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7c673cae FG |
1 | binary_ufunc |
2 | ============ | |
3 | ||
4 | .. contents :: Table of Contents | |
5 | ||
6 | A ``binary_ufunc`` is a struct used as an intermediate step to broadcast two arguments so that a C++ function can be converted to a ufunc like function | |
7 | ||
8 | ``<boost/python/numpy/ufunc.hpp>`` contains the ``binary_ufunc`` structure definitions | |
9 | ||
10 | ||
11 | synopsis | |
12 | -------- | |
13 | ||
14 | :: | |
15 | ||
16 | namespace boost | |
17 | { | |
18 | namespace python | |
19 | { | |
20 | namespace numpy | |
21 | { | |
22 | ||
23 | template <typename TBinaryFunctor, | |
24 | typename TArgument1=typename TBinaryFunctor::first_argument_type, | |
25 | typename TArgument2=typename TBinaryFunctor::second_argument_type, | |
26 | typename TResult=typename TBinaryFunctor::result_type> | |
27 | ||
28 | struct binary_ufunc | |
29 | { | |
30 | ||
31 | static object call(TBinaryFunctor & self, | |
32 | object const & input1, | |
33 | object const & input2, | |
34 | object const & output); | |
35 | ||
36 | static object make(); | |
37 | }; | |
38 | ||
39 | } | |
40 | } | |
41 | } | |
42 | ||
43 | ||
44 | constructors | |
45 | ------------ | |
46 | ||
47 | :: | |
48 | ||
49 | struct example_binary_ufunc | |
50 | { | |
51 | typedef any_valid first_argument_type; | |
52 | typedef any_valid second_argument_type; | |
53 | typedef any_valid result_type; | |
54 | }; | |
55 | ||
56 | :Requirements: The ``any_valid`` type must be defined using typedef as a valid C++ type in order to use the struct methods correctly | |
57 | ||
58 | :Note: The struct must be exposed as a Python class, and an instance of the class must be created to use the ``call`` method corresponding to the ``__call__`` attribute of the Python object | |
59 | ||
60 | accessors | |
61 | --------- | |
62 | ||
63 | :: | |
64 | ||
65 | template <typename TBinaryFunctor, | |
66 | typename TArgument1=typename TBinaryFunctor::first_argument_type, | |
67 | typename TArgument2=typename TBinaryFunctor::second_argument_type, | |
68 | typename TResult=typename TBinaryFunctor::result_type> | |
69 | static object call(TBinaryFunctor & self, | |
70 | object const & input, | |
71 | object const & output); | |
72 | ||
73 | :Requires: Typenames ``TBinaryFunctor`` and optionally ``TArgument1`` and ``TArgument2`` for argument type and ``TResult`` for result type | |
74 | ||
75 | :Effects: Passes a Python object to the underlying C++ functor after broadcasting its arguments | |
76 | ||
77 | :: | |
78 | ||
79 | template <typename TBinaryFunctor, | |
80 | typename TArgument1=typename TBinaryFunctor::first_argument_type, | |
81 | typename TArgument2=typename TBinaryFunctor::second_argument_type, | |
82 | typename TResult=typename TBinaryFunctor::result_type> | |
83 | static object make(); | |
84 | ||
85 | :Requires: Typenames ``TBinaryFunctor`` and optionally ``TArgument1`` and ``TArgument2`` for argument type and ``TResult`` for result type | |
86 | ||
87 | :Returns: A Python function object to call the overloaded () operator in the struct (in typical usage) | |
88 | ||
89 | Example(s) | |
90 | ---------- | |
91 | ||
92 | :: | |
93 | ||
94 | namespace p = boost::python; | |
95 | namespace np = boost::python::numpy; | |
96 | ||
97 | struct BinarySquare | |
98 | { | |
99 | typedef double first_argument_type; | |
100 | typedef double second_argument_type; | |
101 | typedef double result_type; | |
102 | ||
103 | double operator()(double a,double b) const { return (a*a + b*b) ; } | |
104 | }; | |
105 | ||
106 | p::object ud = p::class_<BinarySquare, boost::shared_ptr<BinarySquare> >("BinarySquare").def("__call__", np::binary_ufunc<BinarySquare>::make()); | |
107 | p::object inst = ud(); | |
108 | result_array = inst.attr("__call__")(demo_array,demo_array) ; | |
109 | std::cout << "Square of list with binary ufunc is " << p::extract <char const * > (p::str(result_array)) << std::endl ; | |
110 |