# Iteratively compute eigenvalues of non-Hermitian sparse matrix

**URL:** <https://discourse.julialang.org/t/iteratively-compute-eigenvalues-of-non-hermitian-sparse-matrix/79236>\
**Category:** Numerics\
**Created:** [April 8, 2022, 6:58pm UTC](https://discourse.julialang.org/t/iteratively-compute-eigenvalues-of-non-hermitian-sparse-matrix/79236 "2022-04-08T18:58:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jamblejoe](https://avatars.discourse-cdn.com/v4/letter/j/ee7513/32.png) [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Post date:** [April 8, 2022, 6:58pm UTC](https://discourse.julialang.org/t/iteratively-compute-eigenvalues-of-non-hermitian-sparse-matrix/79236/1 "2022-04-08T18:58:11Z")

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Let `A` be a real, non-symmetric, sparse matrix with eigenvalues having real part smaller than or equal to 0. We can assume that if the real part of an eigenvalue `λ` is 0 then `λ=0`. The multiplicity of the 0 eigenvalue is greater than or equal to 1.

I want to iteratively calculate the eigenvalues with largest real part (beginning from 0) and stop, whenever an eigenvalue with real part \< 0 was found. I want to record that eigenvalue. I do not care about the eigenvectors.

With what Julia package can I do that? I am especially interested in aborting the calculation of largest real part eigenvalues, when an eigenvalue with real part \< 0 was found.