A bug on ceil function?

asked 2025-09-08 12:07:02 +0200

Ys1123
17 ●1 ●3 ●9

A following code

from math import ceil

val = (3**38 / (2*3 - 1) - 1) / 2
print(ceil(val) - val)

return

38/5

But this is weird since the value should be $< 1$ by the definition of the ceil function.

answered 2025-09-08 16:33:47 +0200

Max Alekseyev

7243 ●10 ●61 ●177

updated 2025-09-08 18:10:55 +0200

from math import ceil imports ceil function from Python's math module. So this bug (probably related to an insufficient precision of the float number resulting from division of 3**38) has nothing to do with Sage.

If you want ceil function from Sage, use from sage.all import ceil instead.

edit flag offensive delete link

Comments

Thank you, you're right. Then is this a bug of Python? Should I report this?

Ys1123 ( 2025-09-08 17:02:51 +0200 )edit

It's up to you. However, I think it's not a bug but just an insufficient precision of the standard Python's float type, which you obtain as the result of division of two ints.

Max Alekseyev ( 2025-09-08 18:09:24 +0200 )edit

add a comment

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

A bug on ceil function?

1 Answer

Comments

Your Answer

Question Tools

Stats

Related questions

A bug on ceil function? edit

1 Answer

Comments

Your Answer

Question Tools

Stats

Related questions

A bug on ceil function?