Algorithm 1 Atomic base A

From: Performant implementation of the atomic cluster expansion (PACE) and application to copper and silicon

 Aiμnlm = 0

 for j ← neighbors of atom i do

  μ = type of atom j

  compute Rnl, dRnl, Ylm, dYlm

  forn,l,(m ≥ 0) do

   Aiμnlm += RnlYlm

  end for

 end for

 for n,l,(m > 0) do

  \({A}_{i\mu nl-m}={(-1)}^{m}{A}_{i\mu nlm}^{* }\)

 end for