Numerical derivatives and integrals of functions bs() and ns() at their first argument.
dns(x, df = NULL, knots = NULL, intercept = FALSE, 
    Boundary.knots = range(x), eps = 1e-03)dbs(x, df = NULL, knots = NULL, intercept = FALSE, 
    Boundary.knots = range(x), eps = 1e-03)
ins(x, df = NULL, knots = NULL, intercept = FALSE, 
    Boundary.knots = range(x), from = 0, weight.fun = NULL, 
    integrand.fun = NULL, ...)
ibs(x, df = NULL, knots = NULL, intercept = FALSE, 
    Boundary.knots = range(x), from = 0, weight.fun = NULL, 
    integrand.fun = NULL, ...)
an object of class dns, dbs, ins or ibs.
see the help pages of functions ns() and bs().
a numeric scalar denoting the step length for the central difference approximation, which calculates the derivative.
a numeric scalar denoting the lower limit of the integral.
a function to be applied as weights.
a function to be applied in the integrand.
extra arguments passed to weight.fun.
Dimitris Rizopoulos d.rizopoulos@erasmusmc.nl