Arguments
x
A numeric vector of the values of the first covariate at which to evaluate the B-spline marginal functions.
The values in x must be between xk[m[1]+2] and
xk[length(xk) - m[1] - 1].
z
A numeric vector of the values of the second covariate at which to evaluate the B-spline marginal functions.
The values in z must be between zk[m[2]+2] and
zk[length(zk) - m[2] - 1].
xk
A numeric vector of knot positions for the first covariate, x, with non-decreasing values.
zk
A numeric vector of knot positions for the second covariate,z, with non-decreasing values.
m
A pair of two numbers where m[i]+1 denotes the order of the basis of the $i^{th}$ marginal smooth
(e.g. m[i] = 2 for a cubic spline.)
q1
A number denoting the basis dimension of the first marginal smooth.
q2
A number denoting the basis dimension of the second marginal smooth.