Imprecise Rounding in Python

Question

Is there an easy way to make Python round using 32 bits instead of 64 bits? It would work in the same way as JavaScript's Math.fround, but I've ran circles in my head failing to come up with a solution.

It would help giving examples of what you are trying to do, does this help: stackoverflow.com/a/11523128/5236575? — shoaib30
– shoaib30, Commented Sep 10, 2021 at 6:36
Is there a reason you would need to round from 32 bits instead of 64 bits? — Jason Chia
– Jason Chia, Commented Sep 10, 2021 at 6:41
I'm using a seeded pseudorandom generator from a video game and the values were off because it wasn't being rounded from 32 bits. — TrueGrace
– TrueGrace, Commented Sep 10, 2021 at 12:07

blhsing · Accepted Answer · 2021-09-10 06:55:46Z

3

One quick way to do it is to assign the number to the value of a ctypes.c_float object:

from ctypes import c_float

d = 1.2345678901234567890
f = c_float()
f.value = d
print(d) # 64-bit double
print(f.value) # 32-bit float

This outputs:

1.2345678901234567
1.2345678806304932

Compared to Math.fround in JavaScript:

console.log(Math.fround(1.2345678901234567890))

edited Sep 10, 2021 at 6:55

answered Sep 10, 2021 at 6:43

blhsing

109k9 gold badges88 silver badges132 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

JPcode · Accepted Answer · 2021-09-10 06:55:13Z

2

try using numpy float32

np.float32(6.33333333333)

you should read this other question.

answered Sep 10, 2021 at 6:55

JPcode

907 bronze badges

1 Comment

TrueGrace Over a year ago

Unfortunately, np.round() and np.around() don't function the same as Math.fround(). Thank you though!

Collectives™ on Stack Overflow

Imprecise Rounding in Python

2 Answers 2

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related