#deviance loss function
loss = function(y,phat,wht=0.0000001) {
#y should be 0/1
#wht shrinks probs in phat towards .5, don't log 0!
   if(is.factor(y)) y = as.numeric(y)-1
   phat = (1-wht)*phat + wht*.5
   py = ifelse(y==1,phat,1-phat)
   return(-2*sum(log(py)))
}