Aspects for submatrix operations in neural network are described herein. The aspects may include a controller unit configured to receive a submatrix instruction. The submatrix instruction may include a starting address of a submatrix of a matrix, a width of the submatrix, a height of the submatrix, and a stride that indicates a position of the submatrix relative to the matrix. The aspects may further include a computation module configured to select one or more values from the matrix as elements of the submatrix in accordance with the starting address of the matrix, the starting address of the submatrix, the width of the submatrix, the height of the submatrix, and the stride.