oregMclust {edci} | R Documentation |
Computation of center points for regression data by orthogonal regression. A cluster method based on redescending M-estimators is used.
oregMclust(datax, datay, bw, method="const", xrange=range(datax), yrange=range(datay), prec=4, na=1, sa=NULL, nl=10, nc=NULL, brmaxit=1000) regparm(reg) plot.oregMclust(x, datax, datay, prec=3, rcol="black", rlty=1, rlwd=3, ...) print.oregMclust(x, ...)
datax,datay |
numerical vectors of coordinates of the
observations. Alternativly, a matrix with two or three columns can
be given. The first two columns are interpreted as coordinates of
the observations and, if available, the third is passed to parameter
sa . |
bw |
positive number. Bandwidth for the cluster method. |
method |
optional string. Method of choosing starting values for
maximization. Possible values are:
|
xrange, yrange |
optional numerical intervals describing the domains of the observations. This is only used for normalization of the data. Note, that both intervals should have approximately the same length or should be transformed otherwise. This is not done automatically since this transformation affects the choice of the bandwidth. |
prec |
optional positive integer. Tuning parameter for
distinguishing different clusters, which is passed to
deldupMclust . |
na |
optional positive integer. Number of angles per observation
used as starting values if method="const" is chosen (default). |
sa |
optional numerical vector. Angles (within [0,2pi)) used as
starting values if method="const" is chosen (default). |
nl |
optional positive integer. Number of starting lines in each
iteration, if method="prob" is chosen. |
nc |
optional positive integer. Number of clusters to search, if
method="prob" is chosen. Note that, if nc is to
large, e.g. nc clusters cannot be found, the function does not
terminate. Attention! Using Windows, the routine cannot even be
breaked manually in this case! |
brmaxit |
optional positive integer. Since the maximization could
be very slow in some cases depending on the starting value, the
maximization is stopped after brmaxit iterations. |
reg,x |
Object returned from oregMclust . |
rcol,rlty,rlwd |
optional graphic parameters used for plotting regression lines. |
... |
Additional parameters passed to plot . |
oregMclust
implements a cluster method based on redescending
M-estimators for the case of orthogonal regression. This method is
introduced by Müller and Garlipp in 2003 (see references).
regparm
transforms the columns "alpha" and "beta" to
"intersept" and "slope".
See also bestMclust
, projMclust
, and
envMclust
for choosing the 'real' clusters out of the
found.
Return value is a numerical matrix containing one row for every found
regression center line. The Columns "alpha" and "beta" are their
parameters in the representation (cos(alpha),sin(alpha))(x,y)' =
beta, where alpha is within [0,2pi). For representation y=mx+b,
the return value can be passed to regparm
.
The columns "value" and "count" give the value of the objective
function and the number, how often they are found.
Tim Garlipp, garlipp@mathematik.uni-oldenburg.de
Müller, C.H., Garlipp, T. (2003) Simple consistent cluster methods based on redescending M-estimators with an application to edge identification in images, to appear in JMVA.
bestMclust
, projMclust
,
envMclust
, deldupMclust
x <- c(rnorm(100,0,3),rnorm(100,5,3)) y <- c(-2*x[1:100]-5,0.5*x[101:200]+30)/2 x <- x + rnorm(200,0,0.5) y <- y + rnorm(200,0,0.5) reg <- oregMclust(x,y,1,method="prob") reg <- projMclust(reg,x,y) reg plot(bestMclust(reg,2,crit="proj"),x,y)