# Plots an FEM functional data object. Plots a FEM object fdobj over a rectangular grid defined by vectors Xgrid and Ygrid. ```r plotFEM.fd(fdobj, Xgrid=NULL, Ygrid=NULL, nderivs=rep(0,2), xlab="X", ylab="Y", zlab="Z", main="", ticktype="detailed", r=10, phi=15, theta=30) ``` ## Arguments - `fdobj`: A surface defined by a finite element FEM basis. - `Xgrid`: A vector of X coordinate values. - `Ygrid`: A vector of Y coordinate values. - `nderivs`: A vector of length 2 indicating order of partial derivatives. - `xlab`: A character vector for labelling the X-axis when using function `persp`. - `ylab`: A character vector for labelling the Y-axis when using function `persp`. - `zlab`: A character vector for labelling the Z-axis when using function `persp`. - `main`: A character vector for the title when using function `persp`. - `ticktype`: A character vector for defining the tick marks when using function `persp`. - `r`: A positive number for the distance of the eyepoint from the center of the plot when using function `persp`. - `phi`: A number specifying the collatitude when using function `persp`. - `theta`: A number specifying the azimuthal direction when using function `persp`. ## Returns No return value, called for side effects. ## See Also `plotFEM.mesh`, `eval.FEM.fd` ## Examples ```r # Set up and plot a square with side length one with 32 interior triangles, # and then create an order one functional basis object of type FEM. m <- 4 petList <- squareMesh(m) pts <- petList$p edg <- petList$e tri <- petList$t pts <- pts/m plotFEM.mesh(pts, tri) norder <- 1 FEMbasis <- create.FEM.basis(pts, edg, tri, norder) # set up surface values on the nodes of this mesh data <- sin(2*pi*pts[,1])*cos(2*pi*pts[,2]) # smooth the data FEMList <- smooth.FEM.basis(pts, data, FEMbasis) sincosfd <- FEMList$fd # set up a 21 by 21 grid of plotting points Npts <- 21 Xpts <- seq(0,1,len=Npts) Ypts <- Xpts # plot the surface oldpar <- par(no.readonly = TRUE) plotFEM.fd(sincosfd, Xpts, Ypts) # plot the X partial derivative of the surface plotFEM.fd(sincosfd, Xpts, Ypts, c(1,0)) # plot the Y partial derivative of the surface plotFEM.fd(sincosfd, Xpts, Ypts, c(0,1)) par(oldpar) ```

plotFEM.fd function