question: public static void c2ir ( double c [ ] , int nc , double hh [ ] , int leng ) { hh [ 0 ] = Math . exp ( c [ 0 ] ) ; for ( int n = 1 ; n < leng ; n ++ ) { double d = 0 ; int upl = ( n >= nc ) ? nc - 1 : n ; for ( int k = 1 ; k <= upl ; k ++ ) d += k * c [ k ] * hh [ n - k ] ; hh [ n ] = d / n ; } }
target:  c2ir: The minimum phase impulse response is evaluated from the minimum phase cepstrum