torch.sparse_compressed_tensor

torch.sparse_compressed_tensor(compressed_indices, plain_indices, values, size=None, *, dtype=None, layout=None, device=None, requires_grad=False) → Tensor

Constructs a sparse tensor in Compressed Sparse format - CSR, CSC, BSR, or BSC - with specified values at the given compressed_indices and plain_indices. Sparse matrix multiplication operations in Compressed Sparse format are typically faster than that for sparse tensors in COO format. Make you have a look at the note on the data type of the indices.

Parameters:

• compressed_indices (array_like) – (B+1)-dimensional array of size (*batchsize, compressed_dim_size + 1). The last element of each batch is the number of non-zero elements or blocks. This tensor encodes the index in values and plain_indices depending on where the given compressed dimension (row or column) starts. Each successive number in the tensor subtracted by the number before it denotes the number of elements or blocks in a given compressed dimension.

• plain_indices (array_like) – Plain dimension (column or row) co-ordinates of each element or block in values. (B+1)-dimensional tensor with the same length as values.

• values (array_list) – Initial values for the tensor. Can be a list, tuple, NumPy ndarray, scalar, and other types. that represents a (1+K)-dimensional or (1+2+K)-dimensional tensor where K is the number of dense dimensions.

• size (list, tuple, torch.Size, optional) – Size of the sparse tensor: (*batchsize, nrows * blocksize[0], ncols * blocksize[1], *densesize) where blocksize[0] == blocksize[1] == 1 for CSR and CSC formats. If not provided, the size will be inferred as the minimum size big enough to hold all non-zero elements or blocks.

Keyword Arguments:

• dtype (torch.dtype, optional) – the desired data type of returned tensor. Default: if None, infers data type from values.

• layout (torch.layout, required) – the desired layout of returned tensor: torch.sparse_csr, torch.sparse_csc, torch.sparse_bsr, or torch.sparse_bsc.

• device (torch.device, optional) – the desired device of returned tensor. Default: if None, uses the current device for the default tensor type (see torch.set_default_tensor_type()). device will be the CPU for CPU tensor types and the current CUDA device for CUDA tensor types.

• requires_grad (bool, optional) – If autograd should record operations on the returned tensor. Default: False.

Example::

>>> compressed_indices = [0, 2, 4]
>>> plain_indices = [0, 1, 0, 1]
>>> values = [1, 2, 3, 4]
>>> torch.sparse_compressed_tensor(torch.tensor(compressed_indices, dtype=torch.int64),
...                                torch.tensor(plain_indices, dtype=torch.int64),
...                                torch.tensor(values), dtype=torch.double, layout=torch.sparse_csr)
tensor(crow_indices=tensor([0, 2, 4]),
       col_indices=tensor([0, 1, 0, 1]),
       values=tensor([1., 2., 3., 4.]), size=(2, 2), nnz=4,
       dtype=torch.float64, layout=torch.sparse_csr)