Possible bug of sum function
Consider the following code:
def s(n): return sum(k/n for k in range(n + 1)) L0 = s(2) for n in range(2, 3): L1 = s(n)
The answers are (using sage 7.1):
print L0, L1 (3/2, 1)
In the second case sage is using the usual integer division of python 2.x while in the first one it is using the exact representation of rationals. Is this a known bug?