-0.2129, -0.4206,  0.1968])
      >>> torch.cumprod(a, dim=0)
      tensor([ 0.6001,  0.1241, -0.0238, -0.0233, -0.0157, -0.0158, -0.0065,
               0.0014, -0.0006, -0.0001])
  >>> a[5] = 0.0
  >>> torch.cumprod(a, dim=0)
  tensor([ 0.6001,  0.1241, -0.0238, -0.0233, -0.0157, -0.0000, -0.0000,
           0.0000, -0.0000, -0.0000])
