A very interesting algorithm has been recently suggested by H. W. Lenstra, Jr.  for solving integer programming problems. One part of that algorithm was further improved in . The algorithm was shown to be polynomial in the length of the input, for a fixed number of variables. On the other hand the algorithm is impractical for a large number of variables and its implementation is not clear even for a small number of variables. We suggest here a few simplifications and improvements to that algorithm, making its implementation easy (though still impractical for a great number of variables). As a byproduct we show how to solve diophantine linear equations over the nonnegative integers. For a small number of variables (3 or 4) a practical and fast algorithm for solving such equation results.