x-0.5: what is the - before performing?

Question

while finding a square-root, we perform number**0.5, but what is the meaning of - sign before 0.5.

I was looking at a code (I was specificially looking at ViT Code, and here for scaling, they have added:

self.scale = self.head_dim ** -0.5

Please help me understanding it meaning. I did few experiments on my terminal but did not understand what's happening:

>>> a = 4
>>> a**0.5
2.0
>>>
>>> a**-0.5
0.5

Look for "Negative exponents" here: [Exponentiation - Wikipdeia](https://en.wikipedia.org/wiki/Exponentiation). — wohlstad, Apr 29 '23 at 05:30
@mousetail Yeah, sorry I missed the fact that negative sign is just reciprocal (I knew it just could not recollect). Thanks for the answers. I will accept it once the timer is off. — Yogendra Yatnalkar, Apr 29 '23 at 05:31

score 2 · Accepted Answer · edited Apr 29 '23 at 05:30

2

Reciprocal. x**-n == 1/(x**n).......

edited Apr 29 '23 at 05:30

Ry-

answered Apr 29 '23 at 05:19

Mark Adler

x**-0.5: what is the - before ** performing?