# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1713

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

**Page:** 1714

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## [Read multiple DataFrames stored in a single text file](https://discourse.julialang.org/t/read-multiple-dataframes-stored-in-a-single-text-file/41673)

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**Author:** [@evad](https://discourse.julialang.org/u/evad)\
**Replies:** 8\
**Last updated:** [June 19, 2020, 1:19am UTC](https://discourse.julialang.org/t/read-multiple-dataframes-stored-in-a-single-text-file/41673 "2020-06-19T01:19:33Z")

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I have a text file with multiple DataFrames in the following format (tab separated): %T table1 %F col1 col2 col3 %R 1 2 3 %T table2 %F col1 col2 col3 col4 %R 1 2 3 4 %R 5 6 …

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## [OpenBLAS is faster than Intel MKL on AMD Hardware (Ryzen)](https://discourse.julialang.org/t/openblas-is-faster-than-intel-mkl-on-amd-hardware-ryzen/8033)

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**Author:** [@Elrod](https://discourse.julialang.org/u/Elrod)\
**Replies:** 40\
**Last updated:** [June 19, 2020, 1:03am UTC](https://discourse.julialang.org/t/openblas-is-faster-than-intel-mkl-on-amd-hardware-ryzen/8033 "2020-06-19T01:03:05Z")

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Questions about MKL vs OpenBLAS come up a lot, for example in comparisons with Matlab (linked to MKL), and a lot of users have issues building with MKL, eg here. Of course, one can easily download an MKL binary with Juli…

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## [ODE solver save intermediate outputs (y = C\*x + D\*u)](https://discourse.julialang.org/t/ode-solver-save-intermediate-outputs-y-c-x-d-u/41697)

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**Author:** [@mopg](https://discourse.julialang.org/u/mopg)\
**Replies:** 5\
**Last updated:** [June 19, 2020, 12:38am UTC](https://discourse.julialang.org/t/ode-solver-save-intermediate-outputs-y-c-x-d-u/41697 "2020-06-19T00:38:04Z")

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I am using DifferentialEquations.jl for solving an ODE, and it works great. However, I’d like to save intermediate outputs, and I can’t figure out how to do that. Consider the example below: using DifferentialEquations…

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## [Why no Base.Iterators.map?](https://discourse.julialang.org/t/why-no-base-iterators-map/14280)

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**Author:** [@Orbots](https://discourse.julialang.org/u/Orbots)\
**Replies:** 12\
**Last updated:** [June 18, 2020, 11:01pm UTC](https://discourse.julialang.org/t/why-no-base-iterators-map/14280 "2020-06-18T23:01:42Z")

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There is a Base.Iterators.filter, why no map? I see there used to be an imap function which was something like imap(f,a...) = (f(i...) for i in Iterators.zip(a...) ) which is what I have put in my local utilities …

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## [Signal Handlers with Embedded Julia](https://discourse.julialang.org/t/signal-handlers-with-embedded-julia/41701)

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**Author:** [@SMShane](https://discourse.julialang.org/u/SMShane)\
**Replies:** 0\
**Last updated:** [June 18, 2020, 9:57pm UTC](https://discourse.julialang.org/t/signal-handlers-with-embedded-julia/41701 "2020-06-18T21:57:36Z")

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We are embedding Julia in a larger software suite on Linux/MacOS/Windows. This existing software makes use of some signal handlers and where it doesn’t some users expect behaviours such as Ctrl-C to interrupt to work. …

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## [Inlining and function boundaries](https://discourse.julialang.org/t/inlining-and-function-boundaries/41686)

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**Author:** [@Kiuhnm\_Mnhuik](https://discourse.julialang.org/u/Kiuhnm_Mnhuik)\
**Replies:** 1\
**Last updated:** [June 18, 2020, 7:45pm UTC](https://discourse.julialang.org/t/inlining-and-function-boundaries/41686 "2020-06-18T19:45:42Z")

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I read that inlining, by removing function boundaries, may cause type instability. Is this true? This doesn’t seem too hard to fix, but I’m not familiar with Julia internals.

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## [Formatting syntax question](https://discourse.julialang.org/t/formatting-syntax-question/41650)

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**Author:** [@pauljurczak](https://discourse.julialang.org/u/pauljurczak)\
**Replies:** 3\
**Last updated:** [June 18, 2020, 8:59pm UTC](https://discourse.julialang.org/t/formatting-syntax-question/41650 "2020-06-18T20:59:08Z")

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I have this code snippet: using Formatting printfmtln("{} total RAM", format(Sys.total\_memory(), precision=2, autoscale=:binary)) which nicely prints what I expected: 15.56Gi total RAM Is there a way to pack both for…

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## [RFC: 2020 Julia User and Developer Survey](https://discourse.julialang.org/t/rfc-2020-julia-user-and-developer-survey/38442)

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**Author:** [@viralbshah](https://discourse.julialang.org/u/viralbshah)\
**Replies:** 67\
**Last updated:** [June 18, 2020, 7:45pm UTC](https://discourse.julialang.org/t/rfc-2020-julia-user-and-developer-survey/38442 "2020-06-18T19:45:34Z")

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Dear all, It is time again this year to launch our annual User and Developer Survey. For those who didn’t see last year’s survey, please do see: Julia User - Developer Survey 2019 We plan to launch this survey in a few…

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## [Strange exception in Julia v1.4.x could not load library "libcholmod"](https://discourse.julialang.org/t/strange-exception-in-julia-v1-4-x-could-not-load-library-libcholmod/41689)

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**Author:** [@uwechsler](https://discourse.julialang.org/u/uwechsler)\
**Replies:** 0\
**Last updated:** [June 18, 2020, 7:02pm UTC](https://discourse.julialang.org/t/strange-exception-in-julia-v1-4-x-could-not-load-library-libcholmod/41689 "2020-06-18T19:02:44Z")

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I am using Julia v.1.4.2 on a Windows Server 2016. In order to make Julia with Version \> 1.3.0 run, I copy the libopenblas64\_.dll from version 1.2.0 into the bin folder. This approach worked so far pretty well for month…

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## [Testing private package fails based on dependency](https://discourse.julialang.org/t/testing-private-package-fails-based-on-dependency/41619)

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**Author:** [@doomphoenix-qxz](https://discourse.julialang.org/u/doomphoenix-qxz)\
**Replies:** 8\
**Last updated:** [June 18, 2020, 6:39pm UTC](https://discourse.julialang.org/t/testing-private-package-fails-based-on-dependency/41619 "2020-06-18T18:39:42Z")

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I have a private package that I am trying to test. When I run the test suite, it fails, claiming it can’t find CSV: ERROR: LoadError: ArgumentError: Package CSV not found in current path: - Run \`import Pkg; Pkg.add("CSV…

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## [Help speedup a tight triple loop](https://discourse.julialang.org/t/help-speedup-a-tight-triple-loop/41648)

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**Author:** [@biona001](https://discourse.julialang.org/u/biona001)\
**Replies:** 7\
**Last updated:** [June 18, 2020, 6:15pm UTC](https://discourse.julialang.org/t/help-speedup-a-tight-triple-loop/41648 "2020-06-18T18:15:44Z")

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Hello Julia, The following code is inside a multithreaded loop which gets called a lot. It essentially loops over a symmetric matrix M (dimension ~50k at most) and computes the minimum with respect to each row of N in a…

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## [Array of Plot objects](https://discourse.julialang.org/t/array-of-plot-objects/41679)

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**Author:** [@jmurray](https://discourse.julialang.org/u/jmurray)\
**Replies:** 11\
**Last updated:** [June 18, 2020, 6:13pm UTC](https://discourse.julialang.org/t/array-of-plot-objects/41679 "2020-06-18T18:13:23Z")

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I want to make an array containing plots, but the two approaches I’ve tried both fail. My first approach was to allocate an empty array and push! new plot objects: p\_arr1 = Array{Plots.Plot{Plots.GRBackend},1}\[\] push!(…

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## [Issue with include](https://discourse.julialang.org/t/issue-with-include/41676)

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**Author:** [@mkphys](https://discourse.julialang.org/u/mkphys)\
**Replies:** 4\
**Last updated:** [June 18, 2020, 4:36pm UTC](https://discourse.julialang.org/t/issue-with-include/41676 "2020-06-18T16:36:44Z")

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I am seeing an odd issue with how include works. I am using Julia 1.0.2. Here is the simplest case that seems to cause issues: julia\_include\_issue.jl function f1() println("In f1()") include("params.jl") pri…

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## [Mapreduce with function that has multiple return values](https://discourse.julialang.org/t/mapreduce-with-function-that-has-multiple-return-values/41674)

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**Author:** [@jebej](https://discourse.julialang.org/u/jebej)\
**Replies:** 2\
**Last updated:** [June 18, 2020, 4:22pm UTC](https://discourse.julialang.org/t/mapreduce-with-function-that-has-multiple-return-values/41674 "2020-06-18T16:22:38Z")

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I frequently run into an issue where I want to apply a function over a range of inputs and combine the output into arrays, where the function returns more than 1 value, and each return value should be collected in a diff…

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## [Callbacks for parameters in a stiff system of ODEs?](https://discourse.julialang.org/t/callbacks-for-parameters-in-a-stiff-system-of-odes/41580)

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**Author:** [@dynova](https://discourse.julialang.org/u/dynova)\
**Replies:** 8\
**Last updated:** [June 18, 2020, 3:46pm UTC](https://discourse.julialang.org/t/callbacks-for-parameters-in-a-stiff-system-of-odes/41580 "2020-06-18T15:46:18Z")

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I have a stiff system of 21 ODEs, for which I want to use callback functions on some time-dependent parameters. Looking for some help on this, as I’m running into some error messages and I’m new to callbacks. Not entire…

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## [Couldn't process recipe args: (Array{Float64,2}, Array{Float64,2}, Array{Float64,2}, Array{Float64,2})](https://discourse.julialang.org/t/couldnt-process-recipe-args-array-float64-2-array-float64-2-array-float64-2-array-float64-2/41672)

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**Author:** [@hafez\_ahmad](https://discourse.julialang.org/u/hafez_ahmad)\
**Replies:** 1\
**Last updated:** [June 18, 2020, 3:41pm UTC](https://discourse.julialang.org/t/couldnt-process-recipe-args-array-float64-2-array-float64-2-array-float64-2-array-float64-2/41672 "2020-06-18T15:41:13Z")

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I am trying to learn Channel Flow with Navier-Stokes from this link Welcome to CFD Julia. I am getting error . nx = 41; ny = 41; nt = 500; nit=50; c = 1; dx = 2/(nx-1); dy = 2/(ny-1); x=range(0, stop=2, length…

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## [Testing package where the test depends on local dev'ed package fails in Julia 1.4.2 with ERROR: can not merge projects](https://discourse.julialang.org/t/testing-package-where-the-test-depends-on-local-deved-package-fails-in-julia-1-4-2-with-error-can-not-merge-projects/41611)

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**Author:** [@alkoedl](https://discourse.julialang.org/u/alkoedl)\
**Replies:** 3\
**Last updated:** [June 18, 2020, 2:30pm UTC](https://discourse.julialang.org/t/testing-package-where-the-test-depends-on-local-deved-package-fails-in-julia-1-4-2-with-error-can-not-merge-projects/41611 "2020-06-18T14:30:38Z")

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I have a package (say AAA) where the package itself and the tests depend on a local dev’ed package (BBB). Accordingly, I have package BBB both in AAA’s environment and in AAA/test environment like this: Project AAA v0.1…

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## [Completely eliminating any inference for certain functions](https://discourse.julialang.org/t/completely-eliminating-any-inference-for-certain-functions/41582)

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**Author:** [@jules](https://discourse.julialang.org/u/jules)\
**Replies:** 6\
**Last updated:** [June 18, 2020, 2:00pm UTC](https://discourse.julialang.org/t/completely-eliminating-any-inference-for-certain-functions/41582 "2020-06-18T14:00:26Z")

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Is there a way to completely skip internal type inference for functions? If I have tons of high-level API functions in a package and only a couple of performance-critical functions, I would like the top part to be like …

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## [CSV.jl: Write csv row by row](https://discourse.julialang.org/t/csv-jl-write-csv-row-by-row/41593)

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**Author:** [@altre](https://discourse.julialang.org/u/altre)\
**Replies:** 3\
**Last updated:** [June 18, 2020, 1:52pm UTC](https://discourse.julialang.org/t/csv-jl-write-csv-row-by-row/41593 "2020-06-18T13:52:38Z")

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I have an application which writes a csv as an output but never holds the complete csv in memory. I would like to use a library such as CSV.jl to a) take advantage of optimizations (CSV.jl is super fast for reading!) …

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## [Calculate Hessian after providing gradient: NLSolversBase, Optim](https://discourse.julialang.org/t/calculate-hessian-after-providing-gradient-nlsolversbase-optim/41629)

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**Author:** [@marinooss](https://discourse.julialang.org/u/marinooss)\
**Replies:** 0\
**Last updated:** [June 17, 2020, 8:48pm UTC](https://discourse.julialang.org/t/calculate-hessian-after-providing-gradient-nlsolversbase-optim/41629 "2020-06-17T20:48:53Z")

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I am using the following special interface from NLSolversBase, to minimize a function. function fg!(F, G, x) common\_calc(…) if !(G == nothing) # mutating calculations specific to g! end if !(F …

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## [CUDA.jl errors with basic functions](https://discourse.julialang.org/t/cuda-jl-errors-with-basic-functions/41605)

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**Author:** [@sw72](https://discourse.julialang.org/u/sw72)\
**Replies:** 1\
**Last updated:** [June 18, 2020, 1:32pm UTC](https://discourse.julialang.org/t/cuda-jl-errors-with-basic-functions/41605 "2020-06-18T13:32:41Z")

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I’m getting ERROR: MethodError: no method matching personality!(::LLVM.Function, ::Nothing) when attempting to multiply a CuArray by a scalar. Any ideas what could be wrong? Full error details below: julia\> using C…

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## [Type assertion?](https://discourse.julialang.org/t/type-assertion/35950)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 25\
**Last updated:** [June 18, 2020, 12:51pm UTC](https://discourse.julialang.org/t/type-assertion/35950 "2020-06-18T12:51:48Z")

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I’m playing around with a function where the argument should be a vector of same-sized vectors, i.e., v = \[v1,v2,v3,...,vN\] where v1, …, vN etc. are vectors containing scalar elements, and of the same size. How can I …

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## [3D line plot of the elements of 3 vectors](https://discourse.julialang.org/t/3d-line-plot-of-the-elements-of-3-vectors/41662)

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**Author:** [@fusion809](https://discourse.julialang.org/u/fusion809)\
**Replies:** 2\
**Last updated:** [June 18, 2020, 12:29pm UTC](https://discourse.julialang.org/t/3d-line-plot-of-the-elements-of-3-vectors/41662 "2020-06-18T12:29:38Z")

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I’d like to generate a 3D line plot using data in three vectors labelled x, y and z. I’ve tried using PyPlot’s plot3D and I received the error: PyError ($(Expr(:escape, :(ccall(#= /home/fusion809/.julia/packages/PyCall/…

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## [How to initialize an empty 1x2-dimensional row-array in Julia?](https://discourse.julialang.org/t/how-to-initialize-an-empty-1x2-dimensional-row-array-in-julia/41653)

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**Author:** [@Dito](https://discourse.julialang.org/u/Dito)\
**Replies:** 7\
**Last updated:** [June 18, 2020, 11:57am UTC](https://discourse.julialang.org/t/how-to-initialize-an-empty-1x2-dimensional-row-array-in-julia/41653 "2020-06-18T11:57:02Z")

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I can do this: julia\> vec=\[\] 0-element Array{Any,1} julia\> for i in 1:10 global vec=vcat(vec,i) end julia\> vec 10-element Array{Any,1}: 1 2 3 4 5 6 7 8 9 10 but how can I crea…

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## [Parrallel programming](https://discourse.julialang.org/t/parrallel-programming/41659)

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**Author:** [@hyacykcharel](https://discourse.julialang.org/u/hyacykcharel)\
**Replies:** 1\
**Last updated:** [June 18, 2020, 11:04am UTC](https://discourse.julialang.org/t/parrallel-programming/41659 "2020-06-18T11:04:04Z")

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hello im trying to to a parallel compuing but it is not workig can someone please correct this code for me thans? using Distributed addprocs(1) nprocs() procs() workers() nworkers() @everywhere using Distri…

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## [Can I build webpages and especially dashboards in Julia](https://discourse.julialang.org/t/can-i-build-webpages-and-especially-dashboards-in-julia/10913)

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**Author:** [@vikram-rawat](https://discourse.julialang.org/u/vikram-rawat)\
**Replies:** 19\
**Last updated:** [August 3, 2019, 9:05pm UTC](https://discourse.julialang.org/t/can-i-build-webpages-and-especially-dashboards-in-julia/10913 "2019-08-03T21:05:47Z")

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I have no prior knowledge of the language yet I have heard a lot of good things about the language. but before I want to start it I want to know can I build web pages and dashboards in Julia. If so what library should I…

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## [Custom XGBoost Loss function w/ Zygote. Julia Computing blog post](https://discourse.julialang.org/t/custom-xgboost-loss-function-w-zygote-julia-computing-blog-post/35811)

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**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 36\
**Last updated:** [April 29, 2020, 8:07am UTC](https://discourse.julialang.org/t/custom-xgboost-loss-function-w-zygote-julia-computing-blog-post/35811 "2020-04-29T08:07:25Z")

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There is a really cool recent blog post @ Julia Computing about how easily custom loss functions can be implemented in XGBoost w/ Zygote. They use the Titanic survival data from Kaggle & compare scores on the Leaderboard…

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## [I can't start a Jupyter notebook from the Julia terminal](https://discourse.julialang.org/t/i-cant-start-a-jupyter-notebook-from-the-julia-terminal/4649)

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**Author:** [@Jean-Victor](https://discourse.julialang.org/u/Jean-Victor)\
**Replies:** 6\
**Last updated:** [June 18, 2020, 5:24am UTC](https://discourse.julialang.org/t/i-cant-start-a-jupyter-notebook-from-the-julia-terminal/4649 "2020-06-18T05:24:02Z")

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All I get is the following message → Process(setenv(jupyter notebook --NotebookApp.iopub\_data\_rate\_limit=2147483647; dir=“/home/jean-victor”), ProcessExited(1))

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## [Solving heat diffusion PDE using DiffEqTools.jl and DifferentialEquations.jl](https://discourse.julialang.org/t/solving-heat-diffusion-pde-using-diffeqtools-jl-and-differentialequations-jl/41630)

<div class="topic-metadata">

**Author:** [@g4lvanix](https://discourse.julialang.org/u/g4lvanix)\
**Replies:** 2\
**Last updated:** [June 18, 2020, 5:20am UTC](https://discourse.julialang.org/t/solving-heat-diffusion-pde-using-diffeqtools-jl-and-differentialequations-jl/41630 "2020-06-18T05:20:00Z")

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Hi, I saw a great talk by Chris Rackauckas from JuliaCon 2018 on how to solve PDEs using Julia and decided to give it a whirl. The problem I’m trying to solve is the diffusion equation: Find u(t,x) such that u\_t = alph…

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## [Announcement hands-on Julia 101 online Meetup](https://discourse.julialang.org/t/announcement-hands-on-julia-101-online-meetup/41647)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 0\
**Last updated:** [June 18, 2020, 5:00am UTC](https://discourse.julialang.org/t/announcement-hands-on-julia-101-online-meetup/41647 "2020-06-18T05:00:03Z")

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Julia User Group Munich started a new introductory series for everyone to get to know this awesome language. It’s online, hence everyone from everywhere is cordially invited to join! Please spread the word.

[Previous page](https://discourse.julialang.org/latest.md?page=1712)

[Next page](https://discourse.julialang.org/latest.md?page=1714)