Function oblate_to_cart_position

examples/pde/bhrt.cpp:304–321

* @brief Transform the position vectors from oblate to cartesian coordinates * * @param vel * @param pos * @return af::array */

 * @return af::array
 */
af::array oblate_to_cart_position(const af::array& pos) {
    if (pos.dims()[0] != 3)
        throw make_error("Arrays must have 3 principal coordintes");

    af::array r = pos(0, af::span);
    af::array o = pos(1, af::span);
    af::array p = pos(2, af::span);
    auto a      = J / M;
    auto R      = af::sqrt(r * r + a * a);

    af::array x = R * af::sin(o) * af::cos(p);
    af::array y = R * af::sin(o) * af::sin(p);
    af::array z = r * af::cos(o);

    af::array transformed_pos = af::join(0, x, y, z);

    return transformed_pos;
}

/**
 * @brief Transform the velocity vectors from oblate to cartesian coordinates