R/fcab.R

In ldbounds: Lan-DeMets Method for Group Sequential Boundaries

"fcab" <- function(last,nints,yam1,h,x,stdv){
    f <- last*dnorm(h*c(0:nints)+yam1,mean=matrix(rep(x,nints+1),nints+1,length(x),byrow=TRUE),sd=stdv)
    area <- 0.5*h*(2*colSums(f)-f[1,]-f[nrow(f),]) # This is "trap"
    return(area)
  }