'Test accuracy of math.hypot()'

from math import hypot, fsum, sqrt
from random import expovariate
from decimal import Decimal
from sys import float_info
from collections import Counter
from pprint import pprint

EPS = float_info.epsilon

hist = Counter()

def althypot(*args):
    scale = max(map(abs, args))
    return scale * sqrt(fsum((x/scale)**2.0 for x in args))

k = 100
n = 100_000
reverse = True
# hypot = althypot

for i in range(n):
    args = [expovariate(1.0) for i in range(k)]
    args.sort(reverse=reverse)
    expected = float(sum(x**2 for x in map(Decimal, args)).sqrt())
    actual = hypot(*args)
    ulps = ((actual / expected) - 1.0) / EPS
    hist[ulps] += 1
    #print(expected.hex(), actual.hex(), ulps)

print(f'k={k}, n={n}, reverse={reverse!r}')
pprint(hist.most_common())