size_species_matrix: Calculate the dimensions of the cladogenesis/speciation matrix
Description
This function calculates the dimensions of the
cladogenesis/speciation matrix describing the transition
probabilities between ancestral geographic ranges and
descendant geographic range pairs on Left (L) and Right
(R) branches.
A list of states, where each state
consists of a list of areas. A default example list is
provided.
printwarn
If printwarn>0
(printwarn=1 by default), then print to screen a
message describing the size of the cladogenesis matrix.
Value
spmat_dimensions The dimensions of the
cladogenesis matrix.
Details
Under a cladogenesis model of geographic range change,
the model will give the conditional probability of each
possible combination of geographic ranges on the Left (L)
and Right (R) descendant branches, conditional on a
particular ancestral state. A matrix representing these
transitions will have numstates ancestral states,
and numstates*numstates possible descendant pairs.
Many of these will have 0 conditional probability under
the model, but, for visualization or experimental
purposes it can be useful to display them all.
However, because numstates = 2^numareas under
default conditions, and the number of cells the processor
has to consider (without optimization tricks) is
numstates^3, this transition matrix can very
quickly become cumbersome to explicitly calculate or
display. size_species_matrix allows the user to
check this ahead of time.