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- binary_ufunc
- ============
- .. contents :: Table of Contents
- 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
- ``<boost/python/numpy/ufunc.hpp>`` contains the ``binary_ufunc`` structure definitions
- synopsis
- --------
- ::
- namespace boost
- {
- namespace python
- {
- namespace numpy
- {
- template <typename TBinaryFunctor,
- typename TArgument1=typename TBinaryFunctor::first_argument_type,
- typename TArgument2=typename TBinaryFunctor::second_argument_type,
- typename TResult=typename TBinaryFunctor::result_type>
- struct binary_ufunc
- {
- static object call(TBinaryFunctor & self,
- object const & input1,
- object const & input2,
- object const & output);
- static object make();
- };
- }
- }
- }
- constructors
- ------------
- ::
- struct example_binary_ufunc
- {
- typedef any_valid first_argument_type;
- typedef any_valid second_argument_type;
- typedef any_valid result_type;
- };
- :Requirements: The ``any_valid`` type must be defined using typedef as a valid C++ type in order to use the struct methods correctly
- :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
- accessors
- ---------
- ::
- template <typename TBinaryFunctor,
- typename TArgument1=typename TBinaryFunctor::first_argument_type,
- typename TArgument2=typename TBinaryFunctor::second_argument_type,
- typename TResult=typename TBinaryFunctor::result_type>
- static object call(TBinaryFunctor & self,
- object const & input,
- object const & output);
- :Requires: Typenames ``TBinaryFunctor`` and optionally ``TArgument1`` and ``TArgument2`` for argument type and ``TResult`` for result type
- :Effects: Passes a Python object to the underlying C++ functor after broadcasting its arguments
- ::
- template <typename TBinaryFunctor,
- typename TArgument1=typename TBinaryFunctor::first_argument_type,
- typename TArgument2=typename TBinaryFunctor::second_argument_type,
- typename TResult=typename TBinaryFunctor::result_type>
- static object make();
- :Requires: Typenames ``TBinaryFunctor`` and optionally ``TArgument1`` and ``TArgument2`` for argument type and ``TResult`` for result type
- :Returns: A Python function object to call the overloaded () operator in the struct (in typical usage)
- Example(s)
- ----------
- ::
- namespace p = boost::python;
- namespace np = boost::python::numpy;
- struct BinarySquare
- {
- typedef double first_argument_type;
- typedef double second_argument_type;
- typedef double result_type;
- double operator()(double a,double b) const { return (a*a + b*b) ; }
- };
- p::object ud = p::class_<BinarySquare, boost::shared_ptr<BinarySquare> >("BinarySquare").def("__call__", np::binary_ufunc<BinarySquare>::make());
- p::object inst = ud();
- result_array = inst.attr("__call__")(demo_array,demo_array) ;
- std::cout << "Square of list with binary ufunc is " << p::extract <char const * > (p::str(result_array)) << std::endl ;
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