# \#solver

**URL:** https://discourse.julialang.org/tag/solver/1561.md

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## [Large Sparse Hermitian Matrix - Intermediate Eigenvalue Problem](https://discourse.julialang.org/t/large-sparse-hermitian-matrix-intermediate-eigenvalue-problem/131600)

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**Author:** [@Neilis](https://discourse.julialang.org/u/Neilis)\
**Replies:** 9\
**Last updated:** [September 23, 2025, 2:22pm UTC](https://discourse.julialang.org/t/large-sparse-hermitian-matrix-intermediate-eigenvalue-problem/131600 "2025-09-23T14:22:14Z")

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Hi, I am trying to find eigenvalues and eigenvectors for a rather large, sparse, hermitian matrix (size ~1E7 x 1E7). I am mainly interested in around 40 eigenvalues in the middle of the spectrum. To solve this original…

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## [\[ANN\] JuLS - Julia Local Search solver from Amazon Science](https://discourse.julialang.org/t/ann-juls-julia-local-search-solver-from-amazon-science/132254)

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**Author:** [@navaxel](https://discourse.julialang.org/u/navaxel)\
**Replies:** 2\
**Last updated:** [September 10, 2025, 4:03pm UTC](https://discourse.julialang.org/t/ann-juls-julia-local-search-solver-from-amazon-science/132254 "2025-09-10T16:03:06Z")

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Behind Amazon’s logistics operations lie some of the most complex combinatorial optimization challenges in industry. Curious how we solve it? We built a generic solver from scratch, and today, it’s open-source. :rocket: …

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## [JuMP solve\_time not matching actual time](https://discourse.julialang.org/t/jump-solve-time-not-matching-actual-time/126397)

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**Author:** [@BMI\_OR](https://discourse.julialang.org/u/BMI_OR)\
**Replies:** 3\
**Last updated:** [February 27, 2025, 9:33pm UTC](https://discourse.julialang.org/t/jump-solve-time-not-matching-actual-time/126397 "2025-02-27T21:33:40Z")

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I am executing an algorithm that iteratively executes the following function to solve a problem: function solve\_subproblem(model, z, q, v) fix.(model\[:z\_copy\], z) fix.(model\[:q\_copy\], q) fix.(model\[:v\_copy\],…

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## [MATLAB is faster for my large system of ODEs?](https://discourse.julialang.org/t/matlab-is-faster-for-my-large-system-of-odes/122610)

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**Author:** [@martru](https://discourse.julialang.org/u/martru)\
**Replies:** 21\
**Last updated:** [November 15, 2024, 6:12pm UTC](https://discourse.julialang.org/t/matlab-is-faster-for-my-large-system-of-odes/122610 "2024-11-15T18:12:50Z")

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Excuse the deliberately provocative title :slight\_smile: I have a very large system of ODEs of the form: dot{x} = Ax + Bu A is a sparse matrix 5505x5505. B\*u is a 5505 element vector. Using ode45 in matlab, it solves …

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## [Sparse non-square linear problem](https://discourse.julialang.org/t/sparse-non-square-linear-problem/122650)

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**Author:** [@Nichola](https://discourse.julialang.org/u/Nichola)\
**Replies:** 3\
**Last updated:** [November 15, 2024, 1:00am UTC](https://discourse.julialang.org/t/sparse-non-square-linear-problem/122650 "2024-11-15T01:00:17Z")

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I would like to solve Ax = b where A is a sparse non-square array. For example : using SparseArrays using LinearSolve n = 3 m = 4 A = sparse(rand(ComplexF64, m, n)) b = rand(ComplexF64, m) prob = LinearProblem(A, b) …

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## [Best practices for NonlinearSolve definition with temporary arrays](https://discourse.julialang.org/t/best-practices-for-nonlinearsolve-definition-with-temporary-arrays/115763)

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**Author:** [@dieg0](https://discourse.julialang.org/u/dieg0)\
**Replies:** 6\
**Last updated:** [October 7, 2024, 1:01pm UTC](https://discourse.julialang.org/t/best-practices-for-nonlinearsolve-definition-with-temporary-arrays/115763 "2024-10-07T13:01:48Z")

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Hi all, I am relatively new to Julia. Apologies as it’s a long one but I couldn’t find a solution. I am using NonlinearSolve.jl to solve a somewhat “complicated” system of equations g(u, p) = 0. The reason the function …

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## [How to test a Solver functionality availability](https://discourse.julialang.org/t/how-to-test-a-solver-functionality-availability/117266)

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**Author:** [@K5Julien](https://discourse.julialang.org/u/K5Julien)\
**Replies:** 2\
**Last updated:** [July 24, 2024, 9:41pm UTC](https://discourse.julialang.org/t/how-to-test-a-solver-functionality-availability/117266 "2024-07-24T21:41:46Z")

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In JuMP, depending on the solver, there are some functionalities that are available, and some which are not, see for instance here. How should I test that before creating a Model(optimizer) ? As an example: if optimiz…

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## [IDA solver error (possibly) for a DAE problem with complex number](https://discourse.julialang.org/t/ida-solver-error-possibly-for-a-dae-problem-with-complex-number/115045)

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**Author:** [@Hamed](https://discourse.julialang.org/u/Hamed)\
**Replies:** 11\
**Last updated:** [June 2, 2024, 9:21am UTC](https://discourse.julialang.org/t/ida-solver-error-possibly-for-a-dae-problem-with-complex-number/115045 "2024-06-02T09:21:41Z")

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Hi there. I have a problem with this code here. I’m trying to simulate a three-phase short circuit fault in a power system according to the instructions in Example 2 here: https://github.com/NREL-Sienna/PowerSimulations…

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## [Best performance for initialising a variable number of matrices/vectors within a Crank-Nicolson scheme](https://discourse.julialang.org/t/best-performance-for-initialising-a-variable-number-of-matrices-vectors-within-a-crank-nicolson-scheme/113083)

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**Author:** [@lhcgeneva](https://discourse.julialang.org/u/lhcgeneva)\
**Replies:** 4\
**Last updated:** [April 19, 2024, 6:56am UTC](https://discourse.julialang.org/t/best-performance-for-initialising-a-variable-number-of-matrices-vectors-within-a-crank-nicolson-scheme/113083 "2024-04-19T06:56:05Z")

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I’m solving a diffusion problem of several connected domains. I use a Crank-Nicolson scheme on each domain, and at every time step I connect the domains by some matching conditions at the boundary. To do the Crank-Nicols…

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## [Is there any overview of current solvers compatible with \`JuMP\`?](https://discourse.julialang.org/t/is-there-any-overview-of-current-solvers-compatible-with-jump/111720)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 4\
**Last updated:** [March 18, 2024, 3:47am UTC](https://discourse.julialang.org/t/is-there-any-overview-of-current-solvers-compatible-with-jump/111720 "2024-03-18T03:47:56Z")

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The JuMP documentation enumerates several optional optimization solvers. I am curious if this represents the complete collection of optional solvers currently compatible with JuMP, and whether there exists a consolidated…