torch.argsort — PyTorch 2.7 documentation (original) (raw)

torch.argsort(input, dim=-1, descending=False, stable=False) → Tensor¶

Returns the indices that sort a tensor along a given dimension in ascending order by value.

This is the second value returned by torch.sort(). See its documentation for the exact semantics of this method.

If stable is True then the sorting routine becomes stable, preserving the order of equivalent elements. If False, the relative order of values which compare equal is not guaranteed. True is slower.

Parameters

• input (Tensor) – the input tensor.
• dim (int, optional) – the dimension to sort along
• descending (bool, optional) – controls the sorting order (ascending or descending)
• stable (bool, optional) – controls the relative order of equivalent elements

Example:

a = torch.randn(4, 4) a tensor([[ 0.0785, 1.5267, -0.8521, 0.4065], [ 0.1598, 0.0788, -0.0745, -1.2700], [ 1.2208, 1.0722, -0.7064, 1.2564], [ 0.0669, -0.2318, -0.8229, -0.9280]])

torch.argsort(a, dim=1) tensor([[2, 0, 3, 1], [3, 2, 1, 0], [2, 1, 0, 3], [3, 2, 1, 0]])