# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1797

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

**Page:** 1798

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## [Advice on structuring larger codebases](https://discourse.julialang.org/t/advice-on-structuring-larger-codebases/28203)

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**Author:** [@jackf](https://discourse.julialang.org/u/jackf)\
**Replies:** 19\
**Last updated:** [March 19, 2020, 12:39pm UTC](https://discourse.julialang.org/t/advice-on-structuring-larger-codebases/28203 "2020-03-19T12:39:30Z")

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Hi, I currently have a reasonably sized python codebase (10s of thousands of lines across 100s of modules). I rely heavily on hierarchical modules to structure my code - i.e. lots of directories with \_\_init\_\_.py and eit…

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## [How to test \`Int\` vs \`Int64\` correctness on my 64 bit development machine](https://discourse.julialang.org/t/how-to-test-int-vs-int64-correctness-on-my-64-bit-development-machine/36180)

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**Author:** [@tkluck](https://discourse.julialang.org/u/tkluck)\
**Replies:** 7\
**Last updated:** [March 19, 2020, 12:04pm UTC](https://discourse.julialang.org/t/how-to-test-int-vs-int64-correctness-on-my-64-bit-development-machine/36180 "2020-03-19T12:04:18Z")

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Does anyone have any advice on how to test whether I’m using Int vs Int64 correctly? On 64-bit platforms like my laptop, Int === Int64 so it won’t error out when I’m using Int64 where I should use Int or vice-versa. I’m…

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## [Mesh/grid over convex polytope](https://discourse.julialang.org/t/mesh-grid-over-convex-polytope/36047)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 19\
**Last updated:** [March 19, 2020, 10:47am UTC](https://discourse.julialang.org/t/mesh-grid-over-convex-polytope/36047 "2020-03-19T10:47:31Z")

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I have x\_1, \\dots, x\_m points in \\mathbb{R}^n defining a polytope as their convex hull, m \> n. Typically n = 2 or 3 and m = 4 or 5. I would like to make a more or less equispaced (adjusted when necessary) grid \\{ z\_j…

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## [Julia crashes after successful(?) ccall](https://discourse.julialang.org/t/julia-crashes-after-successful-ccall/36157)

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**Author:** [@Iulian.Cioarca](https://discourse.julialang.org/u/Iulian.Cioarca)\
**Replies:** 3\
**Last updated:** [March 19, 2020, 10:17am UTC](https://discourse.julialang.org/t/julia-crashes-after-successful-ccall/36157 "2020-03-19T10:17:53Z")

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I am trying to control a National Instruments PXI oscilloscope using Julia by calling the provided .dlls. So far I managed to initialize the communication with the instrument, configure some settings and almost finished…

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## [Repeatedly optimizing an LP with different data (changing coefficients/constraints)](https://discourse.julialang.org/t/repeatedly-optimizing-an-lp-with-different-data-changing-coefficients-constraints/36125)

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**Author:** [@Smith](https://discourse.julialang.org/u/Smith)\
**Replies:** 7\
**Last updated:** [March 19, 2020, 8:57am UTC](https://discourse.julialang.org/t/repeatedly-optimizing-an-lp-with-different-data-changing-coefficients-constraints/36125 "2020-03-19T08:57:08Z")

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Hi, I would like to solve an LP model for different sets of data and then write results to a CSV file. For illustration, assume the following code for one particular instance using JuMP using GLPK c = \[1,1\] A = \[1,1\] b …

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## [How to call one julia program inside another julia program?](https://discourse.julialang.org/t/how-to-call-one-julia-program-inside-another-julia-program/36175)

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**Author:** [@Eldho.Ashna](https://discourse.julialang.org/u/Eldho.Ashna)\
**Replies:** 1\
**Last updated:** [March 19, 2020, 7:11am UTC](https://discourse.julialang.org/t/how-to-call-one-julia-program-inside-another-julia-program/36175 "2020-03-19T07:11:28Z")

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Suppose I have two programs: code.py and main.py. I want to call code.py in main.py. In python, we can call code.py inside main.py using the command from main import \*. Similarly, in julia suppose I have two programs: ma…

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## [Big Integers on the Alto](https://discourse.julialang.org/t/big-integers-on-the-alto/36164)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 0\
**Last updated:** [March 18, 2020, 9:55pm UTC](https://discourse.julialang.org/t/big-integers-on-the-alto/36164 "2020-03-18T21:55:32Z")

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“Alto System Project: Dan Ingalls demonstrates Smalltalk” One of the things that is nice about this is that, although Smalltalk used small integers, we made sure that you can make large numbers with them. …

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## [Interger Division](https://discourse.julialang.org/t/interger-division/36171)

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**Author:** [@Lee](https://discourse.julialang.org/u/Lee)\
**Replies:** 3\
**Last updated:** [March 19, 2020, 2:36am UTC](https://discourse.julialang.org/t/interger-division/36171 "2020-03-19T02:36:03Z")

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I’m trying to divide between two integers, but a Float is returning. I just need an Int return. Any ideas? Appreciate.

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## [PyCall Won't import gdal or osr](https://discourse.julialang.org/t/pycall-wont-import-gdal-or-osr/36168)

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**Author:** [@scone](https://discourse.julialang.org/u/scone)\
**Replies:** 2\
**Last updated:** [March 19, 2020, 12:20am UTC](https://discourse.julialang.org/t/pycall-wont-import-gdal-or-osr/36168 "2020-03-19T00:20:23Z")

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Hi everyone, I wrote some code a few months ago that was working fine. Now that I am trying to use it again on the same computer without changing the code, I can’t import gdal or osr with pycall. However, numpy still…

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## [Get on GroupedDataFrame](https://discourse.julialang.org/t/get-on-groupeddataframe/36108)

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**Author:** [@Marc.Cox](https://discourse.julialang.org/u/Marc.Cox)\
**Replies:** 11\
**Last updated:** [March 18, 2020, 11:43pm UTC](https://discourse.julialang.org/t/get-on-groupeddataframe/36108 "2020-03-18T23:43:25Z")

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Issue using the Base.get Get a group based on the values of the grouping columns example code here \>\> Functions · DataFrames.jl Base.get — Function. get(gd::GroupedDataFrame, key, default) Get a group based on the va…

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## [Scattergram](https://discourse.julialang.org/t/scattergram/36162)

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**Author:** [@erlebach](https://discourse.julialang.org/u/erlebach)\
**Replies:** 3\
**Last updated:** [March 18, 2020, 10:18pm UTC](https://discourse.julialang.org/t/scattergram/36162 "2020-03-18T22:18:14Z")

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I am making a simple scatterplot: using Plots tk = \[1,2,3,5,8\] y = \[1. for i in 1:length(tk)\] pl = scatter(tk, y, title="Poisson train tk") display(pl) This works. However, I feel that there has to be a more…

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## [Question about performance when iterating](https://discourse.julialang.org/t/question-about-performance-when-iterating/36158)

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**Author:** [@jokasimr](https://discourse.julialang.org/u/jokasimr)\
**Replies:** 3\
**Last updated:** [March 18, 2020, 9:53pm UTC](https://discourse.julialang.org/t/question-about-performance-when-iterating/36158 "2020-03-18T21:53:15Z")

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Hi! Really like julia and want to learn how to debug performance better. I’m doing a project on iterated maps, and started writing in python and then decided to try julia. But when benchmarking, the python version ran …

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## [Possible to set the type of Dict entries for specific keys?](https://discourse.julialang.org/t/possible-to-set-the-type-of-dict-entries-for-specific-keys/36159)

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**Author:** [@mlanghinrichs](https://discourse.julialang.org/u/mlanghinrichs)\
**Replies:** 5\
**Last updated:** [March 18, 2020, 8:47pm UTC](https://discourse.julialang.org/t/possible-to-set-the-type-of-dict-entries-for-specific-keys/36159 "2020-03-18T20:47:51Z")

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Hi all, I would like to use a Dict (or a similar structure) with values that can have different, but concrete types for given keys. For example: mydict = Dict(:a=\> 2, :b=\>\[1.0, 3.0\], :c=\> "hello type") In general, thi…

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## [Generic function for pairwise operations](https://discourse.julialang.org/t/generic-function-for-pairwise-operations/1041)

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**Author:** [@mkborregaard](https://discourse.julialang.org/u/mkborregaard)\
**Replies:** 9\
**Last updated:** [March 18, 2020, 7:37pm UTC](https://discourse.julialang.org/t/generic-function-for-pairwise-operations/1041 "2020-03-18T19:37:51Z")

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A very commonly used design pattern is to apply a function to all unique pairs of elements in a container, e.g. f(x,y) = x\*y a = randn(5) ret = eltype(a)\[\] #the example returns a vector, but in this case an UpperTriangu…

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## [Csv file not a valid file](https://discourse.julialang.org/t/csv-file-not-a-valid-file/36153)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 8\
**Last updated:** [March 18, 2020, 7:22pm UTC](https://discourse.julialang.org/t/csv-file-not-a-valid-file/36153 "2020-03-18T19:22:24Z")

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Excel files are basically CSV files, aren’t they ? What could be the reason my excel file “branch” be not considered a valid CSV file… This is the error msg I get.

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## [Reading bitarray from disk has ordering flipped in groups of 8, how to fix?](https://discourse.julialang.org/t/reading-bitarray-from-disk-has-ordering-flipped-in-groups-of-8-how-to-fix/36123)

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**Author:** [@tlnagy](https://discourse.julialang.org/u/tlnagy)\
**Replies:** 6\
**Last updated:** [March 18, 2020, 6:43pm UTC](https://discourse.julialang.org/t/reading-bitarray-from-disk-has-ordering-flipped-in-groups-of-8-how-to-fix/36123 "2020-03-18T18:43:43Z")

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On Julia 1.4.0-rc2 (I don’t think it’s a new behavior), I see the following: versus the expected: I’m reading in the image as follows: io = open("bilevel\_example.tif") seek(io, 8) data = BitArray(undef, 40160\*8)…

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## [Showing the algorithm used in DifferentialEquations.jl](https://discourse.julialang.org/t/showing-the-algorithm-used-in-differentialequations-jl/36155)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 1\
**Last updated:** [March 18, 2020, 6:30pm UTC](https://discourse.julialang.org/t/showing-the-algorithm-used-in-differentialequations-jl/36155 "2020-03-18T18:30:42Z")

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Consider a simple code to solve an ODE by DifferentialEquations.jl shown in the documentation: using DifferentialEquations f(u,p,t) = 1.01\*u u0 = 1/2 tspan = (0.0,1.0) prob = ODEProblem(f,u0,tspan) sol = solve(prob) In…

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## [Global sensitivity analysis - following time series](https://discourse.julialang.org/t/global-sensitivity-analysis-following-time-series/35770)

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**Author:** [@alewolf](https://discourse.julialang.org/u/alewolf)\
**Replies:** 15\
**Last updated:** [March 18, 2020, 5:56pm UTC](https://discourse.julialang.org/t/global-sensitivity-analysis-following-time-series/35770 "2020-03-18T17:56:16Z")

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I tested the example in https://docs.juliadiffeq.org/stable/analysis/global\_sensitivity/#GSA-examples-1. As expected it all went well. This example, calculates sensitivity with regard to the mean over time on u1 and th…

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## [How to lazily filter an iterator while also applying a function to it](https://discourse.julialang.org/t/how-to-lazily-filter-an-iterator-while-also-applying-a-function-to-it/35902)

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**Author:** [@jeffreyesun](https://discourse.julialang.org/u/jeffreyesun)\
**Replies:** 21\
**Last updated:** [March 18, 2020, 5:45pm UTC](https://discourse.julialang.org/t/how-to-lazily-filter-an-iterator-while-also-applying-a-function-to-it/35902 "2020-03-18T17:45:04Z")

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Hi, I’m trying to figure out how to do the following: given an iterator A, create a generator that goes through each element v of A, and either yields something as a function of v or simply moves on to the next element v…

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## [HELP! "Julia could not be started "](https://discourse.julialang.org/t/help-julia-could-not-be-started/36021)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 5\
**Last updated:** [March 18, 2020, 5:34pm UTC](https://discourse.julialang.org/t/help-julia-could-not-be-started/36021 "2020-03-18T17:34:55Z")

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Please help me fix this. How can I start Julia from Atom… I get this message in the picture. Thank you loads in advance

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## [Access row of matrix based on when value is equal to something specific](https://discourse.julialang.org/t/access-row-of-matrix-based-on-when-value-is-equal-to-something-specific/36149)

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**Author:** [@samantp](https://discourse.julialang.org/u/samantp)\
**Replies:** 1\
**Last updated:** [March 18, 2020, 4:17pm UTC](https://discourse.julialang.org/t/access-row-of-matrix-based-on-when-value-is-equal-to-something-specific/36149 "2020-03-18T16:17:59Z")

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Hi, Sorry that this is such a simple question but I have not been able to figure this out. I have a 1787x2 matrix stored as an array (called dvh\_bs, and I want to access the row in which the second column is equal to 0.…

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## [GitLab CI environment variables](https://discourse.julialang.org/t/gitlab-ci-environment-variables/36150)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 2\
**Last updated:** [March 18, 2020, 4:34pm UTC](https://discourse.julialang.org/t/gitlab-ci-environment-variables/36150 "2020-03-18T16:34:18Z")

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I want to setup a CI/CD pipeline in GitLab. In my testscript I need a password and a username that I don’t want to have in the repo. Is it possible to use the GitLab environment variables to pass this to the script? M…

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## [Simple example of Interactive + Dynamically Updating (VegaLite) graph with Julia backend](https://discourse.julialang.org/t/simple-example-of-interactive-dynamically-updating-vegalite-graph-with-julia-backend/36007)

<div class="topic-metadata">

**Author:** [@robertfeldt](https://discourse.julialang.org/u/robertfeldt)\
**Replies:** 5\
**Last updated:** [March 18, 2020, 3:50pm UTC](https://discourse.julialang.org/t/simple-example-of-interactive-dynamically-updating-vegalite-graph-with-julia-backend/36007 "2020-03-18T15:50:04Z")

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I’m sure there are many ways this can be done in Julia but if anyone has seen very simple examples of how to produce interactive graphs that can be dynamically updated from (backend) Julia code that would be great? My s…

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## [Problem changing Variables from Any to Real](https://discourse.julialang.org/t/problem-changing-variables-from-any-to-real/36116)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 10\
**Last updated:** [March 18, 2020, 3:41pm UTC](https://discourse.julialang.org/t/problem-changing-variables-from-any-to-real/36116 "2020-03-18T15:41:18Z")

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I tried running this using XLSX df = DataFrame(XLSX.readtable("C:/Users/brett/OneDrive/Documents/FemData.xlsx", "Sheet1")...) for name in names(df) df\[!, name\] = identity.(df\[:, name\]) end print(df) It changed…

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## [MySQL.jl connection error](https://discourse.julialang.org/t/mysql-jl-connection-error/36131)

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**Author:** [@zhangliye](https://discourse.julialang.org/u/zhangliye)\
**Replies:** 3\
**Last updated:** [March 18, 2020, 3:11pm UTC](https://discourse.julialang.org/t/mysql-jl-connection-error/36131 "2020-03-18T15:11:29Z")

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I got the following error when try to connect MySQl using MySQL.jl. using MySQL, DBInterface conn = DBInterface.connect(MySQL.Connection, "\*\*", "root", "\*\*"; port=3306) # the connection parameters are hide here The er…

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## [Extracting all struct fields](https://discourse.julialang.org/t/extracting-all-struct-fields/36115)

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**Author:** [@francesco.alemanno](https://discourse.julialang.org/u/francesco.alemanno)\
**Replies:** 7\
**Last updated:** [March 18, 2020, 3:03pm UTC](https://discourse.julialang.org/t/extracting-all-struct-fields/36115 "2020-03-18T15:03:19Z")

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ideally i would like to do this struct MyStruct a b c end function calculation(C::MyStruct) fieldnames(MyStruct)... = C 2a+3b+c end i was trying this workaround struct My a b c end func…

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## [Estimating function intergral - function containing a sine or a cosine](https://discourse.julialang.org/t/estimating-function-intergral-function-containing-a-sine-or-a-cosine/36139)

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**Author:** [@timmm](https://discourse.julialang.org/u/timmm)\
**Replies:** 5\
**Last updated:** [March 18, 2020, 3:01pm UTC](https://discourse.julialang.org/t/estimating-function-intergral-function-containing-a-sine-or-a-cosine/36139 "2020-03-18T15:01:32Z")

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Hi Julia users, I am looking for a package with functionality similar to the FORTRAN package QDAWO: https://docs.roguewave.com/en/imsl/fortran/2018.0/html/fnlmath/index.html#page/FNLMath/mch4.07.08.html. The FORTRAN fu…

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## [Indexing Nonlinear Expressions with nested indices in JuMP](https://discourse.julialang.org/t/indexing-nonlinear-expressions-with-nested-indices-in-jump/36140)

<div class="topic-metadata">

**Author:** [@shoshievass](https://discourse.julialang.org/u/shoshievass)\
**Replies:** 3\
**Last updated:** [March 18, 2020, 1:51pm UTC](https://discourse.julialang.org/t/indexing-nonlinear-expressions-with-nested-indices-in-jump/36140 "2020-03-18T13:51:11Z")

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I’m trying to define a JuMP @NLexpression with embedded indexing and I need to use numerical indices instead of collections. I would have thought that the below would work but I’m getting an error saying that F was alrea…

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## [Julia v1.4.0-rc2 is now available](https://discourse.julialang.org/t/julia-v1-4-0-rc2-is-now-available/35195)

<div class="topic-metadata">

**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 4\
**Last updated:** [March 18, 2020, 1:20pm UTC](https://discourse.julialang.org/t/julia-v1-4-0-rc2-is-now-available/35195 "2020-03-18T13:20:23Z")

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The second release candidate for Julia v1.4.0 is now available. You can get binaries at Download Julia for Linux (i686, x86-64, AArch64; ARMv7 coming soon), macOS, FreeBSD (x86-64), and Windows (32-, 64-bit). Check out t…

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## [Missing 7z.exe in Julia-1.3.0-rc3](https://discourse.julialang.org/t/missing-7z-exe-in-julia-1-3-0-rc3/29575)

<div class="topic-metadata">

**Author:** [@MikeErd](https://discourse.julialang.org/u/MikeErd)\
**Replies:** 6\
**Last updated:** [March 18, 2020, 12:53pm UTC](https://discourse.julialang.org/t/missing-7z-exe-in-julia-1-3-0-rc3/29575 "2020-03-18T12:53:08Z")

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Compared to previous Julia versions it looks like, that 7z.exe file in %JULIA\_HOME%/bin is missing (right after a fresh installation). This issue has been detected when adding JLD2 package. add JLD2 Updating registry…

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