\name{getRatio}
\alias{getRatio}
\title{getRatio}
\usage{getRatio(a, b)}
\description{provide numerator and denominator, return numerator/denominator}
\value{numerator/denominator}
\author{Guangchuang Yu \url{http://ygc.name}}
\arguments{\item{a}{numerator}
\item{b}{denominator}}