[-0.9888,  1.0679, -1.3337, -1.6556,  0.4798,  0.2830]])
      >>> torch.triu(b, diagonal=1)
      tensor([[ 0.0000, -0.0794, -1.8373,  0.6654,  0.2604,  1.5235],
              [ 0.0000,  0.0000, -1.2919,  1.3378, -0.1768, -1.0857],
              [ 0.0000,  0.0000,  0.0000, -1.0432,  0.9348, -0.4410],
              [ 0.0000,  0.0000,  0.0000,  0.0000,  0.4798,  0.2830]])
      >>> torch.triu(b, diagonal=-1)
      tensor([[ 0.5876, -0.0794, -1.8373,  0.6654,  0.2604,  1.5235],
              [-0.2447,  0.9556, -1.2919,  1.3378, -0.1768, -1.0857],
              [ 0.0000,  0.3146,  0.6576, -1.0432,  0.9348, -0.4410],
              [ 0.0000,  0.0000, -1.3337, -1.6556,  0.4798,  0.2830]])