dgl.sparse.from_coo¶

dgl.sparse.from_coo(row: torch.Tensor, col: torch.Tensor, val: Optional[torch.Tensor] = None, shape: Optional[Tuple[int, int]] = None) → dgl.sparse.sparse_matrix.SparseMatrix[source]¶

Creates a sparse matrix from a coordinate list (COO), which stores a list of (row, column, value) tuples.

See COO in Wikipedia.

Parameters

row (torch.Tensor) – The row indices of shape (nnz)
col (torch.Tensor) – The column indices of shape (nnz)
val (torch.Tensor, optional) – The values of shape (nnz) or (nnz, D). If None, it will be a tensor of shape (nnz) filled by 1.
shape (tuple[int, int], optional) – If not specified, it will be inferred from row and col, i.e., (row.max() + 1, col.max() + 1). Otherwise, shape should be no smaller than this.

Returns

Sparse matrix

Return type

SparseMatrix

Examples

Case1: Sparse matrix with row and column indices without values.

>>> dst = torch.tensor([1, 1, 2])
>>> src = torch.tensor([2, 4, 3])
>>> A = dglsp.from_coo(dst, src)
SparseMatrix(indices=tensor([[1, 1, 2],
                             [2, 4, 3]]),
             values=tensor([1., 1., 1.]),
             shape=(3, 5), nnz=3)
>>> # Specify shape
>>> A = dglsp.from_coo(dst, src, shape=(5, 5))
SparseMatrix(indices=tensor([[1, 1, 2],
                             [2, 4, 3]]),
             values=tensor([1., 1., 1.]),
             shape=(5, 5), nnz=3)

Case2: Sparse matrix with scalar values.

>>> indices = torch.tensor([[1, 1, 2], [2, 4, 3]])
>>> val = torch.tensor([[1.], [2.], [3.]])
>>> A = dglsp.spmatrix(indices, val)
SparseMatrix(indices=tensor([[1, 1, 2],
                             [2, 4, 3]]),
             values=tensor([[1.],
                            [2.],
                            [3.]]),
             shape=(3, 5), nnz=3, val_size=(1,))

Case3: Sparse matrix with vector values.

>>> dst = torch.tensor([1, 1, 2])
>>> src = torch.tensor([2, 4, 3])
>>> val = torch.tensor([[1., 1.], [2., 2.], [3., 3.]])
>>> A = dglsp.from_coo(dst, src, val)
SparseMatrix(indices=tensor([[1, 1, 2],
                             [2, 4, 3]]),
             values=tensor([[1., 1.],
                            [2., 2.],
                            [3., 3.]]),
             shape=(3, 5), nnz=3, val_size=(2,))