# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=773

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

**Page:** 774

---

## [Strange test failures on Julia 1.4, possibly related to ForwardDiff.jl](https://discourse.julialang.org/t/strange-test-failures-on-julia-1-4-possibly-related-to-forwarddiff-jl/36398)

<div class="topic-metadata">

**Author:** [@s-broda](https://discourse.julialang.org/u/s-broda)\
**Replies:** 2\
**Last updated:** [March 23, 2020, 3:55pm UTC](https://discourse.julialang.org/t/strange-test-failures-on-julia-1-4-possibly-related-to-forwarddiff-jl/36398 "2020-03-23T15:55:04Z")

</div>

Hi all ARCHModels.jl (registered package) has test failures on Julia 1.4, see here. Tests pass on 1.3 and on nightly. The really strange thing is that I can reproduce this locally, but only within Pkg.test; when I run …

---

## [Error in using DifferentialEquations](https://discourse.julialang.org/t/error-in-using-differentialequations/36012)

<div class="topic-metadata">

**Author:** [@Eris](https://discourse.julialang.org/u/Eris)\
**Replies:** 8\
**Last updated:** [March 23, 2020, 2:47pm UTC](https://discourse.julialang.org/t/error-in-using-differentialequations/36012 "2020-03-23T14:47:30Z")

</div>

I just installed Julia and was testing out some packages. I installed DifferentialEquations but I get the following output when I try using it: using DifferentialEquations \[ Info: Precompiling DifferentialEquations \[0…

---

## [Julia 1.4 can't update registry](https://discourse.julialang.org/t/julia-1-4-cant-update-registry/36390)

<div class="topic-metadata">

**Author:** [@pixel27](https://discourse.julialang.org/u/pixel27)\
**Replies:** 1\
**Last updated:** [March 23, 2020, 1:26pm UTC](https://discourse.julialang.org/t/julia-1-4-cant-update-registry/36390 "2020-03-23T13:26:48Z")

</div>

I have a VM running Manjaro on the test branch. I wanted to check if Julia 1.4 made has made it onto the test branch so I fired up the VM updated it and yes 1.4 has made it into test. So I wanted to test it. I hadn’t …

---

## [How to get the version of Pkg](https://discourse.julialang.org/t/how-to-get-the-version-of-pkg/36388)

<div class="topic-metadata">

**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 1\
**Last updated:** [March 23, 2020, 11:57am UTC](https://discourse.julialang.org/t/how-to-get-the-version-of-pkg/36388 "2020-03-23T11:57:24Z")

</div>

Hi, I want to check which version of Pkg is used inside my julia 1.4 install. How can I get the version of an included library?

---

## [Strange broadcasting results](https://discourse.julialang.org/t/strange-broadcasting-results/36387)

<div class="topic-metadata">

**Author:** [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Replies:** 1\
**Last updated:** [March 23, 2020, 11:55am UTC](https://discourse.julialang.org/t/strange-broadcasting-results/36387 "2020-03-23T11:55:20Z")

</div>

F = 59411.4 n = 12 K = \[220.0, 900.0\] @show S\_1 = F/(n\*K\[1\]) @show S\_2 = F/(n\*K\[2\]) @show S\_dot = F./(K.\*n) @show S\_nodot = F/(n\*K) @. S\_atdot = F/(K\*n) # S\_alldots .= F./(K.\*n) # UndefVarError: S\_alldots not defined p…

---

## [Julia 'sometimes' hangs (until a key is pressed) - Windows10 - Does anybody ever encounter that?](https://discourse.julialang.org/t/julia-sometimes-hangs-until-a-key-is-pressed-windows10-does-anybody-ever-encounter-that/6768)

<div class="topic-metadata">

**Author:** [@bernhard](https://discourse.julialang.org/u/bernhard)\
**Replies:** 10\
**Last updated:** [March 23, 2020, 10:40am UTC](https://discourse.julialang.org/t/julia-sometimes-hangs-until-a-key-is-pressed-windows10-does-anybody-ever-encounter-that/6768 "2020-03-23T10:40:05Z")

</div>

Sometimes when I am calculating a lot of ‘models’ Julia will hang. This happens in ‘cmd’ but also with Powershell. In my case, my code continuously produces output to the console (files that are being written, progress,…

---

## [A lot of memory allocations which I do not understand](https://discourse.julialang.org/t/a-lot-of-memory-allocations-which-i-do-not-understand/36381)

<div class="topic-metadata">

**Author:** [@fedoroff](https://discourse.julialang.org/u/fedoroff)\
**Replies:** 2\
**Last updated:** [March 23, 2020, 9:39am UTC](https://discourse.julialang.org/t/a-lot-of-memory-allocations-which-i-do-not-understand/36381 "2020-03-23T09:39:06Z")

</div>

I try to mimic the DifferentialEquations.jl solver where, as an example, I consider out of place second order Runge-Kutta method. The code below is the content of the .mem file obtained by running Julia with “–track-allo…

---

## [What's the difference between fields and properties?](https://discourse.julialang.org/t/whats-the-difference-between-fields-and-properties/12495)

<div class="topic-metadata">

**Author:** [@anon32405968](https://discourse.julialang.org/u/anon32405968)\
**Replies:** 8\
**Last updated:** [March 23, 2020, 7:32am UTC](https://discourse.julialang.org/t/whats-the-difference-between-fields-and-properties/12495 "2020-03-23T07:32:56Z")

</div>

I’m trying to understand this pull request which will be implemented in V0.7/V1.0: https://github.com/JuliaLang/julia/pull/25311 I read the V0.7 documentation but I coudn’t find any clarification on the specific differ…

---

## [Install a packages from a list](https://discourse.julialang.org/t/install-a-packages-from-a-list/30920)

<div class="topic-metadata">

**Author:** [@ilango3](https://discourse.julialang.org/u/ilango3)\
**Replies:** 6\
**Last updated:** [March 23, 2020, 7:01am UTC](https://discourse.julialang.org/t/install-a-packages-from-a-list/30920 "2020-03-23T07:01:39Z")

</div>

Hi , I need to install packages from a list. I was wondering if julia has an a command to install from list. like python’s "pip install -r requirements.txt " ? Thanks.

---

## [Ipopt in different Julia versions](https://discourse.julialang.org/t/ipopt-in-different-julia-versions/36373)

<div class="topic-metadata">

**Author:** [@greg\_plowman](https://discourse.julialang.org/u/greg_plowman)\
**Replies:** 0\
**Last updated:** [March 23, 2020, 2:43am UTC](https://discourse.julialang.org/t/ipopt-in-different-julia-versions/36373 "2020-03-23T02:43:51Z")

</div>

I get this error with Ipopt (version v0.6.1): ERROR: LoadError: could not load library "C:\\Users\\plowman\\.julia\\packages\\Ipopt\\ruIXY\\deps\\usr\\bin\\libipopt-1.dll" The specified module could not be found. I’m using Julia…

---

## [How to generate the permutation of a vector with elements selected from a certain set](https://discourse.julialang.org/t/how-to-generate-the-permutation-of-a-vector-with-elements-selected-from-a-certain-set/36032)

<div class="topic-metadata">

**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 4\
**Last updated:** [March 23, 2020, 12:01am UTC](https://discourse.julialang.org/t/how-to-generate-the-permutation-of-a-vector-with-elements-selected-from-a-certain-set/36032 "2020-03-23T00:01:18Z")

</div>

Hi guys I am looking for some function that generates the permutation of a vector of a certain length with elements taken from a certain set. For example let us say we are generating the permutation of vectors of length …

---

## [User interface](https://discourse.julialang.org/t/user-interface/36371)

<div class="topic-metadata">

**Author:** [@Smith](https://discourse.julialang.org/u/Smith)\
**Replies:** 0\
**Last updated:** [March 22, 2020, 11:38pm UTC](https://discourse.julialang.org/t/user-interface/36371 "2020-03-22T23:38:03Z")

</div>

Hi, Are there are any stable Julia packages for creating a basic user interface? For example, an interface that allows a user to enter relevant inputs and run the relevant code by click of a button (like forms in VBA). …

---

## [Question about arguments passed to the filter function](https://discourse.julialang.org/t/question-about-arguments-passed-to-the-filter-function/36364)

<div class="topic-metadata">

**Author:** [@CH-8](https://discourse.julialang.org/u/CH-8)\
**Replies:** 2\
**Last updated:** [March 22, 2020, 11:08pm UTC](https://discourse.julialang.org/t/question-about-arguments-passed-to-the-filter-function/36364 "2020-03-22T23:08:40Z")

</div>

Hi, The code block below achieves its purpose but Julia provides a warning for how the argument is passed. key1 = \[ 1, 1, 2, 3, 3, 4\]; key2 = \[ 2, 3, 4, 4, 5, 5\] value = \[0.3, 0.145, 0.032, 0.260, 0.320, 0.500\] Dat…

---

## [Debugger.jl + CSV.jl =\> crash](https://discourse.julialang.org/t/debugger-jl-csv-jl-crash/33713)

<div class="topic-metadata">

**Author:** [@hendri54](https://discourse.julialang.org/u/hendri54)\
**Replies:** 3\
**Last updated:** [March 22, 2020, 10:39pm UTC](https://discourse.julialang.org/t/debugger-jl-csv-jl-crash/33713 "2020-03-22T22:39:58Z")

</div>

How to fix the following crash: using Debugger using CSV function csv1() fPath = joinpath(@\_\_DIR\_\_, "test1.csv"); @assert isfile(fPath) csvFile = CSV.File(fPath, header = true, delim = '\\t'); @bp …

---

## [Parallelization from v1.1.1 to v1.4](https://discourse.julialang.org/t/parallelization-from-v1-1-1-to-v1-4/36365)

<div class="topic-metadata">

**Author:** [@swishmas](https://discourse.julialang.org/u/swishmas)\
**Replies:** 0\
**Last updated:** [March 22, 2020, 9:04pm UTC](https://discourse.julialang.org/t/parallelization-from-v1-1-1-to-v1-4/36365 "2020-03-22T21:04:00Z")

</div>

I just want to know if I missed anything or if there’s a future fix planned. I have code written in v1.1.1 that uses a lot of the multi-threading parallelization listed here When v1.2 and v1.3 came out, there was an att…

---

## [Why is this closure over keyword arguments causing such a dramatic slowdown?](https://discourse.julialang.org/t/why-is-this-closure-over-keyword-arguments-causing-such-a-dramatic-slowdown/36308)

<div class="topic-metadata">

**Author:** [@anon32405968](https://discourse.julialang.org/u/anon32405968)\
**Replies:** 19\
**Last updated:** [March 22, 2020, 8:43pm UTC](https://discourse.julialang.org/t/why-is-this-closure-over-keyword-arguments-causing-such-a-dramatic-slowdown/36308 "2020-03-22T20:43:15Z")

</div>

I’m writing a function that allows a user to freeze some variables of a function (needs to be generic with respect to the names and number of keyword arguments). Design-wise, I now have exactly what I need and the code i…

---

## [Embedding Julia in C++, packages can not be found from embedded script](https://discourse.julialang.org/t/embedding-julia-in-c-packages-can-not-be-found-from-embedded-script/36306)

<div class="topic-metadata">

**Author:** [@gobrad](https://discourse.julialang.org/u/gobrad)\
**Replies:** 1\
**Last updated:** [March 22, 2020, 8:31pm UTC](https://discourse.julialang.org/t/embedding-julia-in-c-packages-can-not-be-found-from-embedded-script/36306 "2020-03-22T20:31:12Z")

</div>

Hi I am working on embedding Julia in a C++ application. Simple Julia programs work fine, I can call Julia functions, access variables etc. But, trying to use any package in Julia, e.g. adding “using Measurements” or “…

---

## [Does anybody know how to get the crumb of YahooFinance?](https://discourse.julialang.org/t/does-anybody-know-how-to-get-the-crumb-of-yahoofinance/31504)

<div class="topic-metadata">

**Author:** [@markushhh](https://discourse.julialang.org/u/markushhh)\
**Replies:** 4\
**Last updated:** [March 22, 2020, 7:40pm UTC](https://discourse.julialang.org/t/does-anybody-know-how-to-get-the-crumb-of-yahoofinance/31504 "2020-03-22T19:40:03Z")

</div>

I am trying for weeks now to find out how HTTP and the YahooFinance API work together. Would love if someone can give me a hint. Thanks!

---

## [Modules and files](https://discourse.julialang.org/t/modules-and-files/36330)

<div class="topic-metadata">

**Author:** [@vinhphunguyen](https://discourse.julialang.org/u/vinhphunguyen)\
**Replies:** 4\
**Last updated:** [March 22, 2020, 5:57pm UTC](https://discourse.julialang.org/t/modules-and-files/36330 "2020-03-22T17:57:01Z")

</div>

Hi all, I have this code with 3 files: MaterialPoint.jl for module MaterialPoint as follows module MaterialPoint using LinearAlgebra export mpmMaterialPoint\_2D\_Classic,createMaterialDomain\_Circle mutable s…

---

## [Finding eigenvectors (simple problems)](https://discourse.julialang.org/t/finding-eigenvectors-simple-problems/36315)

<div class="topic-metadata">

**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 10\
**Last updated:** [March 22, 2020, 5:36pm UTC](https://discourse.julialang.org/t/finding-eigenvectors-simple-problems/36315 "2020-03-22T17:36:21Z")

</div>

I’m studying linear algebra and I’ve run into an issue that I’ve figured out how to solve with Julia, but I’m hoping there’s a better way. Given some simple 2 x 2 transformation matrices, I have to determine which vector…

---

## [Empty Named Tuple](https://discourse.julialang.org/t/empty-named-tuple/36314)

<div class="topic-metadata">

**Author:** [@alphasig329](https://discourse.julialang.org/u/alphasig329)\
**Replies:** 4\
**Last updated:** [March 22, 2020, 3:24pm UTC](https://discourse.julialang.org/t/empty-named-tuple/36314 "2020-03-22T15:24:49Z")

</div>

Is it possible to initialize an empty NamedTuple with the appropriate keys and types for values? Can you then push future NamedTuples into this empty NamedTuple? Thanks!

---

## [Reading fixed-width files?](https://discourse.julialang.org/t/reading-fixed-width-files/30163)

<div class="topic-metadata">

**Author:** [@braamvandyk](https://discourse.julialang.org/u/braamvandyk)\
**Replies:** 22\
**Last updated:** [March 22, 2020, 1:35pm UTC](https://discourse.julialang.org/t/reading-fixed-width-files/30163 "2020-03-22T13:35:19Z")

</div>

I have data files (containing parameters for a 3rd-party, proprietary model) that are supplied in fixed-width format. Unfortunately, the specific format is for Fortran’s fixed field widths, with the effect that some valu…

---

## [Find all indexes of string in string array](https://discourse.julialang.org/t/find-all-indexes-of-string-in-string-array/36302)

<div class="topic-metadata">

**Author:** [@jonjilla](https://discourse.julialang.org/u/jonjilla)\
**Replies:** 12\
**Last updated:** [March 21, 2020, 11:05pm UTC](https://discourse.julialang.org/t/find-all-indexes-of-string-in-string-array/36302 "2020-03-21T23:05:01Z")

</div>

Hello, Can someone help me with this? It seems like it should be easy but I can’t quite figure it out. I’m trying to find all of the array indicies in this String array that matches the search string Something like t…

---

## [Plots How to get exact point of intersection of a plot with axis?](https://discourse.julialang.org/t/plots-how-to-get-exact-point-of-intersection-of-a-plot-with-axis/36304)

<div class="topic-metadata">

**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 4\
**Last updated:** [March 21, 2020, 10:15pm UTC](https://discourse.julialang.org/t/plots-how-to-get-exact-point-of-intersection-of-a-plot-with-axis/36304 "2020-03-21T22:15:04Z")

</div>

Plots How to get exact point of intersection of a plot with axis ? x=range(0,stop=2pi,length=365) plot!(sin.(x)) x is intersecting with y at -1 , I expect on 0 level Paul

---

## [Help in making the code faster and/or reducing allocations?](https://discourse.julialang.org/t/help-in-making-the-code-faster-and-or-reducing-allocations/36299)

<div class="topic-metadata">

**Author:** [@bashonubuntu](https://discourse.julialang.org/u/bashonubuntu)\
**Replies:** 2\
**Last updated:** [March 21, 2020, 7:22pm UTC](https://discourse.julialang.org/t/help-in-making-the-code-faster-and-or-reducing-allocations/36299 "2020-03-21T19:22:08Z")

</div>

Thank you for the replies! I have realized this won’t be productive due to the length of the code so I’m closing this. I believe I can’t delete the thread myself but have flagged it so that it can be deleted sometime in …

---

## [Polynomials & Polyfit](https://discourse.julialang.org/t/polynomials-polyfit/36309)

<div class="topic-metadata">

**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 0\
**Last updated:** [March 21, 2020, 6:26pm UTC](https://discourse.julialang.org/t/polynomials-polyfit/36309 "2020-03-21T18:26:58Z")

</div>

I’m looking at basic use of Polynomials.jl with polyfit, polyval, etc., and have 3 questions: According to the Polynomials.jl documentation, there is a fourth argument for polyfit: sym, which I can use to specify a sym…

---

## [Hdf5plot\_write error](https://discourse.julialang.org/t/hdf5plot-write-error/35036)

<div class="topic-metadata">

**Author:** [@hendri54](https://discourse.julialang.org/u/hendri54)\
**Replies:** 4\
**Last updated:** [March 21, 2020, 11:54am UTC](https://discourse.julialang.org/t/hdf5plot-write-error/35036 "2020-03-21T11:54:45Z")

</div>

Trying to write a plot in hdf5 format yields the following error: using Plots, HDF5 julia\> hdf5() Plots.HDF5Backend() julia\> p=plot(1:10, 1:10); julia\> Plots.hdf5plot\_write(p, "plotsave.hdf5") ERROR: MethodError: no …

---

## [Findfirst ERROR: MethodError: no method matching keys](https://discourse.julialang.org/t/findfirst-error-methoderror-no-method-matching-keys/36292)

<div class="topic-metadata">

**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 1\
**Last updated:** [March 21, 2020, 8:17am UTC](https://discourse.julialang.org/t/findfirst-error-methoderror-no-method-matching-keys/36292 "2020-03-21T08:17:57Z")

</div>

I’m sure this is addressed somewhere, I just can’t (drum-roll) find it. Given some matrix, I want to find the first row whose sum is odd: julia\> m = \[0 0 0; 1 1 1; 2 2 2\] 3×3 Array{Int64,2}: 0 0 0 1 1 1 2 2 2 …

---

## [Infinite matrices in Julia?](https://discourse.julialang.org/t/infinite-matrices-in-julia/36278)

<div class="topic-metadata">

**Author:** [@VikoRifeo](https://discourse.julialang.org/u/VikoRifeo)\
**Replies:** 2\
**Last updated:** [March 20, 2020, 9:47pm UTC](https://discourse.julialang.org/t/infinite-matrices-in-julia/36278 "2020-03-20T21:47:25Z")

</div>

I’m trying to subtype AbstractMatrix for a matrix which has infinite rows. What should axes, size and length return? Floating-point Inf is probably out, because the indices must be integers. I could report it as typemin(…

---

## [How do I lessen memory allocation and speedup block inverse?](https://discourse.julialang.org/t/how-do-i-lessen-memory-allocation-and-speedup-block-inverse/36273)

<div class="topic-metadata">

**Author:** [@the\_daemon\_lord](https://discourse.julialang.org/u/the_daemon_lord)\
**Replies:** 2\
**Last updated:** [March 20, 2020, 9:38pm UTC](https://discourse.julialang.org/t/how-do-i-lessen-memory-allocation-and-speedup-block-inverse/36273 "2020-03-20T21:38:20Z")

</div>

Hello! I was trying to implement block inverses in Julia and noticed that in some cases it’s faster than the builtin inv() but it also allocates way more memory. Is there any way to improve this function? This is my im…

[Previous page](https://discourse.julialang.org/c/usage/6.md?page=772)

[Next page](https://discourse.julialang.org/c/usage/6.md?page=774)