stylewarning/cl-permutation

Permutations and permutation groups in Common Lisp.

cl-permutation's Issues

Add a nice way to write cycles and groups from cycles

Writing (123)(45) as well as <(12)(34), (56)> would be nice shorthands.

Consider simplifying the perm representation

Perms are a structure with a simple-array. Maybe we should just use simple-arrays, and avoid the extra bits and bobs. One idea I had was to use the first element of the array as a sort of sentinel value. It isn't exactly the nicest/safest solution, but it might be Good Enough.

subsystem solver should choose larger blocks when it can

Making a solver for the MU group generates 10 God tables lol

Shortest path to a trivial cubic?

Since the action of the rubik group on the set of rubik states is free, the following proves that there are exactly43252003274489856000 different states on a 3x3 rubik's cube (well done!).

(group-order rubik-3x3)
43252003274489856000

I have heard a rumor that no matter which state you start with, there is a solution taking at most 20 steps to solve a 3x3 rubik cube. Can this program help compute this too?

subsystem solver doesn't know about orientation parity

Side effect of `*print-circle*`

During porting cl-quil for allegro, I found *print-circle* has been modified to t here:

cl-permutation/src/block.lisp

Line 35 in 631b175

(setf *print-circle* t)

Is this top-level side effect mandatory? Will assign customized printers for djs and djs-rep be a potentially better idea?

simplify the representation and treatment of words

Words are represented as integers or lists of integers. Lots of special case code is there because of this. We ought to just have one representation used everywhere.

Implement better methods than our Knuthian Schreier-Sims

There are faster randomized methods for generating the group.

consider gutting the SLPs in group generation

Keeping track of SLPs has to have been the biggest boondoggle of this project. I think they're useless, especially with the new Minkwitz code. We should remove the SLP tracking and generation from the main group theory code.

Some systems failed to build for Quicklisp dist

Building with SBCL 2.1.10 / ASDF 3.3.5 for quicklisp dist creation.

Trying to build commit id 7d441be

cl-permutation-examples fails to build because of a failure in cl-permutation.

cl-permutation-tests fails to build because of a failure in cl-permutation.

cl-permutation fails to build with the following error:

; caught WARNING:
;   * is not permitted as an argument to the FUNCTION type specifier
; 
; caught WARNING:
;   * is not permitted as an argument to the FUNCTION type specifier
...
Unhandled UIOP/LISP-BUILD:COMPILE-FILE-ERROR in thread #<SB-THREAD:THREAD "main thread" RUNNING {1001C08103}>: COMPILE-FILE-ERROR while compiling #<CL-SOURCE-FILE "cl-permutation" "minkwitz">

Full log here

Implement changing the base

Allow the base to be changed or permuted.

allow basic computation with (right-)cosets

don't add computational burden for redundant generators

sometimes you'll want to generate a group with redundant generators; but each one adds a cost. we could eliminate that

avoid consing in RANDOM-GROUP-ELEMENT

we cons deg(G)^2 words when we could just cons deg(G)

don't cons so much in the treatment of free group words

Right now, consing happens all over the place. Maybe we can be a little more conservative?

add Clifford group example

add chief series computation

clean up 4list algorithm