# Extremly slow matrix multiplication with Hermitian(sparse())

**URL:** <https://discourse.julialang.org/t/extremly-slow-matrix-multiplication-with-hermitian-sparse/133774>\
**Category:** General Usage\
**Created:** [November 10, 2025, 11:38am UTC](https://discourse.julialang.org/t/extremly-slow-matrix-multiplication-with-hermitian-sparse/133774 "2025-11-10T11:38:31Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![Boris](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/boris/32/3306_2.png) [@Boris](https://discourse.julialang.org/u/Boris)\
**Post date:** [November 10, 2025, 12:34pm UTC](https://discourse.julialang.org/t/extremly-slow-matrix-multiplication-with-hermitian-sparse/133774/3 "2025-11-10T12:34:31Z")

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I would like to chime in my experience. For my applications it turned out that Julia’s non-sparse algorithms are very good (especially tricks with `@view`, `mul!()`, `div!()`, etc.) that I couldn’t beat it with any sparse implementations.

Remember, that apart from doing the sparse calculations your code probably has also other things going on (potentially a lot of them) that require also converting to and from for those calculations, which also takes time.

[Here is a lengthy topic of mine](https://discourse.julialang.org/t/sparse-arrays-allocation-versus-speed/128726) which, deja vu, I was again navigated through by the generous help and time of @gdalle.

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