On Sun, 24 Feb 2008 12:19:53 -0800, Mensanator wrote: > Out of curiosity, of what use is denominator limits? > > The problems where I've had to use rationals have never afforded me such > luxury, so I don't see what your point is.
It ensures that your fraction's denominator doesn't grow indefinitely, at the cost of some precision. In principle, fraction denominators can grow exponentially. In practice, probably less quickly, but still quickly enough that people on this list have reported that adding two fractions lead to millions of digits in each denominator and massive paging as their computer struggled to perform the addition. The beauty of fractions is that they give you infinite precision. The danger of fractions is that it takes a lot of memory to store infinitely precise numbers :) Frankly, I think that for most real-world data, it's unlikely to be a problem, but Guido's experiences with ABC were the opposite. But then we don't know how naive the ABC fraction libraries were. For all I know they did this: 1/2 + 1/2 = 4/4 4/4 - 1/2 = 4/8 4/8 + 1/2 = 16/16 etc. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
