torch.searchsorted

torch.searchsorted(sorted_sequence, values, *, out_int32=False, right=False, out=None) → Tensor

Find the indices from the innermost dimension of sorted_sequence such that, if the corresponding values in values were inserted before the indices, the order of the corresponding innermost dimension within sorted_sequence would be preserved. Return a new tensor with the same size as values. If right is False (default), then the left boundary of sorted_sequence is closed. More formally, the returned index satisfies the following rules:

sorted_sequence	right	returned index satisfies
1-D	False	sorted_sequence[i-1] < values[m][n]...[l][x] <= sorted_sequence[i]
1-D	True	sorted_sequence[i-1] <= values[m][n]...[l][x] < sorted_sequence[i]
N-D	False	sorted_sequence[m][n]...[l][i-1] < values[m][n]...[l][x] <= sorted_sequence[m][n]...[l][i]
N-D	True	sorted_sequence[m][n]...[l][i-1] <= values[m][n]...[l][x] < sorted_sequence[m][n]...[l][i]

Parameters

• sorted_sequence (Tensor) – N-D or 1-D tensor, containing monotonically increasing sequence on the innermost dimension.
• values (Tensor or Scalar) – N-D tensor or a Scalar containing the search value(s).

Keyword Arguments

• out_int32 (bool, optional) – indicate the output data type. torch.int32 if True, torch.int64 otherwise. Default value is False, i.e. default output data type is torch.int64.
• right (bool, optional) – if False, return the first suitable location that is found. If True, return the last such index. If no suitable index found, return 0 for non-numerical value (eg. nan, inf) or the size of innermost dimension within sorted_sequence (one pass the last index of the innermost dimension). In other words, if False, gets the lower bound index for each value in values on the corresponding innermost dimension of the sorted_sequence. If True, gets the upper bound index instead. Default value is False.
• out (Tensor, optional) – the output tensor, must be the same size as values if provided.

Note

If your use case is always 1-D sorted sequence, torch.bucketize() is preferred, because it has fewer dimension checks resulting in slightly better performance.

Example:

>>> sorted_sequence = torch.tensor([[1, 3, 5, 7, 9], [2, 4, 6, 8, 10]])
>>> sorted_sequence
tensor([[ 1,  3,  5,  7,  9],
        [ 2,  4,  6,  8, 10]])
>>> values = torch.tensor([[3, 6, 9], [3, 6, 9]])
>>> values
tensor([[3, 6, 9],
        [3, 6, 9]])
>>> torch.searchsorted(sorted_sequence, values)
tensor([[1, 3, 4],
        [1, 2, 4]])
>>> torch.searchsorted(sorted_sequence, values, right=True)
tensor([[2, 3, 5],
        [1, 3, 4]])

>>> sorted_sequence_1d = torch.tensor([1, 3, 5, 7, 9])
>>> sorted_sequence_1d
tensor([1, 3, 5, 7, 9])
>>> torch.searchsorted(sorted_sequence_1d, values)
tensor([[1, 3, 4],
        [1, 3, 4]])