblem/9772 "2018-03-19T01:31:29Z")

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Hello, I have a system of ODE, which is rather heterogeneous. That is one equation corresponds to some background property of a system, and then there are many (say, hundred) equations for individual evolution of compo…

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## [Solving a model and its modified copy](https://discourse.julialang.org/t/solving-a-model-and-its-modified-copy/9778)

<div class="topic-metadata">

**Author:** [@varun7rs](https://discourse.julialang.org/u/varun7rs)\
**Replies:** 2\
**Last updated:** [March 18, 2018, 7:30pm UTC](https://discourse.julialang.org/t/solving-a-model-and-its-modified-copy/9778 "2018-03-18T19:30:08Z")

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As a follow-up to IainNZ’s comments on issue #399, I’ve slightly modified the code to experiment with variable fixings. While I only intend to fix variables of the object r, the fixings are applied to object p as well. I…

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## [CUDAnative ERROR: could not load library "libjulia.exe"](https://discourse.julialang.org/t/cudanative-error-could-not-load-library-libjulia-exe/9781)

<div class="topic-metadata">

**Author:** [@Luxemecongineer](https://discourse.julialang.org/u/Luxemecongineer)\
**Replies:** 3\
**Last updated:** [March 18, 2018, 6:35pm UTC](https://discourse.julialang.org/t/cudanative-error-could-not-load-library-libjulia-exe/9781 "2018-03-18T18:35:03Z")

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I have passed tests of LLVM and CUDAdrv (non-documentation tests). But Pkg.test(“CUDAnative”) fails for ERROR: LoadError: could not load library "libjulia.exe" The specified module could not be found. Please, let me kn…

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## [BigFloat precision issue](https://discourse.julialang.org/t/bigfloat-precision-issue/9786)

<div class="topic-metadata">

**Author:** [@vepiteski](https://discourse.julialang.org/u/vepiteski)\
**Replies:** 4\
**Last updated:** [March 18, 2018, 5:12pm UTC](https://discourse.julialang.org/t/bigfloat-precision-issue/9786 "2018-03-18T17:12:44Z")

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julia\> N=BigFloat(2.0,2048); julia\> S=sqrt(N); julia\> S^2-N -1.727233711018888925077270372560079914223200072887256277004740694033718360632485e-77 julia\> S.prec 256 julia\> N.prec 2048 Why only 256 precision from t…

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## [ANN: Docker image for CUDA packages](https://discourse.julialang.org/t/ann-docker-image-for-cuda-packages/5792)

<div class="topic-metadata">

**Author:** [@maleadt](https://discourse.julialang.org/u/maleadt)\
**Replies:** 10\
**Last updated:** [March 18, 2018, 9:27am UTC](https://discourse.julialang.org/t/ann-docker-image-for-cuda-packages/5792 "2018-03-18T09:27:38Z")

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Hi all, Many JuliaGPU packages are pretty hard to install, so I’ve been working a little on a Docker image which comes with some CUDA packages preinstalled: maleadt/juliagpu, requiring nvidia-docker: $ docker pull male…

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