R/estimate_twonn.R
estimate_twonn.Rd
Unlike many intrinsic dimension (ID) estimation methods, est.twonn
only requires
two nearest datapoints from a target point and their distances. This extremely minimal approach
is claimed to redue the effects of curvature and density variation across different locations
in an underlying manifold.
est.twonn(X)
an \((n\times p)\) matrix or data frame whose rows are observations.
a named list containing containing
estimated intrinsic dimension.
Facco E, d'Errico M, Rodriguez A, Laio A (2017). “Estimating the Intrinsic Dimension of Datasets by a Minimal Neighborhood Information.” Scientific Reports, 7(1).
# \donttest{
## create 3 datasets of intrinsic dimension 2.
X1 = aux.gensamples(dname="swiss")
X2 = aux.gensamples(dname="ribbon")
X3 = aux.gensamples(dname="saddle")
## acquire an estimate for intrinsic dimension
out1 = est.twonn(X1)
out2 = est.twonn(X2)
out3 = est.twonn(X3)
## print the results
line1 = paste0("* est.twonn : 'swiss' gives ",round(out1$estdim,2))
line2 = paste0("* est.twonn : 'ribbon' gives ",round(out2$estdim,2))
line3 = paste0("* est.twonn : 'saddle' gives ",round(out3$estdim,2))
cat(paste0(line1,"\n",line2,"\n",line3))
#> * est.twonn : 'swiss' gives 1.96
#> * est.twonn : 'ribbon' gives 2.27
#> * est.twonn : 'saddle' gives 2.09
# }