eanatSelect.Rd
The algorithm automatically selects the key nvecs
and hidden
sparseness
parameters. The user should select the cthresh
regularization parameters for his or her application. The principle used
here is that we want few but sparse pseudo-eigenvectors that are minimally
correlated in row-space. true left and right eigenvectors are uncorrelated
in both row and column (left and right eigenvector) spaces, but this is not
the case when we impose sparsity.
eanatSelect(
inmat,
mask = NULL,
cthresh = 0,
smooth = 0,
maxNEvec = 0,
selectorScale = 1.1,
whiten = FALSE,
verbose = FALSE
)
input matrix
input mask, must match matrix
remove isolated voxel islands of size below this value
smooth the input data first by this value
integer that, if set greater than zero, indicates that we use
a low-rank approximation to the input matrix before proceeding to eanat.
this value should be greater than nvecs
influences automatic selection of nvecs
and tries
to find the knee in the correlation plot. This parameter produces fewer,
less sparse eigenanatomy pseudo-eigenvectors as its value increases. Its
minimum value is 1 and a reasonable range is between 1 and 2. The user
should look at the plot produced when verbosity is turned on.
use ICA style whitening.
controls whether computation is silent or not.
nvecs is output, analogous to nvecs
in
svd(mat,nu=0,nv=nvecs)
if (FALSE) { # \dontrun{
mat <- matrix(rnorm(2000), ncol = 50)
nvecsSel <- eanatSelect(mat, selectorScale = 1.2, maxNEvec = 4)
esol <- sparseDecom(mat, nvecs = nvecsSel)
print(paste("selected", nvecsSel, "pseudo-eigenvectors"))
} # }