How to create a pointcloud from an float array in open3d-cpp

[xenshinu]

I am using open3d-cpp to process some pointclouds. However, the raw input is a float array (say float pts[3000], containing 1000 points), and I didn't find an efficient way to transform it into an open3d::geometry::Pointcloud, as the only parameterized constructor of Pointcloud is a copy constructor and only takes std::vector<Eigen::Vector3d> as input.

I made a naive converter, but I think it is not quite efficient, the first step is casting the float array (farr of size 40000*3) into a double array (darr), then do the following:

    long t01 = CurrTimeMS;
    Eigen::Vector3d *vv = reinterpret_cast<Eigen::Vector3d *>(darr);
    vector<Eigen::Vector3d> vec(vv, vv+40000);
    geometry::PointCloud pcd(vec);
    long t02 = CurrTimeMS;
    std::cout << "pcd init took " << t02-t01 << " ms.\n";
    cout << (void *) vv << " " << (void *) vec.data() << " " << (void *) pcd.points_.data() << endl;

It turned out taking me 3-4ms, and because std::vector(T *start, T *end) is also a copy constructor, this code does 3 times of memory copy (all three addressed are different), which is not optimal.
Is there any more efficient way to create Pointcloud directly from memory?