A multi-harmonic (or multi-tone) trigonometric model of a price series x[i], i=1..n, is given by: x[i] = m + Sum( a[h]*Cos(w[h]*i) + b[h]*Sin(w[h]*i), h=1..H ) where: x[i] - past price at i-th bar, total n past prices; m - bias; a[h] and b[h] - scaling coefficients of harmonics; w[h] - frequency of a harmonic; h - harmonic number; H - total number of fitted harmonics. Fitting this model means finding m, a[h], b[h], and w[h] that make