jackknife.smacofB: SMACOF Jackknife

In smacof: Multidimensional Scaling

SMACOF Jackknife

Description

These methods perform a SMACOF Jackknife and plot the corresponding solution.

Usage

## S3 method for class 'smacofB'
jackmds(object, eps = 1e-6, itmax = 100, verbose = FALSE)

## S3 method for class 'smacofJK'
plot(x, plot.dim = c(1,2), hclpar = list(c = 50, l = 70), 
col.p, col.l, plot.lines = TRUE, legend = FALSE, inset = c(-0.2, 0), cex.legend = 0.7,
main, xlab, ylab, xlim, ylim, asp = 1, ...)

Arguments

object	Object of class "smacofB", i.e., an MDS solution from smacofSym()
itmax	Maximum number of iterations
eps	Convergence criterion
verbose	If TRUE, intermediate stress is printed out
x	Object of class "smacofJK"
plot.dim	Vector with dimensions to be plotted.
hclpar	Chroma and luminance to be used for HCL colors (further details see rainbow_hcl)
col.p	Point color. If omitted, hcl colors will be used; if specified, the corresponding (single) color will be used for plotting.
col.l	Line color. If omitted, hcl colors will be used; if specified, the corresponding (single) color will be used for plotting.
plot.lines	If TRUE, the Jackknife configurations are plotted are connected with their centroid.
legend	If TRUE, the centroid labels are added as legend.
inset	Inset distance from the margins as a fraction of the plot region when legend is placed by keyword.
cex.legend	Character expansion factor for legend.
main	Plot title.
xlab	Label of x-axis.
ylab	Label of y-axis.
xlim	Scale x-axis.
ylim	Scale y-axis.
asp	Aspect ratio.
...	Further plot arguments passed: see plot for detailed information.

Details

In order to examine the stability solution of an MDS, a Jackknife on the configurations can be performed (see de Leeuw & Meulman, 1986) and plotted. The plot shows the jackknife configurations which are connected to their centroid. In addition, the original smacof configuration (transformed through Procrustes) is plotted. The Jackknife function itself returns also a stability measure (as ratio of between and total variance), a measure for cross validity, and the dispersion around the original smacof solution.

Value

smacof.conf	SMACOF configurations
jackknife.conf	An array of n-1 configuration matrices for each Jackknife MDS solution
comparison.conf	Centroid Jackknife configurations (comparison matrix)
stab	Stability measure
cross	Cross validity
disp	Dispersion
loss	Value of the loss function
ndim	Number of dimensions
call	Model call
niter	Number of iterations
nobj	Number of objects

Author(s)

Jan de Leeuw and Patrick Mair

References

De Leeuw, J., & Meulman, J. (1986). A special jackknife for multidimensional scaling. Journal of Classification, 3, 97-112.

Mair, P., Groenen, P. J. F., De Leeuw, J. (2022). More on multidimensional scaling in R: smacof version 2, Journal of Statistical Software, 102(10), 1-47. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v102.i10")}

See Also

bootmds

Examples

## symmetric smacof
data <- na.omit(PVQ40[,1:5])
diss <- dist(t(data))   ## Euclidean distances 
fit <- mds(diss) 
res.jk <- jackmds(fit)

plot(res.jk, col.p = "black", col.l = "gray")
plot(res.jk, hclpar = list(c = 80, l = 40))
plot(res.jk, hclpar = list(c = 80, l = 40), plot.lines = FALSE)

smacof documentation built on Oct. 10, 2024, 5:09 p.m.