a - : input array
ia - : increment for a
b - : work buffer of length: msmmmm. used only for median smoothing
if ityp is 4, then b has weights for smoothing and must be
as I32 as a and with same increment ia
c - : output array
ic - : increment for c
na - : number of points in a
msmmmm - : smoother length
ityp - : smoother type: 1 = box car
2 = triangular
3 = median
4 = weighted smoothing