def pi():
# Compute digits of Pi.
# Algorithm due to LGLT Meertens.
k, a, b, a1, b1 = 2, 4, 1, 12, 4
while 1:
p, q, k = k*k, 2*k+1, k+1
a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1
d, d1 = a//b, a1//b1
while d == d1:
yield d
a, a1 = 10*(a%b), 10*(a1%b1)
d, d1 = a//b, a1//b1
#//python/2393