(A) Relative errors between the directly computed correlation and the correlation as computed by Recipes 1 and 2 for two real-valued functions A, B: ℝ3 → ℝ at varying expansion degrees over 500 randomly-generated rigid-body rotations. For L > 12, the direct correlation is exceedingly slow to compute therefore the relative error is omitted here. (B) The maximum complex value of the correlation score as a different error measure. Note that we used real valued input functions, and hence this table demonstrates the numerical error due to cut-offs. The above experiments were conducted with mixed bases; similar results hold for pure spherical bases, as the speedup scheme for these bases is the same as that used for Recipe 1.
