Creates an observation functor that applies left-censoring at time
tau. Systems that fail after tau are observed exactly;
systems that fail before tau are left-censored (we only know
T < tau).
Value
Observation functor: function(t_true) returning a list
with t, omega ("left" or "exact"), and
t_upper (NA).
Examples
obs <- observe_left_censor(tau = 10)
obs(5) # left: list(t = 10, omega = "left", t_upper = NA)
#> $t
#> [1] 10
#>
#> $omega
#> [1] "left"
#>
#> $t_upper
#> [1] NA
#>
obs(15) # exact: list(t = 15, omega = "exact", t_upper = NA)
#> $t
#> [1] 15
#>
#> $omega
#> [1] "exact"
#>
#> $t_upper
#> [1] NA
#>