The memoisation is the convex hull computation in fundiversity is
controlled via the fundiversity.memoise option:
if unset, the default is to use memoisation if memoise was installed when fundiversity was loaded, and not to use memoisation otherwise.
if
options(fundiversity.memoise = TRUE), memoisation is used and an error is thrown if memoise is not installed.if
options(fundiversity.memoise = FALSE), memoisation is not used.