c++ - Eigen Tensor 示例的编译器警告

Question

我正在对不受支持的 Eigen Tensor 库进行一些试验。在文档中，有一个小示例展示了如何调整张量对象的大小:

Tensor<float, 3> t_3d(2, 3, 4);
t_3d = Tensor<float, 3>(3, 4, 3);

当我编译一个基本上由这两行组成的 main() 时，我从编译器那里得到了一堆废话:

In file included from /usr/local/include/eigen3/unsupported/Eigen/CXX11/Tensor:88:0,
                 from tensor_test.cpp:6:
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h: In instantiation of ‘struct Eigen::TensorEvaluator<const Eigen::Tensor<float, 3>, Eigen::DefaultDevice>’:
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorAssign.h:96:70:   required from ‘struct Eigen::TensorEvaluator<const Eigen::TensorAssignOp<Eigen::Tensor<float, 3>, const Eigen::Tensor<float, 3> >, Eigen::DefaultDevice>’
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:406:14:   required from ‘Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>& Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>::operator=(const Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>&) [with Scalar_ = float; int NumIndices_ = 3; int Options_ = 0; IndexType_ = long int]’
tensor_test.cpp:29:36:   required from here
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h:156:71: warning: ignoring attributes on template argument ‘Eigen::PacketType<float, Eigen::DefaultDevice>::type {aka __vector(4) float}’ [-Wignored-attributes]
     PacketAccess = (internal::unpacket_traits<PacketReturnType>::size > 1),
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h: In instantiation of ‘struct Eigen::TensorEvaluator<Eigen::Tensor<float, 3>, Eigen::DefaultDevice>’:
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorAssign.h:100:65:   required from ‘struct Eigen::TensorEvaluator<const Eigen::TensorAssignOp<Eigen::Tensor<float, 3>, const Eigen::Tensor<float, 3> >, Eigen::DefaultDevice>’
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:406:14:   required from ‘Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>& Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>::operator=(const Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>&) [with Scalar_ = float; int NumIndices_ = 3; int Options_ = 0; IndexType_ = long int]’
tensor_test.cpp:29:36:   required from here
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h:42:71: warning: ignoring attributes on template argument ‘Eigen::PacketType<float, Eigen::DefaultDevice>::type {aka __vector(4) float}’ [-Wignored-attributes]
     PacketAccess = (internal::unpacket_traits<PacketReturnType>::size > 1),
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
In file included from /usr/local/include/eigen3/unsupported/Eigen/CXX11/Tensor:121:0,
                 from tensor_test.cpp:6:
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorExecutor.h: In instantiation of ‘static void Eigen::internal::TensorExecutor<Expression, Eigen::DefaultDevice, true>::run(const Expression&, const Eigen::DefaultDevice&) [with Expression = const Eigen::TensorAssignOp<Eigen::Tensor<float, 3>, const Eigen::Tensor<float, 3> >]’:
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/Tensor.h:407:65:   required from ‘Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>& Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>::operator=(const Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexType>&) [with Scalar_ = float; int NumIndices_ = 3; int Options_ = 0; IndexType_ = long int]’
tensor_test.cpp:29:36:   required from here
/usr/local/include/eigen3/unsupported/Eigen/CXX11/src/Tensor/TensorExecutor.h:61:17: warning: ignoring attributes on template argument ‘Eigen::TensorEvaluator<const Eigen::TensorAssignOp<Eigen::Tensor<float, 3>, const Eigen::Tensor<float, 3> >, Eigen::DefaultDevice>::PacketReturnType {aka __vector(4) float}’ [-Wignored-attributes]
       const int PacketSize = unpacket_traits<typename TensorEvaluator<Expression, DefaultDevice>::PacketReturnType>::size;

我可以添加一些填充张量的代码，然后打印出内容，一切都按预期运行:

for (auto ii = 0; ii < 3; ii++) {
    for (auto jj = 0; jj < 4; jj++) {
        for (auto kk = 0; kk < 3; kk++) {
            t_3d(kk, jj, ii) = val++;
        }
    }
}
for (auto ii = 0; ii < 3; ii++) {
    for (auto jj = 0; jj < 4; jj++) {
        for (auto kk = 0; kk < 3; kk++) {
            std::cout << t_3d(kk, jj, ii) << std::endl;
        }
    }
}

我想知道是否有人熟悉发出的警告，以及如何解决它们？

Answer 1

我能够使用 g++ 的 -isystem 选项关闭来自 unsupported/Eigen/CXX11/src/Tensor 的警告。

我正在使用 gcc 版本 7.4.0 和 Eigen 版本 3.3.7 (323c052e1731)