# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1492

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 1493

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## [What's the recommended way to solve LP problems with \`BigFloat\` constraints and no](https://discourse.julialang.org/t/whats-the-recommended-way-to-solve-lp-problems-with-bigfloat-constraints-and-no/55167)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [February 13, 2021, 6:31am UTC](https://discourse.julialang.org/t/whats-the-recommended-way-to-solve-lp-problems-with-bigfloat-constraints-and-no/55167 "2021-02-13T06:31:03Z")

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What’s the recommended way to solve LP problems with BigFloat constraints and no objective function? Tulip+ JuMP? Cosmo + Convex? Something else? Note that the original poster on Slack cannot see your response here on D…

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## [Util for debugging channels/threads performance: should I publish a package?](https://discourse.julialang.org/t/util-for-debugging-channels-threads-performance-should-i-publish-a-package/55093)

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**Author:** [@pmilovanov](https://discourse.julialang.org/u/pmilovanov)\
**Replies:** 2\
**Last updated:** [February 13, 2021, 5:37am UTC](https://discourse.julialang.org/t/util-for-debugging-channels-threads-performance-should-i-publish-a-package/55093 "2021-02-13T05:37:13Z")

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I wrote some code for myself to better understand what’s going on with threads and channels in my app. It implements TrackingChannel, a wrapper around a channel that measures how long take!, put!, fetch ops took on that …

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## [parse(\<type\>,"Inf")](https://discourse.julialang.org/t/parse-type-inf/55189)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 2\
**Last updated:** [February 13, 2021, 4:18am UTC](https://discourse.julialang.org/t/parse-type-inf/55189 "2021-02-13T04:18:32Z")

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I’m reading in some environment variables and sometimes I need to get Inf. Obviously Inf is not an Int, but can I do something like: arc\_nu = parse(Int,ENV\["ARCNU"\]) # where ENV\["ARCNU"\] = "Inf" @test isinf(arc\_nu) == …

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## [Creating a 3d frequency array for categorical variables from a dataframe](https://discourse.julialang.org/t/creating-a-3d-frequency-array-for-categorical-variables-from-a-dataframe/55163)

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**Author:** [@samerb](https://discourse.julialang.org/u/samerb)\
**Replies:** 3\
**Last updated:** [February 12, 2021, 10:20pm UTC](https://discourse.julialang.org/t/creating-a-3d-frequency-array-for-categorical-variables-from-a-dataframe/55163 "2021-02-12T22:20:31Z")

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I have a dataframe with three categorical variables a,b,c. taking values in 1:2, 1:5, and 1:7 respectively. Then I calculate the number rows with each of the possible 2\*5\*7=70 combinations of a,b,c: df = transform(group…

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## [Need Instructor/Facilitator to conduct Julia workshop at IIT Madras](https://discourse.julialang.org/t/need-instructor-facilitator-to-conduct-julia-workshop-at-iit-madras/55097)

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**Author:** [@Naman\_Jain](https://discourse.julialang.org/u/Naman_Jain)\
**Replies:** 4\
**Last updated:** [February 12, 2021, 10:02pm UTC](https://discourse.julialang.org/t/need-instructor-facilitator-to-conduct-julia-workshop-at-iit-madras/55097 "2021-02-12T22:02:16Z")

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Greetings! This is Vamika and Naman, postgraduate students from IIT Madras. We are hosting our annual research fest for postgraduates and research scholars in the month of April (April 2-4, 2021). Research Scholars Day…

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## [Merging daily and monthly timeseries data](https://discourse.julialang.org/t/merging-daily-and-monthly-timeseries-data/55172)

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**Author:** [@davidoff](https://discourse.julialang.org/u/davidoff)\
**Replies:** 3\
**Last updated:** [February 12, 2021, 9:17pm UTC](https://discourse.julialang.org/t/merging-daily-and-monthly-timeseries-data/55172 "2021-02-12T21:17:26Z")

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Suppose I want to merge two Timeseries. One is daily and might have the first daily observation in the month on the 2nd or 3rd day, and might have a last observation on the 29th. I would hope to collapse the data to mont…

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## [How do Julia packages, e.g. Flux and Knet correspond to Python ecosystem](https://discourse.julialang.org/t/how-do-julia-packages-e-g-flux-and-knet-correspond-to-python-ecosystem/55147)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 1\
**Last updated:** [February 12, 2021, 8:09pm UTC](https://discourse.julialang.org/t/how-do-julia-packages-e-g-flux-and-knet-correspond-to-python-ecosystem/55147 "2021-02-12T20:09:40Z")

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I’m not so much asking if they are better, just some mapping, and trying to get an overview of the mainstream and where there might be big holes in the Julia ecosystem. E.g. Pytorch Lightning corresponds to Keras, and t…

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## [Problems with legend](https://discourse.julialang.org/t/problems-with-legend/55105)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 3\
**Last updated:** [February 12, 2021, 7:55pm UTC](https://discourse.julialang.org/t/problems-with-legend/55105 "2021-02-12T19:55:40Z")

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Hello users, How can I insert a legend correctly on my plots in a layout 3 x 3? Below my code: using Plots plotly() function Euler(f,a,b,α,n) h = (b-a)/n w=zeros(1+n) w\[1\]=α t = \[a + i\*h for i in 0:n\]…

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## [Vector local to loop iteration vs. Static Vector](https://discourse.julialang.org/t/vector-local-to-loop-iteration-vs-static-vector/55109)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 6\
**Last updated:** [February 12, 2021, 7:41pm UTC](https://discourse.julialang.org/t/vector-local-to-loop-iteration-vs-static-vector/55109 "2021-02-12T19:41:41Z")

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In simple the example below, I write two functions that compute “the force” between the particles of a set. To compute the forces between each pair of particles one needs to compute the difference in position of the two …

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## [Tips to cope with scoping rules of top level \`for\` loops etc](https://discourse.julialang.org/t/tips-to-cope-with-scoping-rules-of-top-level-for-loops-etc/24902)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 27\
**Last updated:** [February 12, 2021, 7:28pm UTC](https://discourse.julialang.org/t/tips-to-cope-with-scoping-rules-of-top-level-for-loops-etc/24902 "2021-02-12T19:28:19Z")

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The issue of the scoping rules of top-level for loops (and their kind) revives from time to time, and it seems that this will continue happening for a while; so I thought that it might be useful to share some thoughts an…

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## [@everything copy absolutely everything in main process](https://discourse.julialang.org/t/everything-copy-absolutely-everything-in-main-process/55159)

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**Author:** [@s-baumann](https://discourse.julialang.org/u/s-baumann)\
**Replies:** 4\
**Last updated:** [February 12, 2021, 6:08pm UTC](https://discourse.julialang.org/t/everything-copy-absolutely-everything-in-main-process/55159 "2021-02-12T18:08:52Z")

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I have a long script that has alot of functions defined and packages included. Then there is a big for loop at the end I want to parallelise. For a minimal example: using Distributed Distributed.addprocs(4) @everywhere …

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## [Do I have some way to find out where that function is coming from at runtime?](https://discourse.julialang.org/t/do-i-have-some-way-to-find-out-where-that-function-is-coming-from-at-runtime/55152)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [February 12, 2021, 4:45pm UTC](https://discourse.julialang.org/t/do-i-have-some-way-to-find-out-where-that-function-is-coming-from-at-runtime/55152 "2021-02-12T16:45:53Z")

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Do I have some way to find out where that function is coming from at runtime? Note that the original poster on Slack cannot see your response here on Discourse. Consider transcribing the appropriate answer back to Slack,…

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## [Learning by examples: list of resources](https://discourse.julialang.org/t/learning-by-examples-list-of-resources/52626)

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**Author:** [@RCHG](https://discourse.julialang.org/u/RCHG)\
**Replies:** 2\
**Last updated:** [February 12, 2021, 4:42pm UTC](https://discourse.julialang.org/t/learning-by-examples-list-of-resources/52626 "2021-02-12T16:42:36Z")

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Hello, There are several paths to learn a new language: manual, videos, examples. I am more the kind of person who read once the manual (mostly just to know the basic syntax) and then I try find examples of the language…

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## [How to programmatically create and save an image with some text?](https://discourse.julialang.org/t/how-to-programmatically-create-and-save-an-image-with-some-text/55086)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 6\
**Last updated:** [February 12, 2021, 4:34pm UTC](https://discourse.julialang.org/t/how-to-programmatically-create-and-save-an-image-with-some-text/55086 "2021-02-12T16:34:29Z")

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I would like to programmatically “compose” and save as PNG an image with a white background and a digit in the center, of a given font, colour, size. Which approach may I have? I am thinking to plots, but it seems “exag…

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## [Cannot call \`show(io,MIME...\`](https://discourse.julialang.org/t/cannot-call-show-io-mime/55158)

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**Author:** [@Jean\_Michel](https://discourse.julialang.org/u/Jean_Michel)\
**Replies:** 2\
**Last updated:** [February 12, 2021, 3:54pm UTC](https://discourse.julialang.org/t/cannot-call-show-io-mime/55158 "2021-02-12T15:54:41Z")

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I am surprised by the following julia\> struct Thing end julia\> x=Thing() Thing() julia\> Base.show(io::IO,::MIME"text/plain",x::Thing)=print(io,"hello") julia\> show(stdout,MIME"text/plain",x) ERROR: MethodError: no me…

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## [Best Practice for Logging MCMC Results?](https://discourse.julialang.org/t/best-practice-for-logging-mcmc-results/54832)

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**Author:** [@JonB27](https://discourse.julialang.org/u/JonB27)\
**Replies:** 4\
**Last updated:** [February 12, 2021, 3:37pm UTC](https://discourse.julialang.org/t/best-practice-for-logging-mcmc-results/54832 "2021-02-12T15:37:45Z")

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I will be deploying a custom MCMC algorithm to an external computer as part of my thesis. I’m making heavy use of the Gen PPL, and was wondering how best to return the results of the MCMC. My idea so far was to write eac…

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## [Hi, I am reading through some code and I have something like this happening:\`\`\`](https://discourse.julialang.org/t/hi-i-am-reading-through-some-code-and-i-have-something-like-this-happening/55151)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [February 12, 2021, 3:10pm UTC](https://discourse.julialang.org/t/hi-i-am-reading-through-some-code-and-i-have-something-like-this-happening/55151 "2021-02-12T15:10:25Z")

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Hi, I am reading through some code and I have something like this happening: all(x) = all\_gaus(x, y) Now I cannot seem to find at all where the all\_gaus function is. I see a candidate, but changing that candidate …

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## [Sampling from power posterior](https://discourse.julialang.org/t/sampling-from-power-posterior/54924)

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**Author:** [@theogf](https://discourse.julialang.org/u/theogf)\
**Replies:** 27\
**Last updated:** [February 12, 2021, 3:10pm UTC](https://discourse.julialang.org/t/sampling-from-power-posterior/54924 "2021-02-12T15:10:09Z")

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Hey, I was wondering if someone could guide me (or direct me to the relevant code) on how to sample from the power posterior given a Turing model. By power posterior, I mean the posterior to modified joint : p(x|y; b) \\…

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## [Getting multiple threads working in VS code, have changed envirinment settings.. no joy](https://discourse.julialang.org/t/getting-multiple-threads-working-in-vs-code-have-changed-envirinment-settings-no-joy/55076)

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**Author:** [@PennyL](https://discourse.julialang.org/u/PennyL)\
**Replies:** 3\
**Last updated:** [February 12, 2021, 2:36pm UTC](https://discourse.julialang.org/t/getting-multiple-threads-working-in-vs-code-have-changed-envirinment-settings-no-joy/55076 "2021-02-12T14:36:41Z")

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I followed the guidance in a previous thread, which led me to the environment settings in VS code where I have changed the thread number to 4, for user and workspace. However, julia is apparently still using one thread. …

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## [Help understanding type error: Int64 and Number](https://discourse.julialang.org/t/help-understanding-type-error-int64-and-number/55133)

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**Author:** [@curious](https://discourse.julialang.org/u/curious)\
**Replies:** 4\
**Last updated:** [February 12, 2021, 2:06pm UTC](https://discourse.julialang.org/t/help-understanding-type-error-int64-and-number/55133 "2021-02-12T14:06:19Z")

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I would appreciate if someone could help me understand this. I know that in Julia you don’t have to specify types of function arguments. But if possible, I want to do it because it helps me understand the code more easil…

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## [How to view every n-th row in a DataFrame](https://discourse.julialang.org/t/how-to-view-every-n-th-row-in-a-dataframe/55143)

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**Author:** [@met-j](https://discourse.julialang.org/u/met-j)\
**Replies:** 3\
**Last updated:** [February 12, 2021, 1:42pm UTC](https://discourse.julialang.org/t/how-to-view-every-n-th-row-in-a-dataframe/55143 "2021-02-12T13:42:09Z")

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How to view every n-th row in a DataFrame? My DataFrame is a plane table of 1334400 x 22 entries. I would like to view every 21-th entire row. Could anyone help?

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## [Problems to plot in polar coordinates using Layout](https://discourse.julialang.org/t/problems-to-plot-in-polar-coordinates-using-layout/55146)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 0\
**Last updated:** [February 12, 2021, 1:05pm UTC](https://discourse.julialang.org/t/problems-to-plot-in-polar-coordinates-using-layout/55146 "2021-02-12T13:05:21Z")

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Hello users, I am with a little problem to plot in polar coordinates using a 3x3 layout. Below my code: using Plots plotly() theta = 0:2\*pi/1000:2\*pi+2\*pi/1000 g = plot(proj=:polar;leg=false,layout=(3,3),size=(800,800…

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## [LIBSVM API usage?](https://discourse.julialang.org/t/libsvm-api-usage/54792)

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**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 5\
**Last updated:** [February 12, 2021, 12:34pm UTC](https://discourse.julialang.org/t/libsvm-api-usage/54792 "2021-02-12T12:34:35Z")

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I quite like the simplicity of the basic LIBSVM API. I know that many call it from ScikitLearn, but I am exploring the possibility of just using the Native API. For instance, I discovered (after a good deal of trial a…

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## [GAMS executable not found! - JuMP](https://discourse.julialang.org/t/gams-executable-not-found-jump/54927)

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**Author:** [@GraceMabele](https://discourse.julialang.org/u/GraceMabele)\
**Replies:** 2\
**Last updated:** [February 12, 2021, 12:32pm UTC](https://discourse.julialang.org/t/gams-executable-not-found-jump/54927 "2021-02-12T12:32:14Z")

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Hi, I would like to use the GAMS Optimizer for my JuMP/Julia model. I have installed the GAMS package correctly using GAMS and it is updated however, when I want to use it as an optimizer as follows model\_name = Model…

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## [Fixing parameter values to create new simpler function](https://discourse.julialang.org/t/fixing-parameter-values-to-create-new-simpler-function/55134)

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**Author:** [@danielward27](https://discourse.julialang.org/u/danielward27)\
**Replies:** 2\
**Last updated:** [February 12, 2021, 11:16am UTC](https://discourse.julialang.org/t/fixing-parameter-values-to-create-new-simpler-function/55134 "2021-02-12T11:16:07Z")

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Very new to Julia, so apologies for the naive question. I was wondering if there was a neat way to fix parameter values in a function, to create a new simpler function. The reason I want to do this is because certain opt…

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## [What is the fastest way to perform unary operation inplace?](https://discourse.julialang.org/t/what-is-the-fastest-way-to-perform-unary-operation-inplace/55139)

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**Author:** [@encendre](https://discourse.julialang.org/u/encendre)\
**Replies:** 1\
**Last updated:** [February 12, 2021, 11:09am UTC](https://discourse.julialang.org/t/what-is-the-fastest-way-to-perform-unary-operation-inplace/55139 "2021-02-12T11:09:16Z")

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What is the fastest way to perform unary operation inplace ? I have tried the followings b = rand(1000000) @time b = -b # 0.011017 seconds (2 allocations: 7.629 MiB) @time b = (-).(b) # 0.012952 seconds (2 allocatio…

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## [Error when test GLMakie](https://discourse.julialang.org/t/error-when-test-glmakie/55136)

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**Author:** [@niklund](https://discourse.julialang.org/u/niklund)\
**Replies:** 0\
**Last updated:** [February 12, 2021, 10:29am UTC](https://discourse.julialang.org/t/error-when-test-glmakie/55136 "2021-02-12T10:29:45Z")

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Hello, I am having issues getting GLMakie to work. I have GLFW and was able to install GLMakie successfully but when testing it I get: (@v1.5) pkg\> test GLMakie Testing GLMakie Status \`/tmp/jl\_OLoZBY/Project.toml\` …

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## [Scientific algorithm programmer in Julia (two months)](https://discourse.julialang.org/t/scientific-algorithm-programmer-in-julia-two-months/53784)

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**Author:** [@Jose\_Nunez](https://discourse.julialang.org/u/Jose_Nunez)\
**Replies:** 2\
**Last updated:** [February 12, 2021, 9:11am UTC](https://discourse.julialang.org/t/scientific-algorithm-programmer-in-julia-two-months/53784 "2021-02-12T09:11:30Z")

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Hi there, This is an offer to implement an algorithm in statistics for a web software in statistics. Experience with statistics/mathematical programming is required. Experience in AWS deployment is a plus. This posit…

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## [Iterator over Floats](https://discourse.julialang.org/t/iterator-over-floats/55110)

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**Author:** [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)\
**Replies:** 1\
**Last updated:** [February 12, 2021, 8:21am UTC](https://discourse.julialang.org/t/iterator-over-floats/55110 "2021-02-12T08:21:03Z")

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So I’ve been working on special functions, and to help with that I’ve created this class that implements an Iterator of Float values. struct FloatIterator{T}\<:AbstractVector{T} min::T max::T FloatIterator{T}…

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## [PyError - with ExcelReaders perhaps](https://discourse.julialang.org/t/pyerror-with-excelreaders-perhaps/55092)

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**Author:** [@jmcastro2109](https://discourse.julialang.org/u/jmcastro2109)\
**Replies:** 1\
**Last updated:** [February 12, 2021, 7:12am UTC](https://discourse.julialang.org/t/pyerror-with-excelreaders-perhaps/55092 "2021-02-12T07:12:19Z")

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Hello, I am getting an error with PyCall that I am having a hard time interpreting. I think that the error might be caused by using ExcelReaders . The other weird thing is that if I run my code one, it appears. If I run…

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