Table 2.
Computational complexity of the proposals, likelihood operations and condition under which a proposal is strictly less expensive than a likelihood evaluation (i.e., Cost condition).
| Operation | Complexity | Cost condition |
|---|---|---|
| Full lik. |
|
— |
| Partial lik. |
|
— |
| Partial pars. |
|
— |
| stNNI |
|
|
| eSPR |
|
|
| eTBR |
|
|
| G-stNNI |
|
|
| G-NSPR |
|
|
| A-stNNI |
|
|
| A-2SPR |
|
|
| A-PBJ |
|
|
|
Notes: Alignments have 
sites for 
sequences defined over an alphabet of 
characters (e.g., 
for nucleotide sequences). The Gamma model for rate heterogeneity has a number 
of rate categories (Yang 1994), while a partial likelihood requires 
operations instead of 
. Finally, 
represents the number of splits altered by a move. For the A-PBJ proposal, 
, 
and 
identify the number of edges in the two unstable paths and stable path, respectively.