Falternate3 {EnviroStat} | R Documentation |
Perform simultaneous estimation of coords and exponential or gaussian variogram by alternating weighted least squares.
Falternate3(disp, coords, model = 1, a0 = 0.1, t0 = 0.5, max.iter = 50, max.fcal = 100, alter.lim = 50, tol = 1e-05, prt = 0, dims = 2, lambda = 0, ncoords, dev.mon = NULL, verbose = FALSE)
disp |
n \times n dispersion matrix, equal to 2 - 2 (spatial correlation matrix) |
coords |
n \times 2 coordinate matrix |
model |
type of variogram: 1 for exponential or 2 for gaussian |
a0, t0 |
initial variogram parameter estimates |
max.iter, max.fcal |
control parameter for calls to non-linear optimization routines (same values used in MDS step and in variogram step) |
alter.lim |
maximum number of iterations of pairs of alternating calls to
|
tol |
convergence criterion for coordinate estimates |
prt |
not used |
dims |
dimension of multi-dimensional scaling |
lambda |
smoothing parameter |
ncoords |
n \times 2 optional initial coordinates to use if not G-plane |
dev.mon |
Function to open the graphics device used for plots monitoring the
convergence of objective. If |
verbose |
if |
This version permits dimension > 2 for scaling. In the plotting we'll use a plot symbol proportional to the third coordinate.
A list containing the following named components:
variogfit |
Fitted variogram parameters with new locations |
ncoords |
n\times 2 matrix with coordinates of new locations |
make sure that coords are scaled reasonably small before attempting to compute; otherwise matrix inversion is likely not to work in calculation of bending energy matrix.
This version also passes a smoothing parameter to the optimization. This parameter probably is not scaled exactly the same as it is in sinterp and this has not been investigated yet.