document algorithm, and add configurable variables
document algorithm, and add configurable variables

FredXue/boomerang,forcedotcom/kylie,sdgdsffdsfff/boomerang,sdgdsffdsfff/boomerang,levexis/boomerang,levexis/boomerang,forcedotcom/kylie,yahoo/boomerang,FredXue/boomerang,lognormal/boomerang,lognormal/boomerang