# Supported ARPACK-NG or unsupported old ARPACK? What is better?

**URL:** <https://calculix.discourse.group/t/supported-arpack-ng-or-unsupported-old-arpack-what-is-better/4201>\
**Category:** Code development\
**Created:** [October 21, 2026, 6:43pm UTC](https://calculix.discourse.group/t/supported-arpack-ng-or-unsupported-old-arpack-what-is-better/4201 "2026-10-21T18:43:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Stefano4000](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@Stefano4000](https://calculix.discourse.group/u/Stefano4000)\
**Post date:** [October 21, 2026, 6:43pm UTC](https://calculix.discourse.group/t/supported-arpack-ng-or-unsupported-old-arpack-what-is-better/4201/1 "2026-10-21T18:43:56Z")

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Perhaps an improvement in comparison to old unsupported ARPACK.  
Coupling to this supported lib is possible with own compile.

> **[GitHub - opencollab/arpack-ng: Collection of Fortran77 subroutines designed to...](https://github.com/opencollab/arpack-ng)**
>
> Collection of Fortran77 subroutines designed to solve large scale eigenvalue problems.