[spacedome]

Yes, many of these are "in-place" but will still allocate. I typically use the geev!/ggev!/geevx! routines, if you look at the source code you will see that the work arrays are still allocated inside the call. The in-place here (unfortunately) means only that the input is overwritten, not that there is no allocation.

[DNF2]

The purpose of in-place operations is to avoid allocations, so this seems like an oversight.

Is this a matter of simply wrapping the 'right' LAPACK routines, or is there something missing in the interfaces that could be trivially added in principle?

[spacedome]

It is entirely possible, but is not trivial, especially for the user who then needs to know "arcane knowledge" of BLAS/LAPACK work array sizes and flags. There was some discussion about this on github, but it sort of trailed off without a real resolution. I think it is considered too complicated/niche to be in base, and was recommended to be an external library, but nobody (myself included) seems particularly interested in what amounts to maintaining a fork of the entire BLAS package. The base devs would have more insight, but this is my view from the outside at least.