【PyTorch】scatter
参数：
- dim (int) – the axis along which to index
- index (LongTensor) – the indices of elements to scatter, can be either empty or the same size of src. When empty, the operation returns identity
- src (Tensor) – the source element(s) to scatter, incase value is not specified
- value (float) – the source element(s) to scatter, incase src is not specified
官网例子：
第三个参数为张量时：
>>> x = torch.rand(2, 5)
>>> x
tensor([[ 0.3992, 0.2908, 0.9044, 0.4850, 0.6004],
[ 0.5735, 0.9006, 0.6797, 0.4152, 0.1732]])
>>> torch.zeros(3, 5).scatter_(0, torch.tensor([[0, 1, 2, 0, 0], [2, 0, 0, 1, 2]]), x)
tensor([[ 0.3992, 0.9006, 0.6797, 0.4850, 0.6004],
[ 0.0000, 0.2908, 0.0000, 0.4152, 0.0000],
[ 0.5735, 0.0000, 0.9044, 0.0000, 0.1732]])
第三个参数为标量时：
>>> z = torch.zeros(2, 4).scatter_(1, torch.tensor([[2], [3]]), 1.23)
>>> z
tensor([[ 0.0000, 0.0000, 1.2300, 0.0000],
[ 0.0000, 0.0000, 0.0000, 1.2300]])
又一个栗子：
dim = 0
>>> torch.zeros(3, 5).scatter_(0, torch.tensor([[0, 1, 2, 0, 0], [2, 0, 0, 1, 2]]), 7)
tensor([[7., 7., 7., 7., 7.],
[0., 7., 0., 7., 0.],
[7., 0., 7., 0., 7.]])
dim = 1
>>> torch.zeros(3, 5).scatter_(1, torch.tensor([[0, 1, 2, 0, 0], [2, 0, 0, 1, 2]]), 7)
tensor([[7., 7., 7., 0., 0.],
[7., 7., 7., 0., 0.],
[0., 0., 0., 0., 0.]])
