# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=439

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**Page:** 440

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## [Have you used the IIS/conflict-refiner feature of a solver? How would you like to access it from JuMP?](https://discourse.julialang.org/t/have-you-used-the-iis-conflict-refiner-feature-of-a-solver-how-would-you-like-to-access-it-from-jump/41862)

<div class="topic-metadata">

**Author:** [@dourouc05](https://discourse.julialang.org/u/dourouc05)\
**Replies:** 0\
**Last updated:** [June 22, 2020, 1:51pm UTC](https://discourse.julialang.org/t/have-you-used-the-iis-conflict-refiner-feature-of-a-solver-how-would-you-like-to-access-it-from-jump/41862 "2020-06-22T13:51:42Z")

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Hi all, Right now, the plumbing work has been performed in the JuMP ecosystem to let you access the IIS/conflict-refiner functionality of your solver. More precisely, there is a low-level interface in MathOptInterface t…

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## [Genetic Algorithms with julia](https://discourse.julialang.org/t/genetic-algorithms-with-julia/41844)

<div class="topic-metadata">

**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 3\
**Last updated:** [June 22, 2020, 12:03pm UTC](https://discourse.julialang.org/t/genetic-algorithms-with-julia/41844 "2020-06-22T12:03:12Z")

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hello all, I wish to solve a multi objective optimization problem with GA also I have never worked with GA before and I want to learn more about what are the packages that I can find useful? What are the pros of cons of…

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## [Can't load CuArrays](https://discourse.julialang.org/t/cant-load-cuarrays/31214)

<div class="topic-metadata">

**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 17\
**Last updated:** [June 22, 2020, 10:42am UTC](https://discourse.julialang.org/t/cant-load-cuarrays/31214 "2020-06-22T10:42:08Z")

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Hi, this is ubuntu 18.04 (I think). I have installed julia and the sysop has installed CUDA, but I get using CuArrays \[ Info: CUDAdrv.jl failed to initialize, GPU functionality unavailable (set JULIA\_CUDA\_SILENT or JU…

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## [Parallel optimization/Genetic algorithm/Genetic programming](https://discourse.julialang.org/t/parallel-optimization-genetic-algorithm-genetic-programming/36805)

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**Author:** [@Neurovium](https://discourse.julialang.org/u/Neurovium)\
**Replies:** 4\
**Last updated:** [June 21, 2020, 10:18pm UTC](https://discourse.julialang.org/t/parallel-optimization-genetic-algorithm-genetic-programming/36805 "2020-06-21T22:18:41Z")

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Hi, I was planning to fully port a project to Julia. Checking the evolutionary optimization packages in Julia, I came across a few. It seems that the most mature one, Wallace (GitHub - ChrisTimperley/Wallace.jl: High-pe…

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## [Pmap batch example](https://discourse.julialang.org/t/pmap-batch-example/41849)

<div class="topic-metadata">

**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 0\
**Last updated:** [June 22, 2020, 9:48am UTC](https://discourse.julialang.org/t/pmap-batch-example/41849 "2020-06-22T09:48:40Z")

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Hi, can someone provide me with a good example of using the batch\_size parameter of the pmap function? I found Parallelism - Understanding pmap and the batch\_size parameter which indicates a performance increase by incr…

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## [Optimizing a very expensive function evaluated in C++](https://discourse.julialang.org/t/optimizing-a-very-expensive-function-evaluated-in-c/41312)

<div class="topic-metadata">

**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 15\
**Last updated:** [June 22, 2020, 2:40am UTC](https://discourse.julialang.org/t/optimizing-a-very-expensive-function-evaluated-in-c/41312 "2020-06-22T02:40:26Z")

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I am moving to Julia. I have a function which is implemented in C++ and currently have no time to migrate it to Julia. It depends on lots of parameters. It typically takes 1 hour - 1 week to compute a single value of thi…

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## [Change the label in plot](https://discourse.julialang.org/t/change-the-label-in-plot/41808)

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**Author:** [@m.lavaiyan](https://discourse.julialang.org/u/m.lavaiyan)\
**Replies:** 6\
**Last updated:** [June 21, 2020, 12:30pm UTC](https://discourse.julialang.org/t/change-the-label-in-plot/41808 "2020-06-21T12:30:37Z")

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Hello, I am looking for an efficient way to change the label from to something like operation1 operation2 operation3 … but not with the manual labeling as bellow. Because for a more number of operations it see…

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## [Is the Hessian used in non linear JuMP?](https://discourse.julialang.org/t/is-the-hessian-used-in-non-linear-jump/41804)

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**Author:** [@raphaelchinchilla](https://discourse.julialang.org/u/raphaelchinchilla)\
**Replies:** 3\
**Last updated:** [June 21, 2020, 6:18am UTC](https://discourse.julialang.org/t/is-the-hessian-used-in-non-linear-jump/41804 "2020-06-21T06:18:14Z")

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For non linear optimization, JuMP allows user to create their own function and either use autodiff or specify the derivatives manually: https://jump.dev/JuMP.jl/v0.21.3/nlp/#User-defined-Functions-1 However the documen…

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## [Create empty constraint with JuMP](https://discourse.julialang.org/t/create-empty-constraint-with-jump/41777)

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**Author:** [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)\
**Replies:** 11\
**Last updated:** [June 21, 2020, 1:55am UTC](https://discourse.julialang.org/t/create-empty-constraint-with-jump/41777 "2020-06-21T01:55:57Z")

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I have a part of my code in which it is simpler (far less ifs and edge cases) if I add empty constraints first and then, knowing all constraints I need are present in the model, change the coefficient of some variables i…

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## [Continuing bugs for SecondOrderODE problem solvers](https://discourse.julialang.org/t/continuing-bugs-for-secondorderode-problem-solvers/41559)

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**Author:** [@CosmoProf](https://discourse.julialang.org/u/CosmoProf)\
**Replies:** 34\
**Last updated:** [June 21, 2020, 12:43am UTC](https://discourse.julialang.org/t/continuing-bugs-for-secondorderode-problem-solvers/41559 "2020-06-21T00:43:22Z")

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Hi, working in DiffferentialEquations.jl, I find that a bunch of solvers don’t work with SecondOrderODE. This seems to be a bug at least a couple of years old, is there any way to use these solvers without reducing the p…

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## [Investigating numerical change in function return value between v1.4 vs v1.5](https://discourse.julialang.org/t/investigating-numerical-change-in-function-return-value-between-v1-4-vs-v1-5/41332)

<div class="topic-metadata">

**Author:** [@jmert](https://discourse.julialang.org/u/jmert)\
**Replies:** 7\
**Last updated:** [June 20, 2020, 6:29pm UTC](https://discourse.julialang.org/t/investigating-numerical-change-in-function-return-value-between-v1-4-vs-v1-5/41332 "2020-06-20T18:29:33Z")

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I’ve got a function which is exhibiting a change to the numerical return value when comparing Julia versions 1.2 through 1.4 versus the 1.5beta (and master). I think this is actually an LLVM “error” (or a misunderstandin…

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## [Finding MAP estimate in Turing?](https://discourse.julialang.org/t/finding-map-estimate-in-turing/41761)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 1\
**Last updated:** [June 20, 2020, 4:07am UTC](https://discourse.julialang.org/t/finding-map-estimate-in-turing/41761 "2020-06-20T04:07:19Z")

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I’m working on one of my Data Analysis tutorials. This one involves fitting a nonlinear function to an economic time series. The basic idea is that I have a radial basis function + some annual periodicity + a step funct…

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## [How to get the values in NDSparse as a matrix](https://discourse.julialang.org/t/how-to-get-the-values-in-ndsparse-as-a-matrix/41762)

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**Author:** [@Stephen](https://discourse.julialang.org/u/Stephen)\
**Replies:** 0\
**Last updated:** [June 20, 2020, 2:01am UTC](https://discourse.julialang.org/t/how-to-get-the-values-in-ndsparse-as-a-matrix/41762 "2020-06-20T02:01:07Z")

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julia\> Distance = loadndsparse("distance matrix.csv",indexcols = 1) 1-d NDSparse with 5 values (12 field named tuples): │ BO BR CO HA MN NA NH NL PO PR SP WO ─────┼───────────────────────────…

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## [Julia equivalent of Python (numpy.savetxt) and Matlab (save) commands?](https://discourse.julialang.org/t/julia-equivalent-of-python-numpy-savetxt-and-matlab-save-commands/41738)

<div class="topic-metadata">

**Author:** [@dynova](https://discourse.julialang.org/u/dynova)\
**Replies:** 5\
**Last updated:** [June 19, 2020, 8:37pm UTC](https://discourse.julialang.org/t/julia-equivalent-of-python-numpy-savetxt-and-matlab-save-commands/41738 "2020-06-19T20:37:39Z")

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What is the Julia equivalent of the following Python and MATLAB codes? I’m looking for identical formatting in the output. After searching the documentation (e.g. JLD, CSV, DataFrames), I have not found a satisfactory …

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## [ANN: RegressionTables.jl produces publication-quality regression tables](https://discourse.julialang.org/t/ann-regressiontables-jl-produces-publication-quality-regression-tables/7516)

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**Author:** [@jmboehm](https://discourse.julialang.org/u/jmboehm)\
**Replies:** 41\
**Last updated:** [June 19, 2020, 7:13pm UTC](https://discourse.julialang.org/t/ann-regressiontables-jl-produces-publication-quality-regression-tables/7516 "2020-06-19T19:13:27Z")

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Hi all, I’ve been working on RegressionTables.jl, a package that produces regression tables as seen in scientific journals (similar to R’s stargazer and Stata’s esttab). It currently works with output from the absolute…

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## [Square root of the inverse of a matrix](https://discourse.julialang.org/t/square-root-of-the-inverse-of-a-matrix/41539)

<div class="topic-metadata">

**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 17\
**Last updated:** [June 19, 2020, 6:13pm UTC](https://discourse.julialang.org/t/square-root-of-the-inverse-of-a-matrix/41539 "2020-06-19T18:13:11Z")

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Hello, I am working on square root factorization of the matrix of the form A = I + U'U which is typically positive semi-definite of dimension N \\sim 100. I need to solve a least square problem A^{-1}Y and compute the …

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## [VegaLite Overlay](https://discourse.julialang.org/t/vegalite-overlay/41640)

<div class="topic-metadata">

**Author:** [@Chris\_Anderson](https://discourse.julialang.org/u/Chris_Anderson)\
**Replies:** 3\
**Last updated:** [June 19, 2020, 4:59pm UTC](https://discourse.julialang.org/t/vegalite-overlay/41640 "2020-06-19T16:59:13Z")

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I have a scatter plot of data in VegaLite. I’d like to overlay a regression line on this plot. Is there a way to do this? df |\> @vlplot(:point, x = :Years, y = :Overall, width = 500, height = 500) Can I just add the …

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## [Some tweaks about binary I/O plus some conversions](https://discourse.julialang.org/t/some-tweaks-about-binary-i-o-plus-some-conversions/41586)

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**Author:** [@Xijiang\_Yu](https://discourse.julialang.org/u/Xijiang_Yu)\
**Replies:** 4\
**Last updated:** [June 18, 2020, 10:11pm UTC](https://discourse.julialang.org/t/some-tweaks-about-binary-i-o-plus-some-conversions/41586 "2020-06-18T22:11:59Z")

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Background The genotype data can be stored like: 01212 where, 0 and 2 are homozygotes, 1 is the heterozyges. Frequently they will be read into a Float64 matrix for some dot operations and GEMM things. My question is th…

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## [New Alpha zero replica](https://discourse.julialang.org/t/new-alpha-zero-replica/41432)

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**Author:** [@Fabrice\_Rosay](https://discourse.julialang.org/u/Fabrice_Rosay)\
**Replies:** 6\
**Last updated:** [June 19, 2020, 1:01pm UTC](https://discourse.julialang.org/t/new-alpha-zero-replica/41432 "2020-06-19T13:01:27Z")

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Hello, I posted a new alphazero replica on github: https://github.com/fabricerosay/AGZ0 It’s (very(very)) messy but fast and can easily be tweaked provided you already know alphazero. It uses Flux as only backend. Th…

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## [Questions about contributing to Distributions.jl](https://discourse.julialang.org/t/questions-about-contributing-to-distributions-jl/41530)

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**Author:** [@matvil](https://discourse.julialang.org/u/matvil)\
**Replies:** 41\
**Last updated:** [June 19, 2020, 11:25am UTC](https://discourse.julialang.org/t/questions-about-contributing-to-distributions-jl/41530 "2020-06-19T11:25:17Z")

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Hi all, I am thinking about contributing to Distributions.jl. Two questions: Is it of interest to contribute yet another distribution, or is the philosophy of that package to only include the most widely used distribu…

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## [Silence mosek solver in JuMP](https://discourse.julialang.org/t/silence-mosek-solver-in-jump/41708)

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**Author:** [@stephentu](https://discourse.julialang.org/u/stephentu)\
**Replies:** 2\
**Last updated:** [June 19, 2020, 10:25am UTC](https://discourse.julialang.org/t/silence-mosek-solver-in-jump/41708 "2020-06-19T10:25:50Z")

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How do you disable the output from mosek when solving JuMP problems? I tried the following: model = Model(with\_optimizer(Mosek.Optimizer, QUIET=false)) model = Model(optimizer\_with\_attributes(Mosek.Optimizer, MOI.Silen…

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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)

<div class="topic-metadata">

**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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## [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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## [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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## [Identifying nodes in a Graph](https://discourse.julialang.org/t/identifying-nodes-in-a-graph/41498)

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**Author:** [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Replies:** 4\
**Last updated:** [June 17, 2020, 10:13pm UTC](https://discourse.julialang.org/t/identifying-nodes-in-a-graph/41498 "2020-06-17T22:13:13Z")

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Hi, I have data on users for whom I’d like to create a bipartite network that connects them through their consumption decisions. Since the data is rather big I’m trying to find an efficient implementation to create the …

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## [Handle numerical values as categories in plots](https://discourse.julialang.org/t/handle-numerical-values-as-categories-in-plots/41256)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 4\
**Last updated:** [June 17, 2020, 4:57pm UTC](https://discourse.julialang.org/t/handle-numerical-values-as-categories-in-plots/41256 "2020-06-17T16:57:58Z")

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I am trying to plot boxplots of values with respect to 4 categories represented as numbers. The four categories are powers of two: 16384, 32768, 65536, 131072. Let’s use this MWE dataframe: using DataFrames, StatsPlots…

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## [Apache Zeppelin and Julia](https://discourse.julialang.org/t/apache-zeppelin-and-julia/41587)

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**Author:** [@lungben](https://discourse.julialang.org/u/lungben)\
**Replies:** 0\
**Last updated:** [June 17, 2020, 12:30pm UTC](https://discourse.julialang.org/t/apache-zeppelin-and-julia/41587 "2020-06-17T12:30:15Z")

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Hi, I recently came across Apache Zeppelin, which is somewhat similar to Jupyter (and actually supports Jupyter / IPython notebooks), but more focussed on big data and multi-user capabilities. Especially the latter make…

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## [Getting gradients for DiffEq with single derivative](https://discourse.julialang.org/t/getting-gradients-for-diffeq-with-single-derivative/41519)

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**Author:** [@Janssena](https://discourse.julialang.org/u/Janssena)\
**Replies:** 3\
**Last updated:** [June 17, 2020, 11:06am UTC](https://discourse.julialang.org/t/getting-gradients-for-diffeq-with-single-derivative/41519 "2020-06-17T11:06:52Z")

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Hey All, I’ve been meaning to calculate the gradient of an ODEProblem using Zygote, OrdinaryDiffEq, and DiffEqSensitivity. I’ve been running into a wide scala of errors along the way but found a way to do it. So initia…

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## [Batch size and early stopping in Flux](https://discourse.julialang.org/t/batch-size-and-early-stopping-in-flux/41517)

<div class="topic-metadata">

**Author:** [@Mariana](https://discourse.julialang.org/u/Mariana)\
**Replies:** 5\
**Last updated:** [June 17, 2020, 10:56am UTC](https://discourse.julialang.org/t/batch-size-and-early-stopping-in-flux/41517 "2020-06-17T10:56:58Z")

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I´m starting to work with Flux and I have a neural network with 63 entries, 2 hidden layers and 1 exit. Each entry and exit is a vector of 113344 elements, from which 78801 elements belong to the training set and the rem…

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## [What would you recommend for nolinear optimization with optional gradient and hessian](https://discourse.julialang.org/t/what-would-you-recommend-for-nolinear-optimization-with-optional-gradient-and-hessian/41555)

<div class="topic-metadata">

**Author:** [@sunjin](https://discourse.julialang.org/u/sunjin)\
**Replies:** 5\
**Last updated:** [June 17, 2020, 5:40am UTC](https://discourse.julialang.org/t/what-would-you-recommend-for-nolinear-optimization-with-optional-gradient-and-hessian/41555 "2020-06-17T05:40:52Z")

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Hi, I am solving a numerical box-constrained nonlinear optimization problem with hundreds of unknowns. I currently implemented only the objective function but not the gradient or hessian. However, I expect to do so in th…

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