# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=530

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**Page:** 531

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## [Performance of Optim.jl vs. Matlab's fminunc](https://discourse.julialang.org/t/performance-of-optim-jl-vs-matlabs-fminunc/12866)

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**Author:** [@tyleransom](https://discourse.julialang.org/u/tyleransom)\
**Replies:** 12\
**Last updated:** [August 6, 2018, 11:43am UTC](https://discourse.julialang.org/t/performance-of-optim-jl-vs-matlabs-fminunc/12866 "2018-08-06T11:43:54Z")

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I’ve been comparing the performance of Optim.jl with Matlab’s fminunc. Surprisingly, Optim’s L-BFGS algorithm doesn’t always beat fminunc. I was wondering if anyone knows why this might be. Here’s the set up: Use a si…

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## [Julia interface to Bullet Physics?](https://discourse.julialang.org/t/julia-interface-to-bullet-physics/12617)

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**Author:** [@jbrea](https://discourse.julialang.org/u/jbrea)\
**Replies:** 19\
**Last updated:** [August 6, 2018, 8:42am UTC](https://discourse.julialang.org/t/julia-interface-to-bullet-physics/12617 "2018-08-06T08:42:49Z")

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I came across the Bullet Physics SDK and was impressed by the rich collection of examples. Now I wonder: Is anybody interested in a Julia interface to the Bullet Physics SDK? Did somebody already start working on this? …

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## [Blink webserver](https://discourse.julialang.org/t/blink-webserver/12832)

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**Author:** [@Raf](https://discourse.julialang.org/u/Raf)\
**Replies:** 4\
**Last updated:** [August 6, 2018, 2:53am UTC](https://discourse.julialang.org/t/blink-webserver/12832 "2018-08-06T02:53:44Z")

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So I have Blink.jl running electron locally, with widgets, plotting and simulation visuals etc. But I’d like to run it on a server. Apparently Blink facilitates using Mux to serve a simple app: “Pages may be served over…

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## [Julia Plots.jl: changing marker colour from series recipe](https://discourse.julialang.org/t/julia-plots-jl-changing-marker-colour-from-series-recipe/12914)

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**Author:** [@tanhevg](https://discourse.julialang.org/u/tanhevg)\
**Replies:** 3\
**Last updated:** [August 5, 2018, 7:06pm UTC](https://discourse.julialang.org/t/julia-plots-jl-changing-marker-colour-from-series-recipe/12914 "2018-08-05T19:06:05Z")

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I am trying to put together a Plots.jl user recipe, that would create several scatter plots and histograms arranged in a grid. The scatter plots should occupy the lower triangle of the grid. Histograms go on the diagon…

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## [Should ::SVD \\ ::Vector fall back on pinv?](https://discourse.julialang.org/t/should-svd-vector-fall-back-on-pinv/12900)

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**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 4\
**Last updated:** [August 5, 2018, 3:57pm UTC](https://discourse.julialang.org/t/should-svd-vector-fall-back-on-pinv/12900 "2018-08-05T15:57:16Z")

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At the back of my head, I was wrongly assuming that svd(A) \\ b should be falling back on an efficient pinv(A) \* b. For instance I find it surprising that julia\> qr(zeros(3,3), Val(true)) \\ ones(3) 3-element Array{Float6…

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## [Guroubi decides not to apply usercuts during the search?](https://discourse.julialang.org/t/guroubi-decides-not-to-apply-usercuts-during-the-search/12886)

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**Author:** [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Replies:** 0\
**Last updated:** [August 4, 2018, 8:21am UTC](https://discourse.julialang.org/t/guroubi-decides-not-to-apply-usercuts-during-the-search/12886 "2018-08-04T08:21:27Z")

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\*\* Same question posted on Github at: https://github.com/JuliaOpt/JuMP.jl/issues/1391#issuecomment-410490319 Hello, I have an MILP which I solve through a branch-and-cut procedure (hence using a callback function). I a…

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## [JuMP 0.18 in julia v0.7](https://discourse.julialang.org/t/jump-0-18-in-julia-v0-7/12897)

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**Author:** [@Wikunia](https://discourse.julialang.org/u/Wikunia)\
**Replies:** 4\
**Last updated:** [August 4, 2018, 9:42pm UTC](https://discourse.julialang.org/t/jump-0-18-in-julia-v0-7/12897 "2018-08-04T21:42:49Z")

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Currently trying to get my head around Julia v0.7. I’m not totally sure whether JuMP 0.18 should work in v0.7 or what the current state is. Getting a bit confused with all the different versions lately (v0.6,v0.7, JuMP …

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## [Setting a value for a variable JuMP -- set value does not work](https://discourse.julialang.org/t/setting-a-value-for-a-variable-jump-set-value-does-not-work/12861)

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**Author:** [@jayce\_ram](https://discourse.julialang.org/u/jayce_ram)\
**Replies:** 1\
**Last updated:** [August 3, 2018, 3:43pm UTC](https://discourse.julialang.org/t/setting-a-value-for-a-variable-jump-set-value-does-not-work/12861 "2018-08-03T15:43:08Z")

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I have a huge LP problem and I tried to set values to some variables by using setvalue(variable, value) but surprisingly I have noticed in the final result that my variables got different values than this one I have se…

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## [MPB Callback for both heuristic solution and lazy constraint](https://discourse.julialang.org/t/mpb-callback-for-both-heuristic-solution-and-lazy-constraint/12815)

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**Author:** [@mbesancon](https://discourse.julialang.org/u/mbesancon)\
**Replies:** 1\
**Last updated:** [August 2, 2018, 11:50pm UTC](https://discourse.julialang.org/t/mpb-callback-for-both-heuristic-solution-and-lazy-constraint/12815 "2018-08-02T23:50:21Z")

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Is it possible to have a callback add a heuristic solution and a constraint using MathProgBase? It seemed unclear how to register it in that case, using setlazycallback! or setheuristiccallback!

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## [What is the syntax for vline() in Plots.jl?](https://discourse.julialang.org/t/what-is-the-syntax-for-vline-in-plots-jl/1718)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 7\
**Last updated:** [August 2, 2018, 9:29am UTC](https://discourse.julialang.org/t/what-is-the-syntax-for-vline-in-plots-jl/1718 "2018-08-02T09:29:27Z")

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There is no documentation and reading the source code didn’t help much.

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## [How to give information into a callback function](https://discourse.julialang.org/t/how-to-give-information-into-a-callback-function/12805)

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**Author:** [@CDRPico](https://discourse.julialang.org/u/CDRPico)\
**Replies:** 2\
**Last updated:** [August 2, 2018, 6:40am UTC](https://discourse.julialang.org/t/how-to-give-information-into-a-callback-function/12805 "2018-08-02T06:40:50Z")

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Hi everyone. I’m implementing a callback function for lazy constraints (Benders decomposition). I’m not sure if it is possible to give and recover information to the callback. The idea is to pass a global variable which…

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## [How to authenticate requests with HTTP.jl?](https://discourse.julialang.org/t/how-to-authenticate-requests-with-http-jl/3678)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 4\
**Last updated:** [August 1, 2018, 7:37pm UTC](https://discourse.julialang.org/t/how-to-authenticate-requests-with-http-jl/3678 "2018-08-01T19:37:34Z")

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Suppose we want to get information from GitHub API for various users: using HTTP for user in users resp = HTTP.get("https://api.github.com/users/$user") end The code fails for a large number of users due to the reduc…

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## [Status and Tagging of JuMP 0.18 on Julia 0.7](https://discourse.julialang.org/t/status-and-tagging-of-jump-0-18-on-julia-0-7/12740)

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**Author:** [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)\
**Replies:** 6\
**Last updated:** [August 1, 2018, 3:11pm UTC](https://discourse.julialang.org/t/status-and-tagging-of-jump-0-18-on-julia-0-7/12740 "2018-08-01T15:11:27Z")

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I was glad to see that the PR was merged for updating JuMP 0.18 for Julia 0.7. I was wondering if there were any plans to tag this as 0.18.3, or if it was awaiting further updates (and if so, what needs updating).

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## [Autocategorization of bank expenses](https://discourse.julialang.org/t/autocategorization-of-bank-expenses/12732)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 3\
**Last updated:** [August 1, 2018, 8:08am UTC](https://discourse.julialang.org/t/autocategorization-of-bank-expenses/12732 "2018-08-01T08:08:10Z")

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Continuing the discussion from Personal Finance package?: I want to automatically categorize bank expenses into about 25 different categories. I already have about 3000 expense-category pairs. Each expense is comprised …

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## [In Julia \>= 0.7, will the package "Missings.jl" still be needed or will it be part of core?](https://discourse.julialang.org/t/in-julia-0-7-will-the-package-missings-jl-still-be-needed-or-will-it-be-part-of-core/12733)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 4\
**Last updated:** [August 1, 2018, 7:11am UTC](https://discourse.julialang.org/t/in-julia-0-7-will-the-package-missings-jl-still-be-needed-or-will-it-be-part-of-core/12733 "2018-08-01T07:11:04Z")

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Hello, I tough that the functionality that the package Missings.jl currently provides for Julia 0.6 (the Missing type in substitution of NA from older DataFrames packages) would be in core starting from Julia 0.7/1.x, an…

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## [DimensionMismatch ("A has dimensions (1, 0) but B has dimensions (5,)") How to eliminate this error?](https://discourse.julialang.org/t/dimensionmismatch-a-has-dimensions-1-0-but-b-has-dimensions-5-how-to-eliminate-this-error/12741)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 5\
**Last updated:** [July 31, 2018, 1:14pm UTC](https://discourse.julialang.org/t/dimensionmismatch-a-has-dimensions-1-0-but-b-has-dimensions-5-how-to-eliminate-this-error/12741 "2018-07-31T13:14:51Z")

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DimensionMismatch (“A has dimensions (1, 0) but B has dimensions (5,)”) How to eliminate this error?

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## [File Format for Large Two-Dimensional Dataset](https://discourse.julialang.org/t/file-format-for-large-two-dimensional-dataset/12712)

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**Author:** [@cortner](https://discourse.julialang.org/u/cortner)\
**Replies:** 19\
**Last updated:** [July 31, 2018, 9:38am UTC](https://discourse.julialang.org/t/file-format-for-large-two-dimensional-dataset/12712 "2018-07-31T09:38:51Z")

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I need to store a moderate-to-large matrix, which (essentially) represents a least-squares system, since the matrix entries are much more expensive to evaluate than solving the actual system. I would therefore like to st…

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## [optimal feature subset selection](https://discourse.julialang.org/t/optimal-feature-subset-selection/12746)

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**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 0\
**Last updated:** [July 30, 2018, 5:35pm UTC](https://discourse.julialang.org/t/optimal-feature-subset-selection/12746 "2018-07-30T17:35:29Z")

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Is there a Julia package that implements an optimal feature subset selection algorithm, such as described here: Fast branch & bound algorithms for optimal feature selection - PubMed?

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## [ControlSystems / Frequency in Hz for bodeplot](https://discourse.julialang.org/t/controlsystems-frequency-in-hz-for-bodeplot/12683)

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**Author:** [@Patrick\_Dubus](https://discourse.julialang.org/u/Patrick_Dubus)\
**Replies:** 9\
**Last updated:** [July 30, 2018, 3:31pm UTC](https://discourse.julialang.org/t/controlsystems-frequency-in-hz-for-bodeplot/12683 "2018-07-30T15:31:50Z")

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Hello, I would like to know how to change the xaxis unit (rad/s) to frequency for bodeplot. Thanks in advance. Patrick.

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## [A spreadsheet-like pivot function](https://discourse.julialang.org/t/a-spreadsheet-like-pivot-function/2701)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 5\
**Last updated:** [July 30, 2018, 9:24am UTC](https://discourse.julialang.org/t/a-spreadsheet-like-pivot-function/2701 "2018-07-30T09:24:12Z")

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(crossposting from S.O.: http://stackoverflow.com/questions/42815117/a-generic-sreadsheet-like-pivot-function-for-julia-dataframes) I implemented a generic pivot function for Julia DataFrames, with some of the nice bell…

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## [Weird bug: Printing a variable vs. not printing a variable give different results](https://discourse.julialang.org/t/weird-bug-printing-a-variable-vs-not-printing-a-variable-give-different-results/12728)

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**Author:** [@CanLi1](https://discourse.julialang.org/u/CanLi1)\
**Replies:** 4\
**Last updated:** [July 30, 2018, 7:21am UTC](https://discourse.julialang.org/t/weird-bug-printing-a-variable-vs-not-printing-a-variable-give-different-results/12728 "2018-07-30T07:21:25Z")

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Hi folks, I’m using Julia/JuMP and I recently encountered a weird bug. The whole package I’m writing is too big so I only include the code that this bug occurs. I have the following lines of code The code does not g…

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## [Browsing dataframes and other tables?](https://discourse.julialang.org/t/browsing-dataframes-and-other-tables/12720)

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**Author:** [@Raf](https://discourse.julialang.org/u/Raf)\
**Replies:** 10\
**Last updated:** [July 30, 2018, 3:43am UTC](https://discourse.julialang.org/t/browsing-dataframes-and-other-tables/12720 "2018-07-30T03:43:21Z")

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How are people browsing their dataframes and other kinds of tables? I have sets of model parameter data to explore with my supervisors (auto-generated with Flatten.jl which I’m very excited about!). The columns are thin…

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## [Distributed computing of x = A \\ b](https://discourse.julialang.org/t/distributed-computing-of-x-a-b/12716)

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**Author:** [@ahojukka5](https://discourse.julialang.org/u/ahojukka5)\
**Replies:** 6\
**Last updated:** [July 29, 2018, 8:40pm UTC](https://discourse.julialang.org/t/distributed-computing-of-x-a-b/12716 "2018-07-29T20:40:27Z")

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N = 1000 x = sprand(N, N, 0.5) \\ full(sprand(N, 1, 0.5) The code is giving us some solutions. For N=10000 memory runs out of my laptop machine. What are my options if I want to go, for example, N=10000000, assumed that …

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## [CUDAdrv cannot find \_\_host\_\_ \_\_device\_\_ functions](https://discourse.julialang.org/t/cudadrv-cannot-find-host-device-functions/12682)

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**Author:** [@cnliao](https://discourse.julialang.org/u/cnliao)\
**Replies:** 5\
**Last updated:** [July 29, 2018, 1:55pm UTC](https://discourse.julialang.org/t/cudadrv-cannot-find-host-device-functions/12682 "2018-07-29T13:55:41Z")

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The example vadd.jl in CUDAdrv/examples will fail if one change the memory qualifier from \_\_global\_\_ to \_\_host\_\_ \_\_device\_\_ in the function signature. // vadd.cu extern "C" { \_\_host\_\_ \_\_device\_\_ void kernel\_vadd(const f…

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## [Optim Consumes an Increasingly Large Amount of Memory (Until it Crashes)](https://discourse.julialang.org/t/optim-consumes-an-increasingly-large-amount-of-memory-until-it-crashes/12689)

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**Author:** [@Juser](https://discourse.julialang.org/u/Juser)\
**Replies:** 6\
**Last updated:** [July 29, 2018, 7:19am UTC](https://discourse.julialang.org/t/optim-consumes-an-increasingly-large-amount-of-memory-until-it-crashes/12689 "2018-07-29T07:19:56Z")

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I am using Optim using LBFGS for a statistical application (maximum likelihood), and I have encountered the issue that Optim consumes an increasingly large amount of memory until it runs out and crashes. The data set siz…

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## [Personal Finance package?](https://discourse.julialang.org/t/personal-finance-package/12597)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 33\
**Last updated:** [July 28, 2018, 11:17pm UTC](https://discourse.julialang.org/t/personal-finance-package/12597 "2018-07-28T23:17:24Z")

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Hi all! I’m trying to get my own personal finances in order and would love to get the job done in Julia. Why Julia and not just use hledger or gnucash? I could say that it’s easier to produce reports and graphs in Juli…

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## [OpenBLAS on master -- getting wrong results with multithreading?](https://discourse.julialang.org/t/openblas-on-master-getting-wrong-results-with-multithreading/12694)

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**Author:** [@Elrod](https://discourse.julialang.org/u/Elrod)\
**Replies:** 2\
**Last updated:** [July 28, 2018, 4:16pm UTC](https://discourse.julialang.org/t/openblas-on-master-getting-wrong-results-with-multithreading/12694 "2018-07-28T16:16:31Z")

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I am getting inconsistent results from multiplying the same two matrices together with OpenBLAS on Julia master: julia\> y = randn(400,400); julia\> x = randn(400,400); julia\> cond(x \* y) 3108.7389106095816 julia\> cond…

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## [CSV.read extremely slow wrt readtable](https://discourse.julialang.org/t/csv-read-extremely-slow-wrt-readtable/11726)

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**Author:** [@lucabrugnolini](https://discourse.julialang.org/u/lucabrugnolini)\
**Replies:** 14\
**Last updated:** [July 27, 2018, 6:57pm UTC](https://discourse.julialang.org/t/csv-read-extremely-slow-wrt-readtable/11726 "2018-07-27T18:57:50Z")

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Hello, I have found a huge difference in speed and allocation by switching from the deprecated DataFrames.readtable to CSV.read. I have noticed that this happens with large datasets (high number of columns), thus I star…

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## [JuliaImages error](https://discourse.julialang.org/t/juliaimages-error/12264)

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**Author:** [@microlifecc](https://discourse.julialang.org/u/microlifecc)\
**Replies:** 2\
**Last updated:** [July 27, 2018, 3:44am UTC](https://discourse.julialang.org/t/juliaimages-error/12264 "2018-07-27T03:44:28Z")

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I tried this: using Images, Unitful, AxisArrays using Unitful: mm, s img = AxisArray(rand(256, 256, 100, 50), (:x, :y, :z, :time), (0.4mm, 0.4mm, 1mm, 2s)) imshow(img) I am getting this error: (julia:14656): Gtk-CR…

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## [How to Load images in either Knet or MXNet](https://discourse.julialang.org/t/how-to-load-images-in-either-knet-or-mxnet/12677)

<div class="topic-metadata">

**Author:** [@hskramer](https://discourse.julialang.org/u/hskramer)\
**Replies:** 6\
**Last updated:** [July 27, 2018, 3:28am UTC](https://discourse.julialang.org/t/how-to-load-images-in-either-knet-or-mxnet/12677 "2018-07-27T03:28:48Z")

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My images are from google street views 74K. I read and gone through every tutorial still can’t load an image. They are 50x50 rgb jpg images any help would be greatly appreciated.

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