# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=203

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**Page:** 204

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## [Reducing model building time](https://discourse.julialang.org/t/reducing-model-building-time/97069)

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**Author:** [@math\_opt](https://discourse.julialang.org/u/math_opt)\
**Replies:** 8\
**Last updated:** [April 5, 2023, 3:09am UTC](https://discourse.julialang.org/t/reducing-model-building-time/97069 "2023-04-05T03:09:51Z")

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Is there a difference in the time taken to build the JuMP model if I use for loops for defining variables/constraints. For example: using JuMP model = Model() @variable(model, x\[i in 1:7, j in 1:10\] \>= 0) @constraint(…

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## [NeuralPDE for starting a geophysics repository](https://discourse.julialang.org/t/neuralpde-for-starting-a-geophysics-repository/97047)

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**Author:** [@pkmishra](https://discourse.julialang.org/u/pkmishra)\
**Replies:** 4\
**Last updated:** [April 4, 2023, 10:59pm UTC](https://discourse.julialang.org/t/neuralpde-for-starting-a-geophysics-repository/97047 "2023-04-04T22:59:28Z")

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Hi @ChrisRackauckas, I am writing a research proposal for creating an integrated optimization framework for multi-source geophysical data. The goal is to start something sustainable for long-term. I would like everything…

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## [Gradient-Free Neural Network Optimization](https://discourse.julialang.org/t/gradient-free-neural-network-optimization/97088)

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**Author:** [@liamfdoherty](https://discourse.julialang.org/u/liamfdoherty)\
**Replies:** 3\
**Last updated:** [April 4, 2023, 10:58pm UTC](https://discourse.julialang.org/t/gradient-free-neural-network-optimization/97088 "2023-04-04T22:58:33Z")

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I have a neural network which is real valued (i.e., maps into \\mathbb{R}, with inputs in \\mathbb{R}^{n}), but it has complex weights. Consequently, taking gradients of the loss function is complex differentiation, and th…

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## [GDAL - Write KMZ file with transparency](https://discourse.julialang.org/t/gdal-write-kmz-file-with-transparency/97087)

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**Author:** [@stefanomoro](https://discourse.julialang.org/u/stefanomoro)\
**Replies:** 1\
**Last updated:** [April 4, 2023, 9:54pm UTC](https://discourse.julialang.org/t/gdal-write-kmz-file-with-transparency/97087 "2023-04-04T21:54:30Z")

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I’m trying to save a .kmz file from a dataset representing a DEM of an area stored in a GeoTiff file. My code is reading the DEM, transforming the CRS to UTM, and defining a subset based on coordinates. On this subset I…

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## [UndefVarError: libcuda\_original\_version not defined](https://discourse.julialang.org/t/undefvarerror-libcuda-original-version-not-defined/97049)

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**Author:** [@stephans3](https://discourse.julialang.org/u/stephans3)\
**Replies:** 1\
**Last updated:** [April 4, 2023, 12:33pm UTC](https://discourse.julialang.org/t/undefvarerror-libcuda-original-version-not-defined/97049 "2023-04-04T12:33:37Z")

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Hi all, on a student’s laptop (with Nvidia P620, Windows 10) we installed CUDA.jl and faced the following error message. julia\> CUDA.versioninfo() CUDA runtime 12.1, artifact installation CUDA driver 12.1 NVIDIA driver…

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## [In GaussianProcess.jl it is throwing error if I choose \`MeanConst()\`](https://discourse.julialang.org/t/in-gaussianprocess-jl-it-is-throwing-error-if-i-choose-meanconst/97008)

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**Author:** [@Sourish](https://discourse.julialang.org/u/Sourish)\
**Replies:** 9\
**Last updated:** [April 4, 2023, 12:08pm UTC](https://discourse.julialang.org/t/in-gaussianprocess-jl-it-is-throwing-error-if-i-choose-meanconst/97008 "2023-04-04T12:08:15Z")

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Hi In the following code, I am trying to implement a constant mean function from GaussianProcesses.jl. But it is throwing an error stating no method matching MeanConst() using GaussianProcesses n = 100; x = 2π \* rand(n…

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## [Complete and incomplete sparse cholesky factorization](https://discourse.julialang.org/t/complete-and-incomplete-sparse-cholesky-factorization/96918)

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**Author:** [@shakedregev](https://discourse.julialang.org/u/shakedregev)\
**Replies:** 6\
**Last updated:** [April 4, 2023, 7:28am UTC](https://discourse.julialang.org/t/complete-and-incomplete-sparse-cholesky-factorization/96918 "2023-04-04T07:28:23Z")

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Say I have a CuSparseCSR matrix “A” and I want to take complete and incomplete cholesky factorizations of it, but crucially leave that factorization on the GPU, how can I do that? Things I’ve tried: CuSparse.jl - depr…

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## [Turing.jl: unlikely posterior with bayesian differential equation?](https://discourse.julialang.org/t/turing-jl-unlikely-posterior-with-bayesian-differential-equation/92269)

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**Author:** [@Janssena](https://discourse.julialang.org/u/Janssena)\
**Replies:** 9\
**Last updated:** [April 4, 2023, 6:46am UTC](https://discourse.julialang.org/t/turing-jl-unlikely-posterior-with-bayesian-differential-equation/92269 "2023-04-04T06:46:44Z")

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Hey All, I am trying to approximate the posterior distribution of a random variable inside of a differential equation with a stochastic outcome. I am able to sample from the posterior distribution, I am however unsure i…

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## [JuMP/CPLEX: confusion with number of cuts added in callback](https://discourse.julialang.org/t/jump-cplex-confusion-with-number-of-cuts-added-in-callback/56033)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 6\
**Last updated:** [April 4, 2023, 12:44am UTC](https://discourse.julialang.org/t/jump-cplex-confusion-with-number-of-cuts-added-in-callback/56033 "2023-04-04T00:44:32Z")

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Dear folks, I use JuMP (v0.21.4) and CPLEX (v0.7.3) to solve a MILP with lazy and user cuts added in a generic callback. However, I am confused with the output. To obtain the number of cuts after solving, I wrote the fu…

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## [Polar plot with 0° at the nadir?](https://discourse.julialang.org/t/polar-plot-with-0-at-the-nadir/92119)

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**Author:** [@rmfritz](https://discourse.julialang.org/u/rmfritz)\
**Replies:** 11\
**Last updated:** [April 3, 2023, 5:54pm UTC](https://discourse.julialang.org/t/polar-plot-with-0-at-the-nadir/92119 "2023-04-03T17:54:59Z")

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Is there any simple way to do this? The default is 0° on the right.

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## [Graph.jl error in a\_star() function](https://discourse.julialang.org/t/graph-jl-error-in-a-star-function/96455)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 15\
**Last updated:** [April 3, 2023, 4:47pm UTC](https://discourse.julialang.org/t/graph-jl-error-in-a-star-function/96455 "2023-04-03T16:47:04Z")

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I want to get shortest distance between two edges. using Graphs,GraphRecipes ,Plots,Karnak,NetworkLayout,Colors,SimpleWeightedGraphs begin G=SimpleWeightedGraph(5) add\_edge!(G, 1, 2,2000) add\_edge!(G, 1, 3,180…

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## [Calculation of two-time correlation function and spectrum in quantumoptics.jl](https://discourse.julialang.org/t/calculation-of-two-time-correlation-function-and-spectrum-in-quantumoptics-jl/97009)

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**Author:** [@arpan\_chatterjee](https://discourse.julialang.org/u/arpan_chatterjee)\
**Replies:** 0\
**Last updated:** [April 3, 2023, 10:52am UTC](https://discourse.julialang.org/t/calculation-of-two-time-correlation-function-and-spectrum-in-quantumoptics-jl/97009 "2023-04-03T10:52:26Z")

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If I have some time-dependent Hamiltonian whose frequency is time dependent not amplitude as described in the example of the documentation in quantumoptics.jl. Then How can I construct two-time correlation function for s…

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## [Job shop scheduling](https://discourse.julialang.org/t/job-shop-scheduling/96938)

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**Author:** [@baprata](https://discourse.julialang.org/u/baprata)\
**Replies:** 4\
**Last updated:** [April 3, 2023, 12:52pm UTC](https://discourse.julialang.org/t/job-shop-scheduling/96938 "2023-04-03T12:52:40Z")

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I am studying the mixed-integer linear programming formulation for the job shop with makespan minimization proposed by Manne (see Equations (1)-(7) from Ku and Beck (2016) http://dx.doi.org/10.1016/j.cor.2016.04.006, and…

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## [Which JuMP supported solvers work well on Apple M2?](https://discourse.julialang.org/t/which-jump-supported-solvers-work-well-on-apple-m2/96992)

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**Author:** [@nlaws](https://discourse.julialang.org/u/nlaws)\
**Replies:** 3\
**Last updated:** [April 3, 2023, 3:03am UTC](https://discourse.julialang.org/t/which-jump-supported-solvers-work-well-on-apple-m2/96992 "2023-04-03T03:03:29Z")

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Looking at a new laptop RN and found this interesting discussion regarding Operations Research on M1: There is also this discussion on this discourse regarding CPLEX.jl on M2: However, the first discussion was last u…

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## [Adjusting padding between axis and axisticklabel in gridded layout](https://discourse.julialang.org/t/adjusting-padding-between-axis-and-axisticklabel-in-gridded-layout/96950)

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**Author:** [@iabraham](https://discourse.julialang.org/u/iabraham)\
**Replies:** 3\
**Last updated:** [April 2, 2023, 7:45pm UTC](https://discourse.julialang.org/t/adjusting-padding-between-axis-and-axisticklabel-in-gridded-layout/96950 "2023-04-02T19:45:00Z")

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This question is about being able to adjust the space between ticklabels and their corresponding axis lines in the default GR backed for Plots.jl. Consider: using Plots, Plots.Measures minx, miny, N = 300, 300, 16 Plo…

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## [Combine output of several functions on the same interactive plot](https://discourse.julialang.org/t/combine-output-of-several-functions-on-the-same-interactive-plot/96972)

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**Author:** [@ittomsk](https://discourse.julialang.org/u/ittomsk)\
**Replies:** 0\
**Last updated:** [April 2, 2023, 3:35pm UTC](https://discourse.julialang.org/t/combine-output-of-several-functions-on-the-same-interactive-plot/96972 "2023-04-02T15:35:27Z")

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I need to add some lines on top of the agent’s polygon to represent its properties. However, I am currently stuck at grouping the output of two functions in the following line: Group(\[agent\_poly, agent\_orientation\]) . c…

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## [Why is ModelingToolkit simplifying this way?](https://discourse.julialang.org/t/why-is-modelingtoolkit-simplifying-this-way/96872)

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**Author:** [@jonniedie](https://discourse.julialang.org/u/jonniedie)\
**Replies:** 5\
**Last updated:** [April 2, 2023, 11:16am UTC](https://discourse.julialang.org/t/why-is-modelingtoolkit-simplifying-this-way/96872 "2023-04-02T11:16:54Z")

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I created a pretty simple composed system: using OrdinaryDiffEq, ModelingToolkit, Plots @parameters t d\_dt = Differential(t) function Cart(; init\_pos, init\_vel, mass, name=:cart) @variables pos(t)=init\_pos vel(t)=ini…

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## [Higher accuracy in numerical cumulative integration](https://discourse.julialang.org/t/higher-accuracy-in-numerical-cumulative-integration/96898)

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**Author:** [@roi.holtzman](https://discourse.julialang.org/u/roi.holtzman)\
**Replies:** 15\
**Last updated:** [April 1, 2023, 7:35pm UTC](https://discourse.julialang.org/t/higher-accuracy-in-numerical-cumulative-integration/96898 "2023-04-01T19:35:42Z")

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There are some threads about numerical cumulative integration like this and this. However, I have a more basic question. I am interested in performing the integral S(x; a) = \\int\_a^x f(x') dx' where x \\le b. Note that f…

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## [Package for fast OLS using StaticArrays](https://discourse.julialang.org/t/package-for-fast-ols-using-staticarrays/96943)

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**Author:** [@colintbowers](https://discourse.julialang.org/u/colintbowers)\
**Replies:** 0\
**Last updated:** [April 1, 2023, 11:20am UTC](https://discourse.julialang.org/t/package-for-fast-ols-using-staticarrays/96943 "2023-04-01T11:20:39Z")

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Hi all, I was just wondering if there is a package commonly used for performing OLS when the number of explanatory variables is known (and small), that leverages the benefits of StaticArrays.jl? For example: using Sta…

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## [What is the current status of julia to wasm compilation?](https://discourse.julialang.org/t/what-is-the-current-status-of-julia-to-wasm-compilation/96922)

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**Author:** [@1m1](https://discourse.julialang.org/u/1m1)\
**Replies:** 1\
**Last updated:** [April 1, 2023, 6:38am UTC](https://discourse.julialang.org/t/what-is-the-current-status-of-julia-to-wasm-compilation/96922 "2023-04-01T06:38:16Z")

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i have only found projects that have not had commits for over a year. is this because it works, julia can be compiled to wasm? or does it not work and it is neither a focus? ty

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## [Cannot set an array of constraints @constraint, getting an error](https://discourse.julialang.org/t/cannot-set-an-array-of-constraints-constraint-getting-an-error/96901)

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**Author:** [@Gregoryo](https://discourse.julialang.org/u/Gregoryo)\
**Replies:** 2\
**Last updated:** [April 1, 2023, 5:15am UTC](https://discourse.julialang.org/t/cannot-set-an-array-of-constraints-constraint-getting-an-error/96901 "2023-04-01T05:15:27Z")

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Hi, I want to create a constraint in my model where I have np particles with a mass m at position x,y as variables. I want to set the constraint that the mass of particles is \>0 and I wrote the code below but I get an er…

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## [Iterating through JuMP variables](https://discourse.julialang.org/t/iterating-through-jump-variables/96816)

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**Author:** [@math\_opt](https://discourse.julialang.org/u/math_opt)\
**Replies:** 5\
**Last updated:** [March 31, 2023, 8:33pm UTC](https://discourse.julialang.org/t/iterating-through-jump-variables/96816 "2023-03-31T20:33:01Z")

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I am doing some trivial checks on the variable values output by my optimization model, and I was wondering what is the correct way to iterate through a JuMP variable. For example, if my model has a variable x\[2:9, 10:15\],…

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## [ParallelStencil + ImplicitGlobalGrid with multiple GPUs](https://discourse.julialang.org/t/parallelstencil-implicitglobalgrid-with-multiple-gpus/96585)

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**Author:** [@Teerthal](https://discourse.julialang.org/u/Teerthal)\
**Replies:** 8\
**Last updated:** [March 31, 2023, 7:39pm UTC](https://discourse.julialang.org/t/parallelstencil-implicitglobalgrid-with-multiple-gpus/96585 "2023-03-31T19:39:24Z")

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Hello, I am currently starting out with GPU programming and working out a multiple GPU implementation of my Electroweak field theory simulation code. I have followed the examples on the ParallelStencil git for multi-GP…

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## [Indexing in GPU kernel](https://discourse.julialang.org/t/indexing-in-gpu-kernel/96902)

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**Author:** [@shakedregev](https://discourse.julialang.org/u/shakedregev)\
**Replies:** 2\
**Last updated:** [March 31, 2023, 7:07pm UTC](https://discourse.julialang.org/t/indexing-in-gpu-kernel/96902 "2023-03-31T19:07:11Z")

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I’m building a custom GPU kernel and am having trouble indexing into a GPU vector. Q is a matrix stored in CSR format qrows - row pointers qcols - nonzero column indices qvals - nonzero values Here is a code snippet: …

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## [Approximate inverse of a definite integral](https://discourse.julialang.org/t/approximate-inverse-of-a-definite-integral/83181)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 8\
**Last updated:** [March 31, 2023, 3:09pm UTC](https://discourse.julialang.org/t/approximate-inverse-of-a-definite-integral/83181 "2023-03-31T15:09:41Z")

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For a given (fixed) function f: \[0,1\] \\to \[0, \\infty), let g(x) = \\int\_0^x f(x) dx and h(x) = \\frac{g(x)}{g(1)} h is then, by construction, \[0,1\] \\to \[0,1\]. I need a fast approximation of its inverse: I am OK with …

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## [Nested Sum in NLObjective -](https://discourse.julialang.org/t/nested-sum-in-nlobjective/96890)

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**Author:** [@Gregoryo](https://discourse.julialang.org/u/Gregoryo)\
**Replies:** 2\
**Last updated:** [March 31, 2023, 3:06pm UTC](https://discourse.julialang.org/t/nested-sum-in-nlobjective/96890 "2023-03-31T15:06:00Z")

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Hi, I am totally new to both Julia and Optimization and I am trying to define a non linear objective that requires nested sums. I found some examples that I am trying to replicate, but I get an error. This is how I set m…

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## [MTK -- removing parameters from model?](https://discourse.julialang.org/t/mtk-removing-parameters-from-model/96887)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 2\
**Last updated:** [March 31, 2023, 2:56pm UTC](https://discourse.julialang.org/t/mtk-removing-parameters-from-model/96887 "2023-03-31T14:56:44Z")

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My MTK implementation of a DAE for doing Monte Carlo study of parameter uncertainty doesn’t work. I think it has to do with how MTK removes parameters that do not show up explicitly in the model equations. Here is some …

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## [Apple M1 GPU from Julia?](https://discourse.julialang.org/t/apple-m1-gpu-from-julia/69563)

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**Author:** [@Per](https://discourse.julialang.org/u/Per)\
**Replies:** 20\
**Last updated:** [March 31, 2023, 8:49am UTC](https://discourse.julialang.org/t/apple-m1-gpu-from-julia/69563 "2023-03-31T08:49:13Z")

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Does anyone know if it is possible to access the GPU of the Apple M1 chip from Julia? I really just need Float32 matrix-matrix multiplication (SGEMM). Anything else would be a bonus.

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## [More Extreme Moves in a Downtrending Market?](https://discourse.julialang.org/t/more-extreme-moves-in-a-downtrending-market/96875)

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**Author:** [@dm13450](https://discourse.julialang.org/u/dm13450)\
**Replies:** 0\
**Last updated:** [March 31, 2023, 5:26am UTC](https://discourse.julialang.org/t/more-extreme-moves-in-a-downtrending-market/96875 "2023-03-31T05:26:28Z")

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I’ve written a blog post about that explores whether there are more extreme moves in a down trending market: More Extreme Moves in a Downtrending Market? | Dean Markwick

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## [Using JuMP for variational data assimilation -- scalability and memory usage](https://discourse.julialang.org/t/using-jump-for-variational-data-assimilation-scalability-and-memory-usage/96686)

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**Author:** [@zornsllama](https://discourse.julialang.org/u/zornsllama)\
**Replies:** 9\
**Last updated:** [March 31, 2023, 1:49am UTC](https://discourse.julialang.org/t/using-jump-for-variational-data-assimilation-scalability-and-memory-usage/96686 "2023-03-31T01:49:57Z")

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Hi! I have been using JuMP over the last few months to perform variational data assimilation. Specifically, I am trying to estimate ODE parameters by direct transcription of the equations into a nonlinear program, utiliz…

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