# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=665

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

**Page:** 666

---

## [Clearest Julia stacktrace library](https://discourse.julialang.org/t/clearest-julia-stacktrace-library/52104)

<div class="topic-metadata">

**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 3\
**Last updated:** [December 19, 2020, 11:02pm UTC](https://discourse.julialang.org/t/clearest-julia-stacktrace-library/52104 "2020-12-19T23:02:40Z")

</div>

Hey, I saw this stacktrace library but this is left alone: https://github.com/jkrumbiegel/ClearStacktrace.jl What custom stacktrace do you guys use? I find ClearStacktrace very good but I ran into some situation when…

---

## [SIMD and compiled code](https://discourse.julialang.org/t/simd-and-compiled-code/52082)

<div class="topic-metadata">

**Author:** [@lungben](https://discourse.julialang.org/u/lungben)\
**Replies:** 5\
**Last updated:** [December 19, 2020, 4:33pm UTC](https://discourse.julialang.org/t/simd-and-compiled-code/52082 "2020-12-19T16:33:14Z")

</div>

Hi, Different processors have different SIMD capabilities, especially different vector sizes on which the processor can work at once. However, there are a few points w.r.t. code compilation which I am not sure about. I…

---

## [Impossible to sort Sym elements](https://discourse.julialang.org/t/impossible-to-sort-sym-elements/51810)

<div class="topic-metadata">

**Author:** [@fms-1988](https://discourse.julialang.org/u/fms-1988)\
**Replies:** 9\
**Last updated:** [December 19, 2020, 10:55am UTC](https://discourse.julialang.org/t/impossible-to-sort-sym-elements/51810 "2020-12-19T10:55:06Z")

</div>

I’m trying to order elements (Sym) from a Tuple. I’ve tried several codes but nothing works. I will be grateful if anyone can help. using SymPy using LinearAlgebra a1 = \[Sym("a\_$i^$j") for i=1 for j=1:2\] a2 = \[Sym("a\_…

---

## [Resolve mismatch between running Julia and the compatibility section](https://discourse.julialang.org/t/resolve-mismatch-between-running-julia-and-the-compatibility-section/52064)

<div class="topic-metadata">

**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 2\
**Last updated:** [December 19, 2020, 6:16am UTC](https://discourse.julialang.org/t/resolve-mismatch-between-running-julia-and-the-compatibility-section/52064 "2020-12-19T06:16:03Z")

</div>

Consider a project: Let us say I have specified compatibility as Julia 1.5. Now I run 1.6, which violates the compatibility requirement. When this happens with packages, activating the environment fails. However with the…

---

## [Weave No Longer Works in v1.5](https://discourse.julialang.org/t/weave-no-longer-works-in-v1-5/49485)

<div class="topic-metadata">

**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 6\
**Last updated:** [December 19, 2020, 12:09am UTC](https://discourse.julialang.org/t/weave-no-longer-works-in-v1-5/49485 "2020-12-19T00:09:54Z")

</div>

I recently upgraded to v1.5, and tried to weave a document. When I reloaded Weave, and tried using I got this warning, and it won’t start a document. I tried updating my packages, do I need fix something in Weave, is w…

---

## [Is there a Python Celery equivalent in Julia?](https://discourse.julialang.org/t/is-there-a-python-celery-equivalent-in-julia/52071)

<div class="topic-metadata">

**Author:** [@guilhermebodin](https://discourse.julialang.org/u/guilhermebodin)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 11:14pm UTC](https://discourse.julialang.org/t/is-there-a-python-celery-equivalent-in-julia/52071 "2020-12-18T23:14:15Z")

</div>

Hello, I am very new to this task queue and message broker thing but is there a package or a way to have task queues just like on celery Celery - Distributed Task Queue — Celery 5.2.7 documentation?

---

## [How to fix manifest issues (mistake when merging compathelper pr)](https://discourse.julialang.org/t/how-to-fix-manifest-issues-mistake-when-merging-compathelper-pr/52070)

<div class="topic-metadata">

**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 9:45pm UTC](https://discourse.julialang.org/t/how-to-fix-manifest-issues-mistake-when-merging-compathelper-pr/52070 "2020-12-18T21:45:04Z")

</div>

can I delete a manifest.toml and regenerate it somehow? I was resolving merge conflicts from compathelper pr’s and I made some mistakes (coffee not on-line yet)…

---

## [Can you beat our solutions for the raindrops exercise?](https://discourse.julialang.org/t/can-you-beat-our-solutions-for-the-raindrops-exercise/52006)

<div class="topic-metadata">

**Author:** [@Luapulu](https://discourse.julialang.org/u/Luapulu)\
**Replies:** 16\
**Last updated:** [December 18, 2020, 8:29pm UTC](https://discourse.julialang.org/t/can-you-beat-our-solutions-for-the-raindrops-exercise/52006 "2020-12-18T20:29:48Z")

</div>

So, @cmcaine, @SaschaMann, @tomerarnon and I have been discussing the raindrops exercise in Exercism and solutions to it. The ExerciseCreate a function raindrops, which will return a string given a number as follows: …

---

## [Retour in installing sole packages](https://discourse.julialang.org/t/retour-in-installing-sole-packages/52068)

<div class="topic-metadata">

**Author:** [@koalatif](https://discourse.julialang.org/u/koalatif)\
**Replies:** 0\
**Last updated:** [December 18, 2020, 8:16pm UTC](https://discourse.julialang.org/t/retour-in-installing-sole-packages/52068 "2020-12-18T20:16:07Z")

</div>

Error occures when I want to install some packages like Plots, Plutôt, etc. Here is a Snapshot :

---

## [Erratic segmentation fault - from a package using \`ccall\`](https://discourse.julialang.org/t/erratic-segmentation-fault-from-a-package-using-ccall/52049)

<div class="topic-metadata">

**Author:** [@stla](https://discourse.julialang.org/u/stla)\
**Replies:** 6\
**Last updated:** [December 18, 2020, 7:59pm UTC](https://discourse.julialang.org/t/erratic-segmentation-fault-from-a-package-using-ccall/52049 "2020-12-18T19:59:08Z")

</div>

Hello, I started a new project: Junuran, a Julia wrapper of the UNU.RAN C library. So far the package only allows to sample from a continuous multivariate distribution when the user gives the density of the distributio…

---

## [Fast reading of multiple big-endian binary files](https://discourse.julialang.org/t/fast-reading-of-multiple-big-endian-binary-files/52060)

<div class="topic-metadata">

**Author:** [@Thomas\_Lei](https://discourse.julialang.org/u/Thomas_Lei)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 5:13pm UTC](https://discourse.julialang.org/t/fast-reading-of-multiple-big-endian-binary-files/52060 "2020-12-18T17:13:47Z")

</div>

Hi all, I have to read and preprocess a huge quantity of binary (big-endian) data from thousands of files. I managed to get everything to work properly, but my function is slow… However, as I’m a Julia beginner, I doubt…

---

## [Julia -e "subtypes(Real)" fails](https://discourse.julialang.org/t/julia-e-subtypes-real-fails/51991)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 6\
**Last updated:** [December 18, 2020, 1:57pm UTC](https://discourse.julialang.org/t/julia-e-subtypes-real-fails/51991 "2020-12-18T13:57:09Z")

</div>

As simple as that. Any file calling subtypes fails to be run as a script, or loaded with julia -i: % julia -e "subtypes(Real)" ERROR: UndefVarError: subtypes not defined Stacktrace: \[1\] top-level scope at none:1 lean…

---

## [Synchronizing 2 loops in multi-threading](https://discourse.julialang.org/t/synchronizing-2-loops-in-multi-threading/52015)

<div class="topic-metadata">

**Author:** [@dopamine](https://discourse.julialang.org/u/dopamine)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 1:40pm UTC](https://discourse.julialang.org/t/synchronizing-2-loops-in-multi-threading/52015 "2020-12-18T13:40:13Z")

</div>

What’s the best way to synchronize 2 while loops, each running on its own thread? In the example below, loop1 runs 80 times per second while loop2 (blocking/IO) runs 20 times per second. Currently, without any locks/syn…

---

## [Using @cfunction inside a function](https://discourse.julialang.org/t/using-cfunction-inside-a-function/52030)

<div class="topic-metadata">

**Author:** [@stla](https://discourse.julialang.org/u/stla)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 9:34am UTC](https://discourse.julialang.org/t/using-cfunction-inside-a-function/52030 "2020-12-18T09:34:32Z")

</div>

Hello, I have a function like this: function f(dim::Integer, pdf::Function) ...... function pdf\_j(xptr, distr) x = map(i -\> unsafe\_load(xptr, i), 1:dim) return pdf(x)::Cdouble end pdf\_c = @cfunction( …

---

## [Help subdividing Generators](https://discourse.julialang.org/t/help-subdividing-generators/51957)

<div class="topic-metadata">

**Author:** [@danilo-bc](https://discourse.julialang.org/u/danilo-bc)\
**Replies:** 9\
**Last updated:** [December 18, 2020, 6:05am UTC](https://discourse.julialang.org/t/help-subdividing-generators/51957 "2020-12-18T06:05:44Z")

</div>

I got inspired by this post on how to generate words from a pool of characters (Generate all words of a given size from a fixed alphabet - #4 by bennedich) and wanted to try it for myself for fun and to learn Generators,…

---

## [MutableNamedTuple Type conversion error](https://discourse.julialang.org/t/mutablenamedtuple-type-conversion-error/52020)

<div class="topic-metadata">

**Author:** [@Zq\_F](https://discourse.julialang.org/u/Zq_F)\
**Replies:** 0\
**Last updated:** [December 18, 2020, 2:39am UTC](https://discourse.julialang.org/t/mutablenamedtuple-type-conversion-error/52020 "2020-12-18T02:39:20Z")

</div>

Hello everyone I want to encapsulate a MutableNamedTuple in my own structure, but I always encounter type conversion errors, please help to see, thank you using MutableNamedTuples mutable struct TM{N,T} field1::Int3…

---

## [Package Pkg not found in current path:](https://discourse.julialang.org/t/package-pkg-not-found-in-current-path/51959)

<div class="topic-metadata">

**Author:** [@enjoyable](https://discourse.julialang.org/u/enjoyable)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 5:51am UTC](https://discourse.julialang.org/t/package-pkg-not-found-in-current-path/51959 "2020-12-18T05:51:49Z")

</div>

Hi all, I was trying to move from Atom to VSCode and encountered one problem. I tried to build the package GR but encountered the error below: (v1.0) pkg\> build GR Building MbedTLS → \`C:\\Users\\rmizf\\.julia\\packages\\…

---

## [Watch out! 1.6 can mess up your environment](https://discourse.julialang.org/t/watch-out-1-6-can-mess-up-your-environment/52019)

<div class="topic-metadata">

**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 3:48am UTC](https://discourse.julialang.org/t/watch-out-1-6-can-mess-up-your-environment/52019 "2020-12-18T03:48:02Z")

</div>

If you are like me and you like to try things out, you might be tempted to test your packages with 1.6. If you then commit your environment files, you might not be able to go back to 1.5 without some work. Some of the pa…

---

## [Tensor contractions very inefficient in julia](https://discourse.julialang.org/t/tensor-contractions-very-inefficient-in-julia/52016)

<div class="topic-metadata">

**Author:** [@Nishan](https://discourse.julialang.org/u/Nishan)\
**Replies:** 13\
**Last updated:** [December 18, 2020, 2:21am UTC](https://discourse.julialang.org/t/tensor-contractions-very-inefficient-in-julia/52016 "2020-12-18T02:21:40Z")

</div>

I am new to julia (just few days) and I want to shift from python to julia by rewriting my DMRG code in julia. For Tensor contractions in python I was using np.tensordot, I searched for equivalent packages in julia and t…

---

## [Plotting single density plot for table](https://discourse.julialang.org/t/plotting-single-density-plot-for-table/51962)

<div class="topic-metadata">

**Author:** [@horizon](https://discourse.julialang.org/u/horizon)\
**Replies:** 6\
**Last updated:** [December 17, 2020, 10:37pm UTC](https://discourse.julialang.org/t/plotting-single-density-plot-for-table/51962 "2020-12-17T22:37:59Z")

</div>

Hi, I am trying to plot a density plot of a table with dimension (100000\*30). I was able to get 30 different plots because of 30 columns in one window but I just want one graph for that table. How to do that? Thank you…

---

## [A French book about Julia](https://discourse.julialang.org/t/a-french-book-about-julia/51982)

<div class="topic-metadata">

**Author:** [@stla](https://discourse.julialang.org/u/stla)\
**Replies:** 0\
**Last updated:** [December 17, 2020, 1:45pm UTC](https://discourse.julialang.org/t/a-french-book-about-julia/51982 "2020-12-17T13:45:59Z")

</div>

Preview available online: Introduction à Julia - Programmer des mathématiques. Cheers.

---

## [Matrix-vector multiplication is a bit off from "equivalent" \[Strided\]Matrix-Strided\]Matrix multiplication (and I guess MATLAB)](https://discourse.julialang.org/t/matrix-vector-multiplication-is-a-bit-off-from-equivalent-strided-matrix-strided-matrix-multiplication-and-i-guess-matlab/51976)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 1\
**Last updated:** [December 17, 2020, 1:35pm UTC](https://discourse.julialang.org/t/matrix-vector-multiplication-is-a-bit-off-from-equivalent-strided-matrix-strided-matrix-multiplication-and-i-guess-matlab/51976 "2020-12-17T13:35:07Z")

</div>

I noticed an odd thing when porting code from MATLAB, that this line makes a difference: julia\> gamma\_gls\_hat = gamma\_gls\_hat\[:, :\] 12×1 Matrix{Float64} gamma\_gls\_hat as I calculated before this line was a 12-element …

---

## [Abstract supertype of AbstractAlgebra.jl polynomials and Floats](https://discourse.julialang.org/t/abstract-supertype-of-abstractalgebra-jl-polynomials-and-floats/51958)

<div class="topic-metadata">

**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 4\
**Last updated:** [December 17, 2020, 12:15pm UTC](https://discourse.julialang.org/t/abstract-supertype-of-abstractalgebra-jl-polynomials-and-floats/51958 "2020-12-17T12:15:52Z")

</div>

I have a struct that contains a real number describing some probability. The algorithm that uses this struct performs fairly simple arithmetic that I would like to be able to track both numerically (Floats) and symbolica…

---

## [Passing a Julia function to C, with a double\* input argument](https://discourse.julialang.org/t/passing-a-julia-function-to-c-with-a-double-input-argument/51966)

<div class="topic-metadata">

**Author:** [@stla](https://discourse.julialang.org/u/stla)\
**Replies:** 1\
**Last updated:** [December 17, 2020, 11:34am UTC](https://discourse.julialang.org/t/passing-a-julia-function-to-c-with-a-double-input-argument/51966 "2020-12-17T11:34:27Z")

</div>

Hello, I have to pass a Julia function to C. The C function has one input argument: a double\*. For example function myfun(x) return sum(x) end What is the way? Is it that: myfun\_c = @cfunction(myfun, Cdouble, (Ref…

---

## [How to call my R package by RCall package inside julia?](https://discourse.julialang.org/t/how-to-call-my-r-package-by-rcall-package-inside-julia/51927)

<div class="topic-metadata">

**Author:** [@Ravinder\_Ram](https://discourse.julialang.org/u/Ravinder_Ram)\
**Replies:** 8\
**Last updated:** [December 17, 2020, 11:11am UTC](https://discourse.julialang.org/t/how-to-call-my-r-package-by-rcall-package-inside-julia/51927 "2020-12-17T11:11:26Z")

</div>

if I’ll call my own R package in julia… is my r code will run fast as C? I’m guessing here my r code running in julia jit compiler? please answer me… please

---

## [Julia Binary Heap Benchmark](https://discourse.julialang.org/t/julia-binary-heap-benchmark/51945)

<div class="topic-metadata">

**Author:** [@ndrsh](https://discourse.julialang.org/u/ndrsh)\
**Replies:** 12\
**Last updated:** [December 17, 2020, 10:25am UTC](https://discourse.julialang.org/t/julia-binary-heap-benchmark/51945 "2020-12-17T10:25:26Z")

</div>

Hey Community. Seems like it might be possible that Julia gets adopted at Codeforces. In order to make that happen I need to provide an implementation for this Binary Heap benchmark. My Julia code is quite ugly, becaus…

---

## [Simulation of a multivariate distribution](https://discourse.julialang.org/t/simulation-of-a-multivariate-distribution/51750)

<div class="topic-metadata">

**Author:** [@stla](https://discourse.julialang.org/u/stla)\
**Replies:** 2\
**Last updated:** [December 17, 2020, 10:05am UTC](https://discourse.julialang.org/t/simulation-of-a-multivariate-distribution/51750 "2020-12-17T10:05:05Z")

</div>

Hello, R has the package ‘Runuran’, a wrapper of the UNU.RAN library. It allows to simulate a distribution given its unnormalized density, possibly a multivariate distribution. Is there a package for Julia which allows…

---

## [Understanding Flux and Zygote : Mutating errors not supported and a new error](https://discourse.julialang.org/t/understanding-flux-and-zygote-mutating-errors-not-supported-and-a-new-error/51860)

<div class="topic-metadata">

**Author:** [@kadir-gunel](https://discourse.julialang.org/u/kadir-gunel)\
**Replies:** 4\
**Last updated:** [December 17, 2020, 5:39am UTC](https://discourse.julialang.org/t/understanding-flux-and-zygote-mutating-errors-not-supported-and-a-new-error/51860 "2020-12-17T05:39:34Z")

</div>

Hello, I am having some trouble about understanding the backward pass in Flux using Zygote. I have a model with a user defined loss function. The problem that I am facing is that when calculating the the loss the output…

---

## [How to uniformly get part of string elements from array of strings](https://discourse.julialang.org/t/how-to-uniformly-get-part-of-string-elements-from-array-of-strings/51776)

<div class="topic-metadata">

**Author:** [@Emmanouil\_Bakirtzis](https://discourse.julialang.org/u/Emmanouil_Bakirtzis)\
**Replies:** 4\
**Last updated:** [December 16, 2020, 8:24pm UTC](https://discourse.julialang.org/t/how-to-uniformly-get-part-of-string-elements-from-array-of-strings/51776 "2020-12-16T20:24:16Z")

</div>

Suppose that we have the array z = \["aaa","bbb","ccc"\] and we want to get a new array where each element has only the first two characters z\_target = \["aa","bb","cc"\] I tried getindex.(z,1:2) but it thows the error …

---

## [Jl\_get\_function() throwing Segmentation fault](https://discourse.julialang.org/t/jl-get-function-throwing-segmentation-fault/37186)

<div class="topic-metadata">

**Author:** [@AndresGomez97](https://discourse.julialang.org/u/AndresGomez97)\
**Replies:** 2\
**Last updated:** [December 16, 2020, 5:04pm UTC](https://discourse.julialang.org/t/jl-get-function-throwing-segmentation-fault/37186 "2020-12-16T17:04:59Z")

</div>

I was trying to use jl\_get\_function() julia.h method to call a method implemented on a different .jl file in julia, being both files in the same directory and on Julia1.3.1 . C file: jl\_init(); jl\_eval\_string("include…

[Previous page](https://discourse.julialang.org/c/usage/6.md?page=664)

[Next page](https://discourse.julialang.org/c/usage/6.md?page=666)