# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1193

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

**Page:** 1194

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## [MATLABs \`sprandsym\` in Julia](https://discourse.julialang.org/t/matlabs-sprandsym-in-julia/72251)

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**Author:** [@carstenbauer](https://discourse.julialang.org/u/carstenbauer)\
**Replies:** 1\
**Last updated:** [November 29, 2021, 6:50pm UTC](https://discourse.julialang.org/t/matlabs-sprandsym-in-julia/72251 "2021-11-29T18:50:39Z")

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Hello everyone! I need a function that generates a random sparse matrix of size (n,n) with the following properties: issymmetric isposdef has approximately p \* n^2 non-zero elements (for given p) has a condition numbe…

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## [CUDA.@atomic causes type instability?](https://discourse.julialang.org/t/cuda-atomic-causes-type-instability/72224)

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**Author:** [@guyvdb](https://discourse.julialang.org/u/guyvdb)\
**Replies:** 5\
**Last updated:** [November 29, 2021, 6:27pm UTC](https://discourse.julialang.org/t/cuda-atomic-causes-type-instability/72224 "2021-11-29T18:27:31Z")

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I am not sure why adding CUDA.@atomic in the below code causes an error? # works fine without CUDA.@atomic function f(test) broadcast(CuVector(1:2), transpose(CuVector(1:3))) do i,j v::Float32 = j te…

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## [Isbits union support in CUDA.jl](https://discourse.julialang.org/t/isbits-union-support-in-cuda-jl/72219)

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**Author:** [@guyvdb](https://discourse.julialang.org/u/guyvdb)\
**Replies:** 2\
**Last updated:** [November 29, 2021, 5:18pm UTC](https://discourse.julialang.org/t/isbits-union-support-in-cuda-jl/72219 "2021-11-29T17:18:40Z")

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I’m confused about the support that CUDA.jl has for isbits unions: # Unions of two work fine: map(x-\>1, CuVector(\[1,missing\])); map(x-\>1, CuVector(\[1,nothing\])); # It is possible to move unions of three to the GPU memo…

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## [How to read MAT files containing strings?](https://discourse.julialang.org/t/how-to-read-mat-files-containing-strings/72217)

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**Author:** [@leon](https://discourse.julialang.org/u/leon)\
**Replies:** 2\
**Last updated:** [November 29, 2021, 5:15pm UTC](https://discourse.julialang.org/t/how-to-read-mat-files-containing-strings/72217 "2021-11-29T17:15:28Z")

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I have a MAT file containing some variables that store string vectors. Below is one example of such a variable: "HY0802" "HY0807" "HY0811" "HY0812" "HY0825" When I use the MAT.jl package to read the…

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## [Target Variable is a Deterministic Function of Random Variables](https://discourse.julialang.org/t/target-variable-is-a-deterministic-function-of-random-variables/71935)

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**Author:** [@Stephen2](https://discourse.julialang.org/u/Stephen2)\
**Replies:** 9\
**Last updated:** [November 29, 2021, 4:48pm UTC](https://discourse.julialang.org/t/target-variable-is-a-deterministic-function-of-random-variables/71935 "2021-11-29T16:48:29Z")

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Crossposting this from “New to Julia” as I received no responses. Hi, I am new to Julia and struggling to formulate my model correctly. My model consists of: A regressor x\_t An intermediate variable y\_t = k \* x\_t + ϵ…

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## [\`findlast()\` with predicate: allocations depending on argument types](https://discourse.julialang.org/t/findlast-with-predicate-allocations-depending-on-argument-types/72246)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 0\
**Last updated:** [November 29, 2021, 4:27pm UTC](https://discourse.julialang.org/t/findlast-with-predicate-allocations-depending-on-argument-types/72246 "2021-11-29T16:27:06Z")

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When I run findlast(y -\> y≤x, xrange), the number of allocations changes depending on the sameness of the type of x and the element type of xrange. Here is an example: julia\> VERSION v"1.6.5-pre.0" julia\> using Benchm…

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## [\[ANN\] Announcing FastAI.jl](https://discourse.julialang.org/t/ann-announcing-fastai-jl/65394)

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**Author:** [@holylorenzo](https://discourse.julialang.org/u/holylorenzo)\
**Replies:** 14\
**Last updated:** [November 29, 2021, 3:50pm UTC](https://discourse.julialang.org/t/ann-announcing-fastai-jl/65394 "2021-11-29T15:50:55Z")

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I am excited to announce the release of FastAI.jl which has been in the works for over a year now. FastAI.jl is a high-level, user-friendly library for training deep learning models built on Flux.jl. It draws inspiration…

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## [Inequality operator](https://discourse.julialang.org/t/inequality-operator/72232)

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**Author:** [@pjgorski](https://discourse.julialang.org/u/pjgorski)\
**Replies:** 4\
**Last updated:** [November 29, 2021, 2:57pm UTC](https://discourse.julialang.org/t/inequality-operator/72232 "2021-11-29T14:57:15Z")

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Why is there the difference between != and !== operators? Examples: julia\> a = Any\["D", "A", "s", "t"\] julia\> filter(e-\>e!="s",a) 3-element Array{Any,1}: "D" "A" "t" julia\> filter(e-\>e !== "s",a) 4-element Array{Any…

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## [Support for non-POSIX shells](https://discourse.julialang.org/t/support-for-non-posix-shells/72236)

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**Author:** [@kubouch](https://discourse.julialang.org/u/kubouch)\
**Replies:** 1\
**Last updated:** [November 29, 2021, 2:55pm UTC](https://discourse.julialang.org/t/support-for-non-posix-shells/72236 "2021-11-29T14:55:21Z")

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The Julia’s shell mode does not seem to work properly when a non-POSIX shell is set as the default system shell. I’m using Nushell, however, I imagine a similar issue is also present with other popular non-POSIX shells, …

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## [JuliaCN 2021 winter online meetup](https://discourse.julialang.org/t/juliacn-2021-winter-online-meetup/69880)

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**Author:** [@JohnnyChen94](https://discourse.julialang.org/u/JohnnyChen94)\
**Replies:** 5\
**Last updated:** [November 29, 2021, 2:36pm UTC](https://discourse.julialang.org/t/juliacn-2021-winter-online-meetup/69880 "2021-11-29T14:36:00Z")

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I started to learn Julia three years ago when Julia 1.0 was released. In the past three years, using Julia and contributing to Julia immediately becomes one of the greatest experiences I’ve ever had; I’ve learned a lot b…

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## [What is the most efficient way of obtaining the orthogonal column space of a matrix?](https://discourse.julialang.org/t/what-is-the-most-efficient-way-of-obtaining-the-orthogonal-column-space-of-a-matrix/72212)

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**Author:** [@Joris\_Pinkse](https://discourse.julialang.org/u/Joris_Pinkse)\
**Replies:** 14\
**Last updated:** [November 29, 2021, 12:36pm UTC](https://discourse.julialang.org/t/what-is-the-most-efficient-way-of-obtaining-the-orthogonal-column-space-of-a-matrix/72212 "2021-11-29T12:36:44Z")

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What is the most efficient way of obtaining the orthogonal column space of a matrix? (many more rows than columns) Q, = svd( X; alg = LinearAlgebra.QRIteration() ) gives me what I want, but is there something more eff…

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## [Unable to use lagrange to solve 2 varable functions in modeling toolkit](https://discourse.julialang.org/t/unable-to-use-lagrange-to-solve-2-varable-functions-in-modeling-toolkit/72043)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 29\
**Last updated:** [November 29, 2021, 2:12pm UTC](https://discourse.julialang.org/t/unable-to-use-lagrange-to-solve-2-varable-functions-in-modeling-toolkit/72043 "2021-11-29T14:12:33Z")

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@parameters x\_1 x\_2 @variables u eqs = \[ 0 ~ u - (x\_1+2)\*(x\_2+1), 130 ~ 4\*x\_1+6\*x\_2\] @named sys = NonlinearSystem(eqs, \[x\_1, x\_2\],\[\]) prob = NonlinearProblem(structural\_simplify(sys),\[x\_1=\>1.0,x\_2=\>1.0,u=\>max\]) …

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## [Utilizing Julia's Speed in R](https://discourse.julialang.org/t/utilizing-julias-speed-in-r/72104)

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**Author:** [@HeavyBulb](https://discourse.julialang.org/u/HeavyBulb)\
**Replies:** 15\
**Last updated:** [November 29, 2021, 1:44pm UTC](https://discourse.julialang.org/t/utilizing-julias-speed-in-r/72104 "2021-11-29T13:44:45Z")

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I have a data frame of length 40,000 and a function programmed in R. It takes 20 minutes to iterate through the whole data set with the mapply function that allows to apply a function on each row of a data frame. Would …

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## [How to create a parallel task?](https://discourse.julialang.org/t/how-to-create-a-parallel-task/72194)

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**Author:** [@tomhaber](https://discourse.julialang.org/u/tomhaber)\
**Replies:** 8\
**Last updated:** [November 29, 2021, 1:44pm UTC](https://discourse.julialang.org/t/how-to-create-a-parallel-task/72194 "2021-11-29T13:44:08Z")

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I wanted to create a task that runs in parallel with the rest of the code. Seems pretty straightforward, but I’m running into issues I don’t understand. For some reason the sleep in the following code gives an exception,…

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## [Ccall works on global scope but not within function](https://discourse.julialang.org/t/ccall-works-on-global-scope-but-not-within-function/72119)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 13\
**Last updated:** [November 29, 2021, 12:56pm UTC](https://discourse.julialang.org/t/ccall-works-on-global-scope-but-not-within-function/72119 "2021-11-29T12:56:37Z")

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I’m trying to create bindings to a C library. I generated some Julia code using Clang.jl, and I was able to successfully make some function calls reproducing some C-code program. It’s not very reliable, though. Right now…

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## [Pluto: how to insert a table from LaTeX code into markdown](https://discourse.julialang.org/t/pluto-how-to-insert-a-table-from-latex-code-into-markdown/60481)

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**Author:** [@VivMendes](https://discourse.julialang.org/u/VivMendes)\
**Replies:** 10\
**Last updated:** [November 29, 2021, 9:28am UTC](https://discourse.julialang.org/t/pluto-how-to-insert-a-table-from-latex-code-into-markdown/60481 "2021-11-29T09:28:52Z")

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Pluto is wonderful and I am trying to pass all my slides into Pluto notebooks. A large part of my slides are written in LaTeX and I am struggling with this part in Pluto. For example, I have this table in LaTeX: $$ \\be…

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## [The way to update Julia](https://discourse.julialang.org/t/the-way-to-update-julia/71869)

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**Author:** [@leon](https://discourse.julialang.org/u/leon)\
**Replies:** 13\
**Last updated:** [November 29, 2021, 9:21am UTC](https://discourse.julialang.org/t/the-way-to-update-julia/71869 "2021-11-29T09:21:52Z")

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Is is correct that right now if I want to upgrade my Julia I would have to install it from the scratch? This is a problem, because the users would have to change settings for Juypter and Atom Juno, etc. in order for them…

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## [Functions accepting functions and keeping their types](https://discourse.julialang.org/t/functions-accepting-functions-and-keeping-their-types/72044)

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**Author:** [@grjzwaan](https://discourse.julialang.org/u/grjzwaan)\
**Replies:** 11\
**Last updated:** [November 29, 2021, 9:14am UTC](https://discourse.julialang.org/t/functions-accepting-functions-and-keeping-their-types/72044 "2021-11-29T09:14:53Z")

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I’m new to Julia and looking for a good way / advice on passing functions as arguments and keeping the types. My searches did not yield anything that seemed applicable, or at least I understood to be applicable. As a sa…

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## [Calculation question](https://discourse.julialang.org/t/calculation-question/72042)

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**Author:** [@SergeantMike67](https://discourse.julialang.org/u/SergeantMike67)\
**Replies:** 4\
**Last updated:** [November 29, 2021, 7:57am UTC](https://discourse.julialang.org/t/calculation-question/72042 "2021-11-29T07:57:06Z")

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I am trying to make a graph of over 200 emergence curves from a dataset that is structured below. Row │ Farm Variety Container ED Wasp │ String String String Float64 Int16 ─────┼─────────────…

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## [Significant compile time latency in Flux with a GAN](https://discourse.julialang.org/t/significant-compile-time-latency-in-flux-with-a-gan/68518)

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**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 28\
**Last updated:** [November 29, 2021, 12:00am UTC](https://discourse.julialang.org/t/significant-compile-time-latency-in-flux-with-a-gan/68518 "2021-11-29T00:00:32Z")

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I am trying to implement a SRGAN (super-resolution generative adversarial networks) in Flux (I am happy to share once it works… :-)) The generator network is composed of 5 residual blocks (function resblock below). Unf…

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## [Cannot install a BioJulia package, GenomeGraphs.jl](https://discourse.julialang.org/t/cannot-install-a-biojulia-package-genomegraphs-jl/71786)

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**Author:** [@Xiao](https://discourse.julialang.org/u/Xiao)\
**Replies:** 3\
**Last updated:** [November 29, 2021, 2:14am UTC](https://discourse.julialang.org/t/cannot-install-a-biojulia-package-genomegraphs-jl/71786 "2021-11-29T02:14:47Z")

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cannot install the package. my Julia version is Version 1.6.3 (2021-09-23). Errors as below: (@v1.6) pkg\> add GenomeGraphs Resolving package versions... ERROR: Unsatisfiable requirements detected for package BioSeq…

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## [ForwardDiff error "Cannot determine ordering of Dual tags" when differentiating distributed function with closure](https://discourse.julialang.org/t/forwarddiff-error-cannot-determine-ordering-of-dual-tags-when-differentiating-distributed-function-with-closure/72211)

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**Author:** [@mattwigway](https://discourse.julialang.org/u/mattwigway)\
**Replies:** 1\
**Last updated:** [November 29, 2021, 2:05am UTC](https://discourse.julialang.org/t/forwarddiff-error-cannot-determine-ordering-of-dual-tags-when-differentiating-distributed-function-with-closure/72211 "2021-11-29T02:05:34Z")

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I’m using ForwardDiff to differentiate a function that will be computed across a cluster. When I run the code using a single process everything works fine. However, when I use multiple processes, I get the error Cannot d…

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## [Sampling Groups and individual within the group](https://discourse.julialang.org/t/sampling-groups-and-individual-within-the-group/72199)

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**Author:** [@N\_A](https://discourse.julialang.org/u/N_A)\
**Replies:** 4\
**Last updated:** [November 28, 2021, 2:54pm UTC](https://discourse.julialang.org/t/sampling-groups-and-individual-within-the-group/72199 "2021-11-28T14:54:36Z")

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a\[:,4\] represent group. a= \[1 2 3 1;5 6 7 1;1 2 3 1;1 2 4 1;1 2 3 2;1 2 3 2;1 2 4 2;1 2 4 2;1 3 4 3;1 3 4 3;1 3 4 3;1 2 3 3 \] 12×4 Matrix{Int64}: 1 2 3 1 5 6 7 1 1 2 3 1 1 2 4 1 1 2 3 2 1 2 3 2 …

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## [Set Ipot (with JuMP) to terminate only if max time is reached](https://discourse.julialang.org/t/set-ipot-with-jump-to-terminate-only-if-max-time-is-reached/72160)

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**Author:** [@cricci](https://discourse.julialang.org/u/cricci)\
**Replies:** 3\
**Last updated:** [November 29, 2021, 12:28am UTC](https://discourse.julialang.org/t/set-ipot-with-jump-to-terminate-only-if-max-time-is-reached/72160 "2021-11-29T00:28:31Z")

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I would like to do the following: setting the Ipopt optimizer (used via JuMP) to terminate ONLY when max\_cpu\_time is reached. Is it possible? motivation for doing such a stupid thing: I need to run multiple optimizatio…

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## [DataFrame to Dict via Vector of Nested Named Tuples](https://discourse.julialang.org/t/dataframe-to-dict-via-vector-of-nested-named-tuples/72214)

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**Author:** [@Rob](https://discourse.julialang.org/u/Rob)\
**Replies:** 2\
**Last updated:** [November 28, 2021, 11:17pm UTC](https://discourse.julialang.org/t/dataframe-to-dict-via-vector-of-nested-named-tuples/72214 "2021-11-28T23:17:17Z")

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I am building a JuMP transportation model, and looking for an alternate approach to create a dict from a dataframe. Here is my starting (simplified) DataFrame: using DataFrames using NamedTupleTools df = DataFrame(City…

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## [Ping an IP address](https://discourse.julialang.org/t/ping-an-ip-address/72191)

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**Author:** [@\_RBMK](https://discourse.julialang.org/u/_RBMK)\
**Replies:** 5\
**Last updated:** [November 28, 2021, 10:16pm UTC](https://discourse.julialang.org/t/ping-an-ip-address/72191 "2021-11-28T22:16:37Z")

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How about, I’m working on a P2P module for Julia, and I need to do native ping to a host, there is already a post about this in the forum, but I’m trying to do it internally, from Julia. Is it possible to access the Raw …

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## [Working with text and comments](https://discourse.julialang.org/t/working-with-text-and-comments/72207)

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**Author:** [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Replies:** 2\
**Last updated:** [November 28, 2021, 9:46pm UTC](https://discourse.julialang.org/t/working-with-text-and-comments/72207 "2021-11-28T21:46:23Z")

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Hi, I’d like to add many text blocks to Julia code, like in Literate.jl. Some text sources provide a long single line comment. I am looking for a way to reformat text blocks to a suitable length and make them either b…

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## [Autodifferentiation of a recursive function](https://discourse.julialang.org/t/autodifferentiation-of-a-recursive-function/71972)

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**Author:** [@mvsoom](https://discourse.julialang.org/u/mvsoom)\
**Replies:** 27\
**Last updated:** [November 28, 2021, 9:40pm UTC](https://discourse.julialang.org/t/autodifferentiation-of-a-recursive-function/71972 "2021-11-28T21:40:53Z")

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I am interested in wavelets W\_n(t,p) that are generated by convolving a Chebyshev polynomial of the first kind T\_n(x) with a complex sinusoid \\exp(pt): W\_n(t,p) = T\_n(t) \* \\exp(p t) Here n = 0,1,2,\\ldots, t \\in \\mathb…

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## [Why use Julia to build an Earth System Model?](https://discourse.julialang.org/t/why-use-julia-to-build-an-earth-system-model/53180)

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**Author:** [@AlexisRenchon](https://discourse.julialang.org/u/AlexisRenchon)\
**Replies:** 3\
**Last updated:** [November 28, 2021, 8:54pm UTC](https://discourse.julialang.org/t/why-use-julia-to-build-an-earth-system-model/53180 "2021-11-28T20:54:36Z")

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Hi all, Most Earth System Models are written in Fortran, but may be re-written in another language because Fortran has some issues running on GPU based supercomputer. Some consider using C instead, but there are many a…

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## [Making the font bold or italic in Makie.jl](https://discourse.julialang.org/t/making-the-font-bold-or-italic-in-makie-jl/72089)

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**Author:** [@mmkim1210](https://discourse.julialang.org/u/mmkim1210)\
**Replies:** 11\
**Last updated:** [November 28, 2021, 8:53pm UTC](https://discourse.julialang.org/t/making-the-font-bold-or-italic-in-makie-jl/72089 "2021-11-28T20:53:46Z")

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How can you make your font either bold or italic in Makie? I do not want the Latex font, just good old bold or italic “Arial” font. Thank you.

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