cmath

Complex-number arithmetic implemented in Python. Construct values with complex(real, imag=0) or imaginary literals such as 2j.

import cmath

value = complex(3, 4)
assert value.real == 3.0
assert value.imag == 4.0
assert value.conjugate() == complex(3, -4)
assert cmath.isclose(cmath.sqrt(complex(-1, 0)), complex(0, 1))
radius, angle = cmath.polar(value)
assert cmath.isclose(cmath.rect(radius, angle), value)

Group	Members
Coordinates	`phase(z)`, `polar(z)`, `rect(radius, angle)`
Powers/logarithms	`exp(z)`, `log(z, base=e)`, `log10(z)`, `sqrt(z)`
Trigonometry	`sin`, `cos`, `tan`, `asin`, `acos`, `atan`
Hyperbolic functions	`sinh`, `cosh`, `tanh`, `asinh`, `acosh`, `atanh`
Classification	`isfinite(z)`, `isinf(z)`, `isnan(z)`, `isclose(a, b)`
Constants	`pi`, `e`, `tau`, `inf`, `infj`, `nan`, `nanj`

Pass complex values explicitly to functions that access real and imag. isclose checks the real and imaginary parts with math.isclose; it does not accept CPython's tolerance keywords. Do not assume identical branch-cut or domain-error behavior for all inputs.

Implementation: cmath.py.