1.. highlight:: c
2
3.. _complexobjects:
4
5Complex Number Objects
6----------------------
7
8.. index:: object: complex number
9
10Python's complex number objects are implemented as two distinct types when
11viewed from the C API:  one is the Python object exposed to Python programs, and
12the other is a C structure which represents the actual complex number value.
13The API provides functions for working with both.
14
15
16Complex Numbers as C Structures
17^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
18
19Note that the functions which accept these structures as parameters and return
20them as results do so *by value* rather than dereferencing them through
21pointers.  This is consistent throughout the API.
22
23
24.. c:type:: Py_complex
25
26   The C structure which corresponds to the value portion of a Python complex
27   number object.  Most of the functions for dealing with complex number objects
28   use structures of this type as input or output values, as appropriate.  It is
29   defined as::
30
31      typedef struct {
32         double real;
33         double imag;
34      } Py_complex;
35
36
37.. c:function:: Py_complex _Py_c_sum(Py_complex left, Py_complex right)
38
39   Return the sum of two complex numbers, using the C :c:type:`Py_complex`
40   representation.
41
42
43.. c:function:: Py_complex _Py_c_diff(Py_complex left, Py_complex right)
44
45   Return the difference between two complex numbers, using the C
46   :c:type:`Py_complex` representation.
47
48
49.. c:function:: Py_complex _Py_c_neg(Py_complex complex)
50
51   Return the negation of the complex number *complex*, using the C
52   :c:type:`Py_complex` representation.
53
54
55.. c:function:: Py_complex _Py_c_prod(Py_complex left, Py_complex right)
56
57   Return the product of two complex numbers, using the C :c:type:`Py_complex`
58   representation.
59
60
61.. c:function:: Py_complex _Py_c_quot(Py_complex dividend, Py_complex divisor)
62
63   Return the quotient of two complex numbers, using the C :c:type:`Py_complex`
64   representation.
65
66   If *divisor* is null, this method returns zero and sets
67   :c:data:`errno` to :c:data:`EDOM`.
68
69
70.. c:function:: Py_complex _Py_c_pow(Py_complex num, Py_complex exp)
71
72   Return the exponentiation of *num* by *exp*, using the C :c:type:`Py_complex`
73   representation.
74
75   If *num* is null and *exp* is not a positive real number,
76   this method returns zero and sets :c:data:`errno` to :c:data:`EDOM`.
77
78
79Complex Numbers as Python Objects
80^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
81
82
83.. c:type:: PyComplexObject
84
85   This subtype of :c:type:`PyObject` represents a Python complex number object.
86
87
88.. c:var:: PyTypeObject PyComplex_Type
89
90   This instance of :c:type:`PyTypeObject` represents the Python complex number
91   type. It is the same object as :class:`complex` in the Python layer.
92
93
94.. c:function:: int PyComplex_Check(PyObject *p)
95
96   Return true if its argument is a :c:type:`PyComplexObject` or a subtype of
97   :c:type:`PyComplexObject`.
98
99
100.. c:function:: int PyComplex_CheckExact(PyObject *p)
101
102   Return true if its argument is a :c:type:`PyComplexObject`, but not a subtype of
103   :c:type:`PyComplexObject`.
104
105
106.. c:function:: PyObject* PyComplex_FromCComplex(Py_complex v)
107
108   Create a new Python complex number object from a C :c:type:`Py_complex` value.
109
110
111.. c:function:: PyObject* PyComplex_FromDoubles(double real, double imag)
112
113   Return a new :c:type:`PyComplexObject` object from *real* and *imag*.
114
115
116.. c:function:: double PyComplex_RealAsDouble(PyObject *op)
117
118   Return the real part of *op* as a C :c:type:`double`.
119
120
121.. c:function:: double PyComplex_ImagAsDouble(PyObject *op)
122
123   Return the imaginary part of *op* as a C :c:type:`double`.
124
125
126.. c:function:: Py_complex PyComplex_AsCComplex(PyObject *op)
127
128   Return the :c:type:`Py_complex` value of the complex number *op*.
129
130   If *op* is not a Python complex number object but has a :meth:`__complex__`
131   method, this method will first be called to convert *op* to a Python complex
132   number object.  If ``__complex__()`` is not defined then it falls back to
133   :meth:`__float__`.  If ``__float__()`` is not defined then it falls back
134   to :meth:`__index__`.  Upon failure, this method returns ``-1.0`` as a real
135   value.
136
137   .. versionchanged:: 3.8
138      Use :meth:`__index__` if available.
139