[PPL-devel] Re: Integers as bit arrays

Brian Hurt wrote:

The basic functionality I was thinking of implementing was:

• get, set (to 1), clear (to 0), invert individual bits
• get, set, clear, invert ranges of bits
• bitwise operators- and, or, xor, negation
• shifts (already implemented), rotates.

It is in fact very useful to use GMP integers as sets of naturals (i.e., the set of their positions containing a bit set to one). For this, the following functionality is desirable:

- searching 0 or 1 bits scanning towards less significant bits; - efficiently deciding whether a set of naturals is a (proper or non proper) subset of another.

You can look at our code for doing that at

http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/~checkout~/ppl/src/SatRow.cc?rev=1...

Cheers

Roberto