QDataSets are less abstract and more flexible data model for das2.
QUBE -
Static variable in interface org.virbo.dataset.QDataSet
Boolean.TRUE indicates that the dataset is a "qube," meaning
that all dimensions have fixed length and certain optimizations and operators are allowed.
provides a convenient way of indexing qubes, returning an int[] of
length ds.rank() containing each dimension's length,
or null if the dataset is not a qube.