Compute the information matrix
InfoMatrix(object, initres)A list with three items
Total of Ifull and Iloss, true Fisher information
matrix
Full Fisher information matrix
Loss of information due to intervals (missing event times)
Fit obtained from fitit
Result from init
Three information matrices are computed. One is Ifull which interprets
the imputed R and Y data from object as actual observations.
Iloss gives the loss of information due to imputation. The sum of both matrices
is the true information matrix.