Error Handling, Update Stability, Improved Java SDK

[ashvardanian]

USearch implementation had 2 layers, the core HNSW structure implemented in index.hpp and the high-level wrapper for dense equidimensional vectors in index_dense.hpp. In this release, we've made the top layer thinner and cleaner, also making this APIs more similar, error-handling more consistent, and builds faster.

Reducing Dependencies & Accelerating Builds

Previously index_dense.hpp had the following STL includes:

#include <thread> // `std::thread`
#include <functional> // `std::function`
#include <vector> // `std::vector`
#include <numeric> // `std::iota`

Those are some of the most common includes in C++ projects, also the ones I like the least. Here are a couple of reasons to hate them, taken from the "C++ Compile Health Watchdog":

name	compilation time	lines of code	binary size
<functional>	82 .. 228 ms	12.9 .. 27.4 kLoC	0 .. 141 kB
<vector>	32 .. 48 ms	7.1 .. 8.0 kLoC	0 .. 8.2 kB
<numeric>	7 .. 13 ms	1.6 .. 2.1 kLoC	0 .. 3.3 kB
<thread>	110 .. 189 ms	17.5 .. 20.3 kLoC	0 .. 153 kB

Reduced Memory Consumption for DBMS-like Users

Most databases using USearch, would prefer to have a smaller index at the cost of some functionality. As mentioned by @rschu1ze, if enable_key_lookups is disabled, and some external DBMS is responsible for "key to vector" mappings, the memory consumption of the index_dense_gt can be further reduced.

Other Improvements

• In update-heavy workloads, it's possible to encounter an undefined behavior, leading to a corrupt index state.
• In aligned-alloc an integer overflow was resolved by @antonio2368.
• Search is now exhaustive by default, so if you have ≥10 items in the index and ask for 10 closest vectors, you are expected to get 10, not ≤10.
• Extended get, loadFromPath, and viewFromPath APIs for Java by @mccullocht.
• On GCC 12 and older the #pragma region warning was resolved by @mbautin.
• Casts to uint40_t slot IDs have been fixed by @Ngalstyan4.
• Casts to b1x8_t vectors have been fixed by @Ngalstyan4.
• Python type annotation has been added by @jamesbraza.
• C++ example was patched by @SheldonFung98.
• JavaScript duplicate exports patched by @eryue0220 & @johnhorsema.
• Checking the number of dimensions in Rust by @jbrummack.
• Marking Rust index views unsafe with @bddap.
• Documenting reserve-save-load behavior with @GoodKnight.
• Patching argument types in C# tests with @brittlewis12.