kaivalnp opened a new pull request, #15293: URL: https://github.com/apache/lucene/pull/15293
### Description Intermediate cast from `int` -> `float` -> `int` in the byte vector specific [`cosineBody`](https://github.com/apache/lucene/blob/a4ebe984087cf62e3f8d96a53b2e7ebe96172500/lucene/core/src/java25/org/apache/lucene/internal/vectorization/PanamaVectorUtilSupport.java#L695) function(s) loses precision. This happens for integers >= 2^24, because IEEE 754 single-precision floats use 24 bits to represent the integer part. For example, when `16777217` is cast to `float` and back to `int`, it yields `16777216`. This also avoids CPU cycles related to casting. [`VectorUtilBenchmark`](https://github.com/apache/lucene/blob/a4ebe984087cf62e3f8d96a53b2e7ebe96172500/lucene/benchmark-jmh/src/java/org/apache/lucene/benchmark/jmh/VectorUtilBenchmark.java#L46) shows minor but consistent speedup: `main` ``` Benchmark (size) Mode Cnt Score Error Units VectorUtilBenchmark.binaryCosineVector 1024 thrpt 15 4.782 ± 0.007 ops/us ``` This PR ``` Benchmark (size) Mode Cnt Score Error Units VectorUtilBenchmark.binaryCosineVector 1024 thrpt 15 4.885 ± 0.002 ops/us ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
