HartmutHolzwart wrote:Anybody looking at how to modify robocat? Would it be an option to redo it as a python script for Golly?
Not yet. It's certainly a possibility, but because of the hard-coded constants littered all around, rewriting the whole thing from scratch might well be an easier job than attempting to reverse-engineer the current code.
In point of fact, I've wanted to tackle this ever since the Caterpillar appeared, to produce an efficient high-level description of the Caterpillar -- a Golly script that could at least construct the current Caterpillar from its component pieces, even if it wasn't up to the task of constructing a new variant Caterpillar with an arbitrary helix.
HartmutHolzwart wrote:On a different issue: Would it now be realistic to build a caterpillar gun?
Not really any more realistic than it was before, no. There doesn't seem to be any particular reason to limit a caterpillar gun to the Spartan pieces needed by a self-constructing U.C., nor to come up with all the migraine-inducing "seed" recipes you'd need to synchronize the active parts of the construction. That would just add yet another layer of complexity.
For example, at some point you have to build thousands of pi climbers at the bottom end of the blinker trails, one right after the other, or maybe several simultaneously -- can't do that directly with a slow salvo, or even a Gemini-style slow glider-pair recipe... So I would think it ought to be much, much easier to make a caterpillar gun out of many copies of, say, a period 2^20 edge-shooting gun.
HartmutHolzwart wrote:The idea would be to seed the blinker trails first, then feed appropriate pis to the trails as needed. Maybe you'd also need to seed parts of the helix and some of the rest, but ideally, the pis would build it on their own as they do in the complete ship. Nearly every single part can be built by two gliders coming from two universal constructor arms (at least in my simplistic view). Anybody of the construction experts giving that idea a closer look?
Well, here's what I wrote in 2005, in response to a similar suggestion from Paul Chapman (though I'm pretty sure he was joking -- I
definitely was, especially in the last paragraph):
Actually I think I'd implement it as a glider-to-caterpillar converter -- then I could hook up any period gun I wanted. Unfortunately the "easy" way to build a caterpillar doesn't allow me to use a gun anywhere near the theoretical minimum period: you start out by building the blinker trails, see, and then put the pi climbers in at the bottom of the trails in all the right places -- and then you let the pi climbers generate their gliders and start building the LWSSes and so forth. Which means you have to have a whole bunch of pre-built junk sitting in the right places to suppress the early gliders until the blinker columns are fully populated...
Then your troubles are almost over -- you just have to build blinker trails that are much longer than the final caterpillar, to allow for the extra startup time required by the suppressing junk. And there may be a few unpleasant surprises somewhere with closing the cycle at the tail, or more likely at the head, where you actually have to send in artificial Life support in the form of gliders until the loop becomes self-sustaining (instead of relying on pre-built suppressing junk). But I think that would be a relatively minor problem...
-- I wonder if the blinker trails could be built with a series of slide guns? Come to think of it, if the extra leading blinkers could be constructed in series, just before they're needed, that might bring the minimum repeat time down to around a million generations -- how about p1048576?
... What an utterly ridiculous line of speculation.... I should be thinking about useful stuff, like the potential density of caterpillars in infinite sparse random Life universes. The question is, would most of them spring full-grown from the forehead of Zeus -- would you be able to recognize most of them by generation 100, let's say -- or would more of them come into existence later through random glider collisions?
Besides the utter impracticality (which is never really much of a problem for me) my biggest complaint would probably be that a plain old Caterpillar still runs pretty slowly in Golly. (You can try it out a little more easily in Golly 2.6, by the way -- there's a direct link now in the "Very Large Patterns" collection under Help > Online Archives.) So as a rough estimate, a Caterpillar gun
would probably be even more boring to watch than a Gemini gun...!