Bit type?

[BCS]

Reply to Dan,

> Stewart Gordon Wrote:
> 
>> Meanwhile, Phobos has std.bitarray.  I also have a bit array
>> implementation
>> capable of arbitrary slicing:
>> http://pr.stewartsplace.org.uk/d/sutil/
> Yeah, more or less.
> 
>> 4-bit type?  I guess some of the bit array code could be modified to
>> give nibble arrays, if that's what you mean....
>> 
>> Stewart.
>> 
> Yeah okay.  A nibble[] then.  Or I might opt to go a little smaller.
> 
> See, while almost no complex operations are done on DNA,
> pattern-matches are done often, and trying to do that on the human
> genome is to pattern-match against 3 billion base-pairs (6GB if you're
> tight-ship, 24GB if you use char)

your off by a factor of 8 (or swaped B and b)

3 * 1024^3 * 2 bits =   6Gb = 0.75GB 
3 * 1024^3 * 8 bits = 24Gb = 3.00GB

but 2.25 GB is still a lot of RAM and IO.