Function dot_product

examples/pde/bhrt.cpp:546–559

* @brief Computes the dot product as defined by a metric between two 4-vector * velocities * * @param pos * @param lhs * @param rhs * @return af::array */

 * @return af::array
 */
af::array dot_product(const af::array& pos, const af::array& lhs,
                      const af::array& rhs) {
    if (pos.dims() != lhs.dims())
        throw make_error(
            "Position and lhs velocity must have the same dimensions");
    else if (lhs.dims() != rhs.dims())
        throw make_error(
            "Position and rhs velocity must have the same dimensions");
    else if (rhs.dims()[0] != 4)
        throw make_error("Arrays must have 4 principal coordinates");

    return af::matmul(af::moddims(lhs, 1, 4, lhs.dims()[1]), metric4(pos),
                      af::moddims(rhs, 4, 1, rhs.dims()[1]));
}

af::array norm4(const af::array& pos, const af::array& vel) {
    return dot_product(pos, vel, vel);