pytorch/torch/csrc/utils/tensor_flatten.h
Roy Li c705d9eb1e Introduce DeprecatedTypeProperties class (#17991)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17991

changes:
-Breaks bc: Tensor::type() now returns DeprecatedTypeProperties& rather than Type&.
-Added DeprecatedTypeProperties, it serves as a temporary replacement for Type as the return value of Tensor::type(). This contributes to making Type just for dispatch purposes so that we can make it dtype agnostic.
-Tensor::dispatch_type() now returns Type& like Tensor::type() used to do.
-Changed callsites of Tensor::type() appropriately.

Reviewed By: ezyang

Differential Revision: D14443117

fbshipit-source-id: 239ccb7a09626279a71d1a37f8f82e7f57bf7d9e
2019-04-04 02:24:13 -07:00

77 lines
2.3 KiB
C++

#pragma once
#include <ATen/core/functional.h>
#include <ATen/ATen.h>
#include <utility>
namespace torch { namespace utils {
inline at::Tensor flatten_dense_tensors(at::TensorList tensors) {
static auto flatten = [](const at::Tensor &t) { return t.contiguous().view({-1}); };
if (tensors.size() == 1)
return flatten(tensors[0]);
return at::cat(fmap(tensors, flatten));
}
inline std::vector<at::Tensor> unflatten_dense_tensors(const at::Tensor& flat, at::TensorList tensors) {
std::vector<at::Tensor> outputs;
outputs.reserve(tensors.size());
size_t offset = 0;
for (const auto & tensor : tensors) {
auto numel = tensor.numel();
outputs.push_back(flat.narrow(0, offset, numel).view(tensor.sizes()));
offset += numel;
}
return outputs;
}
struct TensorGroup {
std::vector<at::Tensor> tensors;
size_t size = 0;
at::Type& type() {
AT_ASSERT(!tensors.empty());
return tensors[0].dispatch_type();
}
};
// Helper function that takes a list of tensors and splits them into tensor
// groups by the size limit and outputs these tensor groups. If the input
// tensors are of different tensor types, they will be split into different
// groups as well.
//
// Two options of splitting provided to the user,
//
// Imagine the size_limit is 256 and the list of input tensors are:
// tensor_a(fp16 - 128 bytes),
// tensor_b(fp32 - 256 bytes),
// tensor_c(fp16 - 128 bytes),
//
// when fine_grained == false:
// The function will read the list of tensors sequentially and accumulate
// enough tensors for each data type until the size_limit, therefore:
// it will output: {{tensor_a, tensor_c}, {tensor_b}}
//
// when fine_grained == true:
// The function will read the list of tensors sequentially and accumulate
// enough tensors for all data types until the size_limit, and then split
// the accumulated tensors into different groups by data types, therefore:
// it will output: {{tensor_a}, {tensor_b}, {tensor_c}}
std::vector<TensorGroup> take_tensors(
at::TensorList tensors,
size_t size_limit,
bool fine_grained = false);
void reorder_tensors_like(std::vector<at::Tensor>& tensors, at::TensorList order);
std::pair<at::Tensor, at::Tensor> flatten_sparse_tensors(at::TensorList tensors);
std::vector<at::Tensor> unflatten_sparse_tensors(
const at::Tensor& flat_indices,
const at::Tensor& flat_values,
at::TensorList tensors);
}}