矩阵分块计算 A [ b 1 ⋯ b p ] = [ A b 1 ⋯ A b p ] A\left[\boldsymbol{b}_{1} \cdots \boldsymbol{b}_{p}\right]=\left[A \boldsymbol{b}_{1} \cdots A \boldsymbol{b}_{p}\right] A[b1⋯bp]=[Ab1⋯Ab