# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=449

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**Page:** 450

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## [Zygote: mutating array error with Buffer during parameter gradient call](https://discourse.julialang.org/t/zygote-mutating-array-error-with-buffer-during-parameter-gradient-call/38269)

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**Author:** [@ahl](https://discourse.julialang.org/u/ahl)\
**Replies:** 0\
**Last updated:** [April 27, 2020, 12:51am UTC](https://discourse.julialang.org/t/zygote-mutating-array-error-with-buffer-during-parameter-gradient-call/38269 "2020-04-27T00:51:42Z")

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I’m trying to update the parameters of a multi-input multi-output neural network using a loss function that is some function of the Jacobian of the neural network. However, computing the gradient of the loss produces an …

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## [On-the-fly Animation in IJulia Notebooks](https://discourse.julialang.org/t/on-the-fly-animation-in-ijulia-notebooks/524)

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**Author:** [@cortner](https://discourse.julialang.org/u/cortner)\
**Replies:** 45\
**Last updated:** [April 27, 2020, 1:25am UTC](https://discourse.julialang.org/t/on-the-fly-animation-in-ijulia-notebooks/524 "2020-04-27T01:25:21Z")

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I recently revisited how to do on-the-fly visualisation in an IJulia notebook, i.e., plotting results while the computation is still running. This was discussed a while back in Google groups link I’ve tried the same sch…

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## [Fast implementations of integrodifference equations?](https://discourse.julialang.org/t/fast-implementations-of-integrodifference-equations/38265)

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**Author:** [@peterj](https://discourse.julialang.org/u/peterj)\
**Replies:** 0\
**Last updated:** [April 26, 2020, 9:50pm UTC](https://discourse.julialang.org/t/fast-implementations-of-integrodifference-equations/38265 "2020-04-26T21:50:37Z")

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Are there any libraries which have fast implementations of integrodifference equations? These are discrete time, continuous space dynamical systems used a lot in mathematical ecology where diffusion is replaced by integ…

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## [Block sparse matrix multiplication with repeated blocks](https://discourse.julialang.org/t/block-sparse-matrix-multiplication-with-repeated-blocks/38107)

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**Author:** [@jlchan](https://discourse.julialang.org/u/jlchan)\
**Replies:** 4\
**Last updated:** [April 26, 2020, 6:51pm UTC](https://discourse.julialang.org/t/block-sparse-matrix-multiplication-with-repeated-blocks/38107 "2020-04-26T18:51:09Z")

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I’m trying to find a good way to compute V^TAV where A is a sparse CSC matrix A and V = I \\otimes B is a block diagonal matrix with repeating dense blocks (size of B is around \\mathbb{R}^{20 \\times 10}). Looping through…

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## [Simplifying simulation by clusters](https://discourse.julialang.org/t/simplifying-simulation-by-clusters/35870)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 18\
**Last updated:** [April 26, 2020, 3:10pm UTC](https://discourse.julialang.org/t/simplifying-simulation-by-clusters/35870 "2020-04-26T15:10:01Z")

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This is partly a question asking for recommendations on an algorithm, ideally something that is implemented some Julia package, or can be done simply using one. I am simulating a process in \\mathbb{R}^3 (I can constrai…

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## [Statistic errors for histograms with Plots recipes](https://discourse.julialang.org/t/statistic-errors-for-histograms-with-plots-recipes/37327)

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**Author:** [@misha\_mikhasenko](https://discourse.julialang.org/u/misha_mikhasenko)\
**Replies:** 5\
**Last updated:** [April 25, 2020, 4:36pm UTC](https://discourse.julialang.org/t/statistic-errors-for-histograms-with-plots-recipes/37327 "2020-04-25T16:36:56Z")

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I would love to have a recipe for Plots.jl that creates a histogram with xerror of the size of the bin, and yerror according to e.g. sqrt(h.weight). So, there are two problems: x-errors do not show up. The scatterhis…

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## [LightGraphs users (and other interested parties): please opine below](https://discourse.julialang.org/t/lightgraphs-users-and-other-interested-parties-please-opine-below/37660)

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**Author:** [@anon94023334](https://discourse.julialang.org/u/anon94023334)\
**Replies:** 25\
**Last updated:** [April 25, 2020, 4:21pm UTC](https://discourse.julialang.org/t/lightgraphs-users-and-other-interested-parties-please-opine-below/37660 "2020-04-25T16:21:23Z")

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Not quite sure how to narrow down the audience to interested parties, so I’m placing this here. LightGraphs 2.0 is in active development. One of the big changes is the movement of functions into separate submodules. (In…

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## [LoadError: UndefVarError: Penalty not defined](https://discourse.julialang.org/t/loaderror-undefvarerror-penalty-not-defined/38046)

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**Author:** [@DKad](https://discourse.julialang.org/u/DKad)\
**Replies:** 16\
**Last updated:** [April 24, 2020, 9:58pm UTC](https://discourse.julialang.org/t/loaderror-undefvarerror-penalty-not-defined/38046 "2020-04-24T21:58:37Z")

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Hello, I want to adapt parameters of a differential equation to available data on a computer with julia 1.4.1 on a linux system. julia 1.4.0 has the same problem. Running using DifferentialEquations using Plots is o.…

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## [Get power flow equations from PowerModels?](https://discourse.julialang.org/t/get-power-flow-equations-from-powermodels/33673)

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**Author:** [@timueh](https://discourse.julialang.org/u/timueh)\
**Replies:** 5\
**Last updated:** [April 24, 2020, 7:27pm UTC](https://discourse.julialang.org/t/get-power-flow-equations-from-powermodels/33673 "2020-04-24T19:27:07Z")

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Is it possible to obtain the power flow equations in the form of f(x) = 0 from PowerModels.jl? Follow-up question, is it possible to get the system of nonlinear equations h(x) = 0 that make up a power flow problem, i.e.…

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## [How to test plot recipes?](https://discourse.julialang.org/t/how-to-test-plot-recipes/2648)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 5\
**Last updated:** [April 24, 2020, 3:29pm UTC](https://discourse.julialang.org/t/how-to-test-plot-recipes/2648 "2020-04-24T15:29:29Z")

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Plot recipes can reduce the test coverage considerably. For example, my coverage is currently at 76% and a big part of the remaining 24% is due to a plot recipe: Codecov How should I go about testing plot recipes? Is th…

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## [DataFramesMeta.jl and the state of the DataFrames ecosystem](https://discourse.julialang.org/t/dataframesmeta-jl-and-the-state-of-the-dataframes-ecosystem/36221)

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**Author:** [@jmboehm](https://discourse.julialang.org/u/jmboehm)\
**Replies:** 36\
**Last updated:** [April 24, 2020, 1:18pm UTC](https://discourse.julialang.org/t/dataframesmeta-jl-and-the-state-of-the-dataframes-ecosystem/36221 "2020-04-24T13:18:34Z")

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Hi all, I’m currently working on a small package that’s supposed to make data wrangling easier (i.e. providing macros for commonly-used operations). As part of that, I’ve found DataFramesMeta.jl quite useful (in particu…

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## [How to import a pre-trained neural network into Flux.jl ?](https://discourse.julialang.org/t/how-to-import-a-pre-trained-neural-network-into-flux-jl/9659)

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**Author:** [@Nirvan101](https://discourse.julialang.org/u/Nirvan101)\
**Replies:** 7\
**Last updated:** [April 24, 2020, 10:42am UTC](https://discourse.julialang.org/t/how-to-import-a-pre-trained-neural-network-into-flux-jl/9659 "2020-04-24T10:42:37Z")

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I’m using the Flux library in Julia. How can I import an Inception neural network into it? I’ve seen that the following can be done in Mocha.jl to import a pre-trained net. using HDF5 h5open("model/bvlc\_reference\_caff…

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## [Dynamic Time Warping in Julia](https://discourse.julialang.org/t/dynamic-time-warping-in-julia/13426)

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**Author:** [@Moses](https://discourse.julialang.org/u/Moses)\
**Replies:** 7\
**Last updated:** [April 24, 2020, 10:35am UTC](https://discourse.julialang.org/t/dynamic-time-warping-in-julia/13426 "2020-04-24T10:35:42Z")

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Hello everybody. I hope, I am in the right domain for this question. I am looking for an implemantation of dynamic time warping in julia. Obviously, there has been some work on this already: here and here. However, bot…

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## [An exemple in order to save figures generated by PGFPlotsX](https://discourse.julialang.org/t/an-exemple-in-order-to-save-figures-generated-by-pgfplotsx/38120)

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**Author:** [@aquarelle332](https://discourse.julialang.org/u/aquarelle332)\
**Replies:** 4\
**Last updated:** [April 24, 2020, 10:20am UTC](https://discourse.julialang.org/t/an-exemple-in-order-to-save-figures-generated-by-pgfplotsx/38120 "2020-04-24T10:20:53Z")

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Julia 1.4.1 \*Kubuntu 18.04 LST \* LaTeX + textlive-full (including LuaLaTeX) + ImageMagik Documentation: PGFPlotsX.jl by Kristoffer Carlsson Hello dear all, Say that I am using an elementary code as follows, extracte…

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## [A question about the Matrix](https://discourse.julialang.org/t/a-question-about-the-matrix/38123)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 2\
**Last updated:** [April 24, 2020, 3:49am UTC](https://discourse.julialang.org/t/a-question-about-the-matrix/38123 "2020-04-24T03:49:48Z")

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How do you define a matrix that doesn’t know how many rows and columns it has. thank you!

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## [SIGKILL from Gurobi.jl?](https://discourse.julialang.org/t/sigkill-from-gurobi-jl/38099)

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**Author:** [@mlhetland](https://discourse.julialang.org/u/mlhetland)\
**Replies:** 5\
**Last updated:** [April 23, 2020, 8:26pm UTC](https://discourse.julialang.org/t/sigkill-from-gurobi-jl/38099 "2020-04-23T20:26:30Z")

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One of my JuMP models seem to be too much for Gurobi/Gurobi.jl – after a while, it kills Julia with SIGKILL. Other models of similar structure work just fine; I suspect the reason is that they are smaller, and that I’m r…

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## [Plots.jl legend: spacing between symbol and text](https://discourse.julialang.org/t/plots-jl-legend-spacing-between-symbol-and-text/38079)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 2\
**Last updated:** [April 23, 2020, 2:01pm UTC](https://discourse.julialang.org/t/plots-jl-legend-spacing-between-symbol-and-text/38079 "2020-04-23T14:01:23Z")

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Hi, is it possible to adjust the spacing between the symol and the text in the legend with Plot.jl? MWE: plot(\[1,2,3\], linewidth=5, legend=true, legendfontsize=30, ) produces Can the spacing between the…

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## [CUDAnative test fails](https://discourse.julialang.org/t/cudanative-test-fails/38085)

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**Author:** [@eaubanel](https://discourse.julialang.org/u/eaubanel)\
**Replies:** 2\
**Last updated:** [April 23, 2020, 1:59pm UTC](https://discourse.julialang.org/t/cudanative-test-fails/38085 "2020-04-23T13:59:33Z")

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I’m experienced with C/CUDA, but trying CUDA with Julia for the first time, on a compute node of a research cluster running CentOS Linux release 7.6.1810 and eight Tesla V100-SXM2 GPUs: nvidia-smi±----------------------…

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## [Finding the root of a minimize-maximize function](https://discourse.julialang.org/t/finding-the-root-of-a-minimize-maximize-function/38068)

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**Author:** [@Xing\_Shi\_Cai](https://discourse.julialang.org/u/Xing_Shi_Cai)\
**Replies:** 1\
**Last updated:** [April 23, 2020, 11:54am UTC](https://discourse.julialang.org/t/finding-the-root-of-a-minimize-maximize-function/38068 "2020-04-23T11:54:55Z")

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Let f1(x,y)=-(1 - x)\* y + 1/2\* (1 - x - x^2 - x^3 - 2\* (1 - x)\* y) f2(x,y)=(1 - 2\*x)\*(1 + x + x^2) - 2\*(-1 + x)^2\*(1 + x)\*y We can define a minimize, maximize function like this using IntervalOptimization g(x) = minim…

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## [JuMP returning incorrect value after deleting/adding anonymous variable and constraint](https://discourse.julialang.org/t/jump-returning-incorrect-value-after-deleting-adding-anonymous-variable-and-constraint/38036)

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**Author:** [@cby](https://discourse.julialang.org/u/cby)\
**Replies:** 2\
**Last updated:** [April 23, 2020, 2:20am UTC](https://discourse.julialang.org/t/jump-returning-incorrect-value-after-deleting-adding-anonymous-variable-and-constraint/38036 "2020-04-23T02:20:12Z")

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When I use an anonymous variable and constraint, optimize, delete and re-add them, then optimize again, I get two different solutions, the second of which is incorrect. However, the model is still printing correctly. Wha…

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## [Scatter plot](https://discourse.julialang.org/t/scatter-plot/37987)

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**Author:** [@AmandaPS22](https://discourse.julialang.org/u/AmandaPS22)\
**Replies:** 9\
**Last updated:** [April 23, 2020, 12:00am UTC](https://discourse.julialang.org/t/scatter-plot/37987 "2020-04-23T00:00:41Z")

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Hi, I’m new to the JULIA language and I’m having trouble plotting a scatter plot. The command entered was: using PyPlot scatter(X.d, X.b, facecolor = “none”, edgecolors=“orange”, s=20, label=“xxx”) Then an error me…

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## [How to save parallel outputs to the same file on HPC cluster](https://discourse.julialang.org/t/how-to-save-parallel-outputs-to-the-same-file-on-hpc-cluster/37993)

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**Author:** [@zxjroger](https://discourse.julialang.org/u/zxjroger)\
**Replies:** 6\
**Last updated:** [April 22, 2020, 10:40pm UTC](https://discourse.julialang.org/t/how-to-save-parallel-outputs-to-the-same-file-on-hpc-cluster/37993 "2020-04-22T22:40:10Z")

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I am doing Monte Carlo study on HPC cluster. I parallel the 100 Monte Carlo replications using job array in Slurm. I want to save the results of each replication to the same file. Let’s say for replication ID n, I have t…

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## [Two level distributed / parallel execution](https://discourse.julialang.org/t/two-level-distributed-parallel-execution/21292)

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**Author:** [@orenbenkiki](https://discourse.julialang.org/u/orenbenkiki)\
**Replies:** 4\
**Last updated:** [April 22, 2020, 6:57am UTC](https://discourse.julialang.org/t/two-level-distributed-parallel-execution/21292 "2020-04-22T06:57:34Z")

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Given a complex, large scale computation that spans a non trivial amount of data (Tens of GBs), I wish to split the work between multiple processes across several hosts in a cluster. Each host has dozens of processors an…

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## [Multiple subplots using StatsPlots](https://discourse.julialang.org/t/multiple-subplots-using-statsplots/37990)

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**Author:** [@Balinus](https://discourse.julialang.org/u/Balinus)\
**Replies:** 2\
**Last updated:** [April 22, 2020, 12:20am UTC](https://discourse.julialang.org/t/multiple-subplots-using-statsplots/37990 "2020-04-22T00:20:32Z")

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Hello, splitting my hair around this and now I need some help. I’m sure it’s straightforward, but I can’t find the answer! Here’s a MWE. It’s a list of subplots that creates multiple qqplot over random values. using S…

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## [Gadfly - non-logarithmic number format for axis in logarithmic scale](https://discourse.julialang.org/t/gadfly-non-logarithmic-number-format-for-axis-in-logarithmic-scale/37944)

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**Author:** [@Humphrey\_Lee](https://discourse.julialang.org/u/Humphrey_Lee)\
**Replies:** 9\
**Last updated:** [April 21, 2020, 11:34pm UTC](https://discourse.julialang.org/t/gadfly-non-logarithmic-number-format-for-axis-in-logarithmic-scale/37944 "2020-04-21T23:34:54Z")

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Something that I missed from Excel chart. Notice the y axis is logarithmic scale, but the number label is non logarithmic. Below is the best I got from Gadfly. The method to set axis limit is also not that friendly. C…

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## [Free legend placing](https://discourse.julialang.org/t/free-legend-placing/37910)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 2\
**Last updated:** [April 21, 2020, 11:28pm UTC](https://discourse.julialang.org/t/free-legend-placing/37910 "2020-04-21T23:28:35Z")

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Hi, is it possible to place the legend using an exact position and not being restricted to :top, :bottom etc with Plots.jl and the pyplot backend? MWE: plot(\[1,2,3\], legend = (2,2) ) Somethink similar for placing th…

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## [Essential tools for neural network based PDE solvers](https://discourse.julialang.org/t/essential-tools-for-neural-network-based-pde-solvers/37149)

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**Author:** [@leonexu](https://discourse.julialang.org/u/leonexu)\
**Replies:** 7\
**Last updated:** [April 21, 2020, 10:09pm UTC](https://discourse.julialang.org/t/essential-tools-for-neural-network-based-pde-solvers/37149 "2020-04-21T22:09:24Z")

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Chris’s post The Essential Tools of Scientific Machine Learning discussed several tools that are “essential for scientific machine learning” including probabilistic programming, structured linear algebra, discretizing pa…

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## [Yet another piping idea](https://discourse.julialang.org/t/yet-another-piping-idea/37597)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 3\
**Last updated:** [April 21, 2020, 8:27pm UTC](https://discourse.julialang.org/t/yet-another-piping-idea/37597 "2020-04-21T20:27:14Z")

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With the upcoming DataFrames 1.0 release and the new select and transform functions, piping will become much idiomatic in basic DataFrames usage, i.e. using DataFrames, Lazy julia\> @\> df begin transform(:b =\> (x …

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## [Benchmarking of PPL](https://discourse.julialang.org/t/benchmarking-of-ppl/37850)

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**Author:** [@mystis](https://discourse.julialang.org/u/mystis)\
**Replies:** 4\
**Last updated:** [April 21, 2020, 8:23pm UTC](https://discourse.julialang.org/t/benchmarking-of-ppl/37850 "2020-04-21T20:23:30Z")

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Hi all, I’ve seen the perf benchmark or sampling for Turing vs Stan but I was wondering if we have benchmarks for Pyro, pymc3, tensorflow-probabiliy with one chain and with multiple chains (since tfp seems to benefit fro…

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## [How to put a derivative into loss function?](https://discourse.julialang.org/t/how-to-put-a-derivative-into-loss-function/37961)

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**Author:** [@vavrines](https://discourse.julialang.org/u/vavrines)\
**Replies:** 1\
**Last updated:** [April 21, 2020, 3:58pm UTC](https://discourse.julialang.org/t/how-to-put-a-derivative-into-loss-function/37961 "2020-04-21T15:58:53Z")

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Hi there, I wonder now if there is a convenient way to put the derivatives from AD into loss function directly. I tried the following code, but it failed with Zygote. using Flux m = Chain(Dense(1, 20, tanh), Dense(20…

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