piecewise_xy {IBMPopSim}

Piecewise real function of two variables.

Description

Given the vectors ⁠(breaks[1],...,breaks[n])⁠ and the list of IBMPopSim compatible functions ⁠funs = (f[0],f[1],...,f[n])⁠ (one value more!), piecewise_xy(breaks, funs) returns the function

f(x,y) = f_0(x) {1}_{y\le breaks[1]}+\sum_{k=1}^{n-1} f_k(x) {1}_{[breaks_{k}, breaks_{k+1})}(y) + f_n(x){1}_{y \ge breaks[n]}

Usage

piecewise_xy(breaks, funs)

Arguments

breaks

Numeric vector giving the breaks of functions given in funs. Must be sorted with unique values.

funs

List of functions.

Details

A C++ version of this function is available. See vignette('IBMPopSim_cpp') for more details.

Value

Piecewise bivariate function built with the given intervals and functions.

Examples

time_dep_function <- piecewise_xy(c(5),
                                  list(gompertz(0.1, 0.005), gompertz(0.08, 0.005)))
time_dep_function(0, 65)  # death intensity at time 0 and age 65.