tf-keras-skeleton.py 文件源码

def var(x, axis=None, keepdims=False):
      """Variance of a tensor, alongside the specified axis.

      Arguments:
          x: A tensor or variable.
          axis: An integer, the axis to compute the variance.
          keepdims: A boolean, whether to keep the dimensions or not.
              If `keepdims` is `False`, the rank of the tensor is reduced
              by 1. If `keepdims` is `True`,
              the reduced dimension is retained with length 1.

      Returns:
          A tensor with the variance of elements of `x`.
      """
      axis = _normalize_axis(axis, ndim(x))
      if x.dtype.base_dtype == dtypes_module.bool:
        x = math_ops.cast(x, floatx())
      m = math_ops.reduce_mean(x, reduction_indices=axis, keep_dims=True)
      devs_squared = math_ops.square(x - m)
      return math_ops.reduce_mean(
          devs_squared, reduction_indices=axis, keep_dims=keepdims)