Operation circuit and method of operation for use in operations that are performed in parallel using multiple operators

An operation circuit contains a parallel operation circuit including operators storage circuits. Each storage circuit has an input storage circuit that stores elements of an input vector in an order based on an index of each element; and a coefficient storage circuit including a ring buffer that stores elements of a row or column vector of a coefficient matrix in an order based on an index of each element. Each operator sequentially multiplies the elements of the coefficient matrix in the storage circuit by a corresponding one of the elements of the input vector, and adds a result of multiplication to a corresponding one of elements of the output vector based on the index thereof.