Help running ntzfind

[globins]

I downloaded ntzfind today and I cannot get it to run on my computer. I'm using Windows and I have Cygwin downloaded. I've gotten as far as compiling it (although I'm not sure I'm doing that right, since I know nothing about C or C++). I just used the command that was listed in the readme:

Code: Select all

g++ -std=c++11 -O3 -march=native -o ntzfind ntzfind.cpp

Whenever I try to run it (using ./ntzfind, I think?), I get an error that says "floating point exception (core dumped)." When I click on the .exe file that was generated by the compilation, it gives me a message that says "The program can't start because cygwin1.dll is missing from your computer. Try reinstalling the program to fix this problem." I have cygwin1.dll on my computer; I went and found the file in C:\cygwin64\bin and it's there. I tried reinstalling Cygwin and nothing changed. How do I fix this?

[wildmyron]

I downloaded ntzfind today and I cannot get it to run on my computer. I'm using Windows and I have Cygwin downloaded. I've gotten as far as compiling it (although I'm not sure I'm doing that right, since I know nothing about C or C++). I just used the command that was listed in the readme:

Code: Select all

g++ -std=c++11 -O3 -march=native -o ntzfind ntzfind.cpp

All good so far

Whenever I try to run it (using ./ntzfind, I think?), I get an error that says "floating point exception (core dumped)."

Try the following command to get usage instructions:

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./ntzfind c

When I click on the .exe file that was generated by the compilation, it gives me a message that says "The program can't start because cygwin1.dll is missing from your computer. Try reinstalling the program to fix this problem." I have cygwin1.dll on my computer; I went and found the file in C:\cygwin64\bin and it's there. I tried reinstalling Cygwin and nothing changed. How do I fix this?

You need to run programs built with Cygwin from the Cygwin terminal, so this error is not unexpected.

[globins]

I get it now. Thanks!

I just ran a search for an expansion of this partial spaceship in B36/S1258 and it returned a result instantly, claiming that it already was a spaceship (it's not).

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x = 23, y = 14, rule = B36/S1258
4$6b5o$7b3o!

Did I do something wrong? Here's what my initrows.txt looked like, which I generated using Sokwe's python script:

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ooo
o.o
oo.
o.o
oo.
oo.
.o.
.oo
o.o
o.o
.oo
...
oo.
...

My command looked like

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 ntzfind B36/S1258 p7 k1 w3 u e initrows.txt

[wildmyron]

I just ran a search for an expansion of this partial spaceship in B36/S1258 and it returned a result instantly, claiming that it already was a spaceship (it's not).

Code: Select all

x = 23, y = 14, rule = B36/S1258
4$6b5o$7b3o!

Did I do something wrong? Here's what my initrows.txt looked like, which I generated using Sokwe's python script:

Code: Select all

ooo
o.o
oo.
o.o
oo.
oo.
.o.
.oo
o.o
o.o
.oo
...
oo.
...

This is pretty much all correct, except that the initial partial isn't long enough to generate a valid set of initial rows. As a rough guide you need p-k+1 extra rows in a single phase partial to generate the initial rows across all phases. So providing the set of rows you generated to zfind results in it finding a spaceship tail that moves at c/7, but it doesn't match a valid frontend. For such a short partial you could try selecting the row three ahead of the front row and running get-rows.py with that. It should generate a set of rows which are mostly empty but with that dot spark showing up in the later phases. You'll also want to start with a wider search. Here's the initrows.txt for width 5:

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.....
.....
.....
.....
.....
.....
.....
.....
.....
....o
.....
....o
.....
....o

This search finishes pretty quickly, but gives the following partial:

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x = 9, y = 9, rule = B36/S1258
2b5o$3b3o2$b7o$2obobob2o$4bo$4bo$2bobobo$2obobob2o!

My command looked like

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 ntzfind B36/S1258 p7 k1 w3 u e initrows.txt

This part is correct, except as mentioned above you'll want to run a wider search - at least w6 or w7.

[globins]

I set a search to run overnight and when I looked this morning I had a “segmentation fault” message. What do I do about that?

[wildmyron]

I set a search to run overnight and when I looked this morning I had a “segmentation fault” message. What do I do about that?

Were you perhaps running a width 11 search? As noted in the README that requires a lot of RAM (up to 19GB for some searches). w10 requires somewhere between 2-4 GB. ntzfind grows the main look up table as required and if there is insufficient RAM at some point then it will crash.

For wider searches you can use gfind - though there's no easy way to specify a partial - or you can use JLS (or WLS on Windows). You can find links to these and other search programs here: https://conwaylife.com/forums/viewtopic.php?p=56#p56 and there is further information and running and installing them in this forum and on the wiki.

[globins]

Yeah, my search width was 14, so it's no wonder it crashed.

You recommended using gfind for larger widths. What's the difference between that and qfind?

[wildmyron]

You recommended using gfind for larger widths. What's the difference between that and qfind?

Please see my post on the other thread: https://conwaylife.com/forums/viewtopic ... 234#p91234