Re: Revised Motion 26 decoration scheme
Dan, Baker, Vincent, P1788
On 18 Jul 2011, at 18:09, Dan Zuras Intervals wrote:
>> From: "Nate Hayes" <nh@xxxxxxxxxxxxxxxxx>
>> John Pryce wrote:
>>> Note also that our text continues to include Nate's "bare object
>>> arithmetic", whose importance for efficiency I accept.
>> I'm glad to hear that, but I note we don't agree on how bare decorations are
>> promoted to decorated intervals: Bare decorations should always be promoted
>> to Empty decorated intervals, not Entire.
> While I don't think we should have bare objects of any kind,
> I agree with Nate on this point. But for a different reason...
The "bare object arithmetic" section comes, I think, from offline discussions between Arnold & Nate. It is QUITE different from the mixed bare/decorated arithmetic I put in before, which I'm glad to see the back of.
If you read that section you'll see it doesn't really suffer the risks Dan fears. It describes (at level 1) a way to (at lower levels) shoe-horn 17 bytes into 16, both gaining & losing in the process. At level 2 this would be a quite distinct interval type from any other decorated or bare interval. The text doesn't yet describe allowed conversions between it and "ordinary" interval types; if these are restricted enough, Dan's fears will be unfounded.
On 19 Jul 2011, at 02:12, Ralph Baker Kearfott wrote:
> Am I correct in my perception that the only reason for
> having either a bare decoration or a bare interval
> is to save storage space and (possibly) bus bandwidth?
> If so, how significant is the savings it gains us...
I found Ian McIntosh's excellent "bedtime story" very instructive on this:
On 6 Jul 2011, at 01:09, Ian McIntosh wrote:
> An analogy may help. Picture a 16 car long subway station platform...
It persuaded me we should get used to the idea that decorating a 16-byte interval should make it 32 bytes wide, not 17, until architectures change drastically. I recall years ago we got used to the fact that Fortran typically stored a Boolean in a 32-bit word, which really offended my cheeseparing mathematical mind...
John