qfeval_functions.functions.bfill

bfill(x, dim=-1)

Backward fill missing values along the specified dimension.

This function propagates the last valid (non-NaN) values backward along the specified dimension. For each NaN value, it is replaced with the nearest valid value that appears after it along the dimension. If no valid value exists after a NaN, it remains NaN.

Parameters:

• x (Tensor) – The input tensor containing values to be filled.

• dim (int) – The dimension along which to perform backward fill. Default is -1 (the last dimension).

Returns:

A tensor of the same shape as the input, with NaN values replaced by the nearest subsequent valid values where possible.

Return type:

Tensor

Example

>>> x = torch.tensor([1.0, nan, nan, 4.0, 5.0])
>>> QF.bfill(x)
tensor([1., 4., 4., 4., 5.])

>>> x = torch.tensor([[nan, 2.0, nan, 4.0],
...                   [5.0, nan, nan, nan]])
>>> QF.bfill(x, dim=1)
tensor([[2., 2., 4., 4.],
        [5., nan, nan, nan]])