Avoid recomputing vacancy numbers for rigged configurations

[tscrim]

Many of rigged configuration operations, such as e() and f(), needlessly recompute the vacancy numbers. We simply need to tell the constructor to avoid doing these computations.

Also, because the Cartan matrices are sparse and general matrix implementation details, it is relatively expensive to iterate over the row. Instead, it is much fast to get the specific entry by CM[i,j].

CC: @sagetrac-sage-combinat @anneschilling @bsalisbury1

Component: combinatorics

Keywords: rigged configurations

Author: Travis Scrimshaw

Branch/Commit: 8591c4a

Reviewer: Anne Schilling

Issue created by migration from https://trac.sagemath.org/ticket/20174

[tscrim]

comment:1

With branch:

sage: RC = RiggedConfigurations(['B',4,1], [[2,1],[3,1]])
sage: %time len(list(RC))
CPU times: user 3.33 s, sys: 19.6 ms, total: 3.35 s
Wall time: 3.33 s
3441
sage: RC = RiggedConfigurations(['A',4,1], [[2,1],[3,1]])
sage: %time len(list(RC))
CPU times: user 41.9 ms, sys: 4.27 ms, total: 46.1 ms
Wall time: 38.8 ms
100
sage: RC = RiggedConfigurations(['D',6,1], [[2,1],[3,1]])
sage: %time len(list(RC))
CPU times: user 7.17 s, sys: 36 ms, total: 7.21 s
Wall time: 7.19 s
15544

vs old version

sage: RC = RiggedConfigurations(['B',4,1], [[2,1],[3,1]])
sage: %time len(list(RC))
CPU times: user 12.5 s, sys: 45 ms, total: 12.5 s
Wall time: 12.5 s
3441
sage: RC = RiggedConfigurations(['A',4,1], [[2,1],[3,1]])
sage: %time len(list(RC))
CPU times: user 97.5 ms, sys: 4.16 ms, total: 102 ms
Wall time: 88.4 ms
100
sage: RC = RiggedConfigurations(['D',6,1], [[2,1],[3,1]])
sage: %time len(list(RC))
CPU times: user 26.5 s, sys: 52.1 ms, total: 26.6 s
Wall time: 26.5 s
15544

Slightly annoying how simple changes these were and resulting in such a large speed gain...

---

New commits:

8d2decd

Avoid needlessly recomputing the vacancy numbers.

[tscrim]

Commit: 8d2decd

[tscrim]

Branch: public/rigged_configurations/speedup_crystal_ops-20174

[sagetrac-git]

Changed commit from 8d2decd to 8591c4a

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

8591c4a

Some other similar tweaks for highest weight/B(oo) RC crystals.

[anneschilling]

Reviewer: Anne Schilling

[vbraun]

Changed branch from public/rigged_configurations/speedup_crystal_ops-20174 to 8591c4a