Neural network device and computing device

A neural network device comprising:

• a control unit to cause a plurality of layers, each of which executes a process, to execute a forward process of propagating a plurality of signal values in a forward direction, and a backward process of propagating a plurality of error values in a backward direction;
• and
• a matrix computation unit to perform computation on a plurality of values propagated at least some of interlayers in the plurality of layers, wherein
• the plurality of layers includes a first layer and a second layer adjacent to the first layer in the forward direction, and
• the matrix computation unit includes:
• (m×n) multipliers provided in one-to-one correspondence with (m×n) coefficients included in a coefficient matrix of m rows and n columns (m and n are integers greater than or equal to one and, in a case where one of m and n is one, the other is greater than or equal to two);
• and
• an addition circuit to switch a pattern for adding values output from the respective (m×n) multipliers between the forward process and the backward process.