【PyTorch】tensor.scatter

【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.]])