# \#scientific-computing

**URL:** https://discourse.julialang.org/tag/scientific-computing/210.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

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## [SciML: Issues using \`GaussAdjoint\` on an \`EnsembleProblem\` with callbacks](https://discourse.julialang.org/t/sciml-issues-using-gaussadjoint-on-an-ensembleproblem-with-callbacks/137503)

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**Author:** [@LucasGrasso](https://discourse.julialang.org/u/LucasGrasso)\
**Replies:** 11\
**Last updated:** [June 21, 2026, 8:30pm UTC](https://discourse.julialang.org/t/sciml-issues-using-gaussadjoint-on-an-ensembleproblem-with-callbacks/137503 "2026-06-21T20:30:04Z")

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Hello there, I am rather new to Julia, and I am trying to implement a Neural ODE model that relies on event callbacks to terminate integration. I am using the GaussAdjoint, given that it supports callbacks and that it w…

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## [Creating and Solving Block Sparse Matrices with PETSc](https://discourse.julialang.org/t/creating-and-solving-block-sparse-matrices-with-petsc/90831)

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**Author:** [@Azurezaber](https://discourse.julialang.org/u/Azurezaber)\
**Replies:** 15\
**Last updated:** [April 27, 2026, 1:12pm UTC](https://discourse.julialang.org/t/creating-and-solving-block-sparse-matrices-with-petsc/90831 "2026-04-27T13:12:55Z")

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Hello! I am using Julia to write a finite volume CFD code, which requires solving large (40,000x40,000) block sparse matrices. Currently, I am using the PETSc interface provided by PETSc.jl, as its GMRES routine is notab…

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## [\[ANN\] LowLevelFEM.jl – assembling PDE systems directly from weak forms](https://discourse.julialang.org/t/ann-lowlevelfem-jl-assembling-pde-systems-directly-from-weak-forms/136136)

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**Author:** [@perebalazs](https://discourse.julialang.org/u/perebalazs)\
**Replies:** 13\
**Last updated:** [March 13, 2026, 8:43pm UTC](https://discourse.julialang.org/t/ann-lowlevelfem-jl-assembling-pde-systems-directly-from-weak-forms/136136 "2026-03-13T20:43:23Z")

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I’ve been working on a small Julia FEM framework called LowLevelFEM.jl. One of the ideas behind the project is to assemble PDE systems directly from their weak form. The core idea is simple: If you know the weak form o…

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## [Minisymposium on Partial Differential Equations and its Applications (Juliacon 2026)](https://discourse.julialang.org/t/minisymposium-on-partial-differential-equations-and-its-applications-juliacon-2026/135600)

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**Author:** [@Arpit\_Babbar](https://discourse.julialang.org/u/Arpit_Babbar)\
**Replies:** 0\
**Last updated:** [February 12, 2026, 4:40pm UTC](https://discourse.julialang.org/t/minisymposium-on-partial-differential-equations-and-its-applications-juliacon-2026/135600 "2026-02-12T16:40:45Z")

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We are eager to receive talk contributions for our minisymposium on partial differential equations (PDE) at Juliacon 2026. The minisymposium will cover everything that relates to Julia and PDEs, including but not limited…

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## [QILaplace.jl: tensor-network Fourier/Laplace transforms (looking for packaging & docs feedback)](https://discourse.julialang.org/t/qilaplace-jl-tensor-network-fourier-laplace-transforms-looking-for-packaging-docs-feedback/135335)

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**Author:** [@Gautameshwar](https://discourse.julialang.org/u/Gautameshwar)\
**Replies:** 1\
**Last updated:** [February 4, 2026, 8:34pm UTC](https://discourse.julialang.org/t/qilaplace-jl-tensor-network-fourier-laplace-transforms-looking-for-packaging-docs-feedback/135335 "2026-02-04T20:34:57Z")

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Hi Julia Community, I am a third-year PhD student with around two years of experience coding in Julia. This is my first time creating and releasing a Julia package, and I’d really love to get feedback from more experien…

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## [Stokes solver as an ODEproblem takes time to initiate](https://discourse.julialang.org/t/stokes-solver-as-an-odeproblem-takes-time-to-initiate/135317)

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**Author:** [@Iddingsite](https://discourse.julialang.org/u/Iddingsite)\
**Replies:** 6\
**Last updated:** [January 29, 2026, 10:15am UTC](https://discourse.julialang.org/t/stokes-solver-as-an-odeproblem-takes-time-to-initiate/135317 "2026-01-29T10:15:42Z")

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Hi everyone. I wrote a small code to solve 2D linear visco-elastic Stokes using finite difference and OrdinaryDiffEq to test how that would work out. So, in this case, I only have algebraic equations and have some param…

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## [Feedback wanted: GPU-accelerated 2D elastic wave simulation (staggered-grid FD) in Julia](https://discourse.julialang.org/t/feedback-wanted-gpu-accelerated-2d-elastic-wave-simulation-staggered-grid-fd-in-julia/134869)

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**Author:** [@Wuheng10086](https://discourse.julialang.org/u/Wuheng10086)\
**Replies:** 10\
**Last updated:** [January 10, 2026, 3:16pm UTC](https://discourse.julialang.org/t/feedback-wanted-gpu-accelerated-2d-elastic-wave-simulation-staggered-grid-fd-in-julia/134869 "2026-01-10T15:16:09Z")

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Hi everyone, I’m currently working on a GPU-accelerated 2D elastic wave simulation code in Julia, based on staggered-grid finite-difference discretization. The original motivation is seismic forward modeling, but I’m …

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## [Very slow training of Neural ODE with exogeneous input compared to jax using dense interpolated solution](https://discourse.julialang.org/t/very-slow-training-of-neural-ode-with-exogeneous-input-compared-to-jax-using-dense-interpolated-solution/134557)

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**Author:** [@johtok](https://discourse.julialang.org/u/johtok)\
**Replies:** 4\
**Last updated:** [December 15, 2025, 11:09pm UTC](https://discourse.julialang.org/t/very-slow-training-of-neural-ode-with-exogeneous-input-compared-to-jax-using-dense-interpolated-solution/134557 "2025-12-15T23:09:39Z")

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Hi guys! Ive been breaking my neck trying to get a julia alternative to this jax neural ode with exogeneous input script working but without luck! The julia version is painfully slow whereas the jax version runs in a c…

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## [Speeding up Ewald summation](https://discourse.julialang.org/t/speeding-up-ewald-summation/80830)

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**Author:** [@dkonstan](https://discourse.julialang.org/u/dkonstan)\
**Replies:** 15\
**Last updated:** [November 3, 2025, 5:41pm UTC](https://discourse.julialang.org/t/speeding-up-ewald-summation/80830 "2025-11-03T17:41:41Z")

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Hi Julia! I am writing a small molecular dynamics engine in Julia to teach myself the language and I noticed that 67% of the time spent running the following Ewald summation function (to calculate coulomb energy of an i…

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## [Problems performing 1D-FDTD for dispersive dielectric uisng lorentz model in Julia](https://discourse.julialang.org/t/problems-performing-1d-fdtd-for-dispersive-dielectric-uisng-lorentz-model-in-julia/110617)

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**Author:** [@geoselenicmonkey](https://discourse.julialang.org/u/geoselenicmonkey)\
**Replies:** 0\
**Last updated:** [February 23, 2024, 1:34am UTC](https://discourse.julialang.org/t/problems-performing-1d-fdtd-for-dispersive-dielectric-uisng-lorentz-model-in-julia/110617 "2024-02-23T01:34:15Z")

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So I am trying to model a dispersive dielectric using the Lorentz model in Julia, more specifically I am trying to obtain the frequency-dependent reflectivity of the material. I am ultimately trying to replicate the resu…

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## [PRIMA: a package for solving general nonlinear optimization problems without using derivatives](https://discourse.julialang.org/t/prima-a-package-for-solving-general-nonlinear-optimization-problems-without-using-derivatives/105134)

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**Author:** [@Zaikun](https://discourse.julialang.org/u/Zaikun)\
**Replies:** 4\
**Last updated:** [October 19, 2023, 2:05am UTC](https://discourse.julialang.org/t/prima-a-package-for-solving-general-nonlinear-optimization-problems-without-using-derivatives/105134 "2023-10-19T02:05:19Z")

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Hi everyone, I am very glad to announce PRIMA, a package for solving general nonlinear optimization problems without using derivatives. PRIMA provides the reference implementation for M.J.D. Powell’s renowned derivativ…

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## [A categorical speaking indictment - making scientific computing more relevant to the general public](https://discourse.julialang.org/t/a-categorical-speaking-indictment-making-scientific-computing-more-relevant-to-the-general-public/102702)

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**Author:** [@g2g](https://discourse.julialang.org/u/g2g)\
**Replies:** 1\
**Last updated:** [August 15, 2023, 6:05pm UTC](https://discourse.julialang.org/t/a-categorical-speaking-indictment-making-scientific-computing-more-relevant-to-the-general-public/102702 "2023-08-15T18:05:40Z")

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Perhaps a way to increase Julia’s relevance to the general public is by increasing scientific computing’s relevance to the general public. For example, the following diagram generated by Julia and GLMakie is a summary of…

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## [Symmetry & SOS Optimization Compatibility Issues?](https://discourse.julialang.org/t/symmetry-sos-optimization-compatibility-issues/98057)

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**Author:** [@ilovemath](https://discourse.julialang.org/u/ilovemath)\
**Replies:** 6\
**Last updated:** [June 5, 2023, 8:29pm UTC](https://discourse.julialang.org/t/symmetry-sos-optimization-compatibility-issues/98057 "2023-06-05T20:29:12Z")

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Hello all, I am trying to implement rotational symmetry for an SOS problem. In particular, I followed the example problem here: Dihedral symmetry of the Robinson form · SumOfSquares. My goal is to use a cyclic group i…

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## [Scientist in Computational Hydrodynamics](https://discourse.julialang.org/t/scientist-in-computational-hydrodynamics/97404)

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**Author:** [@smillerc](https://discourse.julialang.org/u/smillerc)\
**Replies:** 0\
**Last updated:** [April 12, 2023, 7:19pm UTC](https://discourse.julialang.org/t/scientist-in-computational-hydrodynamics/97404 "2023-04-12T19:19:09Z")

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POSITION SUMMARY: The Integrated Modeling Group at the University of Rochester Laboratory for Laser Energetics Theoretical Division seeks a Computational Physicist (Assistant Scientist to Scientist position) to support …

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## [Postdoc position in Scientific Computing/HPC at University of Cologne](https://discourse.julialang.org/t/postdoc-position-in-scientific-computing-hpc-at-university-of-cologne/93128)

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**Author:** [@sloede](https://discourse.julialang.org/u/sloede)\
**Replies:** 0\
**Last updated:** [January 18, 2023, 4:40am UTC](https://discourse.julialang.org/t/postdoc-position-in-scientific-computing-hpc-at-university-of-cologne/93128 "2023-01-18T04:40:10Z")

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The Center for Data and Simulation Science (CDS) is looking for a Postdoc (f/m/d) in the area of Scientific Computing/HPC in the group of Prof. Dr.-Ing. Gregor Gassner (Numerical Simulation | Division of Mathematics, Uni…

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## [Associate Research Physicist (post-doc) in stellarator modeling/HPC developer at PPPL](https://discourse.julialang.org/t/associate-research-physicist-post-doc-in-stellarator-modeling-hpc-developer-at-pppl/93035)

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**Author:** [@benjaminfaber](https://discourse.julialang.org/u/benjaminfaber)\
**Replies:** 0\
**Last updated:** [January 16, 2023, 5:53pm UTC](https://discourse.julialang.org/t/associate-research-physicist-post-doc-in-stellarator-modeling-hpc-developer-at-pppl/93035 "2023-01-16T17:53:14Z")

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The Princeton Plasma Physics Laboratory (PPPL) is hiring a post-doc to join the M3D-C1 team and lead the development of new stellarator modeling capabilities in M3D-C1. The initial focus will be on implementing a model f…

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## [Calling chemical kinetics solvers like CHEMKIN or Cantera from Julia](https://discourse.julialang.org/t/calling-chemical-kinetics-solvers-like-chemkin-or-cantera-from-julia/50568)

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**Author:** [@R\_Surya\_Narayan](https://discourse.julialang.org/u/R_Surya_Narayan)\
**Replies:** 2\
**Last updated:** [January 9, 2023, 9:46pm UTC](https://discourse.julialang.org/t/calling-chemical-kinetics-solvers-like-chemkin-or-cantera-from-julia/50568 "2023-01-09T21:46:12Z")

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Hello Everyone. I am relatively new to Julia and I am using it to solve a chemically-reacting flow problem that requires extensive reaction-rate and species thermodynamic-data. I came across one such open-source software…

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## [\[Ann\] IntervalRootFinding.jl for finding all roots of a multivariate function](https://discourse.julialang.org/t/ann-intervalrootfinding-jl-for-finding-all-roots-of-a-multivariate-function/9515)

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**Author:** [@dpsanders](https://discourse.julialang.org/u/dpsanders)\
**Replies:** 52\
**Last updated:** [September 26, 2022, 5:12am UTC](https://discourse.julialang.org/t/ann-intervalrootfinding-jl-for-finding-all-roots-of-a-multivariate-function/9515 "2022-09-26T05:12:37Z")

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We are excited to announce v0.2 of the IntervalRootFinding.jl package, which has been completely rewritten from scratch. This package exports a function roots that is guaranteed to find all roots of a given function \\ma…

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## [How to use MPI.jl to scatter a matrix to a 2D processor grid?](https://discourse.julialang.org/t/how-to-use-mpi-jl-to-scatter-a-matrix-to-a-2d-processor-grid/80013)

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**Author:** [@Neo](https://discourse.julialang.org/u/Neo)\
**Replies:** 1\
**Last updated:** [April 25, 2022, 11:24pm UTC](https://discourse.julialang.org/t/how-to-use-mpi-jl-to-scatter-a-matrix-to-a-2d-processor-grid/80013 "2022-04-25T23:24:58Z")

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For example, I have a 5 by 5 matrix A = \[1, 2, 3, 4, 5; 1, 2, 3, 4, 5; 1, 2, 3, 4, 5; 1, 2, 3, 4, 5; 1, 2 ,3 ,4, 5\] and I want to scatter A to four processors like \[2,3; 4, 5\]. More precisely, I want to broadcast \[1,2…

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## [\[ANN\] ViscousFlow.jl v0.5.1](https://discourse.julialang.org/t/ann-viscousflow-jl-v0-5-1/77250)

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**Author:** [@jdeldre](https://discourse.julialang.org/u/jdeldre)\
**Replies:** 0\
**Last updated:** [March 1, 2022, 5:41pm UTC](https://discourse.julialang.org/t/ann-viscousflow-jl-v0-5-1/77250 "2022-03-01T17:41:07Z")

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Announcing the release of version 0.5.1 of ViscousFlow.jl, a set of tools for computing and analyzing 2-d (for now) viscous incompressible flows with arbitrary body shapes. The package relies on the method of immersed la…

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## [Postdoc (24 month, extension possible) in Scientific Computing with Trixi.jl](https://discourse.julialang.org/t/postdoc-24-month-extension-possible-in-scientific-computing-with-trixi-jl/75284)

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**Author:** [@sloede](https://discourse.julialang.org/u/sloede)\
**Replies:** 0\
**Last updated:** [January 27, 2022, 12:03pm UTC](https://discourse.julialang.org/t/postdoc-24-month-extension-possible-in-scientific-computing-with-trixi-jl/75284 "2022-01-27T12:03:36Z")

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We have an open postdoc position (100% TVL-13 pay grade) in Scientific Computing at the University of Cologne, Germany. The general goal is to work on/develop/extend our open source Julia code Trixi.jl. For details, ple…

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## [Chebfun equivalent for differentiation matrices in Julia?](https://discourse.julialang.org/t/chebfun-equivalent-for-differentiation-matrices-in-julia/74042)

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**Author:** [@yewalenikhil65](https://discourse.julialang.org/u/yewalenikhil65)\
**Replies:** 4\
**Last updated:** [January 4, 2022, 6:04pm UTC](https://discourse.julialang.org/t/chebfun-equivalent-for-differentiation-matrices-in-julia/74042 "2022-01-04T18:04:12Z")

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Is there yet a differentiation matrices calculating tool in some Julia package ? Something similar to https://github.com/chebfun/chebfun/blob/master/diffmat.m I have tried searching in JuliaApproximation community but c…

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## [SC21: "Comparing Julia to Performance Portable Parallel Programming Models for HPC"](https://discourse.julialang.org/t/sc21-comparing-julia-to-performance-portable-parallel-programming-models-for-hpc/71686)

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**Author:** [@ImreSamu](https://discourse.julialang.org/u/ImreSamu)\
**Replies:** 2\
**Last updated:** [November 17, 2021, 10:01pm UTC](https://discourse.julialang.org/t/sc21-comparing-julia-to-performance-portable-parallel-programming-models-for-hpc/71686 "2021-11-17T22:01:36Z")

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SCI21 paper: Comparing Julia to Performance Portable Parallel Programming Models for HPC \[pdf\] Index Terms—Julia, OpenMP, OpenCL, Kokkos, CUDA, HIP, Performance Portability, Programming Models, GPUs context: Present…

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## [Terminate condition in ContinuousCallback in DifferentialEquations.jl](https://discourse.julialang.org/t/terminate-condition-in-continuouscallback-in-differentialequations-jl/69748)

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**Author:** [@yewalenikhil65](https://discourse.julialang.org/u/yewalenikhil65)\
**Replies:** 13\
**Last updated:** [November 12, 2021, 11:45am UTC](https://discourse.julialang.org/t/terminate-condition-in-continuouscallback-in-differentialequations-jl/69748 "2021-11-12T11:45:09Z")

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using DifferentialEquations u0 = \[1.,0.\] harmonic! = @ode\_def HarmonicOscillator begin dv = -x dx = v end tspan = (0.0,10.0) prob = ODEProblem(harmonic!,u0,tspan) function terminate\_affect!…

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## [NeuralPDE.NNODE ODE system solve](https://discourse.julialang.org/t/neuralpde-nnode-ode-system-solve/70538)

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**Author:** [@Dr\_M\_Umut\_DEMiREZEN](https://discourse.julialang.org/u/Dr_M_Umut_DEMiREZEN)\
**Replies:** 2\
**Last updated:** [October 31, 2021, 12:15pm UTC](https://discourse.julialang.org/t/neuralpde-nnode-ode-system-solve/70538 "2021-10-31T12:15:41Z")

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Hi, I wanted to use NeuralPDE.NNODE function to solve a coupled ODE system (4 ODE equations) The code is given below : (not given completely) @parameters t @variables k(t) r(t) p(t) c(t) D = Differential(t) eqs = \[D…

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## [Performance issues with parallel Julia code](https://discourse.julialang.org/t/performance-issues-with-parallel-julia-code/68919)

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**Author:** [@kfrb](https://discourse.julialang.org/u/kfrb)\
**Replies:** 2\
**Last updated:** [October 29, 2021, 10:16pm UTC](https://discourse.julialang.org/t/performance-issues-with-parallel-julia-code/68919 "2021-10-29T22:16:11Z")

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I am working on a scientific code that is experiencing issues with parallelization. The parallel version is slower than the serial one and I am not sure if the right approaches are used for this application. How can I …

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## [Calculate deseasonalized anomalies](https://discourse.julialang.org/t/calculate-deseasonalized-anomalies/58753)

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**Author:** [@mixstam1453](https://discourse.julialang.org/u/mixstam1453)\
**Replies:** 4\
**Last updated:** [April 8, 2021, 6:47am UTC](https://discourse.julialang.org/t/calculate-deseasonalized-anomalies/58753 "2021-04-08T06:47:00Z")

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Hi to everyone! I am new in Julia and i have monthly values of a climate variable. I calculate the annual cycle but i can’t find the way to compute the anomalies. Here is the part of the code: using DataFrames ; using …

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## [How to do an operation like object.method() in Python](https://discourse.julialang.org/t/how-to-do-an-operation-like-object-method-in-python/57445)

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**Author:** [@zhangqian](https://discourse.julialang.org/u/zhangqian)\
**Replies:** 2\
**Last updated:** [March 19, 2021, 5:47am UTC](https://discourse.julialang.org/t/how-to-do-an-operation-like-object-method-in-python/57445 "2021-03-19T05:47:24Z")

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I am currently using Julia to do some fluid computation. Since I want to see the influence of some variables, like time steps, I need to store and prepare other persistent variables at first, and then pass the variable I…

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## [Julia either very fast or very slow, with little in between?](https://discourse.julialang.org/t/julia-either-very-fast-or-very-slow-with-little-in-between/56307)

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**Author:** [@WouterJRV](https://discourse.julialang.org/u/WouterJRV)\
**Replies:** 10\
**Last updated:** [March 3, 2021, 2:36am UTC](https://discourse.julialang.org/t/julia-either-very-fast-or-very-slow-with-little-in-between/56307 "2021-03-03T02:36:01Z")

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I have the impression that Julia commands are often execute very fast (as advertised), but when they are not, it takes ages (up to the point where I’d have to kill it–and system monitor shows that a processor is at 100% …

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## [Julia project ideas](https://discourse.julialang.org/t/julia-project-ideas/42815)

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**Author:** [@jguo](https://discourse.julialang.org/u/jguo)\
**Replies:** 2\
**Last updated:** [July 10, 2020, 6:20pm UTC](https://discourse.julialang.org/t/julia-project-ideas/42815 "2020-07-10T18:20:03Z")

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Dear Julia Community, I am new to Julia but I believe the best way to learn a new language is to use it to solve problems as much as possible. I use resources like ThinkJulia and lectures on Quantitative Economics with …

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