# Missing cusolver 64bit routines

**URL:** <https://forums.developer.nvidia.com/t/missing-cusolver-64bit-routines/360996>\
**Category:** GPU-Accelerated Libraries\
**Tags:** cusolver\
**Created:** [February 18, 2026, 10:07pm UTC](https://forums.developer.nvidia.com/t/missing-cusolver-64bit-routines/360996 "2026-02-18T22:07:53Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![JeremiahPalmer](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/jeremiahpalmer/32/468962_2.png) [@JeremiahPalmer](https://forums.developer.nvidia.com/u/JeremiahPalmer)\
**Post date:** [February 18, 2026, 10:07pm UTC](https://forums.developer.nvidia.com/t/missing-cusolver-64bit-routines/360996/1 "2026-02-18T22:07:53Z")

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In the cusolver documentation, I see “legacy” routines like cusolverDnDsytrd and cusolverDnDormtr. But, they aren’t mentioned in the 64bit routines documentation. Is there a way to access those 64bit versions directly? I don’t want to use cusolverDnXsyevd because there are some steps I need to do in my algorithm between the householder reduction and the backtransformation.

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**Author:** ![christophk](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@christophk](https://forums.developer.nvidia.com/u/christophk)\
**Post date:** [February 18, 2026, 11:53pm UTC](https://forums.developer.nvidia.com/t/missing-cusolver-64bit-routines/360996/2 "2026-02-18T23:53:24Z")

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Hi Jeremiah,

64-bit APIs of SYTRD and ORMTR are not yet available. The existing legacy APIs for SYTRD and ORMTR will be available at least until the corresponding 64-bit APIs have been added. Please let me know if you encounter any issues using the legacy APIs.

Thanks,

Christoph

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<div class="post-metadata">

**Author:** ![JeremiahPalmer](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/jeremiahpalmer/32/468962_2.png) [@JeremiahPalmer](https://forums.developer.nvidia.com/u/JeremiahPalmer)\
**Post date:** [February 19, 2026, 8:00pm UTC](https://forums.developer.nvidia.com/t/missing-cusolver-64bit-routines/360996/3 "2026-02-19T20:00:05Z")

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That’s good to hear. One benefit to the 64bit routines is that the user-supplied buffers (workspaces) are in a format that the rest of my code already uses.