Construct a stacked list of values from a data frame containing
multiple prey types. Used for creating input to convhulln.
Usage
build.hull.list(frame)
Arguments
frame
A data frame containing a list of isotope values for multiple
organisms. If there are d isotope values and s
organisms, then the frame is assumed to contain ds columns,
where for any 1 ≤q i ≤q s-1 the columns di to
d(i+1)-1 contain the isotope measurements for the ith
organism.
For each organism, the isotopes (columns) must be in the same
order.
Value
A m \times d matrix, where m is the total number of
isotopic measurements (over all organisms) and d is the number
of isotopes.