# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1830

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

**Page:** 1831

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## [JuMP: Hermitian matrix variable and complex numbers in model](https://discourse.julialang.org/t/jump-hermitian-matrix-variable-and-complex-numbers-in-model/34230)

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**Author:** [@martincornejo](https://discourse.julialang.org/u/martincornejo)\
**Replies:** 2\
**Last updated:** [February 6, 2020, 4:01pm UTC](https://discourse.julialang.org/t/jump-hermitian-matrix-variable-and-complex-numbers-in-model/34230 "2020-02-06T16:01:56Z")

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I’ve been playing around with JuMP and trying to develop on my own OPF models and I’ve had some difficulty since JuMP doesn’t support complex numbers. Specially the SDP relaxation of the OPF has been tricky since I don’t…

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## [SLATE project](https://discourse.julialang.org/t/slate-project/34082)

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**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 2\
**Last updated:** [February 6, 2020, 3:59pm UTC](https://discourse.julialang.org/t/slate-project/34082 "2020-02-06T15:59:41Z")

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I found a projetc called Linear Algebra Targeting Exascale SLATE that aims to substitute ScaLapack. Looking around its documentation and articles, they have some concepts similar to Julia like using Templates of C++ in…

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## [How to use PyCall to connect to Splunk's SDK-python?](https://discourse.julialang.org/t/how-to-use-pycall-to-connect-to-splunks-sdk-python/34226)

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**Author:** [@Aizzaac](https://discourse.julialang.org/u/Aizzaac)\
**Replies:** 2\
**Last updated:** [February 6, 2020, 3:44pm UTC](https://discourse.julialang.org/t/how-to-use-pycall-to-connect-to-splunks-sdk-python/34226 "2020-02-06T15:44:58Z")

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Hi I want to connect to Splunk using a Python SDK. This is the code in python: import splunklib.client as client HOST = "localhost" PORT = 8089 USERNAME = "admin" PASSWORD = "passwdSPLUNK" # Create a Service instanc…

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## [Understanding Logging in Julia](https://discourse.julialang.org/t/understanding-logging-in-julia/34252)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 1\
**Last updated:** [February 6, 2020, 3:17pm UTC](https://discourse.julialang.org/t/understanding-logging-in-julia/34252 "2020-02-06T15:17:45Z")

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Hi, guys. I am trying to understand how to use Julia Logging system. For that I am now reading through the julia docs and the corresponding source code. I have a question about the implementation of SimpleLogger (see l…

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## [Maintain connection in ZMQ](https://discourse.julialang.org/t/maintain-connection-in-zmq/34243)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 1\
**Last updated:** [February 6, 2020, 2:41pm UTC](https://discourse.julialang.org/t/maintain-connection-in-zmq/34243 "2020-02-06T14:41:04Z")

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I am trying to establish a socket that listens for requests. Unfortunately, due to a combination of sparse documentation and my lack of familiarity with networking, I am unable to accomplish this through normal means. T…

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## [2D Lotka Volterra parameter estimation with only 1D data](https://discourse.julialang.org/t/2d-lotka-volterra-parameter-estimation-with-only-1d-data/13838)

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**Author:** [@gregory](https://discourse.julialang.org/u/gregory)\
**Replies:** 7\
**Last updated:** [February 6, 2020, 2:28pm UTC](https://discourse.julialang.org/t/2d-lotka-volterra-parameter-estimation-with-only-1d-data/13838 "2020-02-06T14:28:37Z")

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I am testing this with a toy problem first using a simple 2D Lotka Volterra. I feed in the actual params and then make some pseudo time series data. I then want to pretend I only have knowledge of 1 population and feed t…

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## [HELP: Implementing K-means from scratch with Julia](https://discourse.julialang.org/t/help-implementing-k-means-from-scratch-with-julia/34249)

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**Author:** [@PyDataBlog](https://discourse.julialang.org/u/PyDataBlog)\
**Replies:** 4\
**Last updated:** [February 6, 2020, 2:28pm UTC](https://discourse.julialang.org/t/help-implementing-k-means-from-scratch-with-julia/34249 "2020-02-06T14:28:15Z")

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Hi everyone, I am currently stuck trying to port an existing Julia code. Basically a code that builds a simple implementation of the K-means clustering algorithm. Here’s the testing data generated from sklearn: # Repla…

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## [Handle exception with the problem interface of DifferentialEquations](https://discourse.julialang.org/t/handle-exception-with-the-problem-interface-of-differentialequations/34228)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 5\
**Last updated:** [February 6, 2020, 2:25pm UTC](https://discourse.julialang.org/t/handle-exception-with-the-problem-interface-of-differentialequations/34228 "2020-02-06T14:25:45Z")

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Hello, I have an ODE problem with multiple callbacks (continuous and discrete ones). For some initial conditions, the computation of the right hand side will return an ArgumentError, is it possible to use the function t…

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## [Issue with 1.5 month old code based on CuArrays](https://discourse.julialang.org/t/issue-with-1-5-month-old-code-based-on-cuarrays/34248)

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**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 3\
**Last updated:** [February 6, 2020, 1:57pm UTC](https://discourse.julialang.org/t/issue-with-1-5-month-old-code-based-on-cuarrays/34248 "2020-02-06T13:57:14Z")

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Hi, I am updating my library PseudoArcLengthContinuation.jl and one of the tutorials based on CuArrays does not work anymore. It used to work by the end of December. Can someone explain me the error please? Thank you …

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## [How generate a random string correctly?](https://discourse.julialang.org/t/how-generate-a-random-string-correctly/34241)

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**Author:** [@Darione](https://discourse.julialang.org/u/Darione)\
**Replies:** 6\
**Last updated:** [February 6, 2020, 1:19pm UTC](https://discourse.julialang.org/t/how-generate-a-random-string-correctly/34241 "2020-02-06T13:19:17Z")

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Hello, i was trying to generate a random string. Looking for something similar on google, i find this one way: Random.seed!( 0 ) prefix\_result = randstring(12) println(prefix\_result) I understand that force seed to 0…

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## [Error saving a .jld file](https://discourse.julialang.org/t/error-saving-a-jld-file/34246)

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**Author:** [@ennvvy](https://discourse.julialang.org/u/ennvvy)\
**Replies:** 2\
**Last updated:** [February 6, 2020, 11:40am UTC](https://discourse.julialang.org/t/error-saving-a-jld-file/34246 "2020-02-06T11:40:07Z")

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I use julia v1.3.0 and have trouble saving a few variables in a .jld file. I get the following error HDF5-DIAG: Error detected in HDF5 (1.10.4) thread 0: #000: H5F.c line 444 in H5Fcreate(): unable to create file …

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## [It is so nice to program in a sane language!](https://discourse.julialang.org/t/it-is-so-nice-to-program-in-a-sane-language/32227)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 50\
**Last updated:** [February 6, 2020, 10:20am UTC](https://discourse.julialang.org/t/it-is-so-nice-to-program-in-a-sane-language/32227 "2020-02-06T10:20:13Z")

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Just watched Gary Bernhardt’s “wat”. JavaScript: It is so nice to work with a sane programming language rather than this lunacy!

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## [When does Code get optimized for architecture](https://discourse.julialang.org/t/when-does-code-get-optimized-for-architecture/34213)

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**Author:** [@Crown421](https://discourse.julialang.org/u/Crown421)\
**Replies:** 7\
**Last updated:** [February 6, 2020, 8:54am UTC](https://discourse.julialang.org/t/when-does-code-get-optimized-for-architecture/34213 "2020-02-06T08:54:10Z")

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My question might be a simple one: At what point (if at all) does julia code get optimized for the specific architecture it is running on? I dimly remember from some Juliacon talk that precompilation only lowers the cod…

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## [Keyword argument constructor breaks Incomplete constructor](https://discourse.julialang.org/t/keyword-argument-constructor-breaks-incomplete-constructor/34198)

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**Author:** [@milesf](https://discourse.julialang.org/u/milesf)\
**Replies:** 6\
**Last updated:** [February 6, 2020, 8:07am UTC](https://discourse.julialang.org/t/keyword-argument-constructor-breaks-incomplete-constructor/34198 "2020-02-06T08:07:12Z")

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julia\> mutable struct Foo x::Float64 y::Float64 Foo() = new() Foo(;x::Float64, y::Float64) = new(x, y) end julia\> Foo() ERROR: UndefKeywordError: keyword argument x no…

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## [Problem with variable scope when translating from Matlab to Julia](https://discourse.julialang.org/t/problem-with-variable-scope-when-translating-from-matlab-to-julia/34200)

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**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 8\
**Last updated:** [February 6, 2020, 2:43am UTC](https://discourse.julialang.org/t/problem-with-variable-scope-when-translating-from-matlab-to-julia/34200 "2020-02-06T02:43:16Z")

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Hi guys my problem is as follows: buff = g0 for i\_exh in 1:k f\_exh = obj\_rbfS3(x + y\_exh\[i\_exh\] \* v, X, ...) if f\_exh\[1,1\] \> buff\[1,1\] if i\_exh \> 1 gp\_exh = rbf\_dirS3(x + y\_exh\[i\_exh - 1\] \* v…

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## [A Julia Procedural Language Handler for Postgresql](https://discourse.julialang.org/t/a-julia-procedural-language-handler-for-postgresql/18163)

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**Author:** [@Paul\_McVay](https://discourse.julialang.org/u/Paul_McVay)\
**Replies:** 2\
**Last updated:** [February 6, 2020, 1:13am UTC](https://discourse.julialang.org/t/a-julia-procedural-language-handler-for-postgresql/18163 "2020-02-06T01:13:13Z")

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Is there a known procedural language handler for julia for postgresql in development? Something like what’s explained in PostgreSQL: Documentation: 8.3: Writing A Procedural Language Handler. I would like to contribute e…

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## [Accesing a Registry on Private Github](https://discourse.julialang.org/t/accesing-a-registry-on-private-github/19997)

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**Author:** [@Andrew\_Gibb](https://discourse.julialang.org/u/Andrew_Gibb)\
**Replies:** 17\
**Last updated:** [February 6, 2020, 12:17am UTC](https://discourse.julialang.org/t/accesing-a-registry-on-private-github/19997 "2020-02-06T00:17:03Z")

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I’ve just made myself a private registry for my work packages, following the nice instructions here. My organisation uses private github for most of our code, so I’ve put it there. When I try to do a package update, Pkg …

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## [Error installing Pajarito solver](https://discourse.julialang.org/t/error-installing-pajarito-solver/34223)

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**Author:** [@biswajit216](https://discourse.julialang.org/u/biswajit216)\
**Replies:** 1\
**Last updated:** [February 5, 2020, 10:25pm UTC](https://discourse.julialang.org/t/error-installing-pajarito-solver/34223 "2020-02-05T22:25:36Z")

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Hi, I was trying to add Pajarito package to my Julia but I was getting this error. My JuMP version is 0.20.1 pkg\> add Pajarito Resolving package versions… ERROR: Unsatisfiable requirements detected for package JuMP \[4…

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## [The error of using GLPKMathProgInterface pkg](https://discourse.julialang.org/t/the-error-of-using-glpkmathproginterface-pkg/34142)

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**Author:** [@mahsap58](https://discourse.julialang.org/u/mahsap58)\
**Replies:** 3\
**Last updated:** [February 5, 2020, 10:21pm UTC](https://discourse.julialang.org/t/the-error-of-using-glpkmathproginterface-pkg/34142 "2020-02-05T22:21:36Z")

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i have faced to this error in using GLPKMathProgInterface pkg please help me to fix that. Failed to precompile GLPK \[60bf3e95-4087-53dc-ae20-288a0d20c6a6\]

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## [Scalar parameter doesn't update in Flux, but array does](https://discourse.julialang.org/t/scalar-parameter-doesnt-update-in-flux-but-array-does/32548)

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**Author:** [@jonasaugust](https://discourse.julialang.org/u/jonasaugust)\
**Replies:** 10\
**Last updated:** [February 5, 2020, 10:06pm UTC](https://discourse.julialang.org/t/scalar-parameter-doesnt-update-in-flux-but-array-does/32548 "2020-02-05T22:06:30Z")

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When I try to minimize a quadratic function f(x) in a single, scalar parameter x via gradient descent in Flux, there is no progression (no change in x), but the single-component array version of the same works correctly: …

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## [Cloning a project - out of memory error](https://discourse.julialang.org/t/cloning-a-project-out-of-memory-error/34218)

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**Author:** [@lwhitefox](https://discourse.julialang.org/u/lwhitefox)\
**Replies:** 1\
**Last updated:** [February 5, 2020, 7:58pm UTC](https://discourse.julialang.org/t/cloning-a-project-out-of-memory-error/34218 "2020-02-05T19:58:39Z")

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I am trying to instantiate a Julia project environment in a virtual linux machine. I copy the relevant Project.toml, and the Pkg system sees it correctly. However, when I type instantiate I keep getting the errors simi…

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## [ANN MyWorkflow.jl runs on Binder](https://discourse.julialang.org/t/ann-myworkflow-jl-runs-on-binder/34217)

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**Author:** [@terasakisatoshi](https://discourse.julialang.org/u/terasakisatoshi)\
**Replies:** 0\
**Last updated:** [February 5, 2020, 7:36pm UTC](https://discourse.julialang.org/t/ann-myworkflow-jl-runs-on-binder/34217 "2020-02-05T19:36:19Z")

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Hi, everyone! I’m happy to announce I’ve succeeded to build my repository using Binder and share my work on the internet. You can try my repository the following link: Note that you do not have to install julia envir…

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## [How to write code in Julia from Python](https://discourse.julialang.org/t/how-to-write-code-in-julia-from-python/34214)

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**Author:** [@Aizzaac](https://discourse.julialang.org/u/Aizzaac)\
**Replies:** 10\
**Last updated:** [February 5, 2020, 7:34pm UTC](https://discourse.julialang.org/t/how-to-write-code-in-julia-from-python/34214 "2020-02-05T19:34:48Z")

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Hi I am struggling with my first script with Julia. In Python I am using this piece of code to have the PATH of ‘splunk -sdk-python’. import sys, os pa = os.path.join(os.path.abspath(os.path.join('', os.pardir)), "sp…

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## [Add Package on every processor?](https://discourse.julialang.org/t/add-package-on-every-processor/33853)

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**Author:** [@squirrel](https://discourse.julialang.org/u/squirrel)\
**Replies:** 6\
**Last updated:** [February 5, 2020, 7:30pm UTC](https://discourse.julialang.org/t/add-package-on-every-processor/33853 "2020-02-05T19:30:25Z")

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I’m trying to use DistributedArrays (per the example), but it seems like the package needs to be added to every processor. Is this right? When I first start Julia, and run using Distributed addprocs() @everywhere using…

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## [Kmeans problem](https://discourse.julialang.org/t/kmeans-problem/34210)

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**Author:** [@muhammetfaik](https://discourse.julialang.org/u/muhammetfaik)\
**Replies:** 1\
**Last updated:** [February 5, 2020, 5:18pm UTC](https://discourse.julialang.org/t/kmeans-problem/34210 "2020-02-05T17:18:38Z")

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https://github.com/muhammetfaik/julia-tutorial/issues/1

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## [Save data frame with special characters in csv](https://discourse.julialang.org/t/save-data-frame-with-special-characters-in-csv/34022)

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**Author:** [@jayce\_ram](https://discourse.julialang.org/u/jayce_ram)\
**Replies:** 5\
**Last updated:** [February 5, 2020, 5:06pm UTC](https://discourse.julialang.org/t/save-data-frame-with-special-characters-in-csv/34022 "2020-02-05T17:06:28Z")

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The column names of my dataframe has special character like "€. Before updating to v1.3, I was able to write my df in a csv file and keeping the different symbols. However, after updating the csv file doesn’t recognize …

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## [AlexNet import to Julia](https://discourse.julialang.org/t/alexnet-import-to-julia/34209)

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**Author:** [@samantp](https://discourse.julialang.org/u/samantp)\
**Replies:** 1\
**Last updated:** [February 5, 2020, 4:13pm UTC](https://discourse.julialang.org/t/alexnet-import-to-julia/34209 "2020-02-05T16:13:46Z")

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I am trying to download and modify AlexNet, the well known pre-trained neural network into Julia. Are there any packages that have already done this or have well known pre-trained NN’s that are open to modification? I a…

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## [Hide long types in error output for better readability](https://discourse.julialang.org/t/hide-long-types-in-error-output-for-better-readability/32104)

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**Author:** [@Anderssorby](https://discourse.julialang.org/u/Anderssorby)\
**Replies:** 26\
**Last updated:** [February 5, 2020, 3:39pm UTC](https://discourse.julialang.org/t/hide-long-types-in-error-output-for-better-readability/32104 "2020-02-05T15:39:48Z")

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I am new to Julia and I like the language, but one thing I don’t like is the error messages. They are often a big block of mostly incomprehensible text which I suspect might scare some developers away. This is largely du…

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## [Checking if all the array's elements are positive](https://discourse.julialang.org/t/checking-if-all-the-arrays-elements-are-positive/34206)

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**Author:** [@marouane1994](https://discourse.julialang.org/u/marouane1994)\
**Replies:** 8\
**Last updated:** [February 5, 2020, 3:08pm UTC](https://discourse.julialang.org/t/checking-if-all-the-arrays-elements-are-positive/34206 "2020-02-05T15:08:53Z")

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in the usual case i can make sure if all the array’s elements are positive using the nonneg(x)now it’s not working for me everytime i try to use it, an error raises with nonneg is not defined is it deprecated or what?

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## [How to check if a solver supports SOS2 constraints](https://discourse.julialang.org/t/how-to-check-if-a-solver-supports-sos2-constraints/34186)

<div class="topic-metadata">

**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 3\
**Last updated:** [February 5, 2020, 2:22pm UTC](https://discourse.julialang.org/t/how-to-check-if-a-solver-supports-sos2-constraints/34186 "2020-02-05T14:22:59Z")

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I have a piece of code that adds SOS2 constraints to a model. If the solver supports it, I would like to use its interface, if not I would assemble the constraints myself. Is there a way to check if an optimizer suppor…

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