Fits transition-specific cause-specific random survival forests
on a clock-reset duration scale for acyclic, non-recurrent multistate
processes. Entry-conditioned state-occupation probabilities are assembled
from predicted cumulative hazards by semi-Markov entry-mass and sojourn
convolution on a validated regular grid. The one-row-per-subject interface
supports one common initial state, one recorded entry per state, baseline
time-fixed covariates, competing exits, and independent right censoring.
Left truncation, recurrent visits, directed cycles, time-dependent
covariates, and ongoing-sojourn dynamic prediction are not supported.
The package also provides calendar-time Aalen-Johansen point estimates as
a covariate-free descriptive baseline, transition-specific permutation
importance, genuine ranger edge OOB concordance, and patient-level
cross-validated IPCW state-probability scoring. Methods are described in
Ishwaran et al. (2008)