# Specific Domains

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

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**Page:** 450

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## [\[ANN\] DataFrameDBs.jl](https://discourse.julialang.org/t/ann-dataframedbs-jl/35718)

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**Author:** [@waralex](https://discourse.julialang.org/u/waralex)\
**Replies:** 60\
**Last updated:** [May 2, 2020, 3:09pm UTC](https://discourse.julialang.org/t/ann-dataframedbs-jl/35718 "2020-05-02T15:09:59Z")

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Hi all! Julia is my hobby and I had some free time for the last 4 weeks, so here is the first results of my experiments GitHub - waralex/DataFrameDBs.jl: The DateFrameDBs is the prototype of persistent, space efficient …

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## [Statistics package](https://discourse.julialang.org/t/statistics-package/38530)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 4\
**Last updated:** [May 2, 2020, 6:02am UTC](https://discourse.julialang.org/t/statistics-package/38530 "2020-05-02T06:02:48Z")

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Hello, Could you recommend me a package that I can use to find some statistics and how can I install it in Julia by ATOM Thank you

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## [Avoiding memory allocations when simulating combinations of parameter sets in ParallelEnsemble](https://discourse.julialang.org/t/avoiding-memory-allocations-when-simulating-combinations-of-parameter-sets-in-parallelensemble/38583)

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**Author:** [@MFairley](https://discourse.julialang.org/u/MFairley)\
**Replies:** 3\
**Last updated:** [May 2, 2020, 3:58am UTC](https://discourse.julialang.org/t/avoiding-memory-allocations-when-simulating-combinations-of-parameter-sets-in-parallelensemble/38583 "2020-05-02T03:58:28Z")

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I have an array of arrays p = \[a, b\] for p in ode\_model!(du, u, p, t). I am running a ParallelEnsemble where I want to simulate all combinations of a in A and b in B where A and B are arrays of arrays. I noticed that usi…

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## [Matrix profile calculation: STOMP method](https://discourse.julialang.org/t/matrix-profile-calculation-stomp-method/25389)

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**Author:** [@taqtiqa-mark](https://discourse.julialang.org/u/taqtiqa-mark)\
**Replies:** 1\
**Last updated:** [May 1, 2020, 4:13am UTC](https://discourse.julialang.org/t/matrix-profile-calculation-stomp-method/25389 "2020-05-01T04:13:37Z")

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Hi, Is there a Julia package that implements the matrix profile calculation using the STOMP method, i.e. corresponds to Stumpy’s … scalable library that efficiently computes something called the matrix profile Alter…

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## [Number of integration steps used in DifferentialEquations.jl with save\_everystep=false](https://discourse.julialang.org/t/number-of-integration-steps-used-in-differentialequations-jl-with-save-everystep-false/38575)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 1\
**Last updated:** [May 1, 2020, 10:27pm UTC](https://discourse.julialang.org/t/number-of-integration-steps-used-in-differentialequations-jl-with-save-everystep-false/38575 "2020-05-01T22:27:13Z")

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Do solvers in DifferentialEquations.jl count the number of integration steps they used? length(sol) is close because it returns the number of recorded solutions, but if I use save\_everystep=false for speedup, length(sol…

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## [MINLP problem](https://discourse.julialang.org/t/minlp-problem/38566)

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**Author:** [@GiuliaM](https://discourse.julialang.org/u/GiuliaM)\
**Replies:** 1\
**Last updated:** [May 1, 2020, 7:32pm UTC](https://discourse.julialang.org/t/minlp-problem/38566 "2020-05-01T19:32:51Z")

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Hi everyone! I’m fairly new to Julia. I’m trying to solve a MINLP problem with Juniper. I have 4 continuous variables (x\[1:4\]) and a binary variable (xbin). I have the following relationship between x\[1\] and xbin: if …

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## [Infeasibility on SCIP - Problem feasible in other solvers](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507)

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**Author:** [@Diego](https://discourse.julialang.org/u/Diego)\
**Replies:** 7\
**Last updated:** [May 1, 2020, 6:35pm UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507 "2020-05-01T18:35:48Z")

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Dear Team, I have been trying SCIP but whatever I do it always returns an infeasibility. Other solvers I have tried do deliver a solution. The message I keep getting on an on for different problems is: violation: rig…

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## [\[JuMP\] Container Functionality Feature Requests](https://discourse.julialang.org/t/jump-container-functionality-feature-requests/37771)

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**Author:** [@pulsipher](https://discourse.julialang.org/u/pulsipher)\
**Replies:** 10\
**Last updated:** [May 1, 2020, 7:59am UTC](https://discourse.julialang.org/t/jump-container-functionality-feature-requests/37771 "2020-05-01T07:59:46Z")

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I have been using with JuMP’s container types as I am developing my JuMP extension and have two observations that I think would make for 2 relatively simple additions. Observation 1: According to the extension of Base.k…

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## [How to know the elapse time using GLPK solver](https://discourse.julialang.org/t/how-to-know-the-elapse-time-using-glpk-solver/38511)

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**Author:** [@lausilvag](https://discourse.julialang.org/u/lausilvag)\
**Replies:** 1\
**Last updated:** [May 1, 2020, 12:21am UTC](https://discourse.julialang.org/t/how-to-know-the-elapse-time-using-glpk-solver/38511 "2020-05-01T00:21:58Z")

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Hi! I am using the GLPK solver and in the output doesn’t appear the elapsed time: GLPK Simplex Optimizer, v4.64 0: obj = 0.000000000e+000 inf = 3.846e+001 (1) 3: obj = 1.144956706e+007 inf = 0.000e+000 (0) 13: …

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## [Unexpected memory allocation inside ODE function with EnsembleProblem](https://discourse.julialang.org/t/unexpected-memory-allocation-inside-ode-function-with-ensembleproblem/38492)

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**Author:** [@MFairley](https://discourse.julialang.org/u/MFairley)\
**Replies:** 6\
**Last updated:** [April 30, 2020, 7:07pm UTC](https://discourse.julialang.org/t/unexpected-memory-allocation-inside-ode-function-with-ensembleproblem/38492 "2020-04-30T19:07:06Z")

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I am unsure if this is an issue or I just don’t understand how memory allocation works with ensemble problems. I start Julia with --track-allocation=user and run the following small script using DifferentialEquations u…

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## [Plots with string xaxis and y-errorbars gives error](https://discourse.julialang.org/t/plots-with-string-xaxis-and-y-errorbars-gives-error/37228)

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**Author:** [@transarcus](https://discourse.julialang.org/u/transarcus)\
**Replies:** 3\
**Last updated:** [April 30, 2020, 11:48am UTC](https://discourse.julialang.org/t/plots-with-string-xaxis-and-y-errorbars-gives-error/37228 "2020-04-30T11:48:24Z")

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Plotting a bar plot with text as the xaxis gives me an error where it didn’t use to. I’m using Julia 1.4 and plots v1.0.5 plot(\[“a”,“b”\],\[10,2\],yerr=\[1,1\],st=:bar) gives the error “Cannot convert an object of type Strin…

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## [Flux vs Keras time series prediction performance](https://discourse.julialang.org/t/flux-vs-keras-time-series-prediction-performance/38421)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 3\
**Last updated:** [April 30, 2020, 7:45am UTC](https://discourse.julialang.org/t/flux-vs-keras-time-series-prediction-performance/38421 "2020-04-30T07:45:45Z")

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Hi, I compare the prediction quality of two neural networks on a time series. One trained by Keras and one trained by Flux. Unfortunately I´m not able to achieve the same quality (see figure) and I don´t know why. I…

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## [Status of Flux model zoo](https://discourse.julialang.org/t/status-of-flux-model-zoo/38130)

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**Author:** [@Emmanuel-R8](https://discourse.julialang.org/u/Emmanuel-R8)\
**Replies:** 6\
**Last updated:** [April 30, 2020, 6:39am UTC](https://discourse.julialang.org/t/status-of-flux-model-zoo/38130 "2020-04-30T06:39:03Z")

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I was interested in updating Flux’s model zoo since everything I tried is out of date. But I saw that there are a lot of pull requests which are outstanding. Is it still maintained? Did I miss an announcement on that? …

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## [Shared memory limitations](https://discourse.julialang.org/t/shared-memory-limitations/38391)

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**Author:** [@calebwin](https://discourse.julialang.org/u/calebwin)\
**Replies:** 4\
**Last updated:** [April 29, 2020, 10:16pm UTC](https://discourse.julialang.org/t/shared-memory-limitations/38391 "2020-04-29T22:16:48Z")

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My apologies if this has already been asked. But right now, what all operations are supported for shared memory in CUDANative.jl? is it likely that more stuff can/will be added in the future? or a better question - how h…

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## [What is "splatting" in flux (loss?)?](https://discourse.julialang.org/t/what-is-splatting-in-flux-loss/37548)

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**Author:** [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Replies:** 2\
**Last updated:** [April 29, 2020, 8:34pm UTC](https://discourse.julialang.org/t/what-is-splatting-in-flux-loss/37548 "2020-04-29T20:34:04Z")

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In the Flux docs for train! it says In case datapoints d are of numeric array type, assume no splatting is needed and compute the gradient of loss(d) . What does “splatting” mean here? I am guessing that what this m…

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## [Visualizing Jacobians/Gradients(?) - How's this?](https://discourse.julialang.org/t/visualizing-jacobians-gradients-hows-this/36799)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 3\
**Last updated:** [April 29, 2020, 7:22pm UTC](https://discourse.julialang.org/t/visualizing-jacobians-gradients-hows-this/36799 "2020-04-29T19:22:08Z")

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I’ve been studying calculus and in the online course I’m following, the instructor says (in relation to a plot of a particular function): the Jacobian is simply a vector that we can calculate for each location on this …

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## [Controlling save behavior and performance of DiffEqBiological](https://discourse.julialang.org/t/controlling-save-behavior-and-performance-of-diffeqbiological/38387)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 6\
**Last updated:** [April 29, 2020, 2:53pm UTC](https://discourse.julialang.org/t/controlling-save-behavior-and-performance-of-diffeqbiological/38387 "2020-04-29T14:53:57Z")

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I’m interested in the bistable Schlogl model, which, under resevoir assumptions on species A and B, can be represented inside of DiffEqBiological as schlogl = @reaction\_network begin c1 \* a/ V, 2\*S --\> 3\*S c2 / …

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## [Custom width intergers in Clang/LLVM](https://discourse.julialang.org/t/custom-width-intergers-in-clang-llvm/38141)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 2\
**Last updated:** [April 28, 2020, 9:33pm UTC](https://discourse.julialang.org/t/custom-width-intergers-in-clang-llvm/38141 "2020-04-28T21:33:26Z")

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Specialised types for different problems? Now there is a thought!

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## [Combining pmap with EnsembleProblem](https://discourse.julialang.org/t/combining-pmap-with-ensembleproblem/38383)

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**Author:** [@MFairley](https://discourse.julialang.org/u/MFairley)\
**Replies:** 5\
**Last updated:** [April 28, 2020, 8:40pm UTC](https://discourse.julialang.org/t/combining-pmap-with-ensembleproblem/38383 "2020-04-28T20:40:59Z")

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I have an EnsembleProblem defined that calculates outputs for a range of different start times. I need to repeat the the whole EnsembleProblem many times for different parameter values and save the output of each Ensembl…

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## [Thoughts on Jax vs CuArrays and Zygote](https://discourse.julialang.org/t/thoughts-on-jax-vs-cuarrays-and-zygote/19915)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 10\
**Last updated:** [April 28, 2020, 3:00pm UTC](https://discourse.julialang.org/t/thoughts-on-jax-vs-cuarrays-and-zygote/19915 "2020-04-28T15:00:31Z")

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Google’s JAX looks like a combination of CuArrays and Zygote for Python. I wonder if anyone can compare and contrast Jax with CuArrays and Zygote? I can’t gather how Jax is different apart from the fact that it compiles…

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## [Just wrote a package for playing with SAT solvers](https://discourse.julialang.org/t/just-wrote-a-package-for-playing-with-sat-solvers/37822)

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**Author:** [@Xing\_Shi\_Cai](https://discourse.julialang.org/u/Xing_Shi_Cai)\
**Replies:** 2\
**Last updated:** [April 28, 2020, 1:40pm UTC](https://discourse.julialang.org/t/just-wrote-a-package-for-playing-with-sat-solvers/37822 "2020-04-28T13:40:10Z")

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Hi everyone, I just put a small package BEE.jl on github. If you want to play with SAT solvers, this might be helpful.

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## [Passing along data from one time step to the next using DifferentialEquations.jl](https://discourse.julialang.org/t/passing-along-data-from-one-time-step-to-the-next-using-differentialequations-jl/38335)

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**Author:** [@bielim](https://discourse.julialang.org/u/bielim)\
**Replies:** 5\
**Last updated:** [April 28, 2020, 2:28am UTC](https://discourse.julialang.org/t/passing-along-data-from-one-time-step-to-the-next-using-differentialequations-jl/38335 "2020-04-28T02:28:20Z")

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I am using DifferentialEquations.jl to solve an ODE of the form \\frac{d\\boldsymbol{M}}{dt} = \\boldsymbol{f}(\\boldsymbol{M}), where \\boldsymbol{M} = \[M\_1, ..., M\_k\]^T, and \\boldsymbol{f} = \[f\_1(\\boldsymbol{M}), ..., f\_k(\\…

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## [Tree limit JuMP 0.21](https://discourse.julialang.org/t/tree-limit-jump-0-21/38135)

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**Author:** [@baprata](https://discourse.julialang.org/u/baprata)\
**Replies:** 2\
**Last updated:** [April 27, 2020, 8:43pm UTC](https://discourse.julialang.org/t/tree-limit-jump-0-21/38135 "2020-04-27T20:43:43Z")

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I am modeling an optimization problem within Julia/Atom and CPLEX. I need to control the tree limit size. What is the syntax for the tree limit in JuMP 0.21? Thanks in advance, Bruno

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## [Deactivating and reactivating JuMP constraints](https://discourse.julialang.org/t/deactivating-and-reactivating-jump-constraints/38315)

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**Author:** [@Tomas\_Uribe](https://discourse.julialang.org/u/Tomas_Uribe)\
**Replies:** 1\
**Last updated:** [April 27, 2020, 7:33pm UTC](https://discourse.julialang.org/t/deactivating-and-reactivating-jump-constraints/38315 "2020-04-27T19:33:44Z")

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Is there a way to deactivate and reactivate JuMP constraints that are tied to a model? I found delete(model, constraint), but once deleted, constraints can’t be added back again.

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## [Lagrangian Function](https://discourse.julialang.org/t/lagrangian-function/38287)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 18\
**Last updated:** [April 27, 2020, 1:04pm UTC](https://discourse.julialang.org/t/lagrangian-function/38287 "2020-04-27T13:04:43Z")

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Hello everyone, I am trying to solve an optimization problem by using the lagrangian function, which package is best suited for this task specially because I need the equality constraint multipliers to be returned as th…

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## [Reworking Distributions.jl](https://discourse.julialang.org/t/reworking-distributions-jl/32339)

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**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 51\
**Last updated:** [April 27, 2020, 2:33am UTC](https://discourse.julialang.org/t/reworking-distributions-jl/32339 "2020-04-27T02:33:35Z")

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Hello all, I’ve been thinking some more about a refactoring of Distributions.jl, and I’d like to ask for feedback on a proof of concept. First, the abstract types: abstract type Sampleable{P,X} end abstract type Dist…

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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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