# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=277

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**Page:** 278

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## [A few resources to help enable using Distributed.jl on a SLURM cluster](https://discourse.julialang.org/t/a-few-resources-to-help-enable-using-distributed-jl-on-a-slurm-cluster/81911)

<div class="topic-metadata">

**Author:** [@jmair](https://discourse.julialang.org/u/jmair)\
**Replies:** 0\
**Last updated:** [May 30, 2022, 11:38am UTC](https://discourse.julialang.org/t/a-few-resources-to-help-enable-using-distributed-jl-on-a-slurm-cluster/81911 "2022-05-30T11:38:06Z")

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I created some resources for a few colleagues new to Julia, to enable them to use our SLURM cluster effectively, using existing packages like Distributed.jl and ClusterManagers.jl. These scripts and resources do nothing…

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## [SCS Indirect Solver Parallelized?](https://discourse.julialang.org/t/scs-indirect-solver-parallelized/81687)

<div class="topic-metadata">

**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 5\
**Last updated:** [May 30, 2022, 9:36am UTC](https://discourse.julialang.org/t/scs-indirect-solver-parallelized/81687 "2022-05-30T09:36:09Z")

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Is it possible to permit the SCS.jl indirect solver to parallelize its computations with multiple threads running on a multi-core CPU? I am trying to solve a very large LP. problem: variables n: 47251695, constraints m…

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## [Adaptive mesh refinement in JuMP](https://discourse.julialang.org/t/adaptive-mesh-refinement-in-jump/81864)

<div class="topic-metadata">

**Author:** [@Kieran\_Marray](https://discourse.julialang.org/u/Kieran_Marray)\
**Replies:** 2\
**Last updated:** [May 30, 2022, 12:01am UTC](https://discourse.julialang.org/t/adaptive-mesh-refinement-in-jump/81864 "2022-05-30T00:01:30Z")

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I have a non-linear programming problem similar to the space shuttle problem in the JuMP tutorial Optimal control for a Space Shuttle reentry trajectory · JuMP. I want to implement adaptive mesh refinement to ensure an a…

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## [Converting PyTorch to Flux while keeping performance](https://discourse.julialang.org/t/converting-pytorch-to-flux-while-keeping-performance/81877)

<div class="topic-metadata">

**Author:** [@Jarartur](https://discourse.julialang.org/u/Jarartur)\
**Replies:** 7\
**Last updated:** [May 29, 2022, 9:58pm UTC](https://discourse.julialang.org/t/converting-pytorch-to-flux-while-keeping-performance/81877 "2022-05-29T21:58:01Z")

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Hey, I am currently converting some models from pytorch to flux and can’t figure out why I am having performance issues. My function in PyTorch: def stiffness\_reg(x, idx): x\_nn = knn\_gather(x, idx) # basically ind…

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## [Write function "show" for own multi-level structure](https://discourse.julialang.org/t/write-function-show-for-own-multi-level-structure/81882)

<div class="topic-metadata">

**Author:** [@Yuri](https://discourse.julialang.org/u/Yuri)\
**Replies:** 2\
**Last updated:** [May 29, 2022, 7:35pm UTC](https://discourse.julialang.org/t/write-function-show-for-own-multi-level-structure/81882 "2022-05-29T19:35:47Z")

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I want to write a function Base.show for my structure Node: mutable struct Node keys::Vector vals::Vector count::Int end and which will display: nod = Node( \["a", "b", "c", "d"\], \[Node( \["…

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## [MethodError: objects of type Float64 are not callable](https://discourse.julialang.org/t/methoderror-objects-of-type-float64-are-not-callable/81876)

<div class="topic-metadata">

**Author:** [@Hupdup](https://discourse.julialang.org/u/Hupdup)\
**Replies:** 2\
**Last updated:** [May 29, 2022, 6:04pm UTC](https://discourse.julialang.org/t/methoderror-objects-of-type-float64-are-not-callable/81876 "2022-05-29T18:04:11Z")

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Hi, when I want to update the weights of my main\_network, I always get this ERROR: MethodError: objects of type Float64 are not callable The Output is: -24.429102722601773 Float32\[-0.019576067, 0.08515469, -0.026…

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## [Symbolics.jl: Compute determinant](https://discourse.julialang.org/t/symbolics-jl-compute-determinant/81866)

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**Author:** [@DanDoe](https://discourse.julialang.org/u/DanDoe)\
**Replies:** 2\
**Last updated:** [May 29, 2022, 1:28pm UTC](https://discourse.julialang.org/t/symbolics-jl-compute-determinant/81866 "2022-05-29T13:28:35Z")

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I would like to compute the determinant of a matrix involving a symbolic variable: using Symbolics I = # Identity matrix A = # Some non-trivial matrix @variables z aux = I - z \* A det(aux) This webpage claims that co…

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## [Pipeline for different columns](https://discourse.julialang.org/t/pipeline-for-different-columns/81494)

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**Author:** [@jfcal](https://discourse.julialang.org/u/jfcal)\
**Replies:** 11\
**Last updated:** [May 29, 2022, 9:08am UTC](https://discourse.julialang.org/t/pipeline-for-different-columns/81494 "2022-05-29T09:08:23Z")

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Hi everyone, I have mixed type data and want to apply different functions to different types in a pipeline. Like imputation with mean for continuous and knn imputation for categorical and so on… Is it possible with MLJ…

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## [Send http request through specific network interface using HTTP.jl](https://discourse.julialang.org/t/send-http-request-through-specific-network-interface-using-http-jl/81777)

<div class="topic-metadata">

**Author:** [@Anastas](https://discourse.julialang.org/u/Anastas)\
**Replies:** 2\
**Last updated:** [May 29, 2022, 5:08am UTC](https://discourse.julialang.org/t/send-http-request-through-specific-network-interface-using-http-jl/81777 "2022-05-29T05:08:50Z")

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Hello, every one I want to send request through specific network interface using HTTP.jl like it works in here . In lib python requests it works correct. Or if to use curl, request should look like this: curl --interfa…

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## [Training with Flux.jl on the GPU causes ArgumentError: cannot take the CPU address of a CuArray](https://discourse.julialang.org/t/training-with-flux-jl-on-the-gpu-causes-argumenterror-cannot-take-the-cpu-address-of-a-cuarray/81751)

<div class="topic-metadata">

**Author:** [@lfenzo](https://discourse.julialang.org/u/lfenzo)\
**Replies:** 4\
**Last updated:** [May 28, 2022, 4:30pm UTC](https://discourse.julialang.org/t/training-with-flux-jl-on-the-gpu-causes-argumenterror-cannot-take-the-cpu-address-of-a-cuarray/81751 "2022-05-28T16:30:54Z")

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Hello! I’m trying to train a neural network using Flux.jl on the GPU with CUDA.jl. My issue (see error below) is that there seems to be some problem during the data transfer process between the GPU and CPU which causes …

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## [Why do we need "GalacticOptim.instantiate\_function"?](https://discourse.julialang.org/t/why-do-we-need-galacticoptim-instantiate-function/81760)

<div class="topic-metadata">

**Author:** [@mzhenirovskyy](https://discourse.julialang.org/u/mzhenirovskyy)\
**Replies:** 9\
**Last updated:** [May 28, 2022, 3:58pm UTC](https://discourse.julialang.org/t/why-do-we-need-galacticoptim-instantiate-function/81760 "2022-05-28T15:58:28Z")

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This example seems to work even without “instantiate\_function”. https://diffeqflux.sciml.ai/stable/examples/neural\_ode\_galacticoptim/ I can’t find any docs about “instantiate\_function”.

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## [Heat flow in 1d](https://discourse.julialang.org/t/heat-flow-in-1d/81711)

<div class="topic-metadata">

**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 10\
**Last updated:** [May 28, 2022, 10:44am UTC](https://discourse.julialang.org/t/heat-flow-in-1d/81711 "2022-05-28T10:44:09Z")

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I want to Plot Theta vs index " i ". where θ\[i-1\]+b\*θ\[i\]+θ\[i+1\] =0 is the equation that i obtained after discretization . b is parameter. i took m=100 and delta g= 0.01 using Plots begin Δg=0.01 ;m=100 b=-2-(m^2…

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## [Detecting low precision contamination of DoubleFloats.jl](https://discourse.julialang.org/t/detecting-low-precision-contamination-of-doublefloats-jl/77408)

<div class="topic-metadata">

**Author:** [@HexSpin](https://discourse.julialang.org/u/HexSpin)\
**Replies:** 15\
**Last updated:** [May 28, 2022, 7:56am UTC](https://discourse.julialang.org/t/detecting-low-precision-contamination-of-doublefloats-jl/77408 "2022-05-28T07:56:22Z")

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For the last many months I’ve very happily used DoubleFloats.jl to compute series akin to 1+1/2+1/3-1/4-1/5… with varying signs changes and ranges up to (and fractions as as small as) 1/10^15 – or smaller. As these summ…

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## [Arbitrary precision refinnements with Convex.jl & COSMO.jl](https://discourse.julialang.org/t/arbitrary-precision-refinnements-with-convex-jl-cosmo-jl/61806)

<div class="topic-metadata">

**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 9\
**Last updated:** [May 28, 2022, 7:16am UTC](https://discourse.julialang.org/t/arbitrary-precision-refinnements-with-convex-jl-cosmo-jl/61806 "2022-05-28T07:16:53Z")

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Hi, I’m solving a problem through Convex.jl & COSMO.jl. I want to build a BigFloat version of the same problem to refine the solution, and i’d like to warm start it with the low-precision solution. For the dummy problem…

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## [Read .lp file into JuMP model in direct mode](https://discourse.julialang.org/t/read-lp-file-into-jump-model-in-direct-mode/81803)

<div class="topic-metadata">

**Author:** [@MarioSouto](https://discourse.julialang.org/u/MarioSouto)\
**Replies:** 3\
**Last updated:** [May 28, 2022, 2:58am UTC](https://discourse.julialang.org/t/read-lp-file-into-jump-model-in-direct-mode/81803 "2022-05-28T02:58:34Z")

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Is it possible to read a .lp file into a JuMP optimization model in direct mode? I’m not sure how to combine direct\_model and read\_from\_file to achieve this.

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## [Using HSL library for IPOPT in PowerModels.jl](https://discourse.julialang.org/t/using-hsl-library-for-ipopt-in-powermodels-jl/81796)

<div class="topic-metadata">

**Author:** [@aaldik](https://discourse.julialang.org/u/aaldik)\
**Replies:** 4\
**Last updated:** [May 27, 2022, 10:26pm UTC](https://discourse.julialang.org/t/using-hsl-library-for-ipopt-in-powermodels-jl/81796 "2022-05-27T22:26:04Z")

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Hello I would like to ask how to use the HSL library with the solver IPOPT that is used in the library PowerModels.jl.

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## [Plots.jl - Strings as xticks](https://discourse.julialang.org/t/plots-jl-strings-as-xticks/20745)

<div class="topic-metadata">

**Author:** [@mariok90](https://discourse.julialang.org/u/mariok90)\
**Replies:** 5\
**Last updated:** [May 27, 2022, 8:45pm UTC](https://discourse.julialang.org/t/plots-jl-strings-as-xticks/20745 "2022-05-27T20:45:59Z")

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I want to replace the xticks with strings. How can I do that? When I run : using Plots xticks = \["$i" for i in 1:10\] plot(rand(10), xticks=xticks) I get an error: Julia Client – Internal Error MethodError: no method …

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## [Abstract DataFrame not iterable?](https://discourse.julialang.org/t/abstract-dataframe-not-iterable/81799)

<div class="topic-metadata">

**Author:** [@ctrebbau](https://discourse.julialang.org/u/ctrebbau)\
**Replies:** 4\
**Last updated:** [May 27, 2022, 8:14pm UTC](https://discourse.julialang.org/t/abstract-dataframe-not-iterable/81799 "2022-05-27T20:14:53Z")

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Hi there! I have data like so which I then combine according to the number of observations on each group like so Finally I join the new feature with my main df: The problem is when I wrap around function to t…

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## [Save and plot parameter history with ModelingToolkit.jl](https://discourse.julialang.org/t/save-and-plot-parameter-history-with-modelingtoolkit-jl/81778)

<div class="topic-metadata">

**Author:** [@visr](https://discourse.julialang.org/u/visr)\
**Replies:** 1\
**Last updated:** [May 27, 2022, 12:11pm UTC](https://discourse.julialang.org/t/save-and-plot-parameter-history-with-modelingtoolkit-jl/81778 "2022-05-27T12:11:39Z")

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Parameters are currently not saved over time in the solution, the way states are. This was previously discussed in Update parameters in ModelingToolkit using callbacks. Chris mentioned there that one option would be to…

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## [Dynamic NL expression in julia](https://discourse.julialang.org/t/dynamic-nl-expression-in-julia/81658)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 2\
**Last updated:** [May 27, 2022, 10:42am UTC](https://discourse.julialang.org/t/dynamic-nl-expression-in-julia/81658 "2022-05-27T10:42:46Z")

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Hi, I am using Juniper to solve MNILP and with array of nonlinear expression i am getting invalid model error. is there a way to generate nonlinear expression names in a loop like @variable(model,x) zz=0.0 for i in 1:5 …

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## [Cannot multiply a quadratic expression by an aff. expression](https://discourse.julialang.org/t/cannot-multiply-a-quadratic-expression-by-an-aff-expression/81742)

<div class="topic-metadata">

**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 2\
**Last updated:** [May 27, 2022, 10:34am UTC](https://discourse.julialang.org/t/cannot-multiply-a-quadratic-expression-by-an-aff-expression/81742 "2022-05-27T10:34:16Z")

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using Cbc,JuMP,LinearAlgebra, Juniper,Ipopt,HiGHS; optimizer = Juniper.Optimizer; nl\_solver = optimizer\_with\_attributes(Ipopt.Optimizer); mip\_solver = optimizer\_with\_attributes(HiGHS.Optimizer); mod2 = Model(optimizer\_…

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## [GalacticOptim.solve ignores callback](https://discourse.julialang.org/t/galacticoptim-solve-ignores-callback/81670)

<div class="topic-metadata">

**Author:** [@mzhenirovskyy](https://discourse.julialang.org/u/mzhenirovskyy)\
**Replies:** 1\
**Last updated:** [May 27, 2022, 3:09am UTC](https://discourse.julialang.org/t/galacticoptim-solve-ignores-callback/81670 "2022-05-27T03:09:35Z")

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Hi All, It seems the callback doesn’t work when it is called from “GalacticOptim.solve”. using DifferentialEquations, DiffEqFlux, GalacticOptim function lotka\_volterra!(du, u, p, t) x, y = u α, β, δ, γ = p du\[1\]…

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## [Creating a tuple from combination of tuple and vectors](https://discourse.julialang.org/t/creating-a-tuple-from-combination-of-tuple-and-vectors/81705)

<div class="topic-metadata">

**Author:** [@joxane7887](https://discourse.julialang.org/u/joxane7887)\
**Replies:** 5\
**Last updated:** [May 27, 2022, 2:43am UTC](https://discourse.julialang.org/t/creating-a-tuple-from-combination-of-tuple-and-vectors/81705 "2022-05-27T02:43:49Z")

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I’d like to combine three thing; a Vector{Tuple{Int64, Int64}}, Vector{Vector{Int64}}, and a Vector{Int64} under some condition to be able to create a new tuple; in other words; a Vector{Tuple{Int64, Int64, Int64}}. And …

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## [JuMP creating a huge MPS file](https://discourse.julialang.org/t/jump-creating-a-huge-mps-file/81477)

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**Author:** [@Popeye](https://discourse.julialang.org/u/Popeye)\
**Replies:** 22\
**Last updated:** [May 26, 2022, 10:30pm UTC](https://discourse.julialang.org/t/jump-creating-a-huge-mps-file/81477 "2022-05-26T22:30:28Z")

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Further to my question, here How to specify barrier method to use? - Specific Domains / Optimization (Mathematical) - JuliaLang, I have given an example of a case where it is taking too long to build the model or write a…

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## [Archival of discontinued packages in JuliaML](https://discourse.julialang.org/t/archival-of-discontinued-packages-in-juliaml/81375)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 11\
**Last updated:** [May 26, 2022, 9:27pm UTC](https://discourse.julialang.org/t/archival-of-discontinued-packages-in-juliaml/81375 "2022-05-26T21:27:08Z")

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I am cleaning the house in JuliaML and will proceed with a sequence of archival operations to facilitate the lives of newcomers who come to Julia and are completely lost in the middle of packages that don’t even load any…

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## [Need Help to implement my loss function](https://discourse.julialang.org/t/need-help-to-implement-my-loss-function/81724)

<div class="topic-metadata">

**Author:** [@Hupdup](https://discourse.julialang.org/u/Hupdup)\
**Replies:** 0\
**Last updated:** [May 26, 2022, 2:13pm UTC](https://discourse.julialang.org/t/need-help-to-implement-my-loss-function/81724 "2022-05-26T14:13:40Z")

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Hi I want to implement a loss function for the weight-update of the neural network in my Reinforcement learning (DQN) project. The Q Value of the next state should be estimated by my target network (yellow mark) wheras…

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## [To provide Jacobian in non-linear solver, time-stepping or Jacobian](https://discourse.julialang.org/t/to-provide-jacobian-in-non-linear-solver-time-stepping-or-jacobian/81632)

<div class="topic-metadata">

**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 2\
**Last updated:** [May 26, 2022, 12:52pm UTC](https://discourse.julialang.org/t/to-provide-jacobian-in-non-linear-solver-time-stepping-or-jacobian/81632 "2022-05-26T12:52:20Z")

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Is there a good example showing that the effort of providing the Jacobian to either a non-linear solver, a time-stepping solver or an optimization solver does pay off in reducing the number of (non-linear, right-hand sid…

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## [Can we find a DDe's canstant from a table](https://discourse.julialang.org/t/can-we-find-a-ddes-canstant-from-a-table/81676)

<div class="topic-metadata">

**Author:** [@Achraf\_el\_fadli](https://discourse.julialang.org/u/Achraf_el_fadli)\
**Replies:** 6\
**Last updated:** [May 26, 2022, 12:35pm UTC](https://discourse.julialang.org/t/can-we-find-a-ddes-canstant-from-a-table/81676 "2022-05-26T12:35:33Z")

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for finding a,b,c the most compatible with the model

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## [Making Plots place its legend in a better spot](https://discourse.julialang.org/t/making-plots-place-its-legend-in-a-better-spot/74986)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 18\
**Last updated:** [May 26, 2022, 10:27am UTC](https://discourse.julialang.org/t/making-plots-place-its-legend-in-a-better-spot/74986 "2022-05-26T10:27:21Z")

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Apparently this is a feature, or not of the backend, and Plots sends legend=:best to them. PyPlot should place the legend in a nice position by default, avoiding the data, but GR apparently does not have this feature. I…

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## [JuMP writeMPS does not finish writing LP model to file](https://discourse.julialang.org/t/jump-writemps-does-not-finish-writing-lp-model-to-file/81427)

<div class="topic-metadata">

**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 20\
**Last updated:** [May 25, 2022, 8:31pm UTC](https://discourse.julialang.org/t/jump-writemps-does-not-finish-writing-lp-model-to-file/81427 "2022-05-25T20:31:40Z")

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I’m trying to save a large linear program model created with JuMP v0.18.5 in Julia v0.6.4 to a .mps file on disk using writeMPS, but the file maxes out quickly at 711MB and the Julia script trying to write the file event…

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