The invention enables even a CPU having low processing performance to find an
HMM output probability by simplifying arithmetic operations. The dimensions of
an input vector are grouped into several sets, and tables are created for the sets.
When an output probability is calculated, codes corresponding to the first dimension
to n-the dimension of the input vector are sequentially obtained, and for each
code, by referring to the corresponding table, output values for each table are
obtained. By substituting the output values for each table for a formula for finding
an output probability, the output probability is found.
