Source code for torch.sparse
# The Tensor classes are added to this module by python_tensor.cpp
from typing import Optional, Tuple, List, Union
import torch
from torch._C import _add_docstr, _sparse # type: ignore[attr-defined]
from torch import Tensor
# A workaround to support both TorchScript and MyPy:
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from torch.types import _dtype as DType
DimOrDims = Optional[Union[int, Tuple[int], List[int]]]
else:
# The JIT doesn't understand Union, nor torch.dtype here
DType = int
DimOrDims = Optional[Tuple[int]]
__all__ = [
'addmm',
'mm',
'sum',
'softmax',
'log_softmax',
]
addmm = _add_docstr(_sparse._sparse_addmm, r"""
sparse.addmm(mat, mat1, mat2, *, beta=1., alpha=1.) -> Tensor
This function does exact same thing as :func:`torch.addmm` in the forward,
except that it supports backward for sparse matrix :attr:`mat1`. :attr:`mat1`
need to have `sparse_dim = 2`. Note that the gradients of :attr:`mat1` is a
coalesced sparse tensor.
Args:
mat (Tensor): a dense matrix to be added
mat1 (Tensor): a sparse matrix to be multiplied
mat2 (Tensor): a dense matrix to be multiplied
beta (Number, optional): multiplier for :attr:`mat` (:math:`\beta`)
alpha (Number, optional): multiplier for :math:`mat1 @ mat2` (:math:`\alpha`)
""")
[docs]def mm(mat1: Tensor, mat2: Tensor) -> Tensor:
r"""
Performs a matrix multiplication of the sparse matrix :attr:`mat1`
and the (sparse or strided) matrix :attr:`mat2`. Similar to :func:`torch.mm`, If :attr:`mat1` is a
:math:`(n \times m)` tensor, :attr:`mat2` is a :math:`(m \times p)` tensor, out will be a
:math:`(n \times p)` tensor. :attr:`mat1` need to have `sparse_dim = 2`.
This function also supports backward for both matrices. Note that the gradients of
:attr:`mat1` is a coalesced sparse tensor.
Args:
mat1 (SparseTensor): the first sparse matrix to be multiplied
mat2 (Tensor): the second matrix to be multiplied, which could be sparse or dense
Shape:
The format of the output tensor of this function follows:
- sparse x sparse -> sparse
- sparse x dense -> dense
Example::
>>> a = torch.randn(2, 3).to_sparse().requires_grad_(True)
>>> a
tensor(indices=tensor([[0, 0, 0, 1, 1, 1],
[0, 1, 2, 0, 1, 2]]),
values=tensor([ 1.5901, 0.0183, -0.6146, 1.8061, -0.0112, 0.6302]),
size=(2, 3), nnz=6, layout=torch.sparse_coo, requires_grad=True)
>>> b = torch.randn(3, 2, requires_grad=True)
>>> b
tensor([[-0.6479, 0.7874],
[-1.2056, 0.5641],
[-1.1716, -0.9923]], requires_grad=True)
>>> y = torch.sparse.mm(a, b)
>>> y
tensor([[-0.3323, 1.8723],
[-1.8951, 0.7904]], grad_fn=<SparseAddmmBackward>)
>>> y.sum().backward()
>>> a.grad
tensor(indices=tensor([[0, 0, 0, 1, 1, 1],
[0, 1, 2, 0, 1, 2]]),
values=tensor([ 0.1394, -0.6415, -2.1639, 0.1394, -0.6415, -2.1639]),
size=(2, 3), nnz=6, layout=torch.sparse_coo)
"""
if mat1.is_sparse and mat2.is_sparse:
return torch._sparse_sparse_matmul(mat1, mat2)
return torch._sparse_mm(mat1, mat2)
sampled_addmm = _add_docstr(_sparse.sparse_sampled_addmm, r"""
sparse.sampled_addmm(input, mat1, mat2, *, beta=1., alpha=1., out=None) -> Tensor
Performs a matrix multiplication of the dense matrices :attr:`mat1` and :attr:`mat2` at the locations
specified by the sparsity pattern of :attr:`input`. The matrix :attr:`input` is added to the final result.
Mathematically this performs the following operation:
.. math::
\text{out} = \alpha\ (\text{mat1} \mathbin{@} \text{mat2})*\text{spy}(\text{input}) + \beta\ \text{input}
where :math:`\text{spy}(\text{input})` is the sparsity pattern matrix of :attr:`input`, :attr:`alpha`
and :attr:`beta` are the scaling factors.
:math:`\text{spy}(\text{input})` has value 1 at the positions where :attr:`input` has non-zero values, and 0 elsewhere.
.. note::
:attr:`input` must be a sparse CSR tensor. :attr:`mat1` and :attr:`mat2` must be dense tensors.
This function is implemented only for tensors on CUDA devices.
Args:
input (Tensor): a sparse CSR matrix of shape `(m, n)` to be added and used to compute
the sampled matrix multiplication
mat1 (Tensor): a dense matrix of shape `(m, k)` to be multiplied
mat2 (Tensor): a dense matrix of shape `(k, n)` to be multiplied
Keyword args:
beta (Number, optional): multiplier for :attr:`input` (:math:`\beta`)
alpha (Number, optional): multiplier for :math:`mat1 @ mat2` (:math:`\alpha`)
out (Tensor, optional): output tensor. Ignored if `None`. Default: `None`.
Examples::
>>> input = torch.eye(3, device='cuda').to_sparse_csr()
>>> mat1 = torch.randn(3, 5, device='cuda')
>>> mat2 = torch.randn(5, 3, device='cuda')
>>> torch.sparse.sampled_addmm(input, mat1, mat2)
tensor(crow_indices=tensor([0, 1, 2, 3]),
col_indices=tensor([0, 1, 2]),
values=tensor([ 0.2847, -0.7805, -0.1900]), device='cuda:0',
size=(3, 3), nnz=3, layout=torch.sparse_csr)
>>> torch.sparse.sampled_addmm(input, mat1, mat2).to_dense()
tensor([[ 0.2847, 0.0000, 0.0000],
[ 0.0000, -0.7805, 0.0000],
[ 0.0000, 0.0000, -0.1900]], device='cuda:0')
>>> torch.sparse.sampled_addmm(input, mat1, mat2, beta=0.5, alpha=0.5)
tensor(crow_indices=tensor([0, 1, 2, 3]),
col_indices=tensor([0, 1, 2]),
values=tensor([ 0.1423, -0.3903, -0.0950]), device='cuda:0',
size=(3, 3), nnz=3, layout=torch.sparse_csr)
""")
[docs]def sum(input: Tensor, dim: DimOrDims = None,
dtype: Optional[DType] = None) -> Tensor:
r"""
Returns the sum of each row of the sparse tensor :attr:`input` in the given
dimensions :attr:`dim`. If :attr:`dim` is a list of dimensions,
reduce over all of them. When sum over all ``sparse_dim``, this method
returns a dense tensor instead of a sparse tensor.
All summed :attr:`dim` are squeezed (see :func:`torch.squeeze`), resulting an output
tensor having :attr:`dim` fewer dimensions than :attr:`input`.
During backward, only gradients at ``nnz`` locations of :attr:`input`
will propagate back. Note that the gradients of :attr:`input` is coalesced.
Args:
input (Tensor): the input sparse tensor
dim (int or tuple of ints): a dimension or a list of dimensions to reduce. Default: reduce
over all dims.
dtype (:class:`torch.dtype`, optional): the desired data type of returned Tensor.
Default: dtype of :attr:`input`.
Example::
>>> nnz = 3
>>> dims = [5, 5, 2, 3]
>>> I = torch.cat([torch.randint(0, dims[0], size=(nnz,)),
torch.randint(0, dims[1], size=(nnz,))], 0).reshape(2, nnz)
>>> V = torch.randn(nnz, dims[2], dims[3])
>>> size = torch.Size(dims)
>>> S = torch.sparse_coo_tensor(I, V, size)
>>> S
tensor(indices=tensor([[2, 0, 3],
[2, 4, 1]]),
values=tensor([[[-0.6438, -1.6467, 1.4004],
[ 0.3411, 0.0918, -0.2312]],
[[ 0.5348, 0.0634, -2.0494],
[-0.7125, -1.0646, 2.1844]],
[[ 0.1276, 0.1874, -0.6334],
[-1.9682, -0.5340, 0.7483]]]),
size=(5, 5, 2, 3), nnz=3, layout=torch.sparse_coo)
# when sum over only part of sparse_dims, return a sparse tensor
>>> torch.sparse.sum(S, [1, 3])
tensor(indices=tensor([[0, 2, 3]]),
values=tensor([[-1.4512, 0.4073],
[-0.8901, 0.2017],
[-0.3183, -1.7539]]),
size=(5, 2), nnz=3, layout=torch.sparse_coo)
# when sum over all sparse dim, return a dense tensor
# with summed dims squeezed
>>> torch.sparse.sum(S, [0, 1, 3])
tensor([-2.6596, -1.1450])
"""
if dtype is None:
if dim is not None:
return torch._sparse_sum(input, dim)
else:
return torch._sparse_sum(input)
else:
if dim is not None:
return torch._sparse_sum(input, dim, dtype=dtype)
else:
return torch._sparse_sum(input, dtype=dtype)
softmax = _add_docstr(_sparse._sparse_softmax, r"""
sparse.softmax(input, dim, *, dtype=None) -> Tensor
Applies a softmax function.
Softmax is defined as:
:math:`\text{Softmax}(x_{i}) = \frac{exp(x_i)}{\sum_j exp(x_j)}`
where :math:`i, j` run over sparse tensor indices and unspecified
entries are ignores. This is equivalent to defining unspecified
entries as negative infinity so that :math:`exp(x_k) = 0` when the
entry with index :math:`k` has not specified.
It is applied to all slices along `dim`, and will re-scale them so
that the elements lie in the range `[0, 1]` and sum to 1.
Args:
input (Tensor): input
dim (int): A dimension along which softmax will be computed.
dtype (:class:`torch.dtype`, optional): the desired data type
of returned tensor. If specified, the input tensor is
casted to :attr:`dtype` before the operation is
performed. This is useful for preventing data type
overflows. Default: None
""")
log_softmax = _add_docstr(_sparse._sparse_log_softmax, r"""
sparse.log_softmax(input, dim, *, dtype=None) -> Tensor
Applies a softmax function followed by logarithm.
See :class:`~torch.sparse.softmax` for more details.
Args:
input (Tensor): input
dim (int): A dimension along which softmax will be computed.
dtype (:class:`torch.dtype`, optional): the desired data type
of returned tensor. If specified, the input tensor is
casted to :attr:`dtype` before the operation is
performed. This is useful for preventing data type
overflows. Default: None
""")
