Implementation of two helper functions 'empty_like' & 'from_bytes'

[prashant-saxena]

How to implement these two functions using c++

First

auto arr = empty_like(nb::ndarray b);

arr will be same like b in terms of shape, size, dtype & device type but no data

Second

auto arr = from_bytes(nb::bytes bytes, nb::dtype dtype);

Function will convert byte string to nb::ndarray of dtype. From python side, we can call

arr = from_bytes(bytestr, np.int32|np.float32|..all supported numpy data types)

This is what have I tried for one fixed dtype int

 nb::ndarray from_bytes(nb::bytes bytes) {
        
        const int* data = reinterpret_cast<const int*>(bytes.data());
        size_t size = bytes.size() / sizeof(int);
        
        std::initializer_list<size_t> shape = { size };
        std::initializer_list<int64_t> strides = { sizeof(int) };

        nb::ndarray array(bytes.data(), shape, strides, nb::dtype<int>());
        return array;
    }

The code is throwing all type of errors. Any pointers?

Question 1

What's the correct syntax to use generic dtype as function parameter?

nb::dtype dtype

doesn't work