is this c/10 spaceship known?

[Alexey_Nigin]

Would it be okay if I reposted your article on LifeNews?

Of course.

[biggiemac]

Since it hasn't been updated since 2014, it might also be interesting to slide in other discoveries like the 31c/240 ships and the demonoids.

It's actually been updated quite frequently, and includes information about the demonoids, waterbear, HBKs, 31c/240 ships, and other projects. They are all just edited into the same post, which has a timestamp from 2014 and a likely-outdated title/image. The option to "read the whole story" shows the lengthy list of accomplishments. An update that shows these additions more prominently would certainly be welcome, but since I'm not the one who will do that I'll at least point people to the work that Dave has put in thus far

[Linicks]

Edit: How long did it take to find the ship?

I just ran this search in gfind and it refound the ship in a little over an hour. It's really amazing this wasn't found sooner.

velcrorex, can you show the recipe using gfind on how to get this? I have been messing with gfind for hours, but only end up with about 3 ss/gliders that was discovered in pencil and paper days.

Thanks,

Nick

[Sokwe]

I just ran this search in gfind and it refound the ship in a little over an hour.

can you show the recipe using gfind on how to get this?

The ship can be found by running gfind with the following parameters:

Code: Select all

B3/S23/o10/n1/l100/v

• "B3/S23" is the rule
• "o10" means search for orthogonal spaceships with period a multiple of 10
• "n1" means search for spaceships that move 1 cell during their period
• "l100" means search for spaceships of width 100/(2*p) where p=10 is the period of the spaceship
• "v" means search for bilaterally-symmetric ships with even width

To get a list of gfind commands, run gfind with "c" as the only command.

[Linicks]

Post above by Sokwe:

Thanks for a comprehension reply. I know the command line options, as I have read through the code - just didn't understand the syntax of GOL objects and what they do.

Nick

[muzik]

I just ran this search in gfind and it refound the ship in a little over an hour.

can you show the recipe using gfind on how to get this?

The ship can be found by running gfind with the following parameters.

I'm running a similar search using WLS, see if anything pops up overnight

[FractalFusion]

The option to "read the whole story" shows the lengthy list of accomplishments. An update that shows these additions more prominently would certainly be welcome,

I support this as well. Until I saw biggiemac's post, I thought that ConwayLife.com gave up on updating.

The thing I don't get is why someone thought that great discoveries like Demonoid/Geminoid-types, Waterbear, 31c/240 spaceships, HBK-type spaceships, and such don't deserve new standalone newsposts.

[Kiran]

Somewhat irrelevant, but the wiki also keeps repeating the same featured articles over and over, we should write more snippets.

[dvgrn]

The option to "read the whole story" shows the lengthy list of accomplishments. An update that shows these additions more prominently would certainly be welcome,

I support this as well. Until I saw biggiemac's post, I thought that ConwayLife.com gave up on updating.

The thing I don't get is why someone thought that great discoveries like Demonoid/Geminoid-types, Waterbear, 31c/240 spaceships, HBK-type spaceships, and such don't deserve new standalone newsposts.

Thanks to Nathaniel's cleverness, the conwaylife.com main page updates automatically, every time there's a new LifeNews posting, or every time Calcyman or I put something up on my b3s23life blog... the only thing that he didn't manage is an automatic article-writer. All of the old regular bloggers have been getting busier and busier in recent years -- and to be honest, we were all fairly irregular bloggers even in the best of times.

I'm sure a lot of people thought that all those new discoveries were eminently worthy of new articles... but the more complicated the construction is, the more work it is to write a good reasonably detailed description of it. So nobody actually found the time to do the writing.

Also, the likely candidates for generating an article on a newly completed pattern are usually so exhausted from recent late-night efforts to fit all the pieces together, that writing articles the last thing they want to think about. There's also a post-construction phase called "getting caught up on Real Life" -- or maybe just getting caught up on sleep -- that always seems to take priority over documentation issues. (I'm kind of in that mode this week myself, or Alexey's article would be up on the main page by this time.)

-----------------------------------------

Generally, any time anyone wants to write an article on a new discovery, I'll be very happy to see that it finds its way to the main page (perhaps after a little obsessive editing on my part.)

I've been meaning to figure out how to borrow the LifeViewer for use in a Blogger posting. Assuming that works out, candidate articles could even be posted in a new Articles thread here on the forums, to collect comments and corrections.

... Apologies for the tangential topic. Now, back to our regularly scheduled c/10 discussion --

[simeks]

26 cell predecessor (Edit: found another one):

Code: Select all

x = 24, y = 11, rule = LifeHistory
19.2A$2.4A13.2A$18.A2.A$2.A2.A11.2A2.2A$.A.2A.A12.2A$2.A2.A12.A2.A$3.
2A11.A6.A$8A8.A6.A$17.A4.A$19.2A$2.4A12.4A!

[Nathaniel]

Somewhat irrelevant, but the wiki also keeps repeating the same featured articles over and over, we should write more snippets.

If anyone wants to write more snippets, feel free to do so and then just message me and I'll insert them into the front page rotation. To do it, just go to create the snippet at http://www.conwaylife.com/wiki/PAGENAME/Snippet (where PAGENAME is the name of the full wiki page) and make sure it follows the same format as a pre-existing snippet. For example, just copy the snippet from http://www.conwaylife.com/wiki/Block/Snippet and tweak it to whatever pattern you like.

[muzik]

just copy the snippet from http://www.conwaylife.com/wiki/Block/Snippet and tweak it to whatever pattern you like.

Again somewhat irrelevant, but that page is protected from editing. I want to change "outright the smallest" to "the outright smallest" to reflect the real page, but I can't do that. Can you fix that please

[gameoflifeboy]

I think that's only because it's currently featured on the main page. If you wait until it gets off the main page, you can probably edit it again.

[dvgrn]

If anyone wants to write more snippets, feel free to do so and then just message me and I'll insert them into the front page rotation.

It looks like all 22 of the current snippets are editable by any logged-in user, except for whichever one is currently featured on the main page -- makes sense. And it shouldn't be a problem for anyone to create a new snippet for any other page; it just won't actually end up on the main page until Nathaniel adds it to the list.

Almost all of the current snippets seem to have been created back in 2009, and mostly haven't been touched since (!). The first few I checked included such antediluvian gems as

"All known spaceships in Life travel either orthogonally (only horizontal or vertical displacement) or diagonally (equal horizontal and vertical displacement) at one of the twelve known speeds."

"The least infinitely repeating population of any known sawtooth is 260, attained by [[sawtooth 260]]."

[zdr]

It looks like this thread was linked from somewhere, since it now has over 40k views. If anyone is interested in how simple it was to find this spaceship run the following c code with arguments:
b3s23 w5 p10 k1 v

This was the exact program used to find it.

Code: Select all

#include <stdio.h>
#include <stdlib.h>

int sp[8], *gf, *gb, *gl, *gs;
int bc[8] = {0, 1, 1, 2, 1, 2, 2, 3};

void plong(long a){
	if(a > 1000000000)printf("%dM\n", a / 1000000);
	else printf("%d\n", a);
}

int u0_0(int a, int b, int c, int d){
	int r;
	r = bc[(a >> d) & 7];
	r += bc[(b >> d) & 7] + 4 * ((b >> d) & 2);
	r += bc[(c >> d) & 7];
	return (sp[0] >> r) & 1;
}

void u0(){
	int r[10];
	gf = malloc((long)4 << (sp[1] * 3));
	gb = malloc((long)8 << (sp[1] * 3));
	for(r[0] = 0; r[0] < 1 << (3 * sp[1]); r[0]++)gb[2 * r[0]] = 0;
	r[3] = -1;
	r[9] = 0;
	for(r[0] = 0; r[0] < 1 << sp[1]; r[0]++)for(r[1] = 0; r[1] < 1 << sp[1]; r[1]++)for(r[2] = 0; r[2] < 1 << sp[1]; r[2]++){
		r[3]++;
		if(u0_0(r[0], r[1], r[2], sp[1] - 1)){
			gf[r[3]] = -1;
			continue;
		}
		r[4] = (r[0] << 1) + ((r[0] >> sp[6]) & 1);
		r[5] = (r[1] << 1) + ((r[1] >> sp[6]) & 1);
		r[6] = (r[2] << 1) + ((r[2] >> sp[6]) & 1);
		r[7] = u0_0(r[4], r[5], r[6], 0);
		for(r[8] = 1; r[8] < sp[1]; r[8]++)r[7] += u0_0(r[0], r[1], r[2], r[8] - 1) << r[8];
		gf[r[3]] = r[7];
		gb[2 * (r[3] - r[2] + r[7])]++;
		r[9]++;
	}
	gl = malloc(4 * r[9]);
	r[1] = 0;
	for(r[0] = 0; r[0] < 1 << (3 * sp[1]); r[0]++){
		r[1] += gb[2 * r[0]];
		gb[2 * r[0] + 1] = r[1];
	}
	r[3] = -1;
	for(r[0] = 0; r[0] < (1 << (2 * sp[1])); r[0]++)for(r[1] = 0; r[1] < (1 << sp[1]); r[1]++){
		r[3]++;
		r[2] = gf[r[3]];
		if(r[2] < 0)continue;
		r[4] = r[3] - r[1] + r[2];
		gb[2 * r[4] + 1]--;
		gl[gb[2 * r[4] + 1]] = r[1];
	}
	free(gf);
}

void u1_0(int a){
	int r[10];
	for(r[2] = a - 1; r[2] >= 0; r[2]--)if(gs[4 * r[2] + 2])break;
	for(r[0] = 2 * sp[2]; r[0] <= r[2]; r[0] += sp[2]){
		for(r[1] = 0; r[1] < sp[1]; r[1]++){
			if((gs[4 * r[0] + 2] >> r[1]) & 1)printf("o");
			else printf(".");
		}
		printf("\n");
	}
	printf("%d\n", r[2]);
}

int u1_1(int a){
	int r[30];
	r[2] = (gs[4 * (a - sp[2] - sp[3]) + 2] << (2 * sp[1])) + (gs[4 * (a - sp[3]) + 2] << sp[1]);
	r[3] = gb[2 * (r[2] + gs[4 * a + 2])];
	if(!r[3])return 0;
	r[1] = gb[2 * (r[2] + gs[4 * a + 2]) + 1];
	r[2] = (gs[4 * (a - sp[2] - 2 * sp[3]) + 2] << (2 * sp[1])) + (gs[4 * (a - 2 * sp[3]) + 2] << sp[1]);
	r[6] = gb[2 * (r[2] + gs[4 * (a - sp[3]) + 2])];
	r[7] = gb[2 * (r[2] + gs[4 * (a - sp[3]) + 2]) + 1];
	r[2] = (gs[4 * (a - sp[2] - 3 * sp[3]) + 2] << (2 * sp[1])) + (gs[4 * (a - 3 * sp[3]) + 2] << sp[1]);
	r[10] = gb[2 * (r[2] + gs[4 * (a - 2 * sp[3]) + 2])];
	r[11] = gb[2 * (r[2] + gs[4 * (a - 2 * sp[3]) + 2]) + 1];
	for(r[0] = 0; r[0] < r[3]; r[0]++){
		r[4] = gl[r[1] + r[0]];
		for(r[5] = 0; r[5] < r[6]; r[5]++){
			r[8] = gl[r[7] + r[5]];
			r[9] = (gs[4 * (a - 2 * sp[3]) + 2] << (2 * sp[1])) + (r[8] << sp[1]) + r[4];
			if(!gb[2 * r[9]])continue;
			r[15] = gb[2 * r[9]];
			r[16] = gb[2 * r[9] + 1];
			for(r[12] = 0; r[12] < r[10]; r[12]++){
				r[13] = gl[r[11] + r[12]];
				r[14] = (gs[4 * (a - 3 * sp[3]) + 2] << (2 * sp[1])) + (r[13] << sp[1]) + r[8];
				if(!gb[2 * r[14]])continue;
				r[17] = gb[2 * r[14]];
				r[18] = gb[2 * r[14] + 1];
				for(r[19] = 0; r[19] < r[15]; r[19]++){
					r[20] = gl[r[16] + r[19]];
					for(r[21] = 0; r[21] < r[17]; r[21]++){
						r[22] = gl[r[18] + r[21]];
						r[23] = (r[13] << (2 * sp[1])) + (r[22] << sp[1]) + r[20];
						if(gb[2 * r[23]])return 1;
					}
				}
			}
		}
	}
	return 0;
}

void u1(){
	int r[10];
	long i;
	gs = malloc(40000);
	r[0] = 2 * sp[2];
	for(r[1] = 0; r[1] < r[0]; r[1]++)gs[4 * r[1] + 2] = 0;
	gs[4 * r[0]] = gb[0] - 1;
	gs[4 * r[0] + 1] = gb[1];
	i = 0;
	r[5] = 0;
	time_t ms = clock();
	for(;;){
		i++;
		if(r[0] > r[5] || !(i & 0xffffffff)){
			u1_0(r[0]);
			printf("%d\n", r[0]);
			plong(i);
			plong(clock() - ms);			
			if(r[0] > r[5])r[5] = r[0];
		}
		if(!gs[4 * r[0]]){
			r[0]--;
			if(r[0] < 2 * sp[2]){
				printf("end\n");
				plong(i);
				return;
			}
			continue;
		}
		gs[4 * r[0]]--;
		gs[4 * r[0] + 2] = gl[gs[4 * r[0] + 1] + gs[4 * r[0]]];
		if(!u1_1(r[0]))continue;
		r[0]++;
		if(r[0] > sp[4]){
			printf("done\n");
			plong(i);
			return;
		}
		r[4] = (gs[4 * (r[0] - 2 * sp[2]) + 2] << (2 * sp[1])) + (gs[4 * (r[0] - sp[2]) + 2] << sp[1]) + gs[4 * (r[0] - sp[2] + sp[3]) + 2];
		gs[4 * r[0]] = gb[2 * r[4]];
		gs[4 * r[0] + 1] = gb[2 * r[4] + 1];
	}
}

int main(int argc, char *argv[]){
	int r[10];
	sp[0] = 6152;
	sp[1] = 6;
	sp[2] = 3;
	sp[3] = 1;
	sp[4] = 500;
	sp[5] = 1;
	sp[6] = 0;
	sp[7] = 1;
	for(r[0] = 1; r[0] < argc; r[0]++){
		switch(argv[r[0]][0]){
			case 'b':
				sp[0] = 0;
				r[1] = 0;
				for(r[2] = 1; r[2] < 100; r[2]++){
					r[3] = argv[r[0]][r[2]];
					if(!r[3])break;
					if(r[3] == 's')r[1] = 9;
					if(r[3] >= '0' && r[3] <= '8')sp[0] += 1 << (r[1] + r[3] - '0');
				}
			break;
			case 'w': sscanf(&argv[r[0]][1], "%d", &sp[1]); break;
			case 'p': sscanf(&argv[r[0]][1], "%d", &sp[2]); break;
			case 'k': sscanf(&argv[r[0]][1], "%d", &sp[3]); break;
			case 'l': sscanf(&argv[r[0]][1], "%d", &sp[4]); break;
			case 'u': sp[6] = 1; break;
			case 'v': sp[6] = 0; break;
		}
	}
	time_t ms = clock();
	u0();
	plong(clock() - ms);
	ms = clock();
	u1();
	plong(clock() - ms);
	return 0;
}

[Apple Bottom]

It looks like this thread was linked from somewhere, since it now has over 40k views. If anyone is interested in how simple it was to find this spaceship run the following c code with arguments:
b3s23 w5 p10 k1 v

This was the exact program used to find it.

The Register tweeted about it. May well have been mentioned elsewhere yet, too.

Thanks for sharing your code!

[muzik]

May well have been mentioned elsewhere yet, too.

Indeed; it was featured on hacker news.

I also posted it on the conways game of life subreddit

[Linicks]

It looks like this thread was linked from somewhere, since it now has over 40k views. If anyone is interested in how simple it was to find this spaceship run the following c code with arguments:
b3s23 w5 p10 k1 v

This was the exact program used to find it.

The Register tweeted about it. May well have been mentioned elsewhere yet, too.

Thanks for sharing your code!

That was me - I e-mailed their 'news tip' address pointing to this thread.

Nick

[Linicks]

It looks like this thread was linked from somewhere, since it now has over 40k views. If anyone is interested in how simple it was to find this spaceship run the following c code with arguments:
b3s23 w5 p10 k1 v

This was the exact program used to find it.

Code: Select all

o....
oo...
.....
ooo..
oo...
.....
.oo..
.o.oo
.o...
.....
.....
o....
o....
147
500
418530519
142230000
done
418530519
142230000

What does that mean? EDIT - ignore that - I now see it is the right hand side - just mirror it on the left hand side.

Good stuff!

Nick

[Linicks]

BTW, zdr - who coded it and what is the licence on this code (way over my head)? Public Domain?

Nick

[thunk]

Thank you again, zdr.

My initial thoughts for what I will call zfind (pronounced beginning with 'zed') is that it does seem to be faster than existing programs like gfind. Both V and U modes seem to produce nice partials; W (gutter) and A (asymmetric) seem to default to even symmetry). What options should one set for gutter/asymm searches, or will support be added later?

Also, the options you demonstrated allow search for orthogonal ships. Is there support for diagonal or oblique ship velocities?

[codeholic]

I examined collisions of single gliders and *WSS with copperheads and it seems there are no collisions that can be forced to explode. It means, no simple puffer a la Jason Summers

There is probably a way to ignite a reaction with a glider or *WSS flotilla, but that would require to build a versatile puffer with an integrated universal constructor (similar to weekender distaff) to restore it and close the loop. I haven't checked what copperheads can do with methuselahs, but I'm not very optimistic, having in mind how scanty glider and *WSS reactions were.

[muzik]

There is probably a way to ignite a reaction with a glider or *WSS flotilla,

What about WSS tagalongs? Like Coe ships or sidecars?

[codeholic]

Good luck synthesizing them

[fluffykitty]

Speaking of 2c/5, I think this the first time a length 3 geometric progression of speeds has occurred. (2c/5,c/5,c/10)
Also how does zsearch work?