Timing of handling negative numbers raised to fractional powers.

gistfile1.txt

import cmath
import timeit


def test_a(s, p):
    try:
        x = s ** p
    except ValueError:
        # on python2, sqrt(negative number) does not
        # automatically lead to a complex number, but this is
        # needed for the corner case of mag=-0.4*dex
        x = cmath.exp(p * cmath.log(s))


def test_b(s, p):
    if s < 0.0 and p % 1.0 != 0.0:
        x = cmath.exp(p * cmath.log(s))
    else:
        x = s ** p


def test_a_neg():
    test_a(-0.4, 0.5)


def test_b_neg():
    test_b(-0.4, 0.5)


def test_a_pos():
    test_a(0.4, 0.5)


def test_b_pos():
    test_b(0.4, 0.5)


print min(timeit.repeat(test_a_neg, repeat=3, number=100000))
print min(timeit.repeat(test_a_pos, repeat=3, number=100000))
print min(timeit.repeat(test_b_neg, repeat=3, number=100000))
print min(timeit.repeat(test_b_pos, repeat=3, number=100000))