Calculate the h_{ij} = <φ_i, s_j> + <φ_j, s_i> garbage polynomials
In the paper, h_{ij} is defined with a factor of 1/2 in front
However, since we’re using q = 2^32, division by 2 is problematic in Z_q
So we store h’{ij} = 2*h{ij} = <φ_i, s_j> + <φ_j, s_i> directly
Exploits symmetry by only calculating for i ≤ j since h_{ij} = h_{ji}