MData-class: A Reference Class which represents multivariate data.
Description
MData is a reference class which represents multivariate objects. The data
can be ordered by time (multivariate time series). In the last case, the
field X represents the time.
Arguments
Fields
X
Numeric vector of length m.
Y
Matrix of size \((m, d)\) representing a \(d\) dimension
function of X observed at points \(1,\dots,m\).