Getter for transition probability matrix
Examples
data(test_data)
get_transition_matrix(test_data, "without_drug")
#> to
#> from Asymptomatic_disease Progressive_disease Dead
#> Asymptomatic_disease 0.9521 0.0100 0.0379
#> Progressive_disease 0.0000 0.8121 0.1879
#> Dead 0.0000 0.0000 1.0000
