Edit - Stack Overflow

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Rev

9

I'm always amazed by how simple this method is, and how fast it converges. It was known loooooong before Newton, BTW.

Eric Duminil
– Eric Duminil

2022-01-21 21:48:15 +00:00
Commented Jan 21, 2022 at 21:48
6

@EricDuminil Still, a Python implementation of Newton's method for sqrt will probably always be much slower than the builtin sqrt function and therefore not recommended for practical purposes. The answer would be improved if it would discuss when this implementation should be used (higher accuracy maybe even or faster for arbitrary roots or showcasing what math.sqrt likely does)?

NoDataDumpNoContribution
– NoDataDumpNoContribution

2022-01-22 15:46:27 +00:00
Commented Jan 22, 2022 at 15:46
5

@Trilarion math.sqrt probably directly calls a processor's square root instruction. The only good reason I can think of for using something else is when you have unique requirements, e.g. looking for an integer square root.

Mark Ransom
– Mark Ransom

2022-01-22 19:23:54 +00:00
Commented Jan 22, 2022 at 19:23
You can swap types in this version too, and using fractions or fixed point numbers can fix the problem of this being a slower math.sqrt too.

Uncle Dino
– Uncle Dino

2022-01-25 14:35:59 +00:00
Commented Jan 25, 2022 at 14:35
I don't think it is a good idea to implement such a critical function in Python itself. I'd rather make this a C function and call that from Python.

Shambhav
– Shambhav

2022-01-27 07:18:03 +00:00
Commented Jan 27, 2022 at 7:18

| Show 1 more comment

Correct minor typos or mistakes
Clarify meaning without changing it
Add related resources or links
Always respect the author’s intent
Don’t use edits to reply to the author

create code fences with backticks ` or tildes ~
```
like so
```
add language identifier to highlight code
```python
def function(foo):
print(foo)
```
put returns between paragraphs
for linebreak add 2 spaces at end
_italic_ or **bold**
indent code by 4 spaces
backtick escapes `like _so_`
quote by placing > at start of line
to make links (use https whenever possible)

<https://example.com>

[example](https://example.com)

<a href="https://example.com">example</a>

formatting help »
answering help »

Collectives™ on Stack Overflow