Call:
ddhazard(formula = survival::Surv(stop, event) ~ group, data = head_neck_cancer, 
    by = 1, max_T = 20, a_0 = rep(0, 2), Q_0 = diag(1, 2), Q = diag(0.1, 
        2), order = 1, control = ddhazard_control(eps = 0.1))

'logit' model fitted with the 'EKF' method in 2 iterations of the EM algorithm.

Smoothed time-varying coefficients are:
   (Intercept)       sd     group1       sd 
 0   -2.806424 0.4064023 0.1519309 0.4488750
 1   -2.900230 0.2963087 0.1576313 0.3710721
 2   -2.882709 0.3038966 0.1967654 0.3681009
 3   -2.705877 0.3083772 0.3465329 0.3669497
 4   -2.493780 0.3060795 0.3738359 0.3596999
 5   -2.155285 0.3000692 0.6179947 0.3550072
 6   -2.220863 0.2842865 0.6247045 0.3420799
 7   -2.533987 0.2894582 0.4792392 0.3488193
 8   -2.745337 0.3070891 0.5477254 0.3696573
 9   -2.888184 0.3244203 0.5569002 0.3892709
10   -3.023716 0.3398963 0.5499547 0.4092841
11   -3.211450 0.3551100 0.4901311 0.4309866
12   -3.332078 0.3735791 0.5122906 0.4560824
13   -3.398163 0.3907957 0.6133135 0.4794959
14   -3.310568 0.4066644 0.7951986 0.5002089
15   -3.359136 0.4145446 0.7807030 0.5151636
16   -3.455511 0.4285787 0.7508514 0.5382961
17   -3.527923 0.4512216 0.7830024 0.5705099
18   -3.479997 0.4831253 0.8774581 0.6095133
19   -3.506452 0.5226339 0.9443396 0.6533208
20   -3.421549 0.5820568 1.0707865 0.7075980

The estimated diagonal entries of the covariance matrix in the state equation are:
(Intercept)      group1 
 0.10291497  0.09050972 

96 individuals used in estimation with 65 observed events.
