# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=412

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**Page:** 413

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## [Can't fit nonlinear function including '^' in LsqFit](https://discourse.julialang.org/t/cant-fit-nonlinear-function-including-in-lsqfit/49199)

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**Author:** [@gedankenexperiment](https://discourse.julialang.org/u/gedankenexperiment)\
**Replies:** 2\
**Last updated:** [October 29, 2020, 8:33am UTC](https://discourse.julialang.org/t/cant-fit-nonlinear-function-including-in-lsqfit/49199 "2020-10-29T08:33:18Z")

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Hi there, When I try to fit to a concentration-response curve (Hill equation) and use the exponent as a free parameter, Julia throws me an error complaining that the base should be a complex number. Even using lower bou…

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## [Unioning MetaGraphs](https://discourse.julialang.org/t/unioning-metagraphs/49204)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 0\
**Last updated:** [October 28, 2020, 8:33pm UTC](https://discourse.julialang.org/t/unioning-metagraphs/49204 "2020-10-28T20:33:40Z")

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I don’t completely understand the error, but looks like some methods from Base might need to be exended. What is the minimum I would need to implement to make this work?: g1 = MetaDiGraph(4) add\_edge!(g1, 1, 2) add\_edg…

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## [Extract model coefficients with FixedEffectModels.jl package](https://discourse.julialang.org/t/extract-model-coefficients-with-fixedeffectmodels-jl-package/49174)

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**Author:** [@Antonina\_Klyuyeva](https://discourse.julialang.org/u/Antonina_Klyuyeva)\
**Replies:** 14\
**Last updated:** [October 28, 2020, 6:26pm UTC](https://discourse.julialang.org/t/extract-model-coefficients-with-fixedeffectmodels-jl-package/49174 "2020-10-28T18:26:55Z")

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Hi everyone! In my regression model (Y ~ A:B), a numeric variable (A) interacts with a categorical variable (B). Since the categorical variable has a lot of unique levels, fitting the model using GLM.jl package consumes…

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## [COBOL and Julia comparison](https://discourse.julialang.org/t/cobol-and-julia-comparison/49166)

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**Author:** [@bocc](https://discourse.julialang.org/u/bocc)\
**Replies:** 16\
**Last updated:** [October 28, 2020, 6:25pm UTC](https://discourse.julialang.org/t/cobol-and-julia-comparison/49166 "2020-10-28T18:25:46Z")

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Hello, I’d like to state in advance that I have negligible familiarity with number representations, so please excuse any inaccuracies. I also enjoy getting rid of legacy systems. I have recently read an article which p…

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## [L1 regularization with box constraint in JuMP?](https://discourse.julialang.org/t/l1-regularization-with-box-constraint-in-jump/49105)

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**Author:** [@yewalenikhil65](https://discourse.julialang.org/u/yewalenikhil65)\
**Replies:** 4\
**Last updated:** [October 28, 2020, 3:07pm UTC](https://discourse.julialang.org/t/l1-regularization-with-box-constraint-in-jump/49105 "2020-10-28T15:07:01Z")

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Does JuMP have L1 regularization with box constraint in following form as utility ? minimize || Ax - b || subject to 1st norm of x i.e. |x| \< lambda (some parameter) and 0 \<= x\[i\] \<= kappa (some parameter) where, A i…

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## [Plots.jl: Combine two plots into one with two series](https://discourse.julialang.org/t/plots-jl-combine-two-plots-into-one-with-two-series/4185)

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**Author:** [@phlavenk](https://discourse.julialang.org/u/phlavenk)\
**Replies:** 8\
**Last updated:** [October 28, 2020, 2:38pm UTC](https://discourse.julialang.org/t/plots-jl-combine-two-plots-into-one-with-two-series/4185 "2020-10-28T14:38:55Z")

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Hi, I’m using the Plots.jl package and I’d like to do some manipulation to graph layout inside my functions, that return an aray of plot objects, that I finaly plot with grid layout. When I run the function with two set…

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## [Splatting keyword arguments to @variable macro in JuMP](https://discourse.julialang.org/t/splatting-keyword-arguments-to-variable-macro-in-jump/49130)

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**Author:** [@gobs](https://discourse.julialang.org/u/gobs)\
**Replies:** 2\
**Last updated:** [October 28, 2020, 12:57pm UTC](https://discourse.julialang.org/t/splatting-keyword-arguments-to-variable-macro-in-jump/49130 "2020-10-28T12:57:00Z")

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I have a function which returns a particular variable, but defines it differently depending on my model type. I’ve recreated a MWE below. using JuMP function get\_z\_kwargs(m::Model) if m.ext\[:model\_type\] == "binary"…

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## [Modifying CuArray elements in-place with index arrays](https://discourse.julialang.org/t/modifying-cuarray-elements-in-place-with-index-arrays/49091)

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**Author:** [@berquist](https://discourse.julialang.org/u/berquist)\
**Replies:** 4\
**Last updated:** [October 28, 2020, 8:23am UTC](https://discourse.julialang.org/t/modifying-cuarray-elements-in-place-with-index-arrays/49091 "2020-10-28T08:23:20Z")

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I’m trying to implement the vectorized square root for complex CUDA arrays, and am starting from the commented-out implementation in https://github.com/JuliaLang/julia/blob/5d8225a1116685e449fcc08b207acdd0f5106409/base/c…

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## [Fit Poisson ditribution to histogram](https://discourse.julialang.org/t/fit-poisson-ditribution-to-histogram/48883)

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**Author:** [@phlavenk](https://discourse.julialang.org/u/phlavenk)\
**Replies:** 4\
**Last updated:** [October 28, 2020, 7:43am UTC](https://discourse.julialang.org/t/fit-poisson-ditribution-to-histogram/48883 "2020-10-28T07:43:43Z")

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Is there a way how to fit a Poisson distribution (determine the lambda parameter) from a histogram of an experimental process? In the experimental setup, in each event we are recording the number of detected photons and…

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## [\[ANN\] MPI.jl 0.14 changes](https://discourse.julialang.org/t/ann-mpi-jl-0-14-changes/39126)

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**Author:** [@simonbyrne](https://discourse.julialang.org/u/simonbyrne)\
**Replies:** 6\
**Last updated:** [October 27, 2020, 8:30pm UTC](https://discourse.julialang.org/t/ann-mpi-jl-0-14-changes/39126 "2020-10-27T20:30:30Z")

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I’ve just tagged MPI.jl 0.14: the major change in this release is that it will now use a BinaryBuilder-provided MPI binary (Microsoft MPI on Windows, MPICH on other platforms). If you are running on a HPC system you wil…

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## [Normalized densities in Gadfly](https://discourse.julialang.org/t/normalized-densities-in-gadfly/49141)

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**Author:** [@yarnton](https://discourse.julialang.org/u/yarnton)\
**Replies:** 1\
**Last updated:** [October 27, 2020, 7:40pm UTC](https://discourse.julialang.org/t/normalized-densities-in-gadfly/49141 "2020-10-27T19:40:07Z")

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As a newcomer I’ve found Gadfly very easy to learn and elegant to use. I encountered a little issue. A simple Geom.density seems to be non-normalized. That is, to be a function of frequencies, not probabilities. @tlnag…

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## [Objective function error in a robust model](https://discourse.julialang.org/t/objective-function-error-in-a-robust-model/49123)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 2\
**Last updated:** [October 27, 2020, 7:29pm UTC](https://discourse.julialang.org/t/objective-function-error-in-a-robust-model/49123 "2020-10-27T19:29:42Z")

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I need to put this objective function in Julia. Can someone help me? I started doing this, but I still couldn’t compile the objective function using JuMP, JuMPeR, DataFrames, MathOptInterface, GLPKMathProgInterface M…

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## [Is LsqFit mantained?](https://discourse.julialang.org/t/is-lsqfit-mantained/49127)

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**Author:** [@shiroghost](https://discourse.julialang.org/u/shiroghost)\
**Replies:** 4\
**Last updated:** [October 27, 2020, 6:08pm UTC](https://discourse.julialang.org/t/is-lsqfit-mantained/49127 "2020-10-27T18:08:22Z")

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Dear all, I have seen that LsqFit has several pull requests that are not being merged. Does anyone know if the package is still matained? If not, what are good alternatives? Many thanks,

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## [Why my heatmap contour plot in polar coordinates is small/tiny?](https://discourse.julialang.org/t/why-my-heatmap-contour-plot-in-polar-coordinates-is-small-tiny/47955)

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**Author:** [@RBraghiere](https://discourse.julialang.org/u/RBraghiere)\
**Replies:** 4\
**Last updated:** [October 27, 2020, 10:14am UTC](https://discourse.julialang.org/t/why-my-heatmap-contour-plot-in-polar-coordinates-is-small-tiny/47955 "2020-10-27T10:14:58Z")

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Hi, I am trying to plot a heatmap in a polar plot like so: contourf(deg2rad.(collect((0:360))),deg2rad.(collect(0:1:85)), B, aspect\_ratio=:equal, proj=:polar, color=:viridis, alpha=0.5) But I get a tiny little figu…

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## [AmplNLWriter.jl with Ipopt from Ipopt.jl](https://discourse.julialang.org/t/amplnlwriter-jl-with-ipopt-from-ipopt-jl/49038)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [October 27, 2020, 8:42am UTC](https://discourse.julialang.org/t/amplnlwriter-jl-with-ipopt-from-ipopt-jl/49038 "2020-10-27T08:42:40Z")

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I am trying to use Ipopt, as “shipped” with Ipopt.jl, using AmplNLWriter.jl. The way indicated in the AmplNLWriter.jl readme, myModel = Model(() -\> AmplNLWriter.Optimizer(Ipopt.amplexe)), returns me a MethodError. How…

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## [LaTeX table reader in Julia](https://discourse.julialang.org/t/latex-table-reader-in-julia/49067)

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**Author:** [@sswatson](https://discourse.julialang.org/u/sswatson)\
**Replies:** 5\
**Last updated:** [October 27, 2020, 12:23am UTC](https://discourse.julialang.org/t/latex-table-reader-in-julia/49067 "2020-10-27T00:23:24Z")

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Is there a LaTeX table reader in Julia? I know there are several writers, but I haven’t been able to find something that takes the LaTeX source as input. The reason I’m interested is that MathPix is really good at OCRin…

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## [Animated plot and CUDA computations with Makie](https://discourse.julialang.org/t/animated-plot-and-cuda-computations-with-makie/48974)

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**Author:** [@R366Y](https://discourse.julialang.org/u/R366Y)\
**Replies:** 2\
**Last updated:** [October 26, 2020, 8:20pm UTC](https://discourse.julialang.org/t/animated-plot-and-cuda-computations-with-makie/48974 "2020-10-26T20:20:39Z")

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Hello everyone , I’m learning GPU programming with Julia and I want to generate a procedurally animated picture inside a window with CUDA , for instance I’m porting the GPU Ripple example from Chapter 5 “Cuda by example…

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## [Difference-Differential system in ModelingToolkit.jl](https://discourse.julialang.org/t/difference-differential-system-in-modelingtoolkit-jl/48605)

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**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 5\
**Last updated:** [October 26, 2020, 7:34pm UTC](https://discourse.julialang.org/t/difference-differential-system-in-modelingtoolkit-jl/48605 "2020-10-26T19:34:10Z")

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Dear All, I would like to ask for advice regarding ModellingToolkit.jl. I am working on a problem (macroeconomic model) that reduces to the solution of a highly nonlinear dynamic system. Because of high-nonlinearity and…

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## [Formalizing a governance structure for JuMP](https://discourse.julialang.org/t/formalizing-a-governance-structure-for-jump/49017)

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**Author:** [@odow](https://discourse.julialang.org/u/odow)\
**Replies:** 2\
**Last updated:** [October 26, 2020, 6:53pm UTC](https://discourse.julialang.org/t/formalizing-a-governance-structure-for-jump/49017 "2020-10-26T18:53:23Z")

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Dear all, Recently, JuMP turned eight years old. (The first commit for “Julp” was made on 10 October 2012!) It has come a long way since it’s creation as a side-project of two graduate students at MIT, and as we approac…

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## [Visualizing the grid JuAFEM](https://discourse.julialang.org/t/visualizing-the-grid-juafem/49052)

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**Author:** [@Hrishikesh\_Das](https://discourse.julialang.org/u/Hrishikesh_Das)\
**Replies:** 1\
**Last updated:** [October 26, 2020, 3:50pm UTC](https://discourse.julialang.org/t/visualizing-the-grid-juafem/49052 "2020-10-26T15:50:44Z")

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I am new to Julia. Cn someone tell me how to visualize the grid I have generated?

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## [Is garbage collection bad for gpu programming?](https://discourse.julialang.org/t/is-garbage-collection-bad-for-gpu-programming/48942)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 15\
**Last updated:** [October 25, 2020, 11:34pm UTC](https://discourse.julialang.org/t/is-garbage-collection-bad-for-gpu-programming/48942 "2020-10-25T23:34:48Z")

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I was hearing this podcast: and the Swift guy at a moment (about minute 56) said something like that no language would replace Python if one of the qualities of Python is not followed, concerning not having garbage co…

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## [Multipath TCP awareness in Sockets.jl](https://discourse.julialang.org/t/multipath-tcp-awareness-in-sockets-jl/48952)

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**Author:** [@mks](https://discourse.julialang.org/u/mks)\
**Replies:** 3\
**Last updated:** [October 25, 2020, 7:50pm UTC](https://discourse.julialang.org/t/multipath-tcp-awareness-in-sockets-jl/48952 "2020-10-25T19:50:55Z")

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Hello, I’m new to the Julia community and currently try to understand the basic lower level networks terminology, even if it’s above my skill level. There is work going on by the IETF Multipath TCP Working Group that s…

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## [Principal Components Analysis on datasets with missing data](https://discourse.julialang.org/t/principal-components-analysis-on-datasets-with-missing-data/48962)

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**Author:** [@clibassi](https://discourse.julialang.org/u/clibassi)\
**Replies:** 5\
**Last updated:** [October 25, 2020, 2:16pm UTC](https://discourse.julialang.org/t/principal-components-analysis-on-datasets-with-missing-data/48962 "2020-10-25T14:16:47Z")

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Hey all - I’m sort of new to principal components analysis - especially in Julia, but I’ve been digging through @nassarhuda’s great Dimensionality Reduction notebook but am running into an issue because the data I’m wor…

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## [Fixing and freeing variables o JuMP](https://discourse.julialang.org/t/fixing-and-freeing-variables-o-jump/48838)

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**Author:** [@baprata](https://discourse.julialang.org/u/baprata)\
**Replies:** 13\
**Last updated:** [October 24, 2020, 4:45pm UTC](https://discourse.julialang.org/t/fixing-and-freeing-variables-o-jump/48838 "2020-10-24T16:45:49Z")

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I am studying a combinatorial optimization problem with JuMP and Gurobi. I need to fix some decision variables for a given number of iterations or a given time limit. After that, I would like to unfix these variables pre…

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## [CUDA under julia 1.5.0](https://discourse.julialang.org/t/cuda-under-julia-1-5-0/44789)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 13\
**Last updated:** [October 24, 2020, 6:46am UTC](https://discourse.julialang.org/t/cuda-under-julia-1-5-0/44789 "2020-10-24T06:46:03Z")

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Hi, this is ubuntu 20.04 fresh install, also Julia 1.5.0 add CUDA \[ Info: Resolving package identifier \`CUDA\` as a directory at \`~/CUDA\`. ERROR: Did not find a git repository at \`CUDA\` no CUDA whatsoever… what am I do…

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## [Building Julia from source on old Cray XE/XK system](https://discourse.julialang.org/t/building-julia-from-source-on-old-cray-xe-xk-system/48899)

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**Author:** [@asaxton](https://discourse.julialang.org/u/asaxton)\
**Replies:** 0\
**Last updated:** [October 23, 2020, 6:04pm UTC](https://discourse.julialang.org/t/building-julia-from-source-on-old-cray-xe-xk-system/48899 "2020-10-23T18:04:00Z")

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Hi, as the title says, I’m building Julia from source on a Cray XE/XK system (Blue Waters). I keep getting compiler errors similar to "error: expected ')' before 'PRIx32'". They have to do with macros defined under intty…

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## [\[ANN\]\[STANDUP\] New biweekly JuliaWeb dev discussion (via google meet): Upcoming Oct 23 10:15-11:15 ET](https://discourse.julialang.org/t/ann-standup-new-biweekly-juliaweb-dev-discussion-via-google-meet-upcoming-oct-23-1015-et/48674)

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**Author:** [@quinnj](https://discourse.julialang.org/u/quinnj)\
**Replies:** 6\
**Last updated:** [October 23, 2020, 5:42pm UTC](https://discourse.julialang.org/t/ann-standup-new-biweekly-juliaweb-dev-discussion-via-google-meet-upcoming-oct-23-1015-et/48674 "2020-10-23T17:42:25Z")

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As there’s been interest here on discourse and on slack, I’ve set up a recurring (biweekly/every other week) google meet call where anyone is invited to participate. Link to calendar event/google meet details: https://c…

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## [Is it possible to implement custom inference in Turing?](https://discourse.julialang.org/t/is-it-possible-to-implement-custom-inference-in-turing/48468)

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**Author:** [@yarnton](https://discourse.julialang.org/u/yarnton)\
**Replies:** 1\
**Last updated:** [October 23, 2020, 1:45pm UTC](https://discourse.julialang.org/t/is-it-possible-to-implement-custom-inference-in-turing/48468 "2020-10-23T13:45:44Z")

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I’m new to Turing, but I have quite a lot of experience in probabilistic programming. Particularly with models that can be expressed as factor graphs (e.g. Infer NET or ForneyLab.jl). Turing looks really neat. Is it rea…

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## [Detailed simplex, branch and bound and transportation solvers for Julia](https://discourse.julialang.org/t/detailed-simplex-branch-and-bound-and-transportation-solvers-for-julia/46538)

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**Author:** [@fusion809](https://discourse.julialang.org/u/fusion809)\
**Replies:** 2\
**Last updated:** [October 23, 2020, 11:20am UTC](https://discourse.julialang.org/t/detailed-simplex-branch-and-bound-and-transportation-solvers-for-julia/46538 "2020-10-23T11:20:04Z")

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I’m just wondering whether there are any Julia packages that show: detailed simplex tableaux for each iteration of the simplex method required to solve a linear programming problem; detailed information about the branc…

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## [Flux with Julia master fails with IRCode error](https://discourse.julialang.org/t/flux-with-julia-master-fails-with-ircode-error/48865)

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**Author:** [@Colin\_Beckingham](https://discourse.julialang.org/u/Colin_Beckingham)\
**Replies:** 0\
**Last updated:** [October 23, 2020, 6:14am UTC](https://discourse.julialang.org/t/flux-with-julia-master-fails-with-ircode-error/48865 "2020-10-23T06:14:57Z")

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Using the sample code from the documentation for Flux Optimizers, with Julia 1.5.2 the code works (apart from a warning about slow compilation) but fails with master on julia\> grads = gradient(() -\> loss(x, y), θ) ERROR…

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