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- // Copyright Ankit Daftery 2011-2012.
- // Distributed under the Boost Software License, Version 1.0.
- // (See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- /**
- * @brief An example to demonstrate use of universal functions or ufuncs
- *
- *
- * @todo Calling the overloaded () operator is in a roundabout manner, find a simpler way
- * None of the methods like np::add, np::multiply etc are supported as yet
- */
- #include <boost/python/numpy.hpp>
- #include <iostream>
- namespace p = boost::python;
- namespace np = boost::python::numpy;
- // Create the structs necessary to implement the ufuncs
- // The typedefs *must* be made
- struct UnarySquare
- {
- typedef double argument_type;
- typedef double result_type;
- double operator()(double r) const { return r * r;}
- };
- 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) ; }
- };
- int main(int argc, char **argv)
- {
- // Initialize the Python runtime.
- Py_Initialize();
- // Initialize NumPy
- np::initialize();
- // Expose the struct UnarySquare to Python as a class, and let ud be the class object
- p::object ud = p::class_<UnarySquare, boost::shared_ptr<UnarySquare> >("UnarySquare")
- .def("__call__", np::unary_ufunc<UnarySquare>::make());
- // Let inst be an instance of the class ud
- p::object inst = ud();
- // Use the "__call__" method to call the overloaded () operator and print the value
- std::cout << "Square of unary scalar 1.0 is " << p::extract <char const * > (p::str(inst.attr("__call__")(1.0))) << std::endl ;
- // Create an array in C++
- int arr[] = {1,2,3,4} ;
- // ..and use it to create the ndarray in Python
- np::ndarray demo_array = np::from_data(arr, np::dtype::get_builtin<int>() , p::make_tuple(4), p::make_tuple(4), p::object());
- // Print out the demo array
- std::cout << "Demo array is " << p::extract <char const * > (p::str(demo_array)) << std::endl ;
- // Call the "__call__" method to perform the operation and assign the value to result_array
- p::object result_array = inst.attr("__call__")(demo_array) ;
- // Print the resultant array
- std::cout << "Square of demo array is " << p::extract <char const * > (p::str(result_array)) << std::endl ;
- // Lets try the same with a list
- p::list li ;
- li.append(3);
- li.append(7);
- // Print out the demo list
- std::cout << "Demo list is " << p::extract <char const * > (p::str(li)) << std::endl ;
- // Call the ufunc for the list
- result_array = inst.attr("__call__")(li) ;
- // And print the list out
- std::cout << "Square of demo list is " << p::extract <char const * > (p::str(result_array)) << std::endl ;
- // Now lets try Binary ufuncs
- // Expose the struct BinarySquare to Python as a class, and let ud be the class object
- ud = p::class_<BinarySquare, boost::shared_ptr<BinarySquare> >("BinarySquare")
- .def("__call__", np::binary_ufunc<BinarySquare>::make());
- // Again initialise inst as an instance of the class ud
- inst = ud();
- // Print the two input listsPrint the two input lists
- std::cout << "The two input list for binary ufunc are " << std::endl << p::extract <char const * > (p::str(demo_array)) << std::endl << p::extract <char const * > (p::str(demo_array)) << std::endl ;
- // Call the binary ufunc taking demo_array as both inputs
- 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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