ANTsR (version 0.3.1)

sparseDecomboot: Convenience wrapper for eigenanatomy decomposition.

Description

Decomposes a matrix into sparse eigenevectors to maximize explained variance.

Usage

sparseDecomboot(inmatrix = NA, inmask = 0, sparseness = 0.01,
  nvecs = 50, its = 5, cthresh = 250, statdir = NA, z = 0,
  smooth = 0, initializationList = list(), mycoption = 0, nboot = 10,
  nsamp = 0.9, robust = 0, doseg = TRUE)

Arguments

inmatrix

n by p input images , subjects or time points by row , spatial variable lies along columns

inmask

optional antsImage mask

sparseness

lower values equal more sparse

nvecs

number of vectors

its

number of iterations

cthresh

cluster threshold

statdir

place on disk to save results

z

u penalty, experimental

smooth

smoothness eg 0.5

initializationList

see initializeEigenanatomy

mycoption

0, 1 or 2 all produce different output 0 is combination of 1 (spatial orthogonality) and 2 (subject space orthogonality)

nboot

boostrap integer e.g. 10 equals 10 boostraps

nsamp

value less than or equal to 1, e.g. 0.9 means 90 percent of data will be used in each boostrap resampling

robust

boolean

doseg

orthogonalize bootstrap results

Examples

# NOT RUN {
mat<-replicate(100, rnorm(20))
mydecom<-sparseDecomboot( mat, nboot=5, nsamp=0.9, nvecs=2 )

# }
# NOT RUN {
# for prediction
if ( usePkg("randomForest") & usePkg("spls") ) {
data(lymphoma)
training<-sample( rep(c(TRUE,FALSE),31)  )
sp<-0.001 ; myz<-0 ; nv<-5
ldd<-sparseDecomboot( lymphoma$x[training,], nvecs=nv ,
  sparseness=( sp ), mycoption=1, z=myz , nsamp=0.9, nboot=50 ) # NMF style
outmat<-as.matrix(ldd$eigenanatomyimages )
# outmat<-t(ldd$cca1outAuto)
traindf<-data.frame( lclass=as.factor(lymphoma$y[ training  ]),
  eig = lymphoma$x[training,]  %*% outmat )
testdf<-data.frame(  lclass=as.factor(lymphoma$y[ !training ]),
  eig = lymphoma$x[!training,] %*% outmat )
myrf<-randomForest( lclass ~ . ,   data=traindf )
predlymp<-predict(myrf, newdata=testdf)
print(paste('N-errors:',sum(abs( testdf$lclass != predlymp ) ),
  'non-zero ',sum(abs( outmat ) > 0 ) ) )
for ( i in 1:nv )
  print(paste(' non-zero ',i,' is: ',sum(abs( outmat[,i] ) > 0 ) ) )
}
# }
# NOT RUN {
 # end dontrun
# }