1. A similarity calculator for calculating a set of similarity measures S(A(u, m), B.sup.c)'s between every one of a set of fragmentary patterns A(u, m)'s of an input pattern A and every one of first through N-th reference patterns B.sup.c (c=1, 2,. .. , N), said input pattern A being given by a time sequence of first through I-th input pattern feature vectors a.sub.i (i=1, 2,. .. , I), said set of fragmentary patterns A(u, m)'s being defined by an end point m (m being representative of each of i) and a plurality of start points u's predetermined relative to the end point m as those parts of said time sequence which consist of (u+1)-th through m-th input pattern feature vectors a.sub.u+1 to a.sub.m, an n-th reference pattern B.sup.n (n being representative of each of c) being given by a time sequence of first through J.sup.n -th reference pattern feature vectors b.sub.j.sup.n (j.sup.n =1, 2,. .. , J.sup.n), said similarity calculator comprising: input pattern buffer means for producing said input pattern feature vectors a.sub.i successively in the ascending order, the m-th input pattern feature vector a.sub.m during an m-th relatively long period of time; a reference pattern memory for memorizing the reference pattern feature vectors b.sub.j.sup.c of the respective reference patterns B.sup.c ; control means operatively coupled to said input pattern buffer means for producing a reference pattern specifying signal specifying said reference patterns B.sup.c successively in a predetermined order in the m-th relatively long period, the n-th reference pattern B.sup.n during an n-th period of first through N-th intermediate poriods of time, a first set of signals specifying in a first fragment of the n-th intermediate period the first through the J.sup.n -th reference pattern feature vectors b.sub.j.sup.n, respectively, an integer specifying signal specifying integers 1 through (J.sup.n +r) (r being representative of a predetermined integer) successively in the descending order in a second fragment next succeeding the first fragment in the n-th intermediate period, one integer k (k being representative of each of 1 through [J.sup.n +r]) during a k-th period of (J.sup.n +r)-th through first relatively short periods of time, and a second set of signals specifying in each relatively short period in the n-th intermediate period those consecutive ones of the first through the J.sup.n -th reference pattern feature vectors b.sub.j.sup.n, respectively, which are prescribed relative to the integer k specified during said each relatively short period; reference pattern output means connected to said reference pattern memory and respective to the reference pattern specifying signal and the first-set signals for making said reference pattern memory produce the first through the J.sup.n -th reference pattern feature vectors b.sub.j.sup.n in the n-th intermediate period; scalar product calculating means connected to said input pattern buffer means and said reference pattern output means for calculating, in the n-th intermediate period of the m-th relatively long period, scalar products (a.sub.m .multidot.b.sub.j.sup.n) of the m-th input pattern feature vector a.sub.m and the respective reference pattern feature vectors b.sub.j.sup.n produced in the meantime; scalar product buffer means connected to said scalar product calculating means and said control means and comprising a plurality of buffer addresses specifiable by the signals of whichever of the first and the second sets for holding the scalar products (a.sub.m .multidot.b.sub.j.sup.n) in the buffer addresses specified by the first-set signals and for producing the scalar products (a.sub.m .multidot.b.sub.j.sup.n) from the buffer addresses specified by the second-set signals; and recurrence value calculating means connected to said scalar product buffer means and responsive to the reference pattern specifying signal, the integer specifying signal, and the second-set signals for carrying out, during the k-th relatively short period in the n-th intermediate period of the m-th relatively long period and for a v-th reference pattern feature vector b.sub.v (v being representative of each of j.sup.n) specified in the meanwhile by a v-th one of the second-set signals, calculation of a recurrence value g.sub.k (m, v) by the use of the scalar product (a.sub.m .multidot.b.sub.v) produced from the buffer address specified by the last-mentioned second-set signal and the recurrence values comprising three recurrence values g.sub.k-1 (m-1, v)'s calculated during the (k-1)-th relatively short period in the n-th intermediate period of the (m-1)-th relatively long period and for three consecutive reference pattern feature vectors b.sub.v 's predetermined relative to the v-th reference pattern feature vector b.sub.v, said recurrence value calculating means providing the similarity measure set S(A(u, m), B.sup.c)'s at the end of the m-th relatively long period.