| eval.FEM.basis {SpatialfdaR} | R Documentation |
Values of a Finite Element Functional Data Object
Description
Evaluate a finite element (FEM) functional data object at specified locations, or evaluate a pair of partial derivatives of the functional object.
Usage
eval.FEM.basis(obspts, FEMbasis, nderivs=rep(0,2))
Arguments
obspts |
a two-column matrix of x- and Y-coordinate values at which the functional data object is to be evaluated. |
FEMbasis |
an FEM functional basis object to be evaluated. |
nderivs |
a vector length 2 containing a pair of orders of derivatives. If the FEM basis is piecewise linear (of order 1), the only admissible pairs are (0,0), (0,1) and (1,0). If the FEM basis is piecewise quadratic (of order 2), the pairs (1,1), (0,2) and (2,0) are also admissible. |
Details
Two common uses of this function are (1) to evaluate the surface at one or more significant points, and (2) evaluate the surface over a bounding rectangle so that the surface can be plotted as either a contour plot are as a persp type plot. Points that are outside of polygon defining the surface are given the value NA, and are therefore not plotted.
Value
an array of 2 or 3 dimensions containing the surface
values. The first two dimension correspond to the arguments obspts and,
if present, the third dimension corresponds to the surface
in the situation where the coefficient matrix has multiple columns.