bitperm

Bit Permutations in Rust

Construction

cargo add derive_more -F add,add_assign,from cargo bench --baseline

TODO BitGrid:

Extend bit operations to 8-bit matrices over u64. Separate OriginBitGrid8 from BitGrid8 (different files that respect boundary and use deref) Functor completed, but needs to be wrapped in Result not Option.

General TODO

Benchmark inversions Understand how to use Nonzero to make Option only take up u64 space. BitTrocCube3 - 2 cube offset inside 3 cube BitTrocCube4 - 3 cube offset inside 4 cube BitTrocOcta2 - 1x1 plates extending through each face of 2x2x2 cube BitTrocOcta3 - 2x2 plates extending through each face of 3x3x3 cube Add to_scad for BitTrocs

Notes of things to be done for useful BitPerm library

TODO BitPerm:

Trait BitPerm

identity
inverse
composition
display, debug
tryFromArray
Double coset equivalence
toArray

Convert from truth table to polynomials for 4 bit perms Convert from truth table to polynomials for 5 bit perms

Bit Permutation: basis fixing Exhaust of affine conjugation that fixes as many weight 2 vectors as possible. 6-bit permutation with [u64; 6]

TODO: 4 bit interleave -

x = 0x00ff&x + (0xff00)<<(32-8) x = 0x0f0f&x + (0xf0f0)<<(16-4) x = 0x3333&x + (0xcccc)<<(8-2) x = 0x5555&x + (0xaaaa)<<(4-1)

13 ops for lookup p[a] = (p4.0 >> (4a)) & 1 p[a] ^= ((p4.1 >> (4a)) & 1) << 1 p[a] ^= ((p4.2 >> (4a)) & 1) << 2 p[a] ^= ((p4.3 >> (4a)) & 1) << 3