Converts the standard plpData to a sparse matrix
toSparseM(plpData, cohort = NULL, map = NULL)
Returns a list, containing the data as a sparse matrix, the plpData covariateRef and a data.frame named map that tells us what covariate corresponds to each column This object is a list with the following components:
A sparse matrix with the rows corresponding to each person in the plpData and the columns corresponding to the covariates.
The plpData covariateRef.
A data.frame containing the data column ids and the corresponding covariateId from covariateRef.
This function converts the covariate file from ffdf in COO format into a sparse matrix from the package Matrix
#TODO