question: public static double [ ] lprefc2lpc ( double [ ] k ) { int p = k . length ; double [ ] [ ] A = new double [ p ] [ ] ; int i , j ; for ( i = 1 ; i <= p ; i ++ ) { A [ i - 1 ] = new double [ i ] ; A [ i - 1 ] [ i - 1 ] = k [ i - 1 ] ; for ( j = 1 ; j < i ; j ++ ) A [ i - 1 ] [ j - 1 ] = A [ i - 2 ] [ j - 1 ] - k [ i - 1 ] * A [ i - 2 ] [ i - j - 1 ] ; } double [ ] oneMinusA = new double [ p + 1 ] ; oneMinusA [ 0 ] = 1.0 ; System . arraycopy ( A [ p - 1 ] , 0 , oneMinusA , 1 , p ) ; return oneMinusA ; }
target:  Converts from the reflection coefficients to the corresponding LPC coefficients.