java - 具有类似数组的性能的 Java Bitset 替代品？

Question

我正在寻找 Java Bitset 实现的替代方案。我正在实现一种高性能算法，似乎使用 Bitset 对象会降低其性能。有什么想法吗？

Answer 1

有人 here将 boolean[] 与 BitSet 进行了比较并得出结论:

BitSet is more memory efficient than boolean[] except for very small sizes. Each boolean in the array takes a byte. The numbers from runtime.freeMemory() are a bit muddled for BitSet, but less.

boolean[] is more CPU efficient except for very large sizes, where they are about even. E.g., for size 1 million boolean[] is about four times faster (e.g. 6ms vs 27ms), for ten and a hundred million they are about even.

如果你谷歌，你也可以找到一些替代实现，比如 JavaEWAH , 由 Apache Hive 使用, Apache Spark和 Eclipse JGit .它声称:

The goal of word-aligned compression is not to achieve the best compression, but rather to improve query processing time. Hence, we try to save CPU cycles, maybe at the expense of storage. However, the EWAH scheme we implemented is always more efficient storage-wise than an uncompressed bitmap as implemented in the BitSet class). Unlike some alternatives, javaewah does not rely on a patented scheme.