mirror of https://github.com/python/cpython
139 lines
4.1 KiB
ReStructuredText
139 lines
4.1 KiB
ReStructuredText
.. highlight:: c
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.. _complexobjects:
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Complex Number Objects
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----------------------
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.. index:: pair: object; complex number
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Python's complex number objects are implemented as two distinct types when
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viewed from the C API: one is the Python object exposed to Python programs, and
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the other is a C structure which represents the actual complex number value.
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The API provides functions for working with both.
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Complex Numbers as C Structures
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Note that the functions which accept these structures as parameters and return
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them as results do so *by value* rather than dereferencing them through
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pointers. This is consistent throughout the API.
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.. c:type:: Py_complex
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The C structure which corresponds to the value portion of a Python complex
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number object. Most of the functions for dealing with complex number objects
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use structures of this type as input or output values, as appropriate. It is
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defined as::
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typedef struct {
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double real;
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double imag;
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} Py_complex;
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.. c:function:: Py_complex _Py_c_sum(Py_complex left, Py_complex right)
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Return the sum of two complex numbers, using the C :c:type:`Py_complex`
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representation.
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.. c:function:: Py_complex _Py_c_diff(Py_complex left, Py_complex right)
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Return the difference between two complex numbers, using the C
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:c:type:`Py_complex` representation.
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.. c:function:: Py_complex _Py_c_neg(Py_complex num)
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Return the negation of the complex number *num*, using the C
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:c:type:`Py_complex` representation.
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.. c:function:: Py_complex _Py_c_prod(Py_complex left, Py_complex right)
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Return the product of two complex numbers, using the C :c:type:`Py_complex`
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representation.
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.. c:function:: Py_complex _Py_c_quot(Py_complex dividend, Py_complex divisor)
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Return the quotient of two complex numbers, using the C :c:type:`Py_complex`
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representation.
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If *divisor* is null, this method returns zero and sets
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:c:data:`errno` to :c:data:`EDOM`.
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.. c:function:: Py_complex _Py_c_pow(Py_complex num, Py_complex exp)
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Return the exponentiation of *num* by *exp*, using the C :c:type:`Py_complex`
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representation.
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If *num* is null and *exp* is not a positive real number,
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this method returns zero and sets :c:data:`errno` to :c:data:`EDOM`.
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Complex Numbers as Python Objects
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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.. c:type:: PyComplexObject
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This subtype of :c:type:`PyObject` represents a Python complex number object.
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.. c:var:: PyTypeObject PyComplex_Type
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This instance of :c:type:`PyTypeObject` represents the Python complex number
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type. It is the same object as :class:`complex` in the Python layer.
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.. c:function:: int PyComplex_Check(PyObject *p)
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Return true if its argument is a :c:type:`PyComplexObject` or a subtype of
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:c:type:`PyComplexObject`. This function always succeeds.
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.. c:function:: int PyComplex_CheckExact(PyObject *p)
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Return true if its argument is a :c:type:`PyComplexObject`, but not a subtype of
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:c:type:`PyComplexObject`. This function always succeeds.
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.. c:function:: PyObject* PyComplex_FromCComplex(Py_complex v)
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Create a new Python complex number object from a C :c:type:`Py_complex` value.
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.. c:function:: PyObject* PyComplex_FromDoubles(double real, double imag)
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Return a new :c:type:`PyComplexObject` object from *real* and *imag*.
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.. c:function:: double PyComplex_RealAsDouble(PyObject *op)
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Return the real part of *op* as a C :c:expr:`double`.
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.. c:function:: double PyComplex_ImagAsDouble(PyObject *op)
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Return the imaginary part of *op* as a C :c:expr:`double`.
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.. c:function:: Py_complex PyComplex_AsCComplex(PyObject *op)
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Return the :c:type:`Py_complex` value of the complex number *op*.
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If *op* is not a Python complex number object but has a :meth:`__complex__`
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method, this method will first be called to convert *op* to a Python complex
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number object. If ``__complex__()`` is not defined then it falls back to
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:meth:`__float__`. If ``__float__()`` is not defined then it falls back
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to :meth:`__index__`. Upon failure, this method returns ``-1.0`` as a real
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value.
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.. versionchanged:: 3.8
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Use :meth:`__index__` if available.
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