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