# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=436

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**Page:** 437

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## [Kronecker times vector with special structure](https://discourse.julialang.org/t/kronecker-times-vector-with-special-structure/42477)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 10\
**Last updated:** [July 5, 2020, 4:39pm UTC](https://discourse.julialang.org/t/kronecker-times-vector-with-special-structure/42477 "2020-07-05T16:39:11Z")

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I would like to evaluate (I\_1 \\otimes a\_2^\\top \\otimes I\_3) \\cdot \\theta where I\_1 and I\_3 are identity matrices with size n \\times n and m \\times m, a\_2 is a vector of length k, \\theta is a vector of length mnk. …

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## [Automatic Parallelization in Julia](https://discourse.julialang.org/t/automatic-parallelization-in-julia/42543)

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**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 5\
**Last updated:** [July 5, 2020, 3:05am UTC](https://discourse.julialang.org/t/automatic-parallelization-in-julia/42543 "2020-07-05T03:05:08Z")

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Dear All, I would like to ask you, whether there is some automatic parallelization tool in Julia similar to auto parallelization capabilities of Intel/gcc compilers for Fortran/C++. It would be really awesome if Julia c…

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## [Flux.jl: Convolutional VAE throws error after upgrading to 1.4.1/10.4](https://discourse.julialang.org/t/flux-jl-convolutional-vae-throws-error-after-upgrading-to-1-4-1-10-4/39746)

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**Author:** [@flo](https://discourse.julialang.org/u/flo)\
**Replies:** 19\
**Last updated:** [July 4, 2020, 7:55pm UTC](https://discourse.julialang.org/t/flux-jl-convolutional-vae-throws-error-after-upgrading-to-1-4-1-10-4/39746 "2020-07-04T19:55:26Z")

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Hello everyone, I am fairly new to Julia and even newer to this forum. I hope, this is the right subforum for my problem. Currently, I am working on a project that involves a Convolutional VAE which I implemented using …

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## [Flux.jl: Error thrown during gradient calculation in conv VAE](https://discourse.julialang.org/t/flux-jl-error-thrown-during-gradient-calculation-in-conv-vae/42397)

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**Author:** [@alecokas](https://discourse.julialang.org/u/alecokas)\
**Replies:** 4\
**Last updated:** [July 4, 2020, 12:18pm UTC](https://discourse.julialang.org/t/flux-jl-error-thrown-during-gradient-calculation-in-conv-vae/42397 "2020-07-04T12:18:01Z")

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Hi, I’m just getting into Flux (and Julia more generally), but I’m finding it impossible to get rid of a very particular error in my convolutional VAE model. The code runs fine until the back(1f0) line where it throws E…

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## [Optimization problem with Julia - Launch sequence](https://discourse.julialang.org/t/optimization-problem-with-julia-launch-sequence/42311)

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**Author:** [@beske](https://discourse.julialang.org/u/beske)\
**Replies:** 14\
**Last updated:** [July 3, 2020, 11:01pm UTC](https://discourse.julialang.org/t/optimization-problem-with-julia-launch-sequence/42311 "2020-07-03T23:01:58Z")

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Say you have n different shops in which you want to launch a product for n different months, and you want to maximize profits. The problem is determining the order of the launch sequence of the product when the price in …

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## [Using complements in JuMP](https://discourse.julialang.org/t/using-complements-in-jump/42486)

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**Author:** [@jovansam](https://discourse.julialang.org/u/jovansam)\
**Replies:** 5\
**Last updated:** [July 3, 2020, 6:47pm UTC](https://discourse.julialang.org/t/using-complements-in-jump/42486 "2020-07-03T18:47:03Z")

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I am trying to use complements in Julia-JuMP. I appreciate the work put into this wonderful package, the manual is not detailed enough unfortunately. A working example that uses this feature in an optimization problem w…

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## [Objective function error](https://discourse.julialang.org/t/objective-function-error/42482)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 2\
**Last updated:** [July 3, 2020, 6:18pm UTC](https://discourse.julialang.org/t/objective-function-error/42482 "2020-07-03T18:18:41Z")

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I need to reproduce that model. using JuMP, Cbc Model1 = Model(with\_optimizer(Cbc.Optimizer)) a = 2 t = 2 w = 2 A = 1:a T = 1:t W = 1:w CR = \[11, 11\] @variable(Model1,r\[A,T\], lower\_bound=0) @variable(Model1,o\[A…

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## [Get to know the seed for the next CUDA random number](https://discourse.julialang.org/t/get-to-know-the-seed-for-the-next-cuda-random-number/42363)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 3\
**Last updated:** [July 3, 2020, 2:19pm UTC](https://discourse.julialang.org/t/get-to-know-the-seed-for-the-next-cuda-random-number/42363 "2020-07-03T14:19:57Z")

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Hi, I’m struggling to debug a code that does random sampling, and for that I use CUDA random numbers. In order to be able to reproduce the same numbers in a second run of the code, I set the random number generator usin…

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## [Fourier transform freezes Julia](https://discourse.julialang.org/t/fourier-transform-freezes-julia/38771)

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**Author:** [@Martijn-R](https://discourse.julialang.org/u/Martijn-R)\
**Replies:** 5\
**Last updated:** [July 3, 2020, 12:56pm UTC](https://discourse.julialang.org/t/fourier-transform-freezes-julia/38771 "2020-07-03T12:56:30Z")

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I am processing an audio sample (about 20minutes long) in small parts of several seconds. At the moment my code freezes every now and then. The example below is a bit silly but is a minimal ‘working’ example which oft…

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## [Flux bilinear upsampling](https://discourse.julialang.org/t/flux-bilinear-upsampling/37717)

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**Author:** [@kevinczimmerman](https://discourse.julialang.org/u/kevinczimmerman)\
**Replies:** 3\
**Last updated:** [July 3, 2020, 12:21pm UTC](https://discourse.julialang.org/t/flux-bilinear-upsampling/37717 "2020-07-03T12:21:49Z")

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What is the best way to use Flux to create a bilinear upsampling layer? Something analogous to tensorflow bilinear upsample. I appreciate your insight in advance.

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## [VegaLite: Facet plots with independent scales for histograms](https://discourse.julialang.org/t/vegalite-facet-plots-with-independent-scales-for-histograms/42464)

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**Author:** [@hellemo](https://discourse.julialang.org/u/hellemo)\
**Replies:** 0\
**Last updated:** [July 3, 2020, 8:27am UTC](https://discourse.julialang.org/t/vegalite-facet-plots-with-independent-scales-for-histograms/42464 "2020-07-03T08:27:13Z")

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I would like to do a facet plot with independent scales for the x-axis, but can’t get it to work. It works for the y-axis though. Any ideas? EDIT: I tried switching the axes to no avail, so it seems it has to do with th…

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## [Makie bug with tetrahedral meshes](https://discourse.julialang.org/t/makie-bug-with-tetrahedral-meshes/41834)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 13\
**Last updated:** [July 3, 2020, 3:27am UTC](https://discourse.julialang.org/t/makie-bug-with-tetrahedral-meshes/41834 "2020-07-03T03:27:52Z")

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In Makie.jl there is a bug with displaying tetrahedral meshes. Using the example from TetGen.jl Note that at the corners there are missing edges and faces in the plot. However, I have verified that those edges/faces…

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## [Getindex without a warning?](https://discourse.julialang.org/t/getindex-without-a-warning/42382)

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**Author:** [@sw72](https://discourse.julialang.org/u/sw72)\
**Replies:** 3\
**Last updated:** [July 2, 2020, 7:57pm UTC](https://discourse.julialang.org/t/getindex-without-a-warning/42382 "2020-07-02T19:57:25Z")

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I need to extract a single value from a CuArray for some calculation. Is there a way to do it without getting the “scalar operations” warning?

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## [Efficient Way of Taking First and Second Order Derivatives of a Neural Net](https://discourse.julialang.org/t/efficient-way-of-taking-first-and-second-order-derivatives-of-a-neural-net/42163)

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**Author:** [@astroboy](https://discourse.julialang.org/u/astroboy)\
**Replies:** 1\
**Last updated:** [July 2, 2020, 7:42pm UTC](https://discourse.julialang.org/t/efficient-way-of-taking-first-and-second-order-derivatives-of-a-neural-net/42163 "2020-07-02T19:42:20Z")

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Hey everyone, hope you’re all doing well and staying safe! I’m just going to preface this by saying that I am a still solidly a novice when it comes to both machine learning and Julia, so please bear with me here. I am a…

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## [How to make a vector of symbols using a macro](https://discourse.julialang.org/t/how-to-make-a-vector-of-symbols-using-a-macro/42439)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 2\
**Last updated:** [July 2, 2020, 5:27pm UTC](https://discourse.julialang.org/t/how-to-make-a-vector-of-symbols-using-a-macro/42439 "2020-07-02T17:27:59Z")

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How do I make a vector of symbols using a macro? macro foo() Expr(:vect, :x1, :x2) end julia\> @foo ERROR: UndefVarError: x1 not defined Clearly this making the expression \[x1, x2\]. However I would like to make the…

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## [Start value Gurobi error](https://discourse.julialang.org/t/start-value-gurobi-error/42437)

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**Author:** [@Miguel\_Goncalves](https://discourse.julialang.org/u/Miguel_Goncalves)\
**Replies:** 6\
**Last updated:** [July 2, 2020, 5:10pm UTC](https://discourse.julialang.org/t/start-value-gurobi-error/42437 "2020-07-02T17:10:48Z")

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I am a casual/academic user of optimization with Julia/JuMP, and I noticed there is the possibility to include initial solution setting the function set\_start\_value, but I just want to set initially some variables of my …

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## [CuArrays/CUDAnative PSA: Simplified package loading](https://discourse.julialang.org/t/cuarrays-cudanative-psa-simplified-package-loading/27897)

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**Author:** [@maleadt](https://discourse.julialang.org/u/maleadt)\
**Replies:** 17\
**Last updated:** [July 2, 2020, 2:20pm UTC](https://discourse.julialang.org/t/cuarrays-cudanative-psa-simplified-package-loading/27897 "2020-07-02T14:20:31Z")

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Hi all, I’ve just tagged new versions of CuArrays/CUDAnative/… and among the usual slurry of features and bug fixes there’s a major change in how the packages are built and loaded. There used to be a Pkg.build step whic…

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## [Derivatives of a production function](https://discourse.julialang.org/t/derivatives-of-a-production-function/42354)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 12\
**Last updated:** [July 2, 2020, 11:16am UTC](https://discourse.julialang.org/t/derivatives-of-a-production-function/42354 "2020-07-02T11:16:34Z")

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I have a production function with several CES levels: function F(L2, A; λ=ones(4)./2, ρ=ones(4)./2) #L2 is 3x2, A is 1x1, λ and ρ are vectors of length 4 λ1 = λ\[1:2\] λ2 = λ\[3:4\] ρ1 = ρ\[1:2\] ρ2 = ρ\[3:…

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## [Allocations when creating graphs, inefficiencies](https://discourse.julialang.org/t/allocations-when-creating-graphs-inefficiencies/42394)

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**Author:** [@erlebach](https://discourse.julialang.org/u/erlebach)\
**Replies:** 12\
**Last updated:** [July 2, 2020, 9:57am UTC](https://discourse.julialang.org/t/allocations-when-creating-graphs-inefficiencies/42394 "2020-07-02T09:57:55Z")

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I am creating my own method to create a graph in 3D because graphplot has a bug, which I reported here and on Github, and I got no reply, and yet I still need the plot. Here is some MWE, which I run 2-3 times to make sur…

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## [A question about module](https://discourse.julialang.org/t/a-question-about-module/42415)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 1\
**Last updated:** [July 2, 2020, 7:56am UTC](https://discourse.julialang.org/t/a-question-about-module/42415 "2020-07-02T07:56:24Z")

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want to use another script’s module in one script,it always tell me “a” is not defind, module asd export a a=2 end include("Julia测试.jl") print(a) thanks!!

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## [ODE Sundials not recognizing \`maxiters\` argument](https://discourse.julialang.org/t/ode-sundials-not-recognizing-maxiters-argument/42377)

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**Author:** [@Yuki-Kanai](https://discourse.julialang.org/u/Yuki-Kanai)\
**Replies:** 2\
**Last updated:** [July 2, 2020, 6:18am UTC](https://discourse.julialang.org/t/ode-sundials-not-recognizing-maxiters-argument/42377 "2020-07-02T06:18:18Z")

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I am using OrdinaryDiffEq with Sundials. While other options such as stability\_limit\_detect max\_hnil\_warns max\_error\_test\_failures seem to be working, the option maxiters doesn’t seem to stop iteration at all; The it…

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## [Ideas for useful packages missing from the ecosystem](https://discourse.julialang.org/t/ideas-for-useful-packages-missing-from-the-ecosystem/42063)

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**Author:** [@Nosferican](https://discourse.julialang.org/u/Nosferican)\
**Replies:** 15\
**Last updated:** [July 2, 2020, 5:57am UTC](https://discourse.julialang.org/t/ideas-for-useful-packages-missing-from-the-ecosystem/42063 "2020-07-02T05:57:17Z")

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I wanted to share two packages which provide useful functionality but are currently not available in Julia. The following two would make Julia even more attractable for users in / with #hpc. SSH Tunneling (https://gi…

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## [Add column names to a GLM.LinearModel estimated in matrix form](https://discourse.julialang.org/t/add-column-names-to-a-glm-linearmodel-estimated-in-matrix-form/40676)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 11\
**Last updated:** [July 1, 2020, 6:20pm UTC](https://discourse.julialang.org/t/add-column-names-to-a-glm-linearmodel-estimated-in-matrix-form/40676 "2020-07-01T18:20:33Z")

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I am estimating a bunch of linear models using GLM.lm(X, y), where X is a matrix. I have column names for X from a database, and I would like to have the result from fit/lm to include them. MWE: using GLM X = hcat(ones(…

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## [How to set up NLconstraints from multi-output user-defined function?](https://discourse.julialang.org/t/how-to-set-up-nlconstraints-from-multi-output-user-defined-function/42309)

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**Author:** [@Liang\_Chen](https://discourse.julialang.org/u/Liang_Chen)\
**Replies:** 5\
**Last updated:** [July 1, 2020, 2:31pm UTC](https://discourse.julialang.org/t/how-to-set-up-nlconstraints-from-multi-output-user-defined-function/42309 "2020-07-01T14:31:22Z")

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I have a non-linear user-defined function, y = myfun(x), where the output y is a 1\*2 array. I am going to use the output y to construct constraints. I will have 2 constraint equations since y has 2 components and each c…

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## [Help Debugging GPU Performance Issue](https://discourse.julialang.org/t/help-debugging-gpu-performance-issue/42274)

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**Author:** [@bmit](https://discourse.julialang.org/u/bmit)\
**Replies:** 5\
**Last updated:** [July 1, 2020, 10:07am UTC](https://discourse.julialang.org/t/help-debugging-gpu-performance-issue/42274 "2020-07-01T10:07:43Z")

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I’m having trouble debugging the following issue with CuArrays. I see very different performance using the findmax function when I call it from the REPL vs when I use it in my application. From the REPL I get the desired…

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## [Statistics functions on GPU?](https://discourse.julialang.org/t/statistics-functions-on-gpu/42245)

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**Author:** [@ogoid](https://discourse.julialang.org/u/ogoid)\
**Replies:** 1\
**Last updated:** [July 1, 2020, 8:12am UTC](https://discourse.julialang.org/t/statistics-functions-on-gpu/42245 "2020-07-01T08:12:43Z")

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Are there available any GPU implementations of the Statistics functions (cor, cov etc.)? Many of the functions on the Statistics module throw the “scalar getindex is disallowed” warning/error. Eg: julia\> Statistics.cor(…

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## [Julia vs GNU Octave for plot fitting / finding peaks](https://discourse.julialang.org/t/julia-vs-gnu-octave-for-plot-fitting-finding-peaks/42237)

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**Author:** [@doronbehar](https://discourse.julialang.org/u/doronbehar)\
**Replies:** 16\
**Last updated:** [July 1, 2020, 7:33am UTC](https://discourse.julialang.org/t/julia-vs-gnu-octave-for-plot-fitting-finding-peaks/42237 "2020-07-01T07:33:34Z")

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I’m currently using GNU octave to fit a simple cosine with a phase to many data sets stored in text files. For most data sets, the fit works well, but for some others, it doesn’t. I’m wondering whether I’d be able to get…

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## [Solve large number of linear inequalities with dynamic arrays](https://discourse.julialang.org/t/solve-large-number-of-linear-inequalities-with-dynamic-arrays/41821)

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**Author:** [@LHR](https://discourse.julialang.org/u/LHR)\
**Replies:** 3\
**Last updated:** [July 1, 2020, 1:15am UTC](https://discourse.julialang.org/t/solve-large-number-of-linear-inequalities-with-dynamic-arrays/41821 "2020-07-01T01:15:59Z")

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Hi, I am trying to make a script to remove dominated strategies from a pay-off matrix G for a game-theoretical problem that I have (2-player game, finite discrete strategy sets). The goal is to automate the iterative e…

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## [Least squares with multi-dimensional output type](https://discourse.julialang.org/t/least-squares-with-multi-dimensional-output-type/42283)

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**Author:** [@akahs](https://discourse.julialang.org/u/akahs)\
**Replies:** 3\
**Last updated:** [July 1, 2020, 12:22am UTC](https://discourse.julialang.org/t/least-squares-with-multi-dimensional-output-type/42283 "2020-07-01T00:22:53Z")

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I am trying to use LsqFit to find out a 2D geometric transformation parameter, say a mapping from (x,y) to (xp,yp): x = \[x for x=-2.:2. for y=-2.:2.\] y = \[y for x=-2.:2. for y=-2.:2.\] in\_data = \[x y\] k = -0.02 @. xp = x…

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## [DiffEqBiological: getting the error "type Symbol has no field head"](https://discourse.julialang.org/t/diffeqbiological-getting-the-error-type-symbol-has-no-field-head/42296)

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**Author:** [@Sanji\_Vinsmoke](https://discourse.julialang.org/u/Sanji_Vinsmoke)\
**Replies:** 5\
**Last updated:** [June 30, 2020, 9:43pm UTC](https://discourse.julialang.org/t/diffeqbiological-getting-the-error-type-symbol-has-no-field-head/42296 "2020-06-30T21:43:21Z")

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I want to make a simple model of enzyme kinetics,but I keep getting some errors This is what I tried: rn = @reaction\_network begin k\_f, E + S → ES k\_r, ES → E + S k\_p, ES → P end and I get the error: type Sym…

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