# Syevd is absent in LinearAlgebra.LAPACK

**URL:** <https://discourse.julialang.org/t/syevd-is-absent-in-linearalgebra-lapack/51714>\
**Category:** General Usage\
**Tags:** linearalgebra, lapack\
**Created:** [December 12, 2020, 12:48pm UTC](https://discourse.julialang.org/t/syevd-is-absent-in-linearalgebra-lapack/51714 "2020-12-12T12:48:35Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Jae-Mo\_Lihm](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jae-mo_lihm/32/20145_2.png) [@Jae-Mo\_Lihm](https://discourse.julialang.org/u/Jae-Mo_Lihm)\
**Post date:** [December 12, 2020, 12:48pm UTC](https://discourse.julialang.org/t/syevd-is-absent-in-linearalgebra-lapack/51714/1 "2020-12-12T12:48:35Z")

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In the LinearAlgebra package, functions `LAPACK.syev!` and `LAPACK.syevr!` for solving the eigenvalue problem are present. But, `LAPACK.syevd!` is absent.

As I understand, the `?syevd` (and its Hermitian counterpart, `zheevd`) also solves the eigenvalue problem but uses different algorithms than `?syev` and `?syevr`.  
[http://www.netlib.org/lapack/explore-html/d2/d8a/group\_\_double\_s\_yeigen\_ga77dfa610458b6c9bd7db52533bfd53a1.html](http://www.netlib.org/lapack/explore-html/d2/d8a/group__double_s_yeigen_ga77dfa610458b6c9bd7db52533bfd53a1.html)

Their performances also differ: [http://www.netlib.org/lapack/lawnspdf/lawn183.pdf](http://www.netlib.org/lapack/lawnspdf/lawn183.pdf)

It is also different from `LAPACK.sygvd!` because `sygvd` solves generalized eigenvalue problem, while `syevd` solves eigenvalue problem.

Is there a simple way to use `syevd`? Or is this a limitation of the `LinearAlgebra` package?