Raymond Hettinger <[email protected]> added the comment:
Would it be reasonable for me to get started with a "mostly good enough"
version using scaling and Kahan summation?
from operator import sub
from math import sqrt, fabs
def kahan_summation(seq):
# https://en.wikipedia.org/wiki/Kahan_summation_algorithm#The_algorithm
csum = 0
err = 0
for x in seq:
x -= err
nsum = csum + x
err = (nsum - csum) - x
csum = nsum
return csum
def hypot(*sides):
scale = max(map(fabs, sides))
return scale * sqrt(kahan_summation((s / scale)**2 for s in sides))
def dist(p, q):
return hypot(*map(sub, p, q))
assert all(hypot(*([1]*d)) == sqrt(d) for d in range(1, 10000))
print(dist(p=(11, 4, 10), q=(9, 10, 13.5)))
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<https://bugs.python.org/issue33089>
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