Dear Jilong, Thanks for your interest in FastBit. It will take me some time to reconstruct a test program from your description. Would you mind share you test program with me?
By the way, would you be willing to describe your use case? It is usually better to avoid iterate through all bit. John On 10/7/13 2:23 PM, wang jilong wrote: > Hi, > > > > I am new to the mailing list. It is about fastbit 1.3.6 and 1.3.7 on a > linux machine. > > > > I am “AND-ing” two bitvectors together. > > > > The 1^st vector: v_vect1, original bitvector, size=42106416, > cnt=42106416, bytes=44, isCompressed=0 > > Its bytes: \xBF\xB9\x14\xC0\xFF\x7F\x00\x00\x0F\x00\x00\x00 > > So the words are: C014B9BF 00007FFF 0000000F > > > > The 2^nd vector: size=42106416, cnt=2922440, bytes=3512672, isCompressed=0 > > > > The result vector: size=42106416, cnt=2922440, bytes=40, isCompressed=1 > > > > Question 1: > > when I iterate through the result vector using > > “for (ibis::bitvector::const_iterator v_iter = > p_ptr_bitvector->begin(); v_iter != p_ptr_bitvector->end(); ++v_iter)”, > > It only runs up to 15 bits. > > > > Is this a expected behavior for iteration? > > > > Question 2: > > The result vector as it is written to words and printed as bytes. > > They (bytes sequence) are: \x00\x00\x00\x00\x0F\x00\x00\x00 > > > > When the result vector is decompressed, it has long byte sequence. > > > > I read your thesis about WAH, had difficult to interpret the bitmap above. > > Can you please help? > > > > Question 3: > > > > If the result vector is stored as bytes sequence and uses it later in > fastbit again, > > Say engaged in BIT-AND operation, the bytes-sequence is treated as > un-compressed. > > > > How can I make it treated as compressed, like when right after the > result-vector is generated? > > > > Thanks > > > > Jilong Wang > > > > > > > > > > _______________________________________________ > FastBit-users mailing list > [email protected] > https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users > _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
