# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1688

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

**Page:** 1689

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## [Differentiable @unpack-ing of function arguments](https://discourse.julialang.org/t/differentiable-unpack-ing-of-function-arguments/43146)

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**Author:** [@mefob](https://discourse.julialang.org/u/mefob)\
**Replies:** 9\
**Last updated:** [July 15, 2020, 10:27pm UTC](https://discourse.julialang.org/t/differentiable-unpack-ing-of-function-arguments/43146 "2020-07-15T22:27:47Z")

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What is the recommended approach to @unpack parameters in a differential equation when using gradient wrt these parameters: I could not get named tuples or dicts to work, this is what I tried: using DiffEqSensitivi…

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## [Variable not defined in module](https://discourse.julialang.org/t/variable-not-defined-in-module/43147)

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**Author:** [@Lewis\_Liu](https://discourse.julialang.org/u/Lewis_Liu)\
**Replies:** 5\
**Last updated:** [July 15, 2020, 9:46pm UTC](https://discourse.julialang.org/t/variable-not-defined-in-module/43147 "2020-07-15T21:46:05Z")

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module TestN1 sum=1 for i in 1:10 sum += i end end The code above doesn’t work. Is something wrong？ Julia version 1.4.2.

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## [Heterogeneous units and ModelingToolkit](https://discourse.julialang.org/t/heterogeneous-units-and-modelingtoolkit/37922)

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**Author:** [@mefob](https://discourse.julialang.org/u/mefob)\
**Replies:** 5\
**Last updated:** [July 15, 2020, 9:04pm UTC](https://discourse.julialang.org/t/heterogeneous-units-and-modelingtoolkit/37922 "2020-07-15T21:04:58Z")

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I am trying to use the ModelingToolkit together with Unitful to model a coupled system of two ODEs with different units. The following code fails on ODEProblem with a DimensionError unless both units in u0 are the same: …

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## [What is the Package Host URL?](https://discourse.julialang.org/t/what-is-the-package-host-url/43137)

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**Author:** [@ctkelley](https://discourse.julialang.org/u/ctkelley)\
**Replies:** 5\
**Last updated:** [July 15, 2020, 8:10pm UTC](https://discourse.julialang.org/t/what-is-the-package-host-url/43137 "2020-07-15T20:10:45Z")

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I’m looking at the web form on JuliaHub. What is the Package Host URL? If the package URL is https://github.com/DrFoo/Bar.jl is the Package host URL https://github.com or something else? I think I’m missing something p…

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## [Where do all the packages come from?](https://discourse.julialang.org/t/where-do-all-the-packages-come-from/43135)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 7\
**Last updated:** [July 15, 2020, 8:07pm UTC](https://discourse.julialang.org/t/where-do-all-the-packages-come-from/43135 "2020-07-15T20:07:07Z")

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Today I was testing one of my packages with the nightly Julia. I noticed that the list of packages during “update” was several dozen entries long. I don’t know how it got so long: I’m pretty sure that most of these pack…

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## [Is there a size limit of array in PyCall.array2py?](https://discourse.julialang.org/t/is-there-a-size-limit-of-array-in-pycall-array2py/43072)

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**Author:** [@shriaas2898](https://discourse.julialang.org/u/shriaas2898)\
**Replies:** 5\
**Last updated:** [July 15, 2020, 6:36pm UTC](https://discourse.julialang.org/t/is-there-a-size-limit-of-array-in-pycall-array2py/43072 "2020-07-15T18:36:05Z")

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I was trying benchmarking package to test performance of sum using python built-in function. I tried converting array with 10^8 elements to a python list using PyCall.array2py and jupyter notebook got hanged I even tried…

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## [Error with SCIP when reoptimize after adding a constraint](https://discourse.julialang.org/t/error-with-scip-when-reoptimize-after-adding-a-constraint/43112)

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**Author:** [@remi-garcia](https://discourse.julialang.org/u/remi-garcia)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 6:20pm UTC](https://discourse.julialang.org/t/error-with-scip-when-reoptimize-after-adding-a-constraint/43112 "2020-07-15T18:20:32Z")

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Hi, I don’t understand why SCIP throws an error when I reoptimize a model after adding a constraint. Error: """ using JuMP; using SCIP; model = Model(SCIP.Optimizer); @variable(model, x);@variable(model, y);@variable(…

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## [Multithreading throw segmentfault occationally](https://discourse.julialang.org/t/multithreading-throw-segmentfault-occationally/43132)

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**Author:** [@Roger-luo](https://discourse.julialang.org/u/Roger-luo)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 5:09pm UTC](https://discourse.julialang.org/t/multithreading-throw-segmentfault-occationally/43132 "2020-07-15T17:09:04Z")

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Hi I’m wondering if this is some kind of known issue, basically I have one simulation task for each Task, and I spawn 72 threads to execute these tasks, then my code throw a segment fault from the BLAS when I create 160 …

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## [Introduce myself](https://discourse.julialang.org/t/introduce-myself/43111)

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**Author:** [@thisisusername123](https://discourse.julialang.org/u/thisisusername123)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 4:50pm UTC](https://discourse.julialang.org/t/introduce-myself/43111 "2020-07-15T16:50:27Z")

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My name’s Kien, I come from Ha Noi, I’m studying International Business at VNU and planning to take an IELTS exam next year. My hobbies are reading English books , playing video games and football, listening to US-UK mus…

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## [The compiler goes in segmentation fault with a fibonacci facuntion call (greater that 1)](https://discourse.julialang.org/t/the-compiler-goes-in-segmentation-fault-with-a-fibonacci-facuntion-call-greater-that-1/43136)

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**Author:** [@phykos](https://discourse.julialang.org/u/phykos)\
**Replies:** 3\
**Last updated:** [July 15, 2020, 4:48pm UTC](https://discourse.julialang.org/t/the-compiler-goes-in-segmentation-fault-with-a-fibonacci-facuntion-call-greater-that-1/43136 "2020-07-15T16:48:09Z")

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my code is: function fib(n::Integer) if n \<= 1 return n end return fib(n - 1) + fib(n + 2) end for i = 0:40 println(fib(i)) end and the output is: 0 1 \[2\] 5540 segmentation fault (core…

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## [Learning Data Science in Julia for fesher](https://discourse.julialang.org/t/learning-data-science-in-julia-for-fesher/43123)

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**Author:** [@Shahmir\_Asif](https://discourse.julialang.org/u/Shahmir_Asif)\
**Replies:** 3\
**Last updated:** [July 15, 2020, 4:46pm UTC](https://discourse.julialang.org/t/learning-data-science-in-julia-for-fesher/43123 "2020-07-15T16:46:35Z")

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I am a Power Engineer who is interested to change his field. I am interested to be aData Scientist. I am new to programming and after reading about different programming languages I have preferred Julia over other in whi…

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## [Optimize combination of element-wise products and matrix multiplication](https://discourse.julialang.org/t/optimize-combination-of-element-wise-products-and-matrix-multiplication/43088)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 10\
**Last updated:** [July 15, 2020, 4:38pm UTC](https://discourse.julialang.org/t/optimize-combination-of-element-wise-products-and-matrix-multiplication/43088 "2020-07-15T16:38:31Z")

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Hello everyone, I heavily use the following operation in my code: d = (A .\* B)\*c where A, B \\in R^{n\_x,n\_y}, c \\in R^{n\_y} and d \\in R^{n\_x}. I couldn’t find a faster way to compute this than the vectorized form d = (…

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## [InPlace FFT Plan and view](https://discourse.julialang.org/t/inplace-fft-plan-and-view/43016)

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**Author:** [@AmarjeetK](https://discourse.julialang.org/u/AmarjeetK)\
**Replies:** 4\
**Last updated:** [July 15, 2020, 4:25pm UTC](https://discourse.julialang.org/t/inplace-fft-plan-and-view/43016 "2020-07-15T16:25:02Z")

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Hi All, I have this view problem with plan\_fft!, Part of the code is below: using FFTW L = (128,16,16); pad = 2; data = rand(ComplexF32,128,16,16); FFT\_buffer = zeros(ComplexF32,128,32,32); FFT\_buffer\[:,1:L\[2\],1:…

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## [Auth: Requested permissions are too broad](https://discourse.julialang.org/t/auth-requested-permissions-are-too-broad/43124)

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**Author:** [@ablekh](https://discourse.julialang.org/u/ablekh)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 3:25pm UTC](https://discourse.julialang.org/t/auth-requested-permissions-are-too-broad/43124 "2020-07-15T15:25:24Z")

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Hi, I’m new to JuliaPro, just installed it and wanted to play with. When trying to add some packages (specifically Modia: https://github.com/ModiaSim/Modia.jl), JuliaPro initiates the authentication flow, which results i…

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## [Updating the solution of ODE at every time step](https://discourse.julialang.org/t/updating-the-solution-of-ode-at-every-time-step/43096)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 5\
**Last updated:** [July 15, 2020, 3:14pm UTC](https://discourse.julialang.org/t/updating-the-solution-of-ode-at-every-time-step/43096 "2020-07-15T15:14:45Z")

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I have a system of differential equations solved as following: ## Lets solve the ODE first without using Kalman Filters function theo\_ode!(du,u,p,t) du\[1\] = u\[2\] du\[2\] = -0.01\*u\[2\] - u\[1\] + sin(2\*t) end u₀ = \[0…

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## [Agents.jl/AgentsPlots.jl/InteractiveChaos.jl errors](https://discourse.julialang.org/t/agents-jl-agentsplots-jl-interactivechaos-jl-errors/42941)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 2:23pm UTC](https://discourse.julialang.org/t/agents-jl-agentsplots-jl-interactivechaos-jl-errors/42941 "2020-07-15T14:23:22Z")

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I’m trying to build a simple model and I’m experiencing some errors that I’m unable to debug. Here’s the code I’m running: using Agents using AgentsPlots using Distributions using LightGraphs mutable struct EmployerAge…

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## [Should readdlm have a default typed value?](https://discourse.julialang.org/t/should-readdlm-have-a-default-typed-value/43128)

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**Author:** [@jmg.duarte](https://discourse.julialang.org/u/jmg.duarte)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 1:57pm UTC](https://discourse.julialang.org/t/should-readdlm-have-a-default-typed-value/43128 "2020-07-15T13:57:10Z")

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Hello everyone! I’m currently developing a project which requires reading old text files, Fortran formated arrays. Which means I have huge text files like this: 0.0071435 0.00745535 0.00776577 0.00807047 0.…

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## [How to generate StatsMakie qqplot?](https://discourse.julialang.org/t/how-to-generate-statsmakie-qqplot/43129)

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**Author:** [@renato](https://discourse.julialang.org/u/renato)\
**Replies:** 0\
**Last updated:** [July 15, 2020, 1:35pm UTC](https://discourse.julialang.org/t/how-to-generate-statsmakie-qqplot/43129 "2020-07-15T13:35:44Z")

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I already know there is a qqplot recipe in StatsMakie (https://github.com/JuliaPlots/StatsMakie.jl/blob/master/src/typerecipes/distribution.jl#L28). Can anyone give me some help on how to use it, with a simple working e…

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## [Double quotes in run() function](https://discourse.julialang.org/t/double-quotes-in-run-function/43117)

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**Author:** [@Bjorn\_De](https://discourse.julialang.org/u/Bjorn_De)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 12:51pm UTC](https://discourse.julialang.org/t/double-quotes-in-run-function/43117 "2020-07-15T12:51:55Z")

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Hi, I want to execute an external tool out of Julia using the run() function: run(\`gdal\_translate -of GTiff HDF4\_EOS:EOS\_GRID:"$(hdf\_path)":MODIS\_Grid\_16DAY\_500m\_VI:"500m 16 days NDVI" $gtiff\_path\`) which produces an …

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## [Workshop on System Level Engineering for Exascale - today](https://discourse.julialang.org/t/workshop-on-system-level-engineering-for-exascale-today/43035)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 3\
**Last updated:** [July 15, 2020, 12:10pm UTC](https://discourse.julialang.org/t/workshop-on-system-level-engineering-for-exascale-today/43035 "2020-07-15T12:10:00Z")

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https://excalibur-sle.github.io/workshop1.html Sorry for the short notice. If you register late ping me for a link to the Zoom session

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## [Remove a package from dependencies](https://discourse.julialang.org/t/remove-a-package-from-dependencies/43056)

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**Author:** [@marouane1994](https://discourse.julialang.org/u/marouane1994)\
**Replies:** 7\
**Last updated:** [July 15, 2020, 11:03am UTC](https://discourse.julialang.org/t/remove-a-package-from-dependencies/43056 "2020-07-15T11:03:26Z")

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I made a package that has Mamba in its dependencies and now i want to delete it, because whenever i use this package it shows me warnings about Mamba but the thing is that i don’t really know how can i remove Mamba from …

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## [Key 2 not found error](https://discourse.julialang.org/t/key-2-not-found-error/43105)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 3\
**Last updated:** [July 15, 2020, 10:30am UTC](https://discourse.julialang.org/t/key-2-not-found-error/43105 "2020-07-15T10:30:42Z")

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Hello, What does this error mean? “Key 2 not found” Nodes\_set=\[1,2,3\] Gen\_set=\[1,3\] Pd=\[0,-4,0\] JuMP.@variable(m, 0.1 ≤ p\[i in Gen\_set\] ≤ 2) JuMP.@variable(m, pij\[i = Nodes\_set, j = Nodes\_set\]) JuMP.@constraint(m, Pnod…

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## [How to wrap using JuMP inside a function](https://discourse.julialang.org/t/how-to-wrap-using-jump-inside-a-function/43004)

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**Author:** [@asavasci](https://discourse.julialang.org/u/asavasci)\
**Replies:** 3\
**Last updated:** [July 15, 2020, 10:06am UTC](https://discourse.julialang.org/t/how-to-wrap-using-jump-inside-a-function/43004 "2020-07-15T10:06:32Z")

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I want to place “using JuMP” inside a function as follows function test() using JuMP ... end However, it gives an error syntax: "using" expression not at top level, is there a way to work around it?

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## [Multithreading a loop with ARPACK eigs()](https://discourse.julialang.org/t/multithreading-a-loop-with-arpack-eigs/43031)

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**Author:** [@dehond](https://discourse.julialang.org/u/dehond)\
**Replies:** 6\
**Last updated:** [July 15, 2020, 9:30am UTC](https://discourse.julialang.org/t/multithreading-a-loop-with-arpack-eigs/43031 "2020-07-15T09:30:10Z")

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I’m attempting to multithread a calculation in which I loop over a function that calls on ARPACK’s eigs(). However, whenever I insert the Threads.@threads macro in front of the loop I either get an error or Julia crashes…

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## [Function type signature](https://discourse.julialang.org/t/function-type-signature/43101)

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**Author:** [@pauljurczak](https://discourse.julialang.org/u/pauljurczak)\
**Replies:** 24\
**Last updated:** [July 15, 2020, 9:17am UTC](https://discourse.julialang.org/t/function-type-signature/43101 "2020-07-15T09:17:31Z")

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I defined two methods of a function, which I thought will have different type signatures: foo((a, b)) = print(a, "--", b) foo(a) = print(a) but I’m getting: julia\> methods(foo) # 1 method for generic function "foo": \[…

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## [Control Arduino](https://discourse.julialang.org/t/control-arduino/29982)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 33\
**Last updated:** [July 15, 2020, 9:12am UTC](https://discourse.julialang.org/t/control-arduino/29982 "2020-07-15T09:12:43Z")

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Hi! I want to control an LED strip (DotStar) from an Arduino UNO. Is there anything new in this domain? I managed to find these 3 resources: but maybe I missed something, perhaps this has some implications on that? …

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## [Extending JuMP.@constraint macro: misunderstanding scope?](https://discourse.julialang.org/t/extending-jump-constraint-macro-misunderstanding-scope/43046)

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**Author:** [@gobs](https://discourse.julialang.org/u/gobs)\
**Replies:** 2\
**Last updated:** [July 15, 2020, 8:11am UTC](https://discourse.julialang.org/t/extending-jump-constraint-macro-misunderstanding-scope/43046 "2020-07-15T08:11:53Z")

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I’ve been toying with the idea of extending the JuMP.@constraint macro to make my code somewhat more concise. Here’s an example of what I currently do: con1 = @constraint(gep.model, \[i=1:10\], x\[i\] \>= 0) # Make an anonym…

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## [\[ANN\] EuclideanDistanceMatrices.jl](https://discourse.julialang.org/t/ann-euclideandistancematrices-jl/43107)

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**Author:** [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)\
**Replies:** 0\
**Last updated:** [July 15, 2020, 7:37am UTC](https://discourse.julialang.org/t/ann-euclideandistancematrices-jl/43107 "2020-07-15T07:37:02Z")

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The package EuclideanDistanceMatrices.jl contains tools for working with said matrices, doing this like Estimating them. Completing them if they have missing entries. Denoising them if they are measured and have noisy …

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## [Package fetch issues with internal SSL certificate](https://discourse.julialang.org/t/package-fetch-issues-with-internal-ssl-certificate/43026)

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**Author:** [@yalwan-iqvia](https://discourse.julialang.org/u/yalwan-iqvia)\
**Replies:** 1\
**Last updated:** [July 15, 2020, 7:31am UTC](https://discourse.julialang.org/t/package-fetch-issues-with-internal-ssl-certificate/43026 "2020-07-15T07:31:34Z")

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I am trying to update julia packages in some environment I don’t fully control. I don’t have administrative access to root certificate store, and I can’t change the network – SSL requests to github are intercepted. I ca…

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## [Promote not working for nothing, while promote\_type works](https://discourse.julialang.org/t/promote-not-working-for-nothing-while-promote-type-works/43028)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 8\
**Last updated:** [July 15, 2020, 7:15am UTC](https://discourse.julialang.org/t/promote-not-working-for-nothing-while-promote-type-works/43028 "2020-07-15T07:15:50Z")

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julia\> promote(nothing, 4) ERROR: promotion of types Nothing and Int64 failed to change any arguments Stacktrace: \[1\] error(::String, ::String, ::String) at ./error.jl:42 \[2\] sametype\_error(::Tuple{Nothing,Int64}) at .…

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