A global variable called X.spmd should exist in the
.pmclustEnv
environment, usually the working environment. The X.spmd
is the data matrix to be clustered, and this matrix has a dimension
N.spmd by p.
The PARAM will be a local variable for the current iteration inside
em.onestep,
and this variable is a list containing all parameters related to models.
This function also updates in the parameters by the EM algorithm, and
return a new PARAM for the next iteration.
The details of list elements are initially
generated by set.global.