# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1893

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

**Page:** 1894

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## [Blas dot doing weird things depending on size](https://discourse.julialang.org/t/blas-dot-doing-weird-things-depending-on-size/30430)

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**Author:** [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)\
**Replies:** 3\
**Last updated:** [October 29, 2019, 12:56pm UTC](https://discourse.julialang.org/t/blas-dot-doing-weird-things-depending-on-size/30430 "2019-10-29T12:56:34Z")

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I’m working on some by hand matrix multiplication. function slowMult!(A::AbstractMatrix{T},B::AbstractMatrix{T}) where T\<:Number C = Matrix{T}(undef,size(A,1),size(B,2)) for i in 1:size(A,1) for j in 1:s…

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## [Benchmarking the cost of allocation](https://discourse.julialang.org/t/benchmarking-the-cost-of-allocation/30435)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 7\
**Last updated:** [October 29, 2019, 12:21pm UTC](https://discourse.julialang.org/t/benchmarking-the-cost-of-allocation/30435 "2019-10-29T12:21:30Z")

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I would like to have an educated guess of how much speed I would gain if I rewrote a rather large codebase with preallocated buffers (all the other low-hanging fruits I could think of have been harvested at this point, e…

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## [Looking for a speaker to show case Julia at a London meetup in November](https://discourse.julialang.org/t/looking-for-a-speaker-to-show-case-julia-at-a-london-meetup-in-november/29444)

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**Author:** [@sevan](https://discourse.julialang.org/u/sevan)\
**Replies:** 12\
**Last updated:** [October 29, 2019, 11:55am UTC](https://discourse.julialang.org/t/looking-for-a-speaker-to-show-case-julia-at-a-london-meetup-in-november/29444 "2019-10-29T11:55:52Z")

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Hello, I’m organising an evening on modern programming languages for the Open Source Specialist Group\[1\] at BCS London on November 21st. I was wondering if someone from this group would be interested in giving a talk…

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## [How to draw this picture?](https://discourse.julialang.org/t/how-to-draw-this-picture/30432)

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**Author:** [@vtchen](https://discourse.julialang.org/u/vtchen)\
**Replies:** 0\
**Last updated:** [October 29, 2019, 8:50am UTC](https://discourse.julialang.org/t/how-to-draw-this-picture/30432 "2019-10-29T08:50:01Z")

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There is such a picture in this video ( JuliaCon 2018 | Solving Partial Differential Equations with Julia | Chris Rackauckas(https://www.youtube.com/watch?v=okGybBmihOE, 34:24)). I want to know how to draw it. Can som…

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## [Warning for unused type variables in where](https://discourse.julialang.org/t/warning-for-unused-type-variables-in-where/30360)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 3\
**Last updated:** [October 29, 2019, 7:21am UTC](https://discourse.julialang.org/t/warning-for-unused-type-variables-in-where/30360 "2019-10-29T07:21:11Z")

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I am wondering whether it would make sense to warn unused extra type variables for cases like foo(a::AbstractVector{T}) where {T,S} = 1 where it is very likely that S is a typo. It is certainly innocuous as long as it…

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## [Extending Base.read, issue with keyword arguments](https://discourse.julialang.org/t/extending-base-read-issue-with-keyword-arguments/30412)

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**Author:** [@emiles](https://discourse.julialang.org/u/emiles)\
**Replies:** 3\
**Last updated:** [October 29, 2019, 7:15am UTC](https://discourse.julialang.org/t/extending-base-read-issue-with-keyword-arguments/30412 "2019-10-29T07:15:53Z")

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In the process of implementing a library (ITensors.jl), we were planning to extend the Base.read methods to support the custom types introduced by our library. So these extensions, in their most basic form, would work by…

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## [Methods seem to match but don't](https://discourse.julialang.org/t/methods-seem-to-match-but-dont/30429)

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**Author:** [@alacritas](https://discourse.julialang.org/u/alacritas)\
**Replies:** 2\
**Last updated:** [October 29, 2019, 6:36am UTC](https://discourse.julialang.org/t/methods-seem-to-match-but-dont/30429 "2019-10-29T06:36:00Z")

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I’m trying to call a function I’ve defined with only on method but will not call although I’m pretty sure all of my types are matching up a=\[1,2,3\] b=\[3,2,1\] function foo(a::Array{Float64,1}, b::Array{Float64,1}, c) …

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## [How to use ForwardDiff.GradientConfig for multiple input functions while calculating gradients in parallel](https://discourse.julialang.org/t/how-to-use-forwarddiff-gradientconfig-for-multiple-input-functions-while-calculating-gradients-in-parallel/30370)

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**Author:** [@bashonubuntu](https://discourse.julialang.org/u/bashonubuntu)\
**Replies:** 3\
**Last updated:** [October 28, 2019, 10:45am UTC](https://discourse.julialang.org/t/how-to-use-forwarddiff-gradientconfig-for-multiple-input-functions-while-calculating-gradients-in-parallel/30370 "2019-10-28T10:45:14Z")

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Hello, I am parallelizing my gradient calculation in a mini-batch stochastic gradient optimization routine. I am wondering what is the best way to configure cfg = ForwardDiff.GradientConfig() when my function’s input is…

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## [Juno - information of current working module](https://discourse.julialang.org/t/juno-information-of-current-working-module/30409)

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**Author:** [@PaulJaval](https://discourse.julialang.org/u/PaulJaval)\
**Replies:** 2\
**Last updated:** [October 28, 2019, 10:22pm UTC](https://discourse.julialang.org/t/juno-information-of-current-working-module/30409 "2019-10-28T22:22:48Z")

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Hi everyone, I’m working with Juno 0.3.0, and my question is on knowing which module we are currently working in. Starting up the REPL in Juno sets me in the “Main” module, and my current version of Julia (1.2) Now…

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## [Using a bi-directional pipe to read and write from 'cmd'](https://discourse.julialang.org/t/using-a-bi-directional-pipe-to-read-and-write-from-cmd/30313)

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**Author:** [@ko56](https://discourse.julialang.org/u/ko56)\
**Replies:** 5\
**Last updated:** [October 28, 2019, 9:57pm UTC](https://discourse.julialang.org/t/using-a-bi-directional-pipe-to-read-and-write-from-cmd/30313 "2019-10-28T21:57:15Z")

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Hi, I’m using a bi-directional pipe for Julia 1.1.1 to communicate back and forth with an external process: cvc4 = open(\`cvc4 --incremental\`, read=true, write=true) The 2-way communication seems to work ok, except whe…

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## [JuMP macro @constraint where variable is in a finite set](https://discourse.julialang.org/t/jump-macro-constraint-where-variable-is-in-a-finite-set/30417)

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**Author:** [@dadada\_dadada](https://discourse.julialang.org/u/dadada_dadada)\
**Replies:** 1\
**Last updated:** [October 28, 2019, 8:23pm UTC](https://discourse.julialang.org/t/jump-macro-constraint-where-variable-is-in-a-finite-set/30417 "2019-10-28T20:23:02Z")

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Is it possible? I’m trying to solve a very simple optimization problem with IPOPT where the variables are binary. But it seems that IPOPT doesn’t support Bin variables, only continuous ones. Would it be possible to cre…

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## [How to delete zeros from matrix?](https://discourse.julialang.org/t/how-to-delete-zeros-from-matrix/30401)

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**Author:** [@Biljana\_Radovanovic](https://discourse.julialang.org/u/Biljana_Radovanovic)\
**Replies:** 4\
**Last updated:** [October 28, 2019, 8:29pm UTC](https://discourse.julialang.org/t/how-to-delete-zeros-from-matrix/30401 "2019-10-28T20:29:59Z")

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How to delete zeros from matrix delete and delete! does not work?

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## [Program structure](https://discourse.julialang.org/t/program-structure/30376)

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**Author:** [@Ebtissam](https://discourse.julialang.org/u/Ebtissam)\
**Replies:** 6\
**Last updated:** [October 28, 2019, 8:05pm UTC](https://discourse.julialang.org/t/program-structure/30376 "2019-10-28T20:05:06Z")

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Hello everyone i am new to Julia language i need help regarding program structure of Julia language. (What is the program structure of Julia language?)

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## [(Interval) subset optimization with JuMP](https://discourse.julialang.org/t/interval-subset-optimization-with-jump/30415)

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**Author:** [@joemiller](https://discourse.julialang.org/u/joemiller)\
**Replies:** 2\
**Last updated:** [October 28, 2019, 7:50pm UTC](https://discourse.julialang.org/t/interval-subset-optimization-with-jump/30415 "2019-10-28T19:50:01Z")

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Hey everyone. I’m trying to figure out how to use JuMP to optimize a function of a slice of data over the left and right endpoints for the range. I’ve never used JuMP before so I’m piecing this together from tutorials a…

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## [NCP-function implementation (ifelse)](https://discourse.julialang.org/t/ncp-function-implementation-ifelse/30411)

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**Author:** [@SingingKim](https://discourse.julialang.org/u/SingingKim)\
**Replies:** 3\
**Last updated:** [October 28, 2019, 7:28pm UTC](https://discourse.julialang.org/t/ncp-function-implementation-ifelse/30411 "2019-10-28T19:28:46Z")

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Hi, I’m trying to implement a model with constraints based on an NCP-function (continuous & differentiable) and put it into an NLP solver such as IPOPT: @constraint(m, f(x,y) \<= 0) where f(x,y) := xy if …

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## [Get task id of \`@asyncmap\`](https://discourse.julialang.org/t/get-task-id-of-asyncmap/30396)

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**Author:** [@innerlee](https://discourse.julialang.org/u/innerlee)\
**Replies:** 2\
**Last updated:** [October 28, 2019, 7:07pm UTC](https://discourse.julialang.org/t/get-task-id-of-asyncmap/30396 "2019-10-28T19:07:00Z")

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How to get the task id in a asyncmap, similar to myid() in pmap? Something like asyncmap(\_-\>myasyncid(), 1:10) I want to use the id to balance workload on GPUs.

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## [Error in "build Special Functions](https://discourse.julialang.org/t/error-in-build-special-functions/27015)

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**Author:** [@Fisheryu1234](https://discourse.julialang.org/u/Fisheryu1234)\
**Replies:** 15\
**Last updated:** [October 28, 2019, 5:53pm UTC](https://discourse.julialang.org/t/error-in-build-special-functions/27015 "2019-10-28T17:53:08Z")

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Hi all, this is a question haunting me for a while. I am using win10 as the admin. I can’t run “build SpecialFunctions” in Julia client. The julia 1.0.4 is indeed run as admin. The error says I did some google on th…

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## [Why do you use JuliaDB?](https://discourse.julialang.org/t/why-do-you-use-juliadb/30410)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 9\
**Last updated:** [October 28, 2019, 5:27pm UTC](https://discourse.julialang.org/t/why-do-you-use-juliadb/30410 "2019-10-28T17:27:16Z")

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I was kinda waiting for CSV.jl to get to as good as it is now before I start DiskFrame.jl which is a sister project to R’s diskframe.com (I am the author). It’s a disk-based data manipulation system. It’s on my laptop at…

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## [How to create a text report saved using Julia Language statistics](https://discourse.julialang.org/t/how-to-create-a-text-report-saved-using-julia-language-statistics/30398)

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**Author:** [@gedmundos](https://discourse.julialang.org/u/gedmundos)\
**Replies:** 2\
**Last updated:** [October 28, 2019, 4:42pm UTC](https://discourse.julialang.org/t/how-to-create-a-text-report-saved-using-julia-language-statistics/30398 "2019-10-28T16:42:58Z")

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I created a procedure using gsadf test in Julia Language. The final procedure generates two graphs and a mini-report. My difficulty has been how to generate a text report saved in the final of procedure. Sincerely yours…

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## [Initializing struct members after struct has been constructed](https://discourse.julialang.org/t/initializing-struct-members-after-struct-has-been-constructed/30403)

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**Author:** [@Jonas\_Hjulstad](https://discourse.julialang.org/u/Jonas_Hjulstad)\
**Replies:** 3\
**Last updated:** [October 28, 2019, 4:29pm UTC](https://discourse.julialang.org/t/initializing-struct-members-after-struct-has-been-constructed/30403 "2019-10-28T16:29:27Z")

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I’m trying to add members to my struct, but get: BoundsError: attempt to access 0-element Array{Node,1} at index \[1\] mutable struct Node i::Int j::Int floor::Bool neighbors::Array{Node} color::Union…

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## [Optimal way of checking neighboring elements in matrix](https://discourse.julialang.org/t/optimal-way-of-checking-neighboring-elements-in-matrix/30404)

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**Author:** [@Jonas\_Hjulstad](https://discourse.julialang.org/u/Jonas_Hjulstad)\
**Replies:** 3\
**Last updated:** [October 28, 2019, 4:03pm UTC](https://discourse.julialang.org/t/optimal-way-of-checking-neighboring-elements-in-matrix/30404 "2019-10-28T16:03:31Z")

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With any two-dimensional matrix, is there an optimal way of checking wether a neighboring element exists (and if it can be accessed)? Example: mat = \[1 0 0 0 1 0 1 1 1 0 0 1 0 0 0 0 …

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## [Optim.jl: bracketing with Newton()](https://discourse.julialang.org/t/optim-jl-bracketing-with-newton/30332)

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**Author:** [@PharmCat](https://discourse.julialang.org/u/PharmCat)\
**Replies:** 9\
**Last updated:** [October 28, 2019, 2:54pm UTC](https://discourse.julialang.org/t/optim-jl-bracketing-with-newton/30332 "2019-10-28T14:54:20Z")

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Is it possible to use Newton() methods with limiting some variables? Like FMinbox?

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## [Correct way of passing paths in the REPL for a project containing sub folders](https://discourse.julialang.org/t/correct-way-of-passing-paths-in-the-repl-for-a-project-containing-sub-folders/30380)

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**Author:** [@aortizb](https://discourse.julialang.org/u/aortizb)\
**Replies:** 5\
**Last updated:** [October 28, 2019, 1:36pm UTC](https://discourse.julialang.org/t/correct-way-of-passing-paths-in-the-repl-for-a-project-containing-sub-folders/30380 "2019-10-28T13:36:20Z")

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Hi all, I’ve been using Atom for a while and now I am trying to run my codes directly from the REPL without using Atom, that is, I write the \*.jl files using an external text editor and then invoke julia.exe to run the c…

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## [Extract alignments from BAM and associated FASTA reference genome](https://discourse.julialang.org/t/extract-alignments-from-bam-and-associated-fasta-reference-genome/30294)

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**Author:** [@Gio](https://discourse.julialang.org/u/Gio)\
**Replies:** 2\
**Last updated:** [October 28, 2019, 11:49am UTC](https://discourse.julialang.org/t/extract-alignments-from-bam-and-associated-fasta-reference-genome/30294 "2019-10-28T11:49:10Z")

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Hello everybody, I’m new to Julia/BioJulia but I’m already appreciating some features of both the language and the Bio libraries (really nice work!). I’m currently trying to do simple stuff to get acquainted with the Bi…

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## [Latexify.jl outputs incorrectly when variable names contain both unicode and ascii](https://discourse.julialang.org/t/latexify-jl-outputs-incorrectly-when-variable-names-contain-both-unicode-and-ascii/30393)

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**Author:** [@anon56330260](https://discourse.julialang.org/u/anon56330260)\
**Replies:** 2\
**Last updated:** [October 28, 2019, 11:26am UTC](https://discourse.julialang.org/t/latexify-jl-outputs-incorrectly-when-variable-names-contain-both-unicode-and-ascii/30393 "2019-10-28T11:26:47Z")

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It seems that if a variable contains both unicode and ascii character, latexify will product incorrect output: julia\> latexify("δa") L"$\\deltaa$" but what I want is :$\\delta a$, adding \_ would not help because it will …

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## [How to read tuples with JSON3?](https://discourse.julialang.org/t/how-to-read-tuples-with-json3/29843)

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**Author:** [@Elmer\_Cusipuma](https://discourse.julialang.org/u/Elmer_Cusipuma)\
**Replies:** 8\
**Last updated:** [October 28, 2019, 10:44am UTC](https://discourse.julialang.org/t/how-to-read-tuples-with-json3/29843 "2019-10-28T10:44:48Z")

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I am new to JSON3.jl and trying to do the following julia\> using JSON3 julia\> tup = (:car,"Mercedes","S500",5,250.1) (:car, "Mercedes", "S500", 5, 250.1) julia\> json = JSON3.write(tup) "\[\\"car\\",\\"Mercedes\\",\\"S500\\",…

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## [Is Base.MPFR.setprecision in Julia 1.3 Thread Safe?](https://discourse.julialang.org/t/is-base-mpfr-setprecision-in-julia-1-3-thread-safe/30394)

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**Author:** [@StevenSiew](https://discourse.julialang.org/u/StevenSiew)\
**Replies:** 1\
**Last updated:** [October 28, 2019, 8:20am UTC](https://discourse.julialang.org/t/is-base-mpfr-setprecision-in-julia-1-3-thread-safe/30394 "2019-10-28T08:20:51Z")

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Is Base.MPFR.setprecision in Julia 1.3 Thread Safe?

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## [Euler project - P 164](https://discourse.julialang.org/t/euler-project-p-164/30135)

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**Author:** [@AlexanderChen](https://discourse.julialang.org/u/AlexanderChen)\
**Replies:** 30\
**Last updated:** [October 27, 2019, 4:31pm UTC](https://discourse.julialang.org/t/euler-project-p-164/30135 "2019-10-27T16:31:49Z")

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Hi, I am doing some small algorithmic puzzles from the Euler Project. I have a working solution in code for P164 but it is so slow that I fear that I am doing something wrong. Could someone give me tips how to make my c…

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## [Type stability with a vector of abstracts inside struct](https://discourse.julialang.org/t/type-stability-with-a-vector-of-abstracts-inside-struct/30353)

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**Author:** [@abelsiqueira](https://discourse.julialang.org/u/abelsiqueira)\
**Replies:** 7\
**Last updated:** [October 28, 2019, 4:32am UTC](https://discourse.julialang.org/t/type-stability-with-a-vector-of-abstracts-inside-struct/30353 "2019-10-28T04:32:31Z")

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Hi all, I appreciate any help in making the following code type stable: abstract type Something{T} end Base.eltype(:: Something{T}) where T = T mutable struct OneThing{T} \<: Something{T} α :: T end # HERE mutable s…

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## [\[ANN\] Schemata.jl v2 New API, new features](https://discourse.julialang.org/t/ann-schemata-jl-v2-new-api-new-features/30386)

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**Author:** [@jocklawrie](https://discourse.julialang.org/u/jocklawrie)\
**Replies:** 0\
**Last updated:** [October 28, 2019, 2:45am UTC](https://discourse.julialang.org/t/ann-schemata-jl-v2-new-api-new-features/30386 "2019-10-28T02:45:24Z")

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Hi all, Version 2 of Schemata.jl brings some new features and breaking changes, chiefly: diagnose and enforce\_schema have been replaced with the simpler compare, which compares a table to its schema. compare handles…

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