# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=496

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**Page:** 497

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## [How to remove the bar strokeline in Plots.jl](https://discourse.julialang.org/t/how-to-remove-the-bar-strokeline-in-plots-jl/24753)

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**Author:** [@babaq](https://discourse.julialang.org/u/babaq)\
**Replies:** 3\
**Last updated:** [May 30, 2019, 6:25am UTC](https://discourse.julialang.org/t/how-to-remove-the-bar-strokeline-in-plots-jl/24753 "2019-05-30T06:25:03Z")

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Hi, I am trying to do a bar plot, with no gap between them, but I don’t know how to remove the black stroke lines around each bar. Anyone knows how to achieve this in Plots? Thanks

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## [Normalized Laplacian with LightGraphs.jl](https://discourse.julialang.org/t/normalized-laplacian-with-lightgraphs-jl/24748)

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**Author:** [@andferrari](https://discourse.julialang.org/u/andferrari)\
**Replies:** 0\
**Last updated:** [May 29, 2019, 9:08pm UTC](https://discourse.julialang.org/t/normalized-laplacian-with-lightgraphs-jl/24748 "2019-05-29T21:08:00Z")

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I want to compute the Normalized Laplacian of a graph g. Is there something more straightforward than? adjmat = LightGraphs.LinAlg.CombinatorialAdjacency(adjacency\_matrix(g)) Ln = I - Diagonal(adjmat.D.^(-1/2))\*(adjmat…

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## [Special method for finding eigenvalues of a large sparse symmetric matrix?](https://discourse.julialang.org/t/special-method-for-finding-eigenvalues-of-a-large-sparse-symmetric-matrix/9621)

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**Author:** [@406700](https://discourse.julialang.org/u/406700)\
**Replies:** 17\
**Last updated:** [May 29, 2019, 5:50pm UTC](https://discourse.julialang.org/t/special-method-for-finding-eigenvalues-of-a-large-sparse-symmetric-matrix/9621 "2019-05-29T17:50:37Z")

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Hi, I am looking to solve the eigenvalues of sparse symmetric matrix of ~ 14000x14000. Eigfact is too slow, and didn’t give results after an hour running. (8gb ram i7 processor) Are there special iteritive methods? …

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## [Lifting a Julia function into a Flux "layer"](https://discourse.julialang.org/t/lifting-a-julia-function-into-a-flux-layer/13712)

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**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 7\
**Last updated:** [May 29, 2019, 4:11pm UTC](https://discourse.julialang.org/t/lifting-a-julia-function-into-a-flux-layer/13712 "2019-05-29T16:11:11Z")

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Flux confused me for a long time. I got the first example in the docs to work: using Flux.Tracker W = param(rand(2, 5)) b = param(rand(2)) predict(x) = W\*x .+ b loss(x, y) = sum((predict(x) .- y).^2) x, y = rand(5), …

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## [Integer variable as index of input matrix](https://discourse.julialang.org/t/integer-variable-as-index-of-input-matrix/24725)

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**Author:** [@Raminel](https://discourse.julialang.org/u/Raminel)\
**Replies:** 2\
**Last updated:** [May 29, 2019, 2:08pm UTC](https://discourse.julialang.org/t/integer-variable-as-index-of-input-matrix/24725 "2019-05-29T14:08:14Z")

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Hi people, Can I formulate an expression in Julia and use an integer variable as an index of an input matrix? @variable(m, 1 \<= t\[1:3, 1:3\] \<= 8, Int) P = \[ 90 80 60 70 50 30 10 0\] for i = 1:3 for j = 1:3 M\[i,j\] =…

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## [Gaussian process in Julia](https://discourse.julialang.org/t/gaussian-process-in-julia/22900)

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**Author:** [@yusri-dh](https://discourse.julialang.org/u/yusri-dh)\
**Replies:** 13\
**Last updated:** [May 29, 2019, 1:33pm UTC](https://discourse.julialang.org/t/gaussian-process-in-julia/22900 "2019-05-29T13:33:29Z")

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Hello all, Julia newbie here. I am sorry I am not sure whether this is the right place to ask this question. If no I will delete it later. Is there any well-maintained package dedicated for gaussian process in Julia lik…

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## [Reading/parsing .ab1 sequencing files](https://discourse.julialang.org/t/reading-parsing-ab1-sequencing-files/23555)

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**Author:** [@solf1re2](https://discourse.julialang.org/u/solf1re2)\
**Replies:** 10\
**Last updated:** [May 29, 2019, 12:42pm UTC](https://discourse.julialang.org/t/reading-parsing-ab1-sequencing-files/23555 "2019-05-29T12:42:27Z")

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Hi, We currently get some sequencing done on 96 well plates. The lab guys manually check the chromatograms (ab1) files for clean reads. But I was wondering if there was a julia package able to open and retrieve the info…

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## [Building JuMP models through functions](https://discourse.julialang.org/t/building-jump-models-through-functions/24636)

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**Author:** [@iharjunk](https://discourse.julialang.org/u/iharjunk)\
**Replies:** 5\
**Last updated:** [May 29, 2019, 10:48am UTC](https://discourse.julialang.org/t/building-jump-models-through-functions/24636 "2019-05-29T10:48:15Z")

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Hello all, I would like to make my Julia/JuMP code more flexible and prepare it for larger test cases. For this I would need to Read in data from a given directory Build a model based on it - here since the model is l…

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## [Monte Carlo problem (distributed computing, DifferentialEquations pkg) with ForwardDiff AD for parameter estimation](https://discourse.julialang.org/t/monte-carlo-problem-distributed-computing-differentialequations-pkg-with-forwarddiff-ad-for-parameter-estimation/24697)

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**Author:** [@moesphere](https://discourse.julialang.org/u/moesphere)\
**Replies:** 1\
**Last updated:** [May 28, 2019, 4:41pm UTC](https://discourse.julialang.org/t/monte-carlo-problem-distributed-computing-differentialequations-pkg-with-forwarddiff-ad-for-parameter-estimation/24697 "2019-05-28T16:41:44Z")

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I am trying to use a Monte Carlo problem (distributed computing) from the Differential Equations package for parameter estimation using AD from ForwardDiff. It is working when I define the objective function directly in…

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## [DiffEqFlux / diffeq\_adjoint: no method matching back!(::Float64)](https://discourse.julialang.org/t/diffeqflux-diffeq-adjoint-no-method-matching-back-float64/24648)

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**Author:** [@mihai](https://discourse.julialang.org/u/mihai)\
**Replies:** 3\
**Last updated:** [May 28, 2019, 1:36pm UTC](https://discourse.julialang.org/t/diffeqflux-diffeq-adjoint-no-method-matching-back-float64/24648 "2019-05-28T13:36:18Z")

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Hi all, I’m new to julia and ML, so maybe it’s something obvious, but I’m a bit lost now. I would like to optimize a large set of parameters (N ODE’s with N \> 2k) to fit to data. From reading the documentation of DiffEq…

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## [DataFramesMeta custom filter: by groups of A, apply filter on B](https://discourse.julialang.org/t/dataframesmeta-custom-filter-by-groups-of-a-apply-filter-on-b/24557)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 4\
**Last updated:** [May 27, 2019, 6:44pm UTC](https://discourse.julialang.org/t/dataframesmeta-custom-filter-by-groups-of-a-apply-filter-on-b/24557 "2019-05-27T18:44:08Z")

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I need to subset a dataframe by groups. that is, in each group there is a different filtering condition to apply. here is a MWE using DataFrames, DataFramesMeta julia\> df = DataFrame(A = repeat(1:3,3), B = rand(1:9,9),…

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## [DataDeps post\_fetch\_method](https://discourse.julialang.org/t/datadeps-post-fetch-method/24649)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 6\
**Last updated:** [May 27, 2019, 4:52pm UTC](https://discourse.julialang.org/t/datadeps-post-fetch-method/24649 "2019-05-27T16:52:26Z")

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I have a bunch of zipped .csv files on an S3 repo. I’m using the excellent DataDeps to retrieve them. Next, I use the also excellent JuliaDB to loadtable the .csvs into tables, and then from there it’s processing etc etc…

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## [Plots: Only one series as primary plot](https://discourse.julialang.org/t/plots-only-one-series-as-primary-plot/24616)

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**Author:** [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)\
**Replies:** 17\
**Last updated:** [May 26, 2019, 3:31pm UTC](https://discourse.julialang.org/t/plots-only-one-series-as-primary-plot/24616 "2019-05-26T15:31:47Z")

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I frequently make figures that look like this m = randn(100) n = m .+ randn(100,50) plot(m, lab="mean", l=(5,)) plot!(n; lab="realizations", l=(:black, 0.1)) Here, I would prefer to only have one of the “realizations…

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## [Custom types in ForwardDiff](https://discourse.julialang.org/t/custom-types-in-forwarddiff/24610)

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**Author:** [@tamasgal](https://discourse.julialang.org/u/tamasgal)\
**Replies:** 8\
**Last updated:** [May 25, 2019, 9:06pm UTC](https://discourse.julialang.org/t/custom-types-in-forwarddiff/24610 "2019-05-25T21:06:21Z")

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This might be trivial but I am currently fighting with JuMP to accept my quality function for the minimisation procedure. I figured out that my custom type: struct Position \<: FieldVector{3, Float64} x::Float64 …

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## [Animation with timeline and play/pause](https://discourse.julialang.org/t/animation-with-timeline-and-play-pause/24575)

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**Author:** [@Seanny123](https://discourse.julialang.org/u/Seanny123)\
**Replies:** 2\
**Last updated:** [May 25, 2019, 6:30am UTC](https://discourse.julialang.org/t/animation-with-timeline-and-play-pause/24575 "2019-05-25T06:30:21Z")

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Often, I want to watch a visual system over time with the same basic controls as a video. Specifically: Play/Pause Drag around on a timeline Encoding a basic SVG animation is often overkill, so in Python, I awkwardly …

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## [Avoiding Memory leaks using CuArrays](https://discourse.julialang.org/t/avoiding-memory-leaks-using-cuarrays/24325)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 3\
**Last updated:** [May 24, 2019, 2:51pm UTC](https://discourse.julialang.org/t/avoiding-memory-leaks-using-cuarrays/24325 "2019-05-24T14:51:53Z")

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Hello, I have read that there is no garbage collection in GPUs. I have an algorithm where I use an Array{Array{CuArrays{Float32,1},1}} as a buffer. From that I sample a batch that I transform in a NTuple{CuArrays, N} to…

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## [Function getindex does not accept keyword arguments](https://discourse.julialang.org/t/function-getindex-does-not-accept-keyword-arguments/24564)

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**Author:** [@Octarosu](https://discourse.julialang.org/u/Octarosu)\
**Replies:** 1\
**Last updated:** [May 24, 2019, 1:21pm UTC](https://discourse.julialang.org/t/function-getindex-does-not-accept-keyword-arguments/24564 "2019-05-24T13:21:05Z")

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Hello, I implemented this function for economic dispatch function solve\_ed(g\_max, g\_min, c\_g, c\_w, d, w\_f) #Define the economic dispatch (ED) model ed=Model() # Define decision variables @defVar(ed, 0 \<= g\[i=1:2…

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## [Shallow water equations with DifferentialEquations.jl](https://discourse.julialang.org/t/shallow-water-equations-with-differentialequations-jl/2691)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 22\
**Last updated:** [May 24, 2019, 12:31am UTC](https://discourse.julialang.org/t/shallow-water-equations-with-differentialequations-jl/2691 "2019-05-24T00:31:41Z")

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I am really interested in using the DifferentialEquations.jl framework to solve the shallow water equations over a 2D domain efficiently instead of coding my own solution. How would you formulate the problem in Differen…

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## [CUDAnative tests failing on Windows 10](https://discourse.julialang.org/t/cudanative-tests-failing-on-windows-10/24465)

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**Author:** [@manderson](https://discourse.julialang.org/u/manderson)\
**Replies:** 5\
**Last updated:** [May 23, 2019, 7:57pm UTC](https://discourse.julialang.org/t/cudanative-tests-failing-on-windows-10/24465 "2019-05-23T19:57:07Z")

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Hello, I’m having some platform dependent problems getting CUDAnative working all the way. On my Ubuntu system I am having no problems, but on my windows machines the tests for the package are failing and I cannot make …

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## [Code optimization a (simple) advection difference scheme](https://discourse.julialang.org/t/code-optimization-a-simple-advection-difference-scheme/24532)

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**Author:** [@fdevuyst](https://discourse.julialang.org/u/fdevuyst)\
**Replies:** 2\
**Last updated:** [May 23, 2019, 6:43pm UTC](https://discourse.julialang.org/t/code-optimization-a-simple-advection-difference-scheme/24532 "2019-05-23T18:43:50Z")

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Hi, I’m beginner in Julia. I tried a simple code, but was a little bit disappointed with the performance. Could you give me hints in optimizing this snippet ? Kind regards, Florian 2D advection equation, periodic boun…

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## [Recipe to plot unit points](https://discourse.julialang.org/t/recipe-to-plot-unit-points/24510)

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**Author:** [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Replies:** 7\
**Last updated:** [May 23, 2019, 4:17pm UTC](https://discourse.julialang.org/t/recipe-to-plot-unit-points/24510 "2019-05-23T16:17:58Z")

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I am bring to define a Recipe for my own data type, but following any thread here (for example Understanding recipes in Plots.jl ) I always end up with No user recipe defined for MyType errors and I would like to unders…

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## [Multi-cut Benders decomposition?](https://discourse.julialang.org/t/multi-cut-benders-decomposition/23472)

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**Author:** [@deschase](https://discourse.julialang.org/u/deschase)\
**Replies:** 4\
**Last updated:** [May 23, 2019, 11:57am UTC](https://discourse.julialang.org/t/multi-cut-benders-decomposition/23472 "2019-05-23T11:57:57Z")

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I have coded a Benders decomposition with JuMP, but it is currently running too slow for my needs. I have a way to speed up the process theoretically by collecting several solutions from the solver at each iteration of m…

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## [CUDAnative: ^ and other operators](https://discourse.julialang.org/t/cudanative-and-other-operators/24506)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 0\
**Last updated:** [May 23, 2019, 9:58am UTC](https://discourse.julialang.org/t/cudanative-and-other-operators/24506 "2019-05-23T09:58:47Z")

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A simple question: is there a particular reason why there is no ^ operator in CUDAnative, but only CUDAnative.pow(x, y)? Could we have something like: x^y = pow(x,y) What about other operators? Can this be added? Tha…

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## [Lagrange Interpolation Function Generator](https://discourse.julialang.org/t/lagrange-interpolation-function-generator/3427)

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**Author:** [@anodos](https://discourse.julialang.org/u/anodos)\
**Replies:** 3\
**Last updated:** [May 22, 2019, 10:31pm UTC](https://discourse.julialang.org/t/lagrange-interpolation-function-generator/3427 "2019-05-22T22:31:59Z")

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I couldn’t find an implementation of Lagrange Interpolation in Julia, so built my own. This function simply takes a set of points, as stored in the two vectors xvals and yvals, and spits out the Lagrange Polynomial that …

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## [JuMP (0.18): summing up elements of solution vector allocates memory?](https://discourse.julialang.org/t/jump-0-18-summing-up-elements-of-solution-vector-allocates-memory/24488)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 9\
**Last updated:** [May 22, 2019, 8:09pm UTC](https://discourse.julialang.org/t/jump-0-18-summing-up-elements-of-solution-vector-allocates-memory/24488 "2019-05-22T20:09:07Z")

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Dear folks, I observe a strange behavior (note that the following snippets are embedded in a function): let x be some decision vector of size n. Then, sum\_x = 0.0 x\_val = getvalue( model\[:x\] ) println("typeof x\_val: ",…

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## [GPU memory layout for custom type with different array lengths: StructArrays?](https://discourse.julialang.org/t/gpu-memory-layout-for-custom-type-with-different-array-lengths-structarrays/24479)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 0\
**Last updated:** [May 22, 2019, 3:04pm UTC](https://discourse.julialang.org/t/gpu-memory-layout-for-custom-type-with-different-array-lengths-structarrays/24479 "2019-05-22T15:04:34Z")

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I have the following example of a structure for a data type (real type has more fields): mutable struct Worker id :: Int # name T :: Int # number of periods observed t :: Int # current period w …

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## [Monte Carlo problem, saving at different time points with 'saveat' from DifferentialEquations pkg](https://discourse.julialang.org/t/monte-carlo-problem-saving-at-different-time-points-with-saveat-from-differentialequations-pkg/24476)

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**Author:** [@moesphere](https://discourse.julialang.org/u/moesphere)\
**Replies:** 1\
**Last updated:** [May 22, 2019, 2:17pm UTC](https://discourse.julialang.org/t/monte-carlo-problem-saving-at-different-time-points-with-saveat-from-differentialequations-pkg/24476 "2019-05-22T14:17:51Z")

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Is it possible to save at different time points for each ODE problem in a Monte Carlo study? DifferentialEquations.solve(MCprob, saveat=\[10.0,20.0\]) works fine, but saves each ODE problem at the same time points. I am…

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## [S3 object stores - current state?](https://discourse.julialang.org/t/s3-object-stores-current-state/24437)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 7\
**Last updated:** [May 22, 2019, 1:34am UTC](https://discourse.julialang.org/t/s3-object-stores-current-state/24437 "2019-05-22T01:34:25Z")

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What is the current state of packages in Julia for accessing S3 object stores. In particular CEPH. Are people just using boto with PyCall? Forgive me if I have asked this one before. Goldfish bowl memory.

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## [Optim user-supplied gradient not working](https://discourse.julialang.org/t/optim-user-supplied-gradient-not-working/24417)

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**Author:** [@tyleransom](https://discourse.julialang.org/u/tyleransom)\
**Replies:** 6\
**Last updated:** [May 21, 2019, 3:45pm UTC](https://discourse.julialang.org/t/optim-user-supplied-gradient-not-working/24417 "2019-05-21T15:45:56Z")

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I’m estimating a maximum likelihood problem, and I’ve specified both the objective function and the gradient correctly. (I know this because I am able to reproduce estimates using the same exact data as a Stata example.) …

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## [CouenneNL in version 1.1.1](https://discourse.julialang.org/t/couennenl-in-version-1-1-1/24405)

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**Author:** [@Raminel](https://discourse.julialang.org/u/Raminel)\
**Replies:** 5\
**Last updated:** [May 21, 2019, 2:42pm UTC](https://discourse.julialang.org/t/couennenl-in-version-1-1-1/24405 "2019-05-21T14:42:15Z")

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Hi, I am a new user of Julia and trying to solve my MINLP problem using CouenneNL. The problem is non convex so the solution I got from Ipopt is not reliable. How can I use CouenneNL in version v. 1.1.1?

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