umbrella function

Umbrella alternative.

Using the umbrella alternative to merge certain entries to make the sequence of ttot/deaths to increase then decrease or to decrease then increase. Note that the pava function imposes non-decreasing or non-increasing order. This function directly uses function pava().

umbrella(time_die,ttot,deaths,indi)

Arguments

• time_die: a sequence of times where deaths happened.
• ttot: the total time on test between each time point and the previous time point (or 0).
• deaths: the number of deaths at each time point.
• indi: an indicator indi == 0: monotonic failure rate (either decrease or increase) indi == 1: denoting the failure rate increase then decrease indi == 2: denoting the failure rate decrease then increase

Returns

time2 == the merged time_die after the umbrealla alternative order restriction; struct == a structure saves the partition information; label == a note about how the failure rate varies; indx == the position where the change point value is.

Examples

data(pava_dfrd)
t_d = pava_dfrd[,1]
t = pava_dfrd[,2]
d = pava_dfrd[,3]
umbrella(t_d, t, d, 2)