Bremer Support
From TNT
Bremer supports are calculated from the trees in memory: it is up to the user to find suboptimal trees. This is done by setting the program to save suboptimal trees during branch -swapping. The degree of suboptimality is set with Analyze/Suboptimal, or with the suboptimal command. Two types of values can be set: the absolute and the relative fit difference between two different arrangements of taxa. These two values take effect also when collapsing trees for consensus calculation with temporary collapsing under SPR or TBR. The relative fit difference (Goloboff & Farris, 2002) is calculated between the tree being swapped and the rearrangement. It is calculated exactly (see Goloboff & Farris, 2002, for details on how this can be done quickly), except for TBR with asymmetric step-matrix characters, where the relative fit difference can be either over or under estimated by the algorithms used.
In the Scripts page there is one script to calculate quite automatically the bremer support (bremer)
N.B. The new technology algorithms (sectorial searches, ratchet, tree-fusing), since they are not designed primarily to save multiple trees, do not have a well-defined behaviour in terms of the suboptimal trees saved; some trees will be saved, others won't. Thus, if you want suboptimal trees, do branch-swapping after having concluded a search with new tech algorithms.
