pybind11/example/example20.cpp

101 lines
2.9 KiB
C++
Raw Normal View History

/*
example/example20.cpp -- Usage of structured numpy dtypes
Copyright (c) 2016 Ivan Smirnov
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#include "example.h"
#include <pybind11/numpy.h>
#include <cstdint>
#include <iostream>
namespace py = pybind11;
struct Struct {
bool x;
uint32_t y;
float z;
};
std::ostream& operator<<(std::ostream& os, const Struct& v) {
return os << v.x << "," << v.y << "," << v.z;
}
struct PackedStruct {
bool x;
uint32_t y;
float z;
} __attribute__((packed));
std::ostream& operator<<(std::ostream& os, const PackedStruct& v) {
return os << v.x << "," << v.y << "," << v.z;
}
struct NestedStruct {
Struct a;
PackedStruct b;
2016-06-19 15:41:15 +00:00
} __attribute__((packed));
std::ostream& operator<<(std::ostream& os, const NestedStruct& v) {
return os << v.a << "|" << v.b;
}
2016-06-19 15:41:15 +00:00
template <typename T>
py::array mkarray_via_buffer(size_t n) {
return py::array(py::buffer_info(nullptr, sizeof(T),
py::format_descriptor<T>::value(),
1, { n }, { sizeof(T) }));
}
template <typename S>
py::array_t<S> create_recarray(size_t n) {
2016-06-19 15:41:15 +00:00
auto arr = mkarray_via_buffer<S>(n);
auto ptr = static_cast<S*>(arr.request().ptr);
for (size_t i = 0; i < n; i++) {
ptr[i].x = i % 2; ptr[i].y = (uint32_t) i; ptr[i].z = (float) i * 1.5f;
}
return arr;
}
py::array_t<NestedStruct> create_nested(size_t n) {
auto arr = mkarray_via_buffer<NestedStruct>(n);
auto ptr = static_cast<NestedStruct*>(arr.request().ptr);
for (size_t i = 0; i < n; i++) {
2016-06-19 15:41:15 +00:00
ptr[i].a.x = i % 2; ptr[i].a.y = (uint32_t) i; ptr[i].a.z = (float) i * 1.5f;
ptr[i].b.x = (i + 1) % 2; ptr[i].b.y = (uint32_t) (i + 1); ptr[i].b.z = (float) (i + 1) * 1.5f;
}
return arr;
}
template <typename S>
void print_recarray(py::array_t<S> arr) {
auto buf = arr.request();
auto ptr = static_cast<S*>(buf.ptr);
for (size_t i = 0; i < buf.size; i++)
std::cout << ptr[i] << std::endl;
}
2016-06-19 15:41:15 +00:00
void print_format_descriptors() {
std::cout << py::format_descriptor<Struct>::value() << std::endl;
std::cout << py::format_descriptor<PackedStruct>::value() << std::endl;
std::cout << py::format_descriptor<NestedStruct>::value() << std::endl;
}
void init_ex20(py::module &m) {
PYBIND11_DTYPE(Struct, x, y, z);
PYBIND11_DTYPE(PackedStruct, x, y, z);
PYBIND11_DTYPE(NestedStruct, a, b);
m.def("create_rec_simple", &create_recarray<Struct>);
m.def("create_rec_packed", &create_recarray<PackedStruct>);
2016-06-19 15:41:15 +00:00
m.def("create_rec_nested", &create_nested);
m.def("print_format_descriptors", &print_format_descriptors);
m.def("print_rec_simple", &print_recarray<Struct>);
m.def("print_rec_packed", &print_recarray<PackedStruct>);
m.def("print_rec_nested", &print_recarray<NestedStruct>);
}