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Added ability to initialize a tensor using an initializer list

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Benoit Steiner 2015-01-14 12:41:30 -08:00
parent b12dd1ae3c
commit 7e0b6c56b4
1 changed files with 82 additions and 0 deletions
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unsupported/Eigen/CXX11/src/Tensor/TensorInitializer.h Normal file
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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2014 Benoit Steiner <benoit.steiner.goog@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_CXX11_TENSOR_TENSOR_INITIALIZER_H
#define EIGEN_CXX11_TENSOR_TENSOR_INITIALIZER_H
#ifdef EIGEN_HAS_VARIADIC_TEMPLATES
#include <initializer_list>
namespace Eigen {
/** \class TensorInitializer
* \ingroup CXX11_Tensor_Module
*
* \brief Helper template to initialize Tensors from std::initializer_lists.
*/
namespace internal {
template <typename Derived, int N>
struct Initializer {
typedef std::initializer_list<
typename Initializer<Derived, N - 1>::InitList> InitList;
static void run(TensorEvaluator<Derived, DefaultDevice>& tensor,
Eigen::array<typename traits<Derived>::Index, traits<Derived>::NumDimensions>* indices,
const InitList& vals) {
int i = 0;
for (auto v : vals) {
(*indices)[traits<Derived>::NumDimensions - N] = i++;
Initializer<Derived, N - 1>::run(tensor, indices, v);
}
}
};
template <typename Derived>
struct Initializer<Derived, 1> {
typedef std::initializer_list<typename traits<Derived>::Scalar> InitList;
static void run(TensorEvaluator<Derived, DefaultDevice>& tensor,
Eigen::array<typename traits<Derived>::Index, traits<Derived>::NumDimensions>* indices,
const InitList& vals) {
int i = 0;
// There is likely a faster way to do that than iterating.
for (auto v : vals) {
(*indices)[traits<Derived>::NumDimensions - 1] = i++;
tensor.coeffRef(*indices) = v;
}
}
};
template <typename Derived>
struct Initializer<Derived, Dynamic> {
typedef std::initializer_list<typename traits<Derived>::Scalar> InitList;
static void run(TensorEvaluator<Derived, DefaultDevice>& tensor,
Eigen::array<typename traits<Derived>::Index, traits<Derived>::NumDimensions>* indices,
const InitList& vals) {
// Static initialization not implemented for VarDims tensors.
eigen_assert(false);
}
};
template <typename Derived, int N>
void initialize_tensor(TensorEvaluator<Derived, DefaultDevice>& tensor,
const typename Initializer<Derived, traits<Derived>::NumDimensions>::InitList& vals) {
Eigen::array<typename traits<Derived>::Index, traits<Derived>::NumDimensions> indices;
Initializer<Derived, traits<Derived>::NumDimensions>::run(tensor, &indices, vals);
}
} // namespace internal
} // namespace Eigen
#endif // EIGEN_HAS_VARIADIC_TEMPLATES
#endif // EIGEN_CXX11_TENSOR_TENSOR_INITIALIZER_H