# \#inverse

**URL:** https://discourse.julialang.org/tag/inverse/713.md

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## [Inverse problem with NeuralPDE and GPU support](https://discourse.julialang.org/t/inverse-problem-with-neuralpde-and-gpu-support/109051)

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**Author:** [@Rene\_Schenkendorf](https://discourse.julialang.org/u/Rene_Schenkendorf)\
**Replies:** 5\
**Last updated:** [January 23, 2024, 8:29am UTC](https://discourse.julialang.org/t/inverse-problem-with-neuralpde-and-gpu-support/109051 "2024-01-23T08:29:00Z")

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Hello everyone. I am new to Julia (at least that’s how it feels from time to time). Using the GPU according to tutorial https://docs.sciml.ai/NeuralPDE/stable/tutorials/gpu/ works; the inverse problem (first-principles m…

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## [ERROR: LinearAlgebra.SingularException(5)](https://discourse.julialang.org/t/error-linearalgebra-singularexception-5/106491)

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**Author:** [@Shayan](https://discourse.julialang.org/u/Shayan)\
**Replies:** 5\
**Last updated:** [November 20, 2023, 10:09pm UTC](https://discourse.julialang.org/t/error-linearalgebra-singularexception-5/106491 "2023-11-20T22:09:48Z")

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How should I deal with this error: ERROR: LinearAlgebra.SingularException(5) I have the following matrix: Xₜ⁽ˡ⁾ = \[ 0.997838 1.01925 1.01489 1.00797 0.997964 0.992047 1.02963 0.987861 0.990278 0.991172 \] And…

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## [Large matrix operations involving inversion](https://discourse.julialang.org/t/large-matrix-operations-involving-inversion/80993)

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**Author:** [@Rajesh\_Nakka](https://discourse.julialang.org/u/Rajesh_Nakka)\
**Replies:** 5\
**Last updated:** [May 13, 2022, 5:57am UTC](https://discourse.julialang.org/t/large-matrix-operations-involving-inversion/80993 "2022-05-13T05:57:35Z")

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In a particular problem, I have the following set of three evaluations involving matrices A, B, C of the SparseMatrixCSC type as B' \* A^{-} \* B B' \* A^{-} \* C C' \* A^{-} \* C Here, shape(A) = (n, n) shape(B) = (n, p…

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## [AutoDiff of function inverse?](https://discourse.julialang.org/t/autodiff-of-function-inverse/75868)

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**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 5\
**Last updated:** [February 5, 2022, 6:55pm UTC](https://discourse.julialang.org/t/autodiff-of-function-inverse/75868 "2022-02-05T18:55:24Z")

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I am using a time-dependent invertible map to define a moving geometry: ξ=f(x,t) where ξ,x have the same dimension. For example, this might be a time-varying shift and rotation ξ=R(θ(t))\*(x-x₀(t)), or it might be somethi…

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## [Matrix multiplied by inverse matrix does not reproduce identity matrix](https://discourse.julialang.org/t/matrix-multiplied-by-inverse-matrix-does-not-reproduce-identity-matrix/65706)

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**Author:** [@mengxiaoliu](https://discourse.julialang.org/u/mengxiaoliu)\
**Replies:** 4\
**Last updated:** [August 3, 2021, 9:12am UTC](https://discourse.julialang.org/t/matrix-multiplied-by-inverse-matrix-does-not-reproduce-identity-matrix/65706 "2021-08-03T09:12:47Z")

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Hello, I found that multiplying a matrix by its inverse does not yield an identity matrix. Please see below a MWE: matrix = \[5.93419 4.8067; 4.8067 5.93419\] invmatrix = inv(matrix) matrix\*invmatrix The last line gener…

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## [Inverse of a boolean (or integer) matrix vs factorization](https://discourse.julialang.org/t/inverse-of-a-boolean-or-integer-matrix-vs-factorization/62554)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 7\
**Last updated:** [June 8, 2021, 7:28am UTC](https://discourse.julialang.org/t/inverse-of-a-boolean-or-integer-matrix-vs-factorization/62554 "2021-06-08T07:28:46Z")

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My understanding is that factorization is almost always better than explicit inversion for a matrix of real (or complex) numbers (because usually you do not actually need the explicit inverse, rather some other operation…