draw_U                  Samples from a Multivariate Normal Distribution
eval_marker             Fast Evaluation of Time-varying Marker Mean
                        Term
eval_surv_base_fun      Evaluates the Survival Function without a
                        Marker
get_gl_rule             Get Gauss–Legendre Quadrature Nodes and Weights
get_ns_spline           Faster Pointwise Function than ns
sim_joint_data_set      Simulate Individuals from a Joint Survival and
                        Marker Model
sim_marker              Simulate a Number of Observed Marker for an
                        Individual
surv_func_joint         Evaluates the Conditional Survival Function
                        Given the Random Effects
