symbian-qemu-0.9.1-12/python-2.6.1/Doc/c-api/complex.rst
author johnathan.white@2718R8BGH51.accenture.com
Mon, 08 Mar 2010 18:45:03 +0000
changeset 46 b6935a90ca64
parent 1 2fb8b9db1c86
permissions -rw-r--r--
Modify framebuffer and NGA framebuffer to read screen size from board model dtb file. Optimise memory usuage of frame buffer Add example minigui application with hooks to profiler (which writes results to S:\). Modified NGA framebuffer to run its own dfc queue at high priority

.. highlightlang:: c

.. _complexobjects:

Complex Number Objects
----------------------

.. index:: object: complex number

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.


.. ctype:: 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;


.. cfunction:: Py_complex _Py_c_sum(Py_complex left, Py_complex right)

   Return the sum of two complex numbers, using the C :ctype:`Py_complex`
   representation.


.. cfunction:: Py_complex _Py_c_diff(Py_complex left, Py_complex right)

   Return the difference between two complex numbers, using the C
   :ctype:`Py_complex` representation.


.. cfunction:: Py_complex _Py_c_neg(Py_complex complex)

   Return the negation of the complex number *complex*, using the C
   :ctype:`Py_complex` representation.


.. cfunction:: Py_complex _Py_c_prod(Py_complex left, Py_complex right)

   Return the product of two complex numbers, using the C :ctype:`Py_complex`
   representation.


.. cfunction:: Py_complex _Py_c_quot(Py_complex dividend, Py_complex divisor)

   Return the quotient of two complex numbers, using the C :ctype:`Py_complex`
   representation.


.. cfunction:: Py_complex _Py_c_pow(Py_complex num, Py_complex exp)

   Return the exponentiation of *num* by *exp*, using the C :ctype:`Py_complex`
   representation.


Complex Numbers as Python Objects
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


.. ctype:: PyComplexObject

   This subtype of :ctype:`PyObject` represents a Python complex number object.


.. cvar:: PyTypeObject PyComplex_Type

   This instance of :ctype:`PyTypeObject` represents the Python complex number
   type. It is the same object as ``complex`` and ``types.ComplexType``.


.. cfunction:: int PyComplex_Check(PyObject *p)

   Return true if its argument is a :ctype:`PyComplexObject` or a subtype of
   :ctype:`PyComplexObject`.

   .. versionchanged:: 2.2
      Allowed subtypes to be accepted.


.. cfunction:: int PyComplex_CheckExact(PyObject *p)

   Return true if its argument is a :ctype:`PyComplexObject`, but not a subtype of
   :ctype:`PyComplexObject`.

   .. versionadded:: 2.2


.. cfunction:: PyObject* PyComplex_FromCComplex(Py_complex v)

   Create a new Python complex number object from a C :ctype:`Py_complex` value.


.. cfunction:: PyObject* PyComplex_FromDoubles(double real, double imag)

   Return a new :ctype:`PyComplexObject` object from *real* and *imag*.


.. cfunction:: double PyComplex_RealAsDouble(PyObject *op)

   Return the real part of *op* as a C :ctype:`double`.


.. cfunction:: double PyComplex_ImagAsDouble(PyObject *op)

   Return the imaginary part of *op* as a C :ctype:`double`.


.. cfunction:: Py_complex PyComplex_AsCComplex(PyObject *op)

   Return the :ctype:`Py_complex` value of the complex number *op*.

   .. versionchanged:: 2.6
      If *op* is not a Python complex number object but has a :meth:`__complex__`
      method, this method will first be called to convert *op* to a Python complex
      number object.