Thanks John. I will try it using the 0x syntax. Andrew On Aug 31, 2009, at 3:27 PM, K. John Wu wrote:
> Hi, Andrew, > > It appears that the packed option might be a more reasonable one. You > can pack up to 32 boolean flags in a 32-bit integer (ibis::INT or > ibis::UINT). The parser understands "packedflags & 0100101001" as a > bitwise expression (following C/C++ definition of bitwise operations > between integral types). However, the constant 0100101001 would be > parsed as a decimal integer. One may prefix the number with 0x (or > 0X) for a hexadecimal number, but there is not way to input a binary > number. > > Please feel free to let us know if you encounter any problems. > > John > > > On 8/31/2009 11:26 AM, Andrew Olson wrote: >> Hi. >> I'm considering creating a table using FastBit that has many boolean >> columns, but it appears that the 8 bit char types are the most >> compact >> format available. I could pack them into an unsigned long int, >> rather >> than store them as separate shorts, but queries on such a column >> (e.g., "packedflags & 0100101001 != 0") would not be able to take >> advantage of the index. >> >> I have 2 questions. >> 1. Are queries like that even possible in FastBit? >> 2. Is there a space and time efficient way to represent and query >> these boolean variables? >> >> Thanks, >> Andrew >> _______________________________________________ >> 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 _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
