“…To handle the removable singularity, we adopt the procedure in [3] (page 510), see also [27]; the code checks whether a source particle coordinate is close to a Chebyshev point; the condition is |y jl − s k | ≤ DBL_MIN, where DBL_MIN = 2.22507e-308 is the smallest positive IEEE double precision oating point number; if this condition is met, then the temporary variables c j,k, , d j,k, are adjusted to enforce the interpolation conditions (8). Having computed the temporary variables c j,k, , d j,k, , the code computes the Hermite basis functions in (20), and then the modi ed charges are computed as indicated in (19). For each cluster this process requires O(n Nc) operations and O(n ) storage.…”