#pragma once
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#include <ATen/ATen.h>
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#include <ATen/SparseTensorImpl.h>
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namespace at { namespace sparse {
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// Just for documentary purposes
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using SparseTensor = Tensor;
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using LongTensor = Tensor;
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using IntTensor = Tensor;
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using SparseType = Type;
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// This is an internal utility function for getting at the SparseTensorImpl,
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// so that we can write sparse tensor specific accessors for special fields
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// in SparseTensor. You should only use this for writing low level
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// setters/getters for SparseTensorImpl fields; otherwise, you should use
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// the low level setters/getters that were implemented using this.
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//
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// This may be called repeatedly, so make sure it's pretty cheap.
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inline SparseTensorImpl* get_sparse_impl(const SparseTensor& self) {
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AT_ASSERTM(!self.is_variable(), "_internal_get_SparseTensorImpl: should not be a variable"); // TODO: remove this when Variable and Tensor are merged
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AT_ASSERTM(self.is_sparse(), "_internal_get_SparseTensorImpl: not a sparse tensor");
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return static_cast<SparseTensorImpl*>(self.unsafeGetTensorImpl());
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}
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// Takes indices and values and directly puts them into the sparse tensor, no
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// copy. This used to be called THSTensor_(_move)
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inline void alias_into_sparse(const SparseTensor& self, const LongTensor& indices, const Tensor& values) {
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get_sparse_impl(self)->set_indices_and_values_unsafe(indices, values);
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}
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// Take indices and values and makes a (data) copy of them to put into the sparse
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// indices/values. This used to be called THSTensor_(_set)
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inline void copy_into_sparse(const SparseTensor& self, const LongTensor& indices, const Tensor& values, bool non_blocking) {
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alias_into_sparse(
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self,
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indices.to(self._indices().options(), non_blocking, /*copy=*/true),
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values.to(self._values().options(), non_blocking, /*copy=*/true));
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}
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// TODO: put this into the public API
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inline bool is_same_tensor(const Tensor& lhs, const Tensor& rhs) {
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return lhs.unsafeGetTensorImpl() == rhs.unsafeGetTensorImpl();
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}
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inline bool is_same_density(const SparseTensor& self, const SparseTensor& src) {
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return self.sparse_dim() == src.sparse_dim() && self.dense_dim() == src.dense_dim();
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}
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// Give us a new values tensor, with the same dimensionality
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// as 'values' but with a new number of non-zero elements.
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// TODO: Expose this for real in ATen, some day?
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// NB: Doesn't preserve data.
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inline Tensor new_values_with_size_of(const Tensor& values, int64_t nnz) {
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std::vector<int64_t> size = values.sizes().vec();
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size[0] = nnz;
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return at::empty(size, values.options());
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}
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// NOTE [ Flatten Sparse Indices ]
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// This helper function flattens a sparse indices tensor (a LongTensor) into a 1D
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// indices tensor. E.g.,
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// input = [[2, 4, 0],
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// [3, 1, 10]]
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// full_size = [2, 12]
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// output = [ 2 * 12 + 3, 4 * 12 + 1, 0 * 12 + 10 ] = [27, 49, 10]
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//
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// In other words, assuming that each `indices[i, :]` is a valid index to a
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// tensor `t` of shape `full_size`. This returns the corresponding indices to
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// the flattened tensor `t.reshape( prod(full_size[:indices.size(0)]), -1 )`.
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// if forceClone is true, the result will forced to be a clone of self.
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// if force_clone is true, the result will forced to be a clone of self.
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inline LongTensor flatten_indices(const Tensor& indices, IntArrayRef full_size, bool force_clone = false) {
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int64_t sparse_dim = indices.size(0);
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if (sparse_dim == 1) {
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if (force_clone) {
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return indices.squeeze(0).clone();
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} else {
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return indices.squeeze(0);
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}
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} else {
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std::vector<int64_t> indices_mult_cpu_vec;
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indices_mult_cpu_vec.reserve(sparse_dim);
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int64_t mult = 1;
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for (int64_t i = sparse_dim - 1; i >= 0; i--) {
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indices_mult_cpu_vec[i] = mult;
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mult *= full_size[i];
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}
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auto indices_mult_cpu = at::from_blob(
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indices_mult_cpu_vec.data(),
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/*size=*/{sparse_dim, 1},
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indices.options().device(kCPU));
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// NB: must be blocking because this blob may be freed after this closure,
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// and non_blocking copy will see garbage.
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auto indices_mult = indices_mult_cpu.to(indices.device(), /*non_blocking=*/false);
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// Ideally we want matmul but matmul is slow on CPU Long and not implemented
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// on CUDA Long. So mul is faster.
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return indices.mul(indices_mult).sum(0);
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}
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}
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// Flatten sparse tensor's indices from nD to 1D, similar to NOTE [ Flatten Sparse Indices ],
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// except this one allows partial flatten: only flatten on specified dims. Note that
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// the flatten indices might be uncoalesced if dims_to_flatten.size() < sparse_dim.
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// Also if input indices is already coalesced, the flattened indices will also be sorted.
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//
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// args:
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// indices: sparse tensor indices
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// sizes: sparse tensor sizes
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// dims_to_flatten: a list of dim index to flatten
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//
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// Ex1:
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// indices = [[2, 4, 0],
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// [3, 1, 3]]
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// sizes = [2, 12]
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// dims_to_flatten = [0, 1]
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// new_indices = [ 2 * 12 + 3, 4 * 12 + 1, 0 * 12 + 3 ] = [27, 49, 3]
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//
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// Ex2:
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// dims_to_flatten = [1]
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// new_indices = [ 3, 1, 3 ] # uncoalesced
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inline LongTensor flatten_indices_by_dims(const LongTensor& indices, const IntArrayRef& sizes, const IntArrayRef& dims_to_flatten){
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LongTensor new_indices = at::zeros({indices.size(1)}, indices.options());
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for (auto d : dims_to_flatten) {
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new_indices.mul_(sizes[d]);
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new_indices.add_(indices.select(0, d));
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}
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return new_indices;
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}
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}} // namespace at::sparse
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