Returns a list with the slots
\(q\) (scalar, number of problems),
\(n\) (vector of length \(q\), number of samples)
and \(p\) (scalar, number of features)
Arguments
x
list of \(q\) matrices,
with \(n_k\) (samples) rows and \(p\) columns (features),
for \(k\) in \(1,\ldots,q\)
y
list of \(q\) vectors,
with \(n_k\) entries,
for \(k\) in \(1,\ldots,q\)