# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=315

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**Page:** 316

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## [MethodError: no method matching isless(::Int64, ::AffExpr)](https://discourse.julialang.org/t/methoderror-no-method-matching-isless-int64-affexpr/69731)

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**Author:** [@Ali9266](https://discourse.julialang.org/u/Ali9266)\
**Replies:** 6\
**Last updated:** [December 16, 2021, 8:37am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-isless-int64-affexpr/69731 "2021-12-16T08:37:56Z")

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I’m receiving an error MethodError: no method matching isless(::Int64, ::AffExpr) while trying to run my code in the constraints “@constraint(model, con8\[k in 1:n,i in 1:m; i==m\], T\_k\[k\]==max(C\_ki\[k,i\]-U\_k\[k\],0))”

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## [When to use pmap vs Threads.@threads?](https://discourse.julialang.org/t/when-to-use-pmap-vs-threads-threads/72805)

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**Author:** [@chelseas](https://discourse.julialang.org/u/chelseas)\
**Replies:** 11\
**Last updated:** [December 16, 2021, 8:28am UTC](https://discourse.julialang.org/t/when-to-use-pmap-vs-threads-threads/72805 "2021-12-16T08:28:31Z")

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Some of my processes may take a minute, and others miliseconds, so load balancing seems like a good idea. Do both do this? Any other things I should know about when using pmap vs. @threads? I’ve tagged jump because I w…

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## [Quadratic Program solver](https://discourse.julialang.org/t/quadratic-program-solver/73125)

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**Author:** [@FH96](https://discourse.julialang.org/u/FH96)\
**Replies:** 3\
**Last updated:** [December 15, 2021, 12:36pm UTC](https://discourse.julialang.org/t/quadratic-program-solver/73125 "2021-12-15T12:36:36Z")

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Is there a list of available solvers for QP which can be used in julia? Googling and finding one by one is taking a lot of time SCS and OSQP are not accurate enough , COSMO doesn’t work for my problem… By the way can …

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## [How to interpret 2nd order Sobol global sensitivity analysis result?](https://discourse.julialang.org/t/how-to-interpret-2nd-order-sobol-global-sensitivity-analysis-result/47804)

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**Author:** [@Janssena](https://discourse.julialang.org/u/Janssena)\
**Replies:** 16\
**Last updated:** [December 15, 2021, 9:20am UTC](https://discourse.julialang.org/t/how-to-interpret-2nd-order-sobol-global-sensitivity-analysis-result/47804 "2021-12-15T09:20:06Z")

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Hey All, I used DiffeqSensitivity’s global sensitivity analysis using the Sobol method in order to explain the influence of specific input parameters of a model I’m building. I’m already getting some exciting results fr…

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## [Factorial on GPU](https://discourse.julialang.org/t/factorial-on-gpu/73116)

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**Author:** [@jeremiedb](https://discourse.julialang.org/u/jeremiedb)\
**Replies:** 1\
**Last updated:** [December 15, 2021, 6:07am UTC](https://discourse.julialang.org/t/factorial-on-gpu/73116 "2021-12-15T06:07:23Z")

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I wanted to perform a factorial calculation within a kernel for implementing a statistical measure (Poisson likelihood) on GPU, It turns out like factorial isn’t supported on GPU: using CUDA function gpu\_fac(y, x) …

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## [Habana Gaudi AI Processors - Julia support?](https://discourse.julialang.org/t/habana-gaudi-ai-processors-julia-support/73093)

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**Author:** [@j\_u](https://discourse.julialang.org/u/j_u)\
**Replies:** 4\
**Last updated:** [December 15, 2021, 12:40am UTC](https://discourse.julialang.org/t/habana-gaudi-ai-processors-julia-support/73093 "2021-12-15T00:40:24Z")

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Hi, Do you think that there is any chance that Habana is going to support Julia on their processors in the future (https://developer.habana.ai/) or is it rather very unlikely?

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## [Entropy maximization with nonlinear constraint](https://discourse.julialang.org/t/entropy-maximization-with-nonlinear-constraint/73104)

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**Author:** [@mvsoom](https://discourse.julialang.org/u/mvsoom)\
**Replies:** 4\
**Last updated:** [December 14, 2021, 11:55pm UTC](https://discourse.julialang.org/t/entropy-maximization-with-nonlinear-constraint/73104 "2021-12-14T23:55:50Z")

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I’m trying to solve the following entropy maximization problem: \\max\_p -\\sum\_{ij} p\_{ij} \\log p\_{ij} s.t. p \\in \\mathbb{R}^{n \\times n} \\\\ p\_{ij} = p\_{ji} \\\\ 0 \\leq p\_{ij} \\leq 1 ~ \\forall (i,j) \\\\ \\sum\_{ij} p\_{ij} …

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## [Generating a nice mesh on a sphere S^2](https://discourse.julialang.org/t/generating-a-nice-mesh-on-a-sphere-s-2/73075)

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**Author:** [@BVPs](https://discourse.julialang.org/u/BVPs)\
**Replies:** 8\
**Last updated:** [December 14, 2021, 10:52pm UTC](https://discourse.julialang.org/t/generating-a-nice-mesh-on-a-sphere-s-2/73075 "2021-12-14T22:52:42Z")

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I would like to generate a nice mesh/grid (i.e., as homogeneous/isotropic as possible) on the unit sphere S^2 in R^3. In particular, I would like to generate two possible grid systems: 1) based on triangles; or 2) based …

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## [Need help proofreading my BLSTM implementation](https://discourse.julialang.org/t/need-help-proofreading-my-blstm-implementation/73015)

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**Author:** [@Qfl3x](https://discourse.julialang.org/u/Qfl3x)\
**Replies:** 4\
**Last updated:** [December 14, 2021, 5:55pm UTC](https://discourse.julialang.org/t/need-help-proofreading-my-blstm-implementation/73015 "2021-12-14T17:55:40Z")

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Hi, I’m implementing a BLSTM for a personal (soon finished) project of mine and I’m currently very confused as to how BLSTM’s are implemented and found various kinds of implementations in papers online, mine should conca…

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## [Computing left-eigenvectors with high precision](https://discourse.julialang.org/t/computing-left-eigenvectors-with-high-precision/72949)

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**Author:** [@yosuga](https://discourse.julialang.org/u/yosuga)\
**Replies:** 15\
**Last updated:** [December 14, 2021, 5:27pm UTC](https://discourse.julialang.org/t/computing-left-eigenvectors-with-high-precision/72949 "2021-12-14T17:27:32Z")

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I need to get left-eigenvectors of a general complex matrix H. Especially, I want to treat a large and ill-conditioned one. I know two ways under using LinearAlgebra: computing the right-eigenvectors of H'. computing…

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## [Create variable based on array](https://discourse.julialang.org/t/create-variable-based-on-array/73070)

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**Author:** [@ahmad88](https://discourse.julialang.org/u/ahmad88)\
**Replies:** 1\
**Last updated:** [December 14, 2021, 4:59pm UTC](https://discourse.julialang.org/t/create-variable-based-on-array/73070 "2021-12-14T16:59:43Z")

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I have a tuple that contains pairs and I want to create a variable based on these pairs as follows E = \[(1, 2), (10, 16), (18, 24), (32, 33), (12, 10), (19, 18), (31, 30), (17, 36)\] for (i,j) in E @variable(model,x\[i…

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## [Best way to plot or display historical and real time trajectory](https://discourse.julialang.org/t/best-way-to-plot-or-display-historical-and-real-time-trajectory/73084)

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**Author:** [@benibilme](https://discourse.julialang.org/u/benibilme)\
**Replies:** 0\
**Last updated:** [December 14, 2021, 4:52pm UTC](https://discourse.julialang.org/t/best-way-to-plot-or-display-historical-and-real-time-trajectory/73084 "2021-12-14T16:52:15Z")

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Hello, I want to display past and present vehicle trajectories which are coming as continuous streams. What will be best way to plot or display streaming trajectory on a map. I looking for capabilities similar to pyth…

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## [Ccall Fortran OpenBLAS multithreading issues with Julia 1.7](https://discourse.julialang.org/t/ccall-fortran-openblas-multithreading-issues-with-julia-1-7/72913)

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**Author:** [@Perrin\_Meyer](https://discourse.julialang.org/u/Perrin_Meyer)\
**Replies:** 7\
**Last updated:** [December 14, 2021, 4:06pm UTC](https://discourse.julialang.org/t/ccall-fortran-openblas-multithreading-issues-with-julia-1-7/72913 "2021-12-14T16:06:28Z")

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I am using Julia to drive a Fortran based Boundary Element code. The Fortran code uses OpenMP and OpenBLAS for multithreading. When I call into the BEM code from Julia 1.7, I now only get single-threaded performance. O…

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## [User MIP start did not produce a new incumbent solution](https://discourse.julialang.org/t/user-mip-start-did-not-produce-a-new-incumbent-solution/72269)

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**Author:** [@ZHEN\_LIN](https://discourse.julialang.org/u/ZHEN_LIN)\
**Replies:** 5\
**Last updated:** [December 14, 2021, 1:57pm UTC](https://discourse.julialang.org/t/user-mip-start-did-not-produce-a-new-incumbent-solution/72269 "2021-12-14T13:57:09Z")

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I have a mixed integer optimization to be solved with Gurobi in JuMP. I am trying to give a warm start to Gurobi, but it gives me the following message User MIP start did not produce a new incumbent solution Processed M…

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## [Translating Binomial N-mixture models from Jags](https://discourse.julialang.org/t/translating-binomial-n-mixture-models-from-jags/72579)

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**Author:** [@FolgertK](https://discourse.julialang.org/u/FolgertK)\
**Replies:** 8\
**Last updated:** [December 14, 2021, 1:50pm UTC](https://discourse.julialang.org/t/translating-binomial-n-mixture-models-from-jags/72579 "2021-12-14T13:50:31Z")

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Hi there! I’m new to Julia and Turing, but I’m trying to translate some ecological models by Kéry and Royle (2016) from JAGS to Turing. The specific model here is a Binomial N-mixture model (or a Poisson-Binomal mixture…

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## [Teaching-Learning-based Optimization](https://discourse.julialang.org/t/teaching-learning-based-optimization/73014)

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**Author:** [@Hans\_W\_Borchers](https://discourse.julialang.org/u/Hans_W_Borchers)\
**Replies:** 3\
**Last updated:** [December 14, 2021, 9:02am UTC](https://discourse.julialang.org/t/teaching-learning-based-optimization/73014 "2021-12-14T09:02:39Z")

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Is there an implementation of the Teaching-Learning-Based Optimization (TLBO) algorithm in a Julia package or somewhere on Github? I found a MATLAB toolbox, but all searches for Julia were not successful. See Teaching …

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## [Graph Neural Networks in Flux.](https://discourse.julialang.org/t/graph-neural-networks-in-flux/21932)

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**Author:** [@FernandoHildebrand](https://discourse.julialang.org/u/FernandoHildebrand)\
**Replies:** 5\
**Last updated:** [December 14, 2021, 7:44am UTC](https://discourse.julialang.org/t/graph-neural-networks-in-flux/21932 "2021-12-14T07:44:12Z")

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Hello, Im starting my master course (Brazil- UFPR) in Bioinformatics. My background is mostly in IT and I´ve been studing Neural Nets(CNN, RNN…) to my upmost abilities. It seems that Graphs Neural Networks and/or Graph…

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## [Writing a multi-objective MPS file](https://discourse.julialang.org/t/writing-a-multi-objective-mps-file/73058)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 2\
**Last updated:** [December 14, 2021, 5:59am UTC](https://discourse.julialang.org/t/writing-a-multi-objective-mps-file/73058 "2021-12-14T05:59:29Z")

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Hi, We’re using JuMP with Gurobi, and specifically Gurobi’s multi-objective support (which is more sequential objectives than multi-objective, but that works because in this case that’s what we want). It would be handy…

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## [ERROR: No applicable\_savers found for UNKNOWN](https://discourse.julialang.org/t/error-no-applicable-savers-found-for-unknown/60339)

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**Author:** [@t-pollington](https://discourse.julialang.org/u/t-pollington)\
**Replies:** 1\
**Last updated:** [December 14, 2021, 12:58am UTC](https://discourse.julialang.org/t/error-no-applicable-savers-found-for-unknown/60339 "2021-12-14T00:58:28Z")

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Got this error coming from FileIO.save which had no Google search results to help. I ran: save("filename","varname", var) Turns out I forgot to include the file extension! This fixed it save("filename.jld","varname", …

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## [Looking for modeling ideas](https://discourse.julialang.org/t/looking-for-modeling-ideas/73013)

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**Author:** [@Emmanuel-R8](https://discourse.julialang.org/u/Emmanuel-R8)\
**Replies:** 3\
**Last updated:** [December 13, 2021, 6:44pm UTC](https://discourse.julialang.org/t/looking-for-modeling-ideas/73013 "2021-12-13T18:44:42Z")

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Hi - I have experience in MTK, Flux and Turing. I have used them in pairs. BUT, I have never used them all three at the same time. I have been looking for easy-ish ideas (think blogpost level) that I could use to educa…

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## [AlgebraOfGraphics question](https://discourse.julialang.org/t/algebraofgraphics-question/72982)

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**Author:** [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Replies:** 4\
**Last updated:** [December 13, 2021, 12:26pm UTC](https://discourse.julialang.org/t/algebraofgraphics-question/72982 "2021-12-13T12:26:16Z")

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In Philosophy · Algebra of Graphics (juliaplots.org) the authors explain that AlgebraOfGraphics doesn’t do mind reading and want to cut down the clutter/repetition when specifying a plot. I wonder what is the price to …

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## [Problem defining Continuos Dynamical Systems](https://discourse.julialang.org/t/problem-defining-continuos-dynamical-systems/73009)

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**Author:** [@pafloxy](https://discourse.julialang.org/u/pafloxy)\
**Replies:** 2\
**Last updated:** [December 13, 2021, 10:47am UTC](https://discourse.julialang.org/t/problem-defining-continuos-dynamical-systems/73009 "2021-12-13T10:47:16Z")

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I am having a problem defining the Rossler system using the following way~ ##eom~~ @inline @inbounds function rossler\_eom( u, p, t) a = p\[1\]; b = p\[2\]; c = p\[3\] du1 = -u\[2\] - u\[3\] du2 = u…

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## [Lazily reading from force data cube](https://discourse.julialang.org/t/lazily-reading-from-force-data-cube/71951)

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**Author:** [@maxfreu](https://discourse.julialang.org/u/maxfreu)\
**Replies:** 1\
**Last updated:** [December 13, 2021, 8:59am UTC](https://discourse.julialang.org/t/lazily-reading-from-force-data-cube/71951 "2021-12-13T08:59:40Z")

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Hi! I would like to read data lazily from a force datacube. Force is a processing pipeline for satellite images and it stores the outputs into a bunch of folders. Each folder (“tile”) covers a rectangular area and conta…

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## [Analogue to lyapunov exponents](https://discourse.julialang.org/t/analogue-to-lyapunov-exponents/70264)

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**Author:** [@pafloxy](https://discourse.julialang.org/u/pafloxy)\
**Replies:** 2\
**Last updated:** [December 13, 2021, 7:21am UTC](https://discourse.julialang.org/t/analogue-to-lyapunov-exponents/70264 "2021-12-13T07:21:22Z")

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Hi! While using the usual lyapunov function from the DynamicalSystems.jl package measures the rate of exponential separation of two slightly perturbed trajectories, I would instead like to measure the rate of exponentia…

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## [OCR with Julia](https://discourse.julialang.org/t/ocr-with-julia/4945)

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**Author:** [@John\_Hearns](https://discourse.julialang.org/u/John_Hearns)\
**Replies:** 7\
**Last updated:** [December 12, 2021, 10:08pm UTC](https://discourse.julialang.org/t/ocr-with-julia/4945 "2021-12-12T22:08:49Z")

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I am looking for suggestion on doing Optical Character Recognition. This does not necessarily have to be native Julia (see below). Also I am not looking for a full-on Machine Learnign framework which will recognise image…

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## [How to move optimiser from gpu to cpu?](https://discourse.julialang.org/t/how-to-move-optimiser-from-gpu-to-cpu/69622)

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**Author:** [@weiqi](https://discourse.julialang.org/u/weiqi)\
**Replies:** 10\
**Last updated:** [December 12, 2021, 6:29pm UTC](https://discourse.julialang.org/t/how-to-move-optimiser-from-gpu-to-cpu/69622 "2021-12-12T18:29:18Z")

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Currently, cpu(optimiser) won’t move it. For instance, the state still consists of variables in GPU.

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## [Deepcopy Flux Model](https://discourse.julialang.org/t/deepcopy-flux-model/72930)

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**Author:** [@tknopp](https://discourse.julialang.org/u/tknopp)\
**Replies:** 8\
**Last updated:** [December 12, 2021, 6:28pm UTC](https://discourse.julialang.org/t/deepcopy-flux-model/72930 "2021-12-12T18:28:02Z")

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Hi, I am struggling with warmstarting Flux models. My idea is to deepcopy both the model and the optimizer. However, if I do that the training error goes significantly up when retraining. If I use BSON: @save/@load it w…

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## [Plotly Slider - how to change data values?](https://discourse.julialang.org/t/plotly-slider-how-to-change-data-values/72939)

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**Author:** [@Dieter](https://discourse.julialang.org/u/Dieter)\
**Replies:** 2\
**Last updated:** [December 12, 2021, 4:17pm UTC](https://discourse.julialang.org/t/plotly-slider-how-to-change-data-values/72939 "2021-12-12T16:17:29Z")

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Hello Community, With the support of @empet I was able to create nice choropleth plots to visualize runoffs in german communities during the flooding in last summer. My next step would be to add a slider in order to sc…

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## [Computational Geometry: Regular Distribution of Points inside of a Polygon](https://discourse.julialang.org/t/computational-geometry-regular-distribution-of-points-inside-of-a-polygon/39523)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 18\
**Last updated:** [December 12, 2021, 1:46pm UTC](https://discourse.julialang.org/t/computational-geometry-regular-distribution-of-points-inside-of-a-polygon/39523 "2021-12-12T13:46:57Z")

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Hello! So I am basically asking since I struggle to figure out if there is an efficient way to do this. Basically I want to be able to take any arbitrary polygon and fill it with particles as shown in this figure: T…

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## [Problem with implementing the objective function with minimum and maximum functions simultaneously!](https://discourse.julialang.org/t/problem-with-implementing-the-objective-function-with-minimum-and-maximum-functions-simultaneously/72917)

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**Author:** [@Sahar](https://discourse.julialang.org/u/Sahar)\
**Replies:** 2\
**Last updated:** [December 11, 2021, 2:31pm UTC](https://discourse.julialang.org/t/problem-with-implementing-the-objective-function-with-minimum-and-maximum-functions-simultaneously/72917 "2021-12-11T14:31:49Z")

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Hi Good morning! I am working on an optimization problem and it has a user defined objective function. the problem is now working well with a simple cost objective function, but I am not able to change it to the attach…

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