Optimize mixed-mode operations with small int's #231
Description
Consider following benchmark, which not uses integer literals during computation:
collatz0.py
# collatz0.py
import pyperf
from gmp import mpz
#from gmpy2 import mpz
zero = mpz(0)
one = mpz(1)
two = mpz(2)
three = mpz(3)
# https://en.wikipedia.org/wiki/Collatz_conjecture
def collatz(n):
total = 0
n = mpz(n)
while n > one:
n = n*three + one if n & one else n//two
total += 1
return total
runner = pyperf.Runner()
for i in [97, 871]:
h = f"collatz({i})"
runner.bench_func(h, collatz, i)| Benchmark | gmpy2.mpz | gmp.mpz |
|---|---|---|
| collatz(97) | 94.5 us | 84.7 us: 1.12x faster |
| collatz(871) | 141 us | 127 us: 1.11x faster |
| Geometric mean | (ref) | 1.11x faster |
But with integer literals in code - things are much worse:
collatz1.py
import pyperf
#from gmp import mpz
from gmpy2 import mpz
# https://en.wikipedia.org/wiki/Collatz_conjecture
def collatz(n):
total = 0
n = mpz(n)
while n > 1:
n = n*3 + 1 if n & 1 else n//2
total += 1
return total
runner = pyperf.Runner()
for i in [97, 871]:
h = f"collatz({i})"
runner.bench_func(h, collatz, i)| Benchmark | gmpy2.mpz | gmp.mpz |
|---|---|---|
| collatz(97) | 91.7 us | 151 us: 1.64x slower |
| collatz(871) | 138 us | 225 us: 1.64x slower |
| Geometric mean | (ref) | 1.64x slower |
This may depend on diofant/zz#3, but clearly does make sense alone.