dvgrn wrote:From what I understand, P2 recipes like this won't work in this engineless caterpillar project, because you want to be able to allow either even or odd distances between successive slow-salvo gliders.
The enginless is a bit non intuitive construction. The distance between the slow salvos will be 59 (at least this I've recipes for - but it's pretty adjustable). The distance between the SLs in the tape is 2*N - which allows any
This is of course nice - but now consider how do we adjust the period. Say we have 59/800, and want 59/801 - the only thing we do is just evolving the "Reading Head" (the constellation of 5-7 *WSS which converts the SL -> G), by 801 ticks instead of 800.
That would be nice on paper, but in practice evolving something by even period, will give single parity. Now if we want periods of 4*N all the gliders will be in same internal state, shoot from each lane, in generations which is 4*N. That essentially means no parity at all, if we want to cover all possible periods.
Of course covering all possible periods has some more hidden issues, but the one with slow salvo is very clear. Either blinkerless slow salvos, or getting into a lot of special cases, or just let go of some periods, like building it for 2*N + 1 periods.
I chose to go for blinkerless slow salvos, as it looks pretty OK, and has the benefit to avoid special cases together with covering all periods. Obviously it has it's own price, but I figure the price is the lowest among other options.
dvgrn wrote: So this could maybe be a 7sL recipe, if the leftover blinker can be dealt with. (There's also a boat suppression option shown, which looks like an improvement on the beehive.)
Thanks, looks very nice. The suppression is really a minor issue, as it costs only one slow salvo glider for clearing, and about 10-15 to placing SL in "tight" place (and 5-8 for placing it in reasonable clearance). Actually it's more important to have a bit more space between SLs, than the number of leftover SLs.
dvgrn wrote:Okay, but as for leftover blinkers that you just want to get rid of: it may be a little cheaper to just handle the cleanup in a period-independent way, instead of building extra still lifes to prevent the blinkers from forming.
Well those interactions are pretty rare - so we need specially place extra SLs in correct position just to clear the blinker. It's the same as just placing the SL in the first place so blinkers wouldn't be born.
As for getting track for even+odd cases - just a waste of effort on my opinion, might work, wouldn't go there.