I was a bit reluctant to post this question here since "support"
shouldn't mean teaching me how to write programs. But Jason Grout
suggested me to post it here anyway.
Here is a very short script that I want to maximize the speed
def lspec(n):
return sorted([k if k^2 < 2*n else 2*n/k for k in divisors
(odd_part(n))])
At first, I think I can make it faster by avoiding computing k^2 in
the for loop by replacing k^2 > 2*n by
k > r where r = sqrt(RDF(2*n)) is computed once outside the for loop.
However, it looks like comparing two entities of different types is
very slow in SAGE so I ended up with a slower script if a do that.
Also I tried to replace k by 2*n/k only for those k in divisors
(odd_part(n)) whose squares are > 2*n (instead of doing a list
comprehension) but the resulting script is not any faster.
Thanks in advance
P.S. I implemented the algorithm using PARI/GP, the result is almost
200 times faster.
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