Is pgvector's `halfvec` dtype supported?

[rsomani95]

I have a table with fp16 embeddings:

\d+ table;


              Column              |           Type           |
----------------------------------+--------------------------+
embedding                         | halfvec(640)             |
...

But when I try to build the index on using CREATE INDEX ON table USING diskann (embedding);, I run into the following error:

ERROR:  data type halfvec has no default operator class for access method "diskann"
HINT:  You must specify an operator class for the index or define a default operator class for the data type.

Are fp16 vectors not yet supported?

[cevian]

Fp16 is not yet supported. We will consider this feature request during our planning, or you are welcome to submit a PR

[npip99]

@cevian Small request that would be nice (If possible), would be to support 4k dimensions if/when FP16 is supported.

OpenAI's text-embedding-3-large would then be able to fit.

[cho-thinkfree-com]

Halfvec is likely to work very well when a database has to store and process a lot of vector data without losing too much precision.