Python 3.6.5 Documentation >  Complex Number Objects

Complex Number Objects
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Python’s complex number objects are implemented as two distinct types
when viewed from the C API: one is the Python object exposed to
Python programs, and the other is a C structure which represents the
actual complex number value. The API provides functions for working
with both.

Complex Numbers as C Structures
===============================

Note that the functions which accept these structures as parameters
and return them as results do so *by value* rather than dereferencing
them through pointers. This is consistent throughout the API.

Py_complex

The C structure which corresponds to the value portion of a Python
complex number object. Most of the functions for dealing with
complex number objects use structures of this type as input or
output values, as appropriate. It is defined as:

typedef struct {
double real;
double imag;
} Py_complex;

Py_complex _Py_c_sum(Py_complex left, Py_complex right)

Return the sum of two complex numbers, using the C "Py_complex"
representation.

Py_complex _Py_c_diff(Py_complex left, Py_complex right)

Return the difference between two complex numbers, using the C
"Py_complex" representation.

Py_complex _Py_c_neg(Py_complex complex)

Return the negation of the complex number *complex*, using the C
"Py_complex" representation.

Py_complex _Py_c_prod(Py_complex left, Py_complex right)

Return the product of two complex numbers, using the C "Py_complex"
representation.

Py_complex _Py_c_quot(Py_complex dividend, Py_complex divisor)

Return the quotient of two complex numbers, using the C
"Py_complex" representation.

If *divisor* is null, this method returns zero and sets "errno" to
"EDOM".

Py_complex _Py_c_pow(Py_complex num, Py_complex exp)

Return the exponentiation of *num* by *exp*, using the C
"Py_complex" representation.

If *num* is null and *exp* is not a positive real number, this
method returns zero and sets "errno" to "EDOM".

Complex Numbers as Python Objects
=================================

PyComplexObject

This subtype of "PyObject" represents a Python complex number
object.

PyTypeObject PyComplex_Type

This instance of "PyTypeObject" represents the Python complex
number type. It is the same object as "complex" in the Python
layer.

int PyComplex_Check(PyObject *p)

Return true if its argument is a "PyComplexObject" or a subtype of
"PyComplexObject".

int PyComplex_CheckExact(PyObject *p)

Return true if its argument is a "PyComplexObject", but not a
subtype of "PyComplexObject".

PyObject* PyComplex_FromCComplex(Py_complex v)
*Return value: New reference.*

Create a new Python complex number object from a C "Py_complex"
value.

PyObject* PyComplex_FromDoubles(double real, double imag)
*Return value: New reference.*

Return a new "PyComplexObject" object from *real* and *imag*.

double PyComplex_RealAsDouble(PyObject *op)

Return the real part of *op* as a C "double".

double PyComplex_ImagAsDouble(PyObject *op)

Return the imaginary part of *op* as a C "double".

Py_complex PyComplex_AsCComplex(PyObject *op)

Return the "Py_complex" value of the complex number *op*.

If *op* is not a Python complex number object but has a
"__complex__()" method, this method will first be called to convert
*op* to a Python complex number object. Upon failure, this method
returns "-1.0" as a real value.