frexp returns mantissa and exponent of input number in Python

frexp() returns the mantissa and exponent of an input number.

frexp(n) # (m,e)

n : is the input number
m : is the mantissa , a floating point number
e : is the exponent , an integer

Relation between input number with Mantissa and exponent

n == m * 2**e

Example

import math
print(math.frexp(4))

Output of this is here.

(0.5,3)

We can check the output

print((0.5)*(2**(3))) # 4.0

Examples with negative numbers

import math
print(math.frexp(-5))    # (-0.625,3)
print((-0.625)*(2**(3))) # -5.0

Using 0

import math
print(math.frexp(0))   # (0.0, 0)

Understanding math.frexp() in Python

Use Case: Scientific Computing
frexp() is useful in breaking down floating-point numbers, particularly in scientific computing or low-level operations where manipulating mantissa and exponents is required.

import math
mantissa, exponent = math.frexp(128.0)  # Outputs: (0.5, 8)
print(f"Mantissa: {mantissa}, Exponent: {exponent}")

Comparison with ldexp()

mantissa, exponent = math.frexp(8)
print(math.ldexp(mantissa, exponent))  # Outputs 8.0

Both functions are often paired to break down and reconstruct numbers.

We can also use ldexp() the inverse function of frexp() to get the number n

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Subhendu Mohapatra

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