如何使用pybind传递numpy数组列表

Howto pass a list of numpy array with pybind

本文关键字：数组 列表 numpy 传递 何使用 pybind      更新时间：2023-10-16

我有一个用python编写的预处理器。此预处理器计算未知数量的 numpy 数组。它们存储在列表中。为了进一步计算，我需要阅读 cpp 中的这些 numpy 数组列表。我不知道如何将列表中的元素转换为数组类型。

main.py

import numpy as np
import myCPPAlgo
my_list = [ np.zeroes(shape=(10, 10), dtype=np.uint32) for _ in range(10)]
myCPPAlgo.call(my_list)

主.cpp

#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
#include <pybind11/stl.h>
#include <iostream>

namespace py = pybind11;
int call(py::list listOfNumpyArrays)
{
for( py::handle array: listOfNumpyArrays)
{
// howto transform?
py::array_t<uint32_t> casted_array = ???
auto requestCastedArray = casted_array.request();
uint32_t nRows = requestCastedArray.shape[1];
uint32_t nCols = requestCastedArray.shape[0];
uint32_t* pBlockedArray = (uint32_t*) requestCastedArray.ptr;
}
return 0;
}

PYBIND11_MODULE(myCPPAlgo, m) {
m.doc() = ""
m.def("call", &call, "");
}

如何将 pybind：：handle 转换为 py：：array_t？

简单地转换为数组：py::array_t<uint32_t> casted_array = py::cast<py::array>(array);.完整的工作示例(模错误检查:)(如下。

#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
#include <pybind11/stl.h>
#include <iostream>
namespace py = pybind11;
int call(py::list listOfNumpyArrays)
{
for( py::handle array: listOfNumpyArrays)
{
// howto transform?
py::array_t<uint32_t> casted_array = py::cast<py::array>(array);
auto requestCastedArray = casted_array.request();
uint32_t nRows = requestCastedArray.shape[1];
uint32_t nCols = requestCastedArray.shape[0];
uint32_t* pBlockedArray = (uint32_t*) requestCastedArray.ptr;
std::cerr << " rows x columns = " << nRows << " x " << nCols << std::endl;
for (int i = 0; i < nCols; ++i) {
for (int j = 0; j < nRows; ++j) {
std::cerr << pBlockedArray[i*nRows + j] << " ";
}
std::cerr << 'n';
}
}
return 0;
}
PYBIND11_MODULE(myCPPAlgo, m) {
m.doc() = "";
m.def("call", &call, "");
}

和测试代码：

import numpy as np
import myCPPAlgo
my_list = [ np.ones(shape=(3, 10), dtype=np.uint32) for _ in range(10)]
my_list[9][1, 0] = 42
myCPPAlgo.call(my_list)
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