In the worst case complexity analysis of all the polynomial algorithms in linear programming such as ellipsoid method and interior point method, there is an assumption that the input data must be integer. Using this assumption, then they bound the bitlength of input data by $L$. Now, the question is as follows:Q: How can this assumption be met for a linear programming with rational data. In other words, does there exist a way to convert the LP with rational data to an integer one? To me, it seems as though there is a way since data integrality is an assumption for these algorithms. 
Rational LP to integer LP
optimization;linear programming