do.cisomap {Rdimtools} | R Documentation |
Conformal Isometric Feature Mapping
Description
Conformal Isomap(C-Isomap) is a variant of a celebrated method of Isomap. It aims at, rather than preserving full isometry, maintaining infinitestimal angles - conformality - in that it alters geodesic distance to reflect scale information.
Usage
do.cisomap(
X,
ndim = 2,
type = c("proportion", 0.1),
symmetric = c("union", "intersect", "asymmetric"),
weight = TRUE,
preprocess = c("center", "scale", "cscale", "whiten", "decorrelate")
)
Arguments
X |
an |
ndim |
an integer-valued target dimension. |
type |
a vector of neighborhood graph construction. Following types are supported;
|
symmetric |
one of |
weight |
|
preprocess |
an additional option for preprocessing the data.
Default is "center". See also |
Value
a named list containing
- Y
an
(n\times ndim)
matrix whose rows are embedded observations.- trfinfo
a list containing information for out-of-sample prediction.
Author(s)
Kisung You
References
Silva VD, Tenenbaum JB (2003). “Global Versus Local Methods in Nonlinear Dimensionality Reduction.” In Becker S, Thrun S, Obermayer K (eds.), Advances in Neural Information Processing Systems 15, 721–728. MIT Press.
Examples
## generate data
set.seed(100)
X <- aux.gensamples(dname="cswiss",n=100)
## 1. original Isomap
output1 <- do.isomap(X,ndim=2)
## 2. C-Isomap
output2 <- do.cisomap(X,ndim=2)
## 3. C-Isomap on a binarized graph
output3 <- do.cisomap(X,ndim=2,weight=FALSE)
## Visualize three different projections
opar <- par(no.readonly=TRUE)
par(mfrow=c(1,3))
plot(output1$Y, main="Isomap")
plot(output2$Y, main="C-Isomap")
plot(output3$Y, main="Binarized C-Isomap")
par(opar)