Bugfix/fix bigint issues

[shardator]

Fix for the bigint issue: Removed any floating point calculations, using an improved integer sqrt algorithm from https://stackoverflow.com/a/31224469/8637159

[shardator]

Links to #2

[n1ngu]

Removing float point calculations is the way to go. But the isqrt implementation shouldn't be responsibility of this package.

As of 2021 the way to go is simply require python>3.8 and use https://docs.python.org/3.8/library/math.html#math.isqrt

For other versions, the gmpy2 library could be required and the isqrt function could be conditionally imported from the correct place:

try:
  from gmpy2 import isqrt
except ImportError:
  from math import isqrt
except ImportError:
  from math import sqrt
  def isqrt(x):
    return int(sqrt(x))

and maybe raise warnings about upgrading your python installations or collecting adequate extra packages unless an underperformant depairing function is acceptable.

At the end, all this is a packaging issue. And I fear this package is rather immature in this regard 😢 . Yet, it shouldn't be hard. I could work it out if the owner is willing to give this package some live.