Figure 1

Classical approach to the forward algorithm. The classical forward algorithm, as described by Rabiner [18]. The rectangles represent matrices and vectors. The black lines denote matrix-vector multiplications. The top row is the $C_{o_i}$ matrices. α _i is obtained from α_i−1 and $C_{o_i}$. Note that the input sequence is inverted to illustrate that the series of matrix-vector multiplication should be carried out from right to left.