wilcox_R: What the package does (short line)

DregG <-
function(x1,y1,x2,y2,nullv=NULL,regfun=tshdreg,nboot=500,xout=FALSE,outfun=outpro,
SEED=TRUE,plotit=FALSE,pr=TRUE,...){
#
#  Global test that two dependent groups have identical 
#  regression parameters.
#
#  Use a variation of Hotelling's test coupled with a bootstrap 
#  estimate of the relevant covariance matrix associated with the differences
#  in the estimates of the parameters.#  For OLS, use DregGOLS
#
#  (plotit=F is used so that in simulations, if xout=T, the seed is not
#  set everytime outpro is called.)
#
if(SEED)set.seed(2)
X=elimna(cbind(x1,y1,x2,y2))
x1=as.matrix(x1)
x2=as.matrix(x2)
p=ncol(x1)
p1=p+1
p2=p+2
p3=p1+p
p4=p3+1
if(is.null(nullv))nullv=rep(0,p1)
x1=X[,1:p]
y1=X[,p1]
x2=X[,p2:p3]
y2=X[,p4]
n=length(y1)
if(xout){
flag1=outfun(x1,...)$out.id
flag2=outfun(x2,...)$out.id
flag=unique(c(flag1,flag2))
if(length(flag)>0)X=X[-flag,]
x1=X[,1:p]
y1=X[,p1]
x2=X[,p2:p3]
y2=X[,p4]
}
x1=as.matrix(x1)
x2=as.matrix(x2)
flagF=FALSE
flagF=identical(regfun,tsreg)
if(flagF){if(pr){
if(sum(duplicated(y1)>0))print('Duplicate values detected; regfun=tshdreg might have more power than tsreg')
pr=FALSE
}
if(pr){
if(sum(duplicated(y2)>0))print('Duplicate values detected; regfun=tshdreg might have more power than tsreg')
}}
data<-matrix(sample(length(y1),size=length(y1)*nboot,replace=TRUE),nrow=nboot)
bvec1<-apply(data,1,regboot,x1,y1,regfun=regfun,xout=FALSE,...)
# bvec is a p+1 by nboot matrix. The first row
#                     contains the bootstrap intercepts, the second row
#                     contains the bootstrap values for first predictor, etc.
bvec2<-apply(data,1,regboot,x2,y2,regfun=regfun,xout=FALSE,...)
dif=t(bvec1-bvec2)
temp<-pdis(rbind(dif,nullv))
sig.level<-sum(temp[nboot+1]<temp[1:nboot])/nboot
est1=regfun(x1,y1)$coef
est2=regfun(x2,y2)$coef
est=est1-est2
list(p.value=sig.level,est.1=est1,est.2=est2,estimate.dif = est)
}