Function flatten

cpp/nd/impl/flat_array.hpp:10–32

namespace nd::impl {

inline nd::array flatten(nd::array a)
{
    if (a.dimensions() <= 1 && !a.is_dynamic()) {
        return a;
    }
    return nd::switch_numeric_dtype(a.dtype(), [&a]<typename T>() {
        icm::vector<T> v;
        v.reserve(a.volume());
        for (int i = 0; i < a.size(); i++) {
            auto arr = flatten(a[i]);
            if (!arr.has_data()) {
                for (int j = 0; j < arr.volume(); ++j) {
                    v.emplace_back(arr.template value<T>(j));
                }
            } else {
                ASSERT(arr.dtype() == a.dtype());
                auto d = arr.template data<T>();
                v.insert(v.end(), d.begin(), d.end());
            }
        }
        return adapt(std::move(v));
    });
}

template <typename T>
class flattened_array