feat: make _canonical_matrix faster

[thofma]

Some low-hanging fruit.

Before:

julia> @time Oscar.Orderings._canonical_matrix(w);
  1.322101 seconds (21.72 M allocations: 826.664 MiB, 14.43% gc time)

After:

julia> @time Oscar.Orderings._canonical_matrix(w);
  0.021654 seconds (3.57 k allocations: 2.066 MiB)

There is still some room for improvement.

[HechtiDerLachs]

Cool, thanks! Definitely an improvement. But as you say: Still room for further improvement, eventually.

[thofma]

I guess I messed something up.

How fast is your sparse version?

[HechtiDerLachs]

How fast is your sparse version?

My sparse version never became functional, unfortunately. I also messed things up and didn't know how to resolve it.

Tests fail at the moment.

[joschmitt]

I pushed a fix for the sparse version. I now get these timings:

# This PR:
julia> @btime Oscar.Orderings._canonical_matrix(M);
  9.841 ms (4095 allocations: 2.09 MiB)

# 4114:
julia> @btime Oscar.Orderings._canonical_matrix(M);
  5.179 ms (260187 allocations: 4.11 MiB)

EDIT: new version of #4114

julia> @btime Oscar.Orderings._canonical_matrix(M);;
  1.505 ms (6669 allocations: 247.57 KiB)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.68%. Comparing base (b5d0b43) to head (81ee7ee).
Report is 10 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4117      +/-   ##
==========================================
+ Coverage   84.66%   84.68%   +0.01%     
==========================================
  Files         626      626              
  Lines       84210    84270      +60     
==========================================
+ Hits        71300    71360      +60     
  Misses      12910    12910              

Files with missing lines	Coverage Δ
src/Rings/orderings.jl	97.58% <100.00%> (+0.01%)	⬆️

... and 12 files with indirect coverage changes

[lgoettgens]

this is no longer used and should be removed (before merging this)