Daniel Lemire's blog

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Compressed bitmaps in Java

7 thoughts on “Compressed bitmaps in Java”

  1. @Anonymous

    My statement is very clear: to my knowledge, there is no patent violation. However, I am a researcher, not a patent lawyer.

  2. Anonymous says:

    I have just downloaded the software. I have just one preliminary question: how are you sure that EWAH is not patented. In other words why do you think that a patent on WAH does not cover EWAH as well.

  3. Jaroslaw says:

    Hi,

    Great paper, great wok, nothing to add… I’m currently in Dublin, Ireland, it is amazing that I can download your paper and enjoy your work. Thanks a lot!

  4. No. It is a matter of trade-off: if you want fast random access, a different (less aggressive) form of compression is required. Thanks for the question.

  5. Igor says:

    Daniel,

    Is there a way to check whether a bit at the given position is set? In the constant time of course, not using the iterator. Thanks in advance.

  6. Sam says:

    What are your thoughts on a Javascript implementation of EWAH?
    I’m curious if the benefits of cache coherency would outweigh the lack of 64-bit integer support and other JS inefficiencies.

    1. I have a fast implementation of regular/uncompressed bitsets in JavaScript and it is mostly decent. I suspect you could make a 32-bit EWAH work.