CODEWITHSUNDEEP
pythonpython-2.7
Charlie Cai
Charlie Cai

Reputation: 79

calcuale ----OverflowError: long int too large to convert to float

en_1 = 1
n = 1
factorial = 1
invfactorial = 1
    while en_1 > 1e-6 :
        en = en_1 +invfactorial
        n = n + 1
        factorial = factorial * n
        invfactorial = float(1.0/factorial)
        en_1 = en 
print "e = %.5f"%en

I want to calculate e via this code, but it cannot work.

Upvotes: 0

Views: 615

Answers (1)

Steven Rumbalski
Steven Rumbalski

Reputation: 45542

en_1 > 1e-6 will never evaluate to True. en_1 just gets bigger and bigger. At some point you end up with numbers so large that Python can't handle the conversions. Instead compare to invfactorial > 1e-6:

en_1 = 1
n = 1
factorial = 1
invfactorial = 1
while invfactorial > 1e-6:  # changed comparison
    en = en_1 +invfactorial
    n = n + 1
    factorial = factorial * n
    invfactorial = float(1.0/factorial)
    en_1 = en # don't need both en_1 and en

This could be made much simpler:

e = n = fac = 1
while 1.0/fac > 1e-6:
    fac *= n
    e += 1.0/fac
    n += 1

Upvotes: 1

Related Questions