prec.py

Created by andreanx

Created on August 11, 2024

443 Bytes

Check floats precision.

Syntax :

precm(b) for the mantissa precision where b is the base.

prece(b) for the exponent precision where b is the base.

Examples :

precm(2) for the maximum number of bits used for the mantissa

precm(10) for the maximum number of significative digits used for the mantissa

prece() for the minimum and maximum values for the exponent.

from math import tan

def precm(b):
  k,b=0,float(b)
  while 1+b**-k-1>0:
    k+=1
  return k

def prece():
  a=-1
  while 2.**a>0:
    a*=2
  while 2.**a==0:
    a+=1
  b=1
  while str(2.**b)[0:3]!='inf':
    b*=2
  while str(2.**b)[0:3]=='inf':
    b-=1
  return [a,b]
  
def precm2(b):
  n = 0
  dold = 0
  while 1:
   d = tan(355/226 + b**-n) - tan(355/226)
   if d == dold or d < 0:
     break
   dold = d
   n += 1
  return n