# nansum¶

paddle. nansum ( x, axis=None, dtype=None, keepdim=False, name=None ) [source]

Computes the sum of tensor elements over the given axis, treating Not a Numbers (NaNs) as zero.

Parameters
• x (Tensor) – An N-D Tensor, the data type is float32, float64, int32 or int64.

• axis (int|list|tuple, optional) – The dimensions along which the nansum is performed. If `None`, nansum all elements of `x` and return a Tensor with a single element, otherwise must be in the range \([-rank(x), rank(x))\). If \(axis[i] < 0\), the dimension to reduce is \(rank + axis[i]\).

• dtype (str, optional) – The dtype of output Tensor. The default value is None, the dtype of output is the same as input Tensor x.

• keepdim (bool, optional) – Whether to reserve the reduced dimension in the output Tensor. The result Tensor will have one fewer dimension than the `x` unless `keepdim` is true, default value is False.

• name (str, optional) – The default value is None. Normally there is no need for user to set this property. For more information, please refer to Name

Returns

Results of summation operation on the specified axis of input Tensor x,

Return type

Tensor

Examples

```import paddle
import numpy as np

# x is a Tensor with following elements:
#    [[nan, 0.3, 0.5, 0.9]
#     [0.1, 0.2, -nan, 0.7]]
# Each example is followed by the corresponding output tensor.
x = np.array([[float('nan'), 0.3, 0.5, 0.9],
[0.1, 0.2, float('-nan'), 0.7]]).astype(np.float32)
out2 = paddle.nansum(x, axis=0)  # [0.1, 0.5, 0.5, 1.6]
out3 = paddle.nansum(x, axis=-1)  # [1.7, 1.0]
out4 = paddle.nansum(x, axis=1, keepdim=True)  # [[1.7], [1.0]]

# y is a Tensor with shape [2, 2, 2] and elements as below:
#      [[[1, nan], [3, 4]],
#      [[5, 6], [-nan, 8]]]
# Each example is followed by the corresponding output tensor.
y = np.array([[[1, float('nan')], [3, 4]],
[[5, 6], [float('-nan'), 8]]])