mindspore.numpy.nanvar

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mindspore.numpy.nanvar(a, axis=None, dtype=None, ddof=0, keepdims=False)[source]

Computes the variance along the specified axis, while ignoring NaNs.

Returns the variance of the array elements, a measure of the spread of a distribution. The variance is computed for the flattened array by default, otherwise over the specified axis.

Note

Numpy arguments out is not supported. On GPU, the supported dtypes are np.float16, and np.float32.

Parameters

  • a (Union[int, float, list, tuple, Tensor]) – Array containing numbers whose variance is desired. If a is not an array, a conversion is attempted.

  • axis (Union[int, tuple of int, None], optional) – Axis or axes along which the variance is computed. The default is to compute the variance of the flattened array.

  • dtype (mindspore.dtype, optional) – Default: None . Overrides the dtype of the output Tensor.

  • ddof (int, optional) – "Delta Degrees of Freedom": the divisor used in the calculation is N - ddof, where N represents the number of non-NaN elements. By default ddof is zero.

  • keepdims (boolean, optional) – Default: False . If this is set to True, the axes which are reduced are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the original a.

Returns

Tensor.

Raises

ValueError – If axes are out of the range of [-a.ndim, a.ndim), or if the axes contain duplicates.

Supported Platforms:

GPU CPU

Examples

>>> import mindspore.numpy as np
>>> a = np.array([[1, np.nan], [3, 4]])
>>> output = np.nanvar(a)
>>> print(output)
1.5555557
>>> output = np.nanvar(a, axis=0)
>>> print(output)
[1. 0.]
>>> output = np.nanvar(a, axis=1)
>>> print(output)
[0.   0.25]