Performs the vector multiplication of the elements of two vectors, constructing the 3x3 matrix.
    :param aa: One vector of size 3
    :param bb: Another vector of size 3
    :return: A 3x3 matrix M composed of the products of the elements of aa and bb :
     M_ij = aa_i * bb_j

def vectorsToMatrix(aa, bb):
    """
    Performs the vector multiplication of the elements of two vectors, constructing the 3x3 matrix.
    :param aa: One vector of size 3
    :param bb: Another vector of size 3
    :return: A 3x3 matrix M composed of the products of the elements of aa and bb :
     M_ij = aa_i * bb_j
    """
    MM = np.zeros([3, 3], np.float)
    for ii in range(3):
        for jj in range(3):
            MM[ii, jj] = aa[ii] * bb[jj]
    return MM