How to use symmetric CatForce:
Technical setup:
Step 0: install clang. This is already on Macs. On Linux, something like
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sudo apt install clang-11 --install-suggests
should work. I don't know how Windows stuff works.
Step 1: clone master and depth-first-periodic branches of CatForce from mvr's GitHub repo.
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git clone https://github.com/mvr/CatForce.git
would work. Or just download zip's via your browser and click and drag the folder.
Step 2a: cd into each folder and run
. You might need to change
to
.
Step 2b (optional): figure out where profiling data for the clang compiler is kept. In the Makefile, set PROFDATAEXE equal to that location, and run
. The location should be something like /usr/bin/llvm-profdata-11 (Linux) or /Library/Developer/CommandLineTools/usr/bin/llvm-profdata (Mac). Apparently this helps performance, but I can't tell you why or how much.
Step 3: inside each folder, create an empty folder named masks. CatForce will store masks here, which dramatically speeds up the initialization step when running a search with catalysts you've used before.
Step 4: run
This should yield: results: 1/1, unfiltered: 3/3.
How to use it to find things:
If you're trying symmetric combinations of active regions, then use a driver bash script that I wrote. This just creates input files and feeds them into CatForce; I've attached the current version that I'm using for a p7 periodic CatForce search. The "main parameters to edit" are marked pretty clearly in the script. It also requires a few other .cpp and .py files: I've posted these previously. (Worth mentioning: the .cpp files use stuff in LifeAPI.h, so they need their own rules in the Makefile. Just copy-paste the rule for CatForce and change each instance of 'CatForce' to 'active_region_occurs:' that should work.) Look for a .zip attachment maybe 10 posts back, titled something like "CatForce_bash_osc_search_v3."
I typically copy-paste around catalysts and sparkers until I have a list I like. I run it in debug mode (debug="true") until I'm satisfied I didn't make any typos. (It's easy to accidentally forget a \n or put two spaces somewhere: always open the temp.txt input file and double-check things.) Then I switch debug to false, and make sure I didn't make a search that'll take forever: I typically aim for 2-5 minutes per offset. (The script prints the averages.) In my experience, this usually means either a 2-catalyst search with about 50 catalysts (eg tiny or small list in catlists folder), or a 3-catalyst search with about 15-20 catalysts, assuming things are non-transparent. (Here I count with symmetry: eg all 8 orientations of fishhook = 8 catalysts.) Once I'm satisfied with that, I'll let it run for a few days. Also, the stop-after-cats-destroyed parameter is very useful for minimizing false positives.
If you're doing a lone active region, then one option is to set a filter for the active region re-occuring in the same spot. However, that won't catch instances where the region flips or reappears in a different spot. CatForce doesn't have filters to catch these things, but mvr made a script that will filter the results, and report which objects resulted. Download the catfilter.py script from mvr's golchemy repo. (This requires setting up Lifelib.) Then run
. This results in two things: a .rlefiltered text document, and a .rlegroups rle. The .rlegroups can be opened in Golly. If you want to look for shuttles, I'd think of using control+F to search the .rlefiltered report for the active region you started with. A few words of warning for using catfilter.py: first, make sure to use a standard form of the active region, not a predecessor. Second, it relies on the results falling between certain (x,y) coordinates: if you open the results file in golly and re-save it, that spacing may change. I also suspect the script only works with stable catalysts, not with sparkers.
Related: catfilter.py makes conduit hunting very feasible. Run CatForce searches (from 1 cat, big list to 4 catalysts, fishhook+block) on an active region (stairstep, century aren't too well-searched), filter the results with catfilter.py, run a second search on the most promising ones, etc.
What I do when I have a partial that might work
0. If there's sparkers involved, work out the period. Also take note of whether the sparkers interact once, or more than once. If things only interact once, you might be able to find other sparkers that divide the period and do the same job.
1. Copy and paste the partial into a new layer in golly. If there's symmetry involved, make sure it's centered: quick way to tell is to use control + A to select the region. If the left edge is at -n, you want the right edge should be at n or n+1. Same for top and bottom. Set the pat parameter in your search file: don't forget the dx dy, the upper right corner of the region.
2. Note the dimensions: if it's C2, even width, odd height, then you want
in your search file. Odd width, odd height is just C2. Even width, even height is C2even. (See the CatForce readme for other symmetries--C2 just has the most variants.)
3. Add a filter to make sure the active region re-occurs. (Might also add filters to make sure the existing catalysts recover ok, and that the sparkers aren't destroyed.)
4. Start by running a 1-catalyst search with the big list. If this doesn't yield anything, then I'll go do a 2 catalyst search with the tiny list.
Attached is a sample for a p90 R hassler. If I keep getting 0/0, I sometimes wonder if I just set things up wrong: a good way to check this is to add a full-results output (which saves solutions that don't meet the filters), or delete the filters one-by-one until you start getting results.