shifts.list_to_vector: Compute the vector of shifts.
Description
shifts.list_to_vector takes the list description of the shifts
to give the vectorial representation of the shifts : the b th element of
the vector has the value of the shift occuring on that branch b.
Usage
shifts.list_to_vector(phy, shifts)
Arguments
phy
Input tree.
shifts
: list description of the shifts : shifts$edges, shifts$values